# Flat Batteries on  my Motorhome



## centerman (Oct 20, 2021)

Hi All I made a mistake and left my refrigerator on 12volt when I moved it of the drive were it is normally hooked up to mains whilst work on our drive and kitchen was being undertaken . All work now completed but when went to start it was all dead all batteries now showing only 6.5.  This is probably caused with fridge. 

But as I have a good battery bank with 3 x 135AH + Cab battery and there is  2 x 85 solar panels on roof I thought these would be enough to keep up the batteries charge with fridge on, was I badly wrong. 3 batteries are showing 6.5 only and engine one is also flat will these be dead now they were replaced 8month ago expensive mistake if they are.

Brian


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## trevskoda (Oct 20, 2021)

If only a day or so try and recharge, but may now be well past their best if lucky, your solar set up is very small for 3 batts, should be more like 400w


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## Robmac (Oct 20, 2021)

I would put them on a smart charger if you have one and see how it goes.

It's never good to fully discharge batteries but I have had them recover before now. Good luck.


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## centerman (Oct 20, 2021)

trevskoda said:


> If only a day or so try and recharge, but may now be well past their best if lucky, your solar set up is very small for 3 batts, should be more like 400w


Thanks for that did not know the solar panels would be too small. also reading the AGM batteries may mean my charger is incorrect type won't fully charge so will contact Sargent who supply there charger on my Swift Kontika 645 as standard. Bur do you recon it was the fridge that has caused main problem?Cheers


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## centerman (Oct 20, 2021)

Robmac said:


> I would put them on a smart charger if you have one and see how it goes.
> 
> It's never good to fully discharge batteries but I have had them recover before now. Good luck.


Thanks have one on charge to see how it goes do you recon it was fridge that flattened it all?


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## Robmac (Oct 20, 2021)

centerman said:


> Thanks for that did not know the solar panels would be too small. also reading the AGM batteries may mean my charger is incorrect type won't fully charge so will contact Sargent who supply there charger on my Swift Kontika 645 as standard. Bur do you recon it was the fridge that has caused main problem?Cheers



How long was the fridge left on for?


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## Canalsman (Oct 20, 2021)

Assuming it's a three way fridge it will only operate on 12 volts whilst the engine is running.

If that's the case your problem lies elsewhere...


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## Robmac (Oct 20, 2021)

Canalsman said:


> Assuming it's a three way fridge it will only operate on 12 volts whilst the engine is running.
> 
> If that's the case your problem lies elsewhere...



Good point, I was assuming a compressor.


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## trevskoda (Oct 20, 2021)

May be an alarm or something else like the brain if it has one, I have seen vans that will run 12v without the donkey running.
Make sure you use a smart pulse charger.


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## Admin (Oct 21, 2021)

Canalsman said:


> Assuming it's a three way fridge it will only operate on 12 volts whilst the engine is running.
> 
> If that's the case your problem lies elsewhere...


The Dometic three-way fridge freezer in my van can be operated on 12v even without the engine running.


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## wildebus (Oct 21, 2021)

Philip Tomlinson said:


> The Dometic three-way fridge freezer in my van can be operated on 12v even without the engine running.


is that due to some setup with solar/battery level to use otherwise wasted energy?  With most vans it is not down to the fridge itself but the way the motorhome was wired I would say.  i.e. with my Autotrail, the 12V supply will only ever be live when the engine is running as goes through a D+ controlled relay.  Wouldn't matter what fridge was at the other end.


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## Phantom (Oct 21, 2021)

The fridge shouldn't be drawing from the starter battery except via the engine running. Hopefully all batteries will charge back up then check that solar is charging LB and SB okay. Check how fridge is wired as it should have triggered a low voltage cut off.


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## Admin (Oct 21, 2021)

wildebus said:


> is that due to some setup with solar/battery level to use otherwise wasted energy?  With most vans it is not down to the fridge itself but the way the motorhome was wired I would say.  i.e. with my Autotrail, the 12V supply will only ever be live when the engine is running as goes through a D+ controlled relay.  Wouldn't matter what fridge was at the other end.


You can choose Auto, 240V, Gas, 12V. On Auto it auto switches.


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## wildebus (Oct 21, 2021)

Philip Tomlinson said:


> You can choose Auto, 240V, Gas, 12V. On Auto it auto switches.


but if 12V is not active (such as when the engine is not running, which is the case in the majority of motorhomes surely), the Auto will never find 12V to switch TO,  and will switch FROM 12V once engine stopped? 
Your Hymer must be wired different from the norm  (may be normal for Hymer though, of course  )


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## colinm (Oct 22, 2021)

Phantom said:


> The fridge shouldn't be drawing from the starter battery except via the engine running. Hopefully all batteries will charge back up then check that solar is charging LB and SB okay. Check how fridge is wired as it should have triggered a low voltage cut off.


As this, the starter battery should be separate from the leisure batteries.
When we had a 12v fridge we had a low volt cut off which would trigger if the solar couldn't keep up.


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## Admin (Oct 22, 2021)

wildebus said:


> but if 12V is not active (such as when the engine is not running, which is the case in the majority of motorhomes surely), the Auto will never find 12V to switch TO,  and will switch FROM 12V once engine stopped?
> Your Hymer must be wired different from the norm  (may be normal for Hymer though, of course  )



AES (auto switching fridges) have a permanent 12v supply otherwise they could not work.
Most modern motorhomes fitted with an EBL and Dometic Fridge will do the same thing. If they are manually switched to 12v they will use the leisure battery to power them. If they are on Auto mode they will not switch without a D+ signal.


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## trevskoda (Oct 22, 2021)

So complicated, glad I built my own yogie.


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## wildebus (Oct 22, 2021)

Philip Tomlinson said:


> AES (auto switching fridges) have a permanent 12v supply otherwise they could not work.
> Most modern motorhomes fitted with an EBL and Dometic Fridge will do the same thing. If they are manually switched to 12v they will use the leisure battery to power them. If they are on Auto mode they will not switch without a D+ signal.


I think we are not talking about the same thing.  Obviously AES fridges have a 12V permenant supply for the electronics.  that is a completely different circuit to the 12V circuit for cooling.  My Thetford was an AES type fridge so did indeed have a permanent 12V, but the 12V supply for 12V running was only live with the engine.  wouldn't matter what you did with the manual overrides.  Selected 12V manually and you would get an error  if the engine was off.

An EBL is a branded product used by certain makes of Motorhome.  you will not find one in a British Motorhome.   
Sorry, Phil, I just don't agree with how you are describing how the fridge typically works on 12V when using Auto or Direct 12V selection   (the permanent 12V bit is a red herring). 
Maybe on Hymers, but maybe not on other brands - if the 12V "cooling supply" is only present by the fridge when the engine is running, then it doesn't matter if the fridge can 'override' the D+ by manually selecting 12V, the supply will still not be there to be used.  (I am pretty sure the Sargent systems commonly found on British Motorhomes still operate this way).


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## Admin (Oct 22, 2021)

wildebus said:


> Sorry, Phil, I just don't agree with how you are describing how the fridge typically works on 12V when using Auto or Direct 12V selection   (the permanent 12V bit is a red herring).



I replied to this quote that states "Assuming it's a three way fridge it will only operate on 12 volts whilst the engine is running."



Canalsman said:


> Assuming it's a three way fridge it will only operate on 12 volts whilst the engine is running.
> 
> If that's the case your problem lies elsewhere...



This is incorrect as my Hymer will operate the fridge on 12v whilst the engine is not running. This is the standard Hymer wiring.

I stated you will find that other vehicles with an *EBL and Dometic fridge* will do the same. I never mentioned British motorhomes and I never mentioned Sargent control units.

On an Electrobloc installation, the D+ and 20A feed from the starter battery are connected to the EBL unit not directly to the fridge. The EBL then sends D+ 12v+ and 12v- to the fridge. The EBL has an internal relay that when the D+ is off the 20A feed is supplied by the leisure batteries and is only switched to the starter battery (by the EBL) when the D+ is on. The fridge has 20A always. The Dometic fridge freezer that I have (and is fitted to many post-2012 motorhomes) can be wired so that it can be AUTO or forced into 12v, 240v or GAS. 

I am going to bow out of this debate now.


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## Canalsman (Oct 22, 2021)

One thing that is certain is that the OP having requested help doesn't appear to have heeded any advice in this thread...


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## molly 2 (Oct 22, 2021)

I have flattened  the starter battery  on many cars  , always recoverd and gave good service , my veiw  is given a second chance .


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## wildebus (Oct 22, 2021)

Phil, to be fair, YOU may not have mentioned British Motorhomes or Sargent systems, but the original poster with the flat battery problem DID (he certainly mentioned Sargent and so by extension would have a British MH), and the replies (at least mine and canalsman) took that into account when saying it should not be possible to do what you later said was possible with your Hymer.


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## Nabsim (Oct 23, 2021)

molly 2 said:


> I have flattened  the starter battery  on many cars  , always recoverd and gave good service , my veiw  is given a second chance .


So have I Baz, it’s the capacity that will probably (but hopefully not) be damaged on the leisure bank. OP will have to see how long he can run on just his battery’s if they recharge okay then decide if they are good enough for his needs

Edit: only 3 way fridges I have had were in caravans and I could set those to run on 12v with the car unhooked and no 240v. Will depend on OP setup


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## colinm (Oct 23, 2021)

Our Globecar (part of same group as Hymer) has an EBL and (non AES) Dometic, whilst the EBL has to be switched on for 12v to work the cooling it won't do that if engine isn't running.


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## centerman (Oct 24, 2021)

Hi All, Sorry I have not replied to your posts have been away till today.  The fridge in my Swift Kontiki 645 is 3 way and can be operated on 12volt when engine was not running it has a auto switch over when being in Gas or on mains it will switch to 12volt as you drive and off when stop if was previously on Gas it will auto start on gas.
So I am convinced it was fact I had switched it to 12volt thinking only be parked up for few days had been like this for a month oops! leisure batteries were actually all 95Amp and showing only 6.2 on the meter. I took one back to Halfords and they changed it on its warranty. reconnected this in motorhome battery container.  This then took the van up to 13,7 and all worked including the solar panels where working showing charge rate. engine battery still flat engine wouldn't start so had recovery out and jump started it then had a nice drive for 40 minutes and battery starts fine now motorhome back on driveway and onto mains.  Following day I had disconnected the the 2 batteries in my battery bank to check them as the breakdown chap seemed to think something in the bank was leaking due to eggy smell and damp area,  positive terminals corroded on both and Negative on one also corroded? I have bought a NOCO Genius 26000 thinking the batteries would be stuffed once I cleaned all terminals up connected to charger AGM cold and within couple of minutes showed both when done fully charged and show 13.6 each on meter.
Given in 2020 last year I had 2 batteries in the bank area had blown up they were in bits loads of acid had been sprayed out in this locker so removed debris and treated the locker with Bicarbonate of Soda which I was told is the same of Baking Soda to neutralise the acid. Thought this had worked but if the ones that were fitted this time are not leaking which cleaned up there is no sign of leakage it is still corroding in the locker and metal L fitting holding cupboard down are black and rotted through. A layer of plywood locker is damp feeling and white powder film I now peeled it off to next layer around lower edges of locker and repeated the area with Bicarbonate Soda leaving it to dry out and then refit batteries. I will may book this into an auto electrician to have charging ok confirmed as you can clearly see I am out of my depth with this problem.

I tested the wires going into the attached leisure battery to test charging rate and it shows 13.6 on meter which would be correct I assume.  But batteries exploding and sign of damage in locker this could the indication of over charging? and if so is this likely to happen again is there any other method of getting rid of the acid by neutralising it. Any Ideas
Cheers


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## centerman (Oct 24, 2021)

Also meant to mention the engine battery is drawn on if leisure battery is depleted so once solar panels where fitted I fitted a charger linked to the engine battery so once leisure battery's are full spare power is pushed onto engine batterie till it is full and have not had any further problem till now


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## wildebus (Oct 24, 2021)

sounds most unsual for a sargent equipped motorhome to have the 12V active when engine not running, but if it does it does 

What model Sargent unit is fitted in your motorhome.  Some of them are set to charge at a rather high rate.


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## centerman (Oct 24, 2021)

My Sargent unit is EC200 and fridge is a domestic and has 12 volt Gas and 230v and warns the refrigerator should only be used on 12volt while the motor is running otherwise it will be discharged within a few hours teaches me to read the manual in future.


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## wildebus (Oct 24, 2021)

I think the EC200 is fairly normal.  I was wondering if you had a EC325 .... that unit apparently charges the batteries at up to 18V according to the user guide (seems a bit extreme to me!).  I have the EX325 but have disabled the charging within it and use external charging only.


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## centerman (Oct 24, 2021)

PSU2007 Sargent is the type


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## trevskoda (Oct 24, 2021)

I would glass fiber out the battery box area for sure and put a floor vent hole in it, sounds something is not right with the charging setup.


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## centerman (Oct 25, 2021)

I plan to use chlorinated Rubber paint which is Acid resistant and can match the locker colour.  I looked into where to put vent, if it is battery gas this is lighter than air so goes up apparently so would not go to floor? I contacted a major battery supplier. They explained that you fit a vent tube to top of battery a in one side route this pipe down through floor and the other side should have a vent bung in to stop gas escaping. My Halford batteries supplied in 2020 had neither so the gas can escape into locker and can be ignited easily which is what clearly happened. I went and spoke to manager there and explained the vent and bung should have been in the original batteries but was not fitted showed him they are on ones on shelf and pointed out the one they exchanged saturday again had neither fitted. But result he changed all batteries to new Yuasa leisure battery's result so starting with new. I agree still thing some over charging problem in set up is going on waiting to have this checked by local auto electrician but they are fully booked till week after next. Bit of a pain will try to find a mobile guy.


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## Sharon the Cat (Oct 26, 2021)

Philip Tomlinson said:


> The Dometic three-way fridge freezer in my van can be operated on 12v even without the engine running.


Same here according to the manual for our Bailey Autograph.


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## trevskoda (Oct 26, 2021)

centerman said:


> I plan to use chlorinated Rubber paint which is Acid resistant and can match the locker colour.  I looked into where to put vent, if it is battery gas this is lighter than air so goes up apparently so would not go to floor? I contacted a major battery supplier. They explained that you fit a vent tube to top of battery a in one side route this pipe down through floor and the other side should have a vent bung in to stop gas escaping. My Halford batteries supplied in 2020 had neither so the gas can escape into locker and can be ignited easily which is what clearly happened. I went and spoke to manager there and explained the vent and bung should have been in the original batteries but was not fitted showed him they are on ones on shelf and pointed out the one they exchanged saturday again had neither fitted. But result he changed all batteries to new Yuasa leisure battery's result so starting with new. I agree still thing some over charging problem in set up is going on waiting to have this checked by local auto electrician but they are fully booked till week after next. Bit of a pain will try to find a mobile guy.


Clor rubber paint is ok but not foolproof, and its a single pack, we used it mainly for outside of tanks but would line the inside with epoxy or grp depending on the use, a small one I did.


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## Chrisinchip (Oct 26, 2021)

my half-pennies worth, bit late in the day because came on to this site to ask my own question about batteries. I feel there are multiple problems.

*Recovering flattened batteries:* Try recharging them, nothing to lose. 40 mins driving won't do it. Put on a charger and leave to charge for a few days. (N.B. charger must be compatible with the battery type - Wet/Flooded, AGM, GEL etc. so best use a decent smart charger). As somebody has already commented, the capacity will probably be reduced by this mishap and therefore their life will have been shortened but hopefully they will get you by for the time-being.

*Why were LBs flattened: *A few things to check here because there should be safeguards to prevent them dropping so low: [*EDIT: Apologies, I had forgotten Centreman's post describing that the fridge is only designed to use 12v off a running engine since it is an absorption (gas) fridge, so I've deleted the content under this heading! ]*

*Why was the starter battery flattened:* I have read the other comments including about fancy auto switching fridges - it is all beyond my experience. So if it were my MH I would be drawing out how the electrics are wired and configured, and aim to isolate the starter battery (SB) from the LB circuit. I'd definitely disable any config that switches an appliance over to the vehicle when it is not running. It is so undesirable to allow the habitation electrics to flatten the SB unexpectedly. Not as easy as it sounds though.  Not only do you need to check for other appliances and devices draining the battery, all the possible cross feeds need to be explored. An example that, though not specifically relevant here, demonstrates peculiar interactions: Solar Technology UK solar panel controllers have twin battery capability but if the two batteries that are connected into B1 and B2 on the controller share a neutral/ground (quite common in a MH I would have thought) the manufacturer reports that the controller can get confused and flatten a battery. Oops, awkward.
Check for stuck vehicle alternator charging relay - possibly embedded in a controller. You may need to remove fuses to isolate the LB side from the LB itself. You'd be looking for an "open circuit" voltage (low and fluctuating) with the engine off and a 13v+ with the engine on.

*Battery charging: *AGM batteries need a higher bulk charge voltage so will never reach full charge and their life shortened if the charger is using a profile suited to the trad wet/flooded battery. Could it be that you were never charging your battery up to max charge? Given the earlier problems with batteries I would want to understand and check the battery charging systems down to the Nth degree - but that's me!

EHU Charging: I don't have personal experience of the Sargent PSU2007 but quickly checked its manual and could not find instructions for setting up the battery type. Happy to be corrected, however I have read elsewhere a rant about how caravan and MH manufacturers are fitting AGM batteries with chargers that lack an AGM config.
Solar charging: The solar charge controller also needs options to select battery type if using AGM batteries in order to maximise the charge and lifespan.
Vehicle alternator charging: I have not a clue how this is controlled with the latest technologies and this was the question I logged on to ask! Old school, a split charge relay would sort out the connecting in of the LB when the engine is running and isolate the LB when not running.
Something that I am not sure how much to worry about is if the SB and LB are different battery types. If the vehicle has stop-start the SB is likely AGM, otherwise probably trad technology. MH and caravans have been installing AGM for a while but there will be a mix of technologies in use out there. I am skeptical that all the 3 charging routes accommodate the different battery technologies across the SB and LB and think we need to be aware of the limitations of the charge set up, almost on a case-by-case basis. Scary!


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## centerman (Nov 1, 2021)

Hi All I
 decided to strip out the locker were my battery bank is kept and re build it as the wood was saturated in Acid i assume from the earlier problem when batteries had exploded last year, so not worth coating better to replace all done now. I realised the batteries that exploded i had replaced in Halfords had no drains and plug in manifold. So went back to them to complain and had all 3 replaced under warranty.  I used google how to check all charging circuits were working correct which they were.  So new batteries are SMF Yuasa YBX3019 95 Amp with fitted bungs on negative side and drain on positive side down through floor to drain any gas outside of locker. All seems well so ready to get away many thanks for all your feedback.
Brian


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## trevskoda (Nov 1, 2021)

Id still GRP line the new wooden box and the drop outs.


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## wildebus (Nov 1, 2021)

Chrisinchip said:


> my half-pennies worth, bit late in the day because came on to this site to ask my own question about batteries. I feel there are multiple problems.
> 
> *Recovering flattened batteries:* Try recharging them, nothing to lose. 40 mins driving won't do it. Put on a charger and leave to charge for a few days. (N.B. charger must be compatible with the battery type - Wet/Flooded, AGM, GEL etc. so best use a decent smart charger). As somebody has already commented, the capacity will probably be reduced by this mishap and therefore their life will have been shortened but hopefully they will get you by for the time-being.
> 
> ...


Just a comment on the AGM battery charging thing ....  I think I know the site you are referring to, and while it has some good info on it, it also has some wrong information which is very misleading (one of the reasons why you cannot post a link to it from here without it being censored).

There is no such thing as "an AGM battery".  They are not a single design needing a single way to charge them up. There are different types of AGM batteries with their own requirements.  For example, I have 3 AGM batteries in my Motorhome...  They are Lead-carbon AGM and they have an absorption charge voltage (this is what you mean by Bulk, I think in fact) of between 14.2V and 14.6V.  I set my charger to 14.2V.  my previous batteries were also Lead Carbon AGM Telecom batteries and they lasted best with a 14.1V charge. 
There are also, slightly oddly, two different approaches with 'normal' (non Lead-Carbon) AGM. There are European AGMs, and Far East AGMs.  The European made AGMs want a higher absorption voltage of 14.7V, whilst the Far East AGMs prefer 14.4V.
All a bit random in many ways when you just want a buy a bleeding battery!  

My advice would be be check the battery data sheet to see what is recommended and if your system can provide that.  
If there is no datasheet available for the battery and the seller cannot provide - knowledgeably, not guesswork - the information for it, just don't buy that battery as you have no idea how best to treat it. 
Ask the battery vendor for advice if you are not sure if a battery will work in your setup.

And finally, personally I would not buy a battery for a motorhome or campervan that needed to be installed in the living area and vented externally. Or any battery at all that ever needed topping up (which are most of the above ones that need venting).


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## Markd (Nov 2, 2021)

Definitely something not quite right somewhere if you've had battery explosions and depletions.
One reads that Sargent chargers of that vintage aren't too smart about dropping charge rates and I wouldn't leave mine on for more than a few hours. Not a problem because I have solar and Votronic MPPT regulator to keep all mine topped up nicely.
As Wildebus says Swift electrics are normally set up to only allow 12v to the fridge heater when the engine is running and if you have AES it should call on gas when you turn that off.
The fridge does have 'permanent' 12v to run interior light and any electronic controls.

It will certainly be worth checking how the fridge cooling circuit is wired up because at 15+ Amps draw it will soon pull down your battery bank overnight and would need a lot of solar to keep up in the day and at this time of year that's unlikely.

Glad to hear that Halfords have been so helpful - slightly amazed actually but I suppose their margins allow for the very occasional leisure battery collapse to be affordable.
Or more likely they don't really know what happened!


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## r4dent (Nov 2, 2021)

Markd said:


> ..... only allow 12v to the fridge heater when the engine is running and if you have AES it should call on gas when you turn that off.



A bit misleading.  It does not select gas immediately, so don't panic if the switch to gas is delayed.

Quote from manual "In order to prevent unintended switching to gas operation during refuelling, the electronic
system starts gas operation of the refrigerator after the motor has been turned off for 15 minutes. "


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## wildebus (Nov 2, 2021)

r4dent said:


> A bit misleading.  It does not select gas immediately, so don't panic if the switch to gas is delayed.
> 
> Quote from manual "In order to prevent unintended switching to gas operation during refuelling, the electronic
> system starts gas operation of the refrigerator after the motor has been turned off for 15 minutes. "


This is a good point to make as it can be confusing.
to add to your comment with maybe some additional useful info .....
The Dometic Fridges don't show the fridge as running on Gas until they are actually running on gas.
However ... the Thetford Fridges with Auto Switching immediately _appear _to switch to gas, with the display showing operating on gas, even though there is this approx 15 minute delay before they attempt to actually ignite.
(Found these details out whilst trouble-shooting my Thetford)


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## r4dent (Nov 2, 2021)

wildebus said:


> This is a good point to make as it can be confusing.
> to add to your comment with maybe some additional useful info .....
> The Dometic Fridges don't show the fridge as running on Gas until they are actually running on gas.
> However ... the Thetford Fridges with Auto Switching immediately _appear _to switch to gas, with the display showing operating on gas, even though there is this approx 15 minute delay before they attempt to actually ignite.
> (Found these details out whilst trouble-shooting my Thetford)



I think the moral is "Don't assume - read the manual".  

My previous MoHo had AES and the salesman said "never use Auto - select the energy source you want, that way you know what is happening"

Current MoHo is not AES.


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## Markd (Nov 2, 2021)

Yes - I was being a bit simplistic about when the gas fires up.
It's my understanding that one of the main reasons for the delay is reduce the likelihood of there being a naked flame burning on petrol forecourts.

Going back to the early posts we were told that it was 'months' before the batteries went down to 6.5V.
If the fridge had been on they would have been completely flat by that time.
So I think there's something else going on because 170w of solar should have kept the batteries reasonably charged.
Mind you a dual channel regulator would be needed - I won't plug my favourite again


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## Markd (Nov 2, 2021)

centerman said:


> Also meant to mention the engine battery is drawn on if leisure battery is depleted so once solar panels where fitted I fitted a charger linked to the engine battery so once leisure battery's are full spare power is pushed onto engine batterie till it is full and have not had any further problem till now


This switchover from leisure to starter is a bit 'risky' - if wilding you could get stranded somewhere.
If I recall correctly Sargent controller will disconnect from starter battery if the voltage drops too low when it's running habitation system.
Perhaps you have a Voltage Sensitive Relay that allows the starter battery to be raided when leisure batteries drop down.


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## wildebus (Nov 2, 2021)

Markd said:


> This switchover from leisure to starter is a bit 'risky' - if wilding you could get stranded somewhere.
> If I recall correctly Sargent controller will disconnect from starter battery if the voltage drops too low when it's running habitation system.
> Perhaps you have a Voltage Sensitive Relay that allows the starter battery to be raided when leisure batteries drop down.


Ref Sargent System, yes, most will switch from Leisure to Starter when the Leisure gets below a preset value (around 10.8V).  And then will shut off entirely once the Starter goes below its preset value (9.0V IIRC).
Both voltage levels are too low really.

I really liked the AES feature actually.   had it running on 240V until the battery dropped to a set SOC and then would disconnect and switch to Gas.   Shame it started playing up, but that is 3-way fridges for you generally.


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## Markd (Nov 2, 2021)

I'm afraid I'm going to disagree about EC200 control unit fitted in this case - according to the 2005 instructions it will change from Starter to Leisure at 10.9V
There is no mention of automatically switching to Starter - rather the default on energizing the hab electrics is LB.


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## wildebus (Nov 2, 2021)

Markd said:


> I'm afraid I'm going to disagree about EC200 control unit fitted in this case - according to the 2005 instructions it will change from Starter to Leisure at 10.9V
> There is no mention of automatically switching to Starter - rather the default on energizing the hab electrics is LB.


I just had a look and you are quite correct.

I have always read that the other way round actually, and I think probably as I would never think of running the Habitation Electrics on the Starter battery until it was flat and then switching to the Leisure.   Where on earth is the logic of that?


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## Markd (Nov 2, 2021)

Indeed that's why the system defaults to Leisure.

@centerman 
This set of wiring diagrams might help track down what's happening on your system


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## Chrisinchip (Nov 5, 2021)

wildebus said:


> Just a comment on the AGM battery charging thing ....  I think I know the site you are referring to, and while it has some good info on it, it also has some wrong information which is very misleading (one of the reasons why you cannot post a link to it from here without it being censored).
> 
> There is no such thing as "an AGM battery".  They are not a single design needing a single way to charge them up. There are different types of AGM batteries with their own requirements.  For example, I have 3 AGM batteries in my Motorhome...  They are Lead-carbon AGM and they have an absorption charge voltage (this is what you mean by Bulk, I think in fact) of between 14.2V and 14.6V.  I set my charger to 14.2V.  my previous batteries were also Lead Carbon AGM Telecom batteries and they lasted best with a 14.1V charge.
> There are also, slightly oddly, two different approaches with 'normal' (non Lead-Carbon) AGM. There are European AGMs, and Far East AGMs.  The European made AGMs want a higher absorption voltage of 14.7V, whilst the Far East AGMs prefer 14.4V.
> *All a bit random in many ways when you just want a buy a bleeding battery! *


Exactly! Great info.


wildebus said:


> My advice would be be check the battery data sheet to see what is recommended and if your system can provide that.
> If there is no datasheet available for the battery and the seller cannot provide - knowledgeably, not guesswork - the information for it, just don't buy that battery as you have no idea how best to treat it.
> Ask the battery vendor for advice if you are not sure if a battery will work in your setup.
> 
> And finally, personally I would not buy a battery for a motorhome or campervan that needed to be installed in the living area and vented externally. Or any battery at all that ever needed topping up (which are most of the above ones that need venting).



If I could pose a question, which is not relating to the OP's original question but is related to this whole subject.
With AGM charging profiles varying so much, then add other LB battery types to the mix is it actually possible to select the optimum type of LB for how you use the van AND have optimum charging capabilities for SB and LB from EHU, solar and alternator? Or am I overthinking it and need to find a chilled beer?

Having just bought an MPPT solar controller I discovered that the charging profile, whilst configurable, is common to both batteries outputs. This set me wondering about EHU and feed from the alternator, both of which charge both LB and SB.


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## Markd (Nov 5, 2021)

I suppose when we are completely all electric there will only be one battery to worry about and we'll have the choice of using it to get around or running our habitation stuff - maybe then we'll only need one profile for our charging system


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## trevskoda (Nov 5, 2021)

Markd said:


> I suppose when we are completely all electric there will only be one battery to worry about and we'll have the choice of using it to get around or running our habitation stuff - maybe then we'll only need one profile for our charging system


My mates gulf electric still has a 12v battery under the hood, think its to keep lights running should the traction batts die.


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## Markd (Nov 5, 2021)

That makes sense I suppose.
It also means you'll be able to listen to the radio while the tow truck arrives


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## trevskoda (Nov 5, 2021)

Good thing is if you two a lecy car the regen charges the batteries up.


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## colinm (Nov 5, 2021)

trevskoda said:


> My mates gulf electric still has a 12v battery under the hood, think its to keep lights running should the traction batts die.


Almost all EV's have a 'standard' 12v battery which runs everything from lights to radio, I think it acts as a buffer to smooth out the 12v supply as the traction batteries fluctuate between driving and regen, there are a couple of 'mild hybrids' that don't have one.


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## trevskoda (Nov 5, 2021)

China now sell a small electric car under £1000, duel seat and 33mph with 2/25 mile range and self assembly.


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## Chrisinchip (Nov 5, 2021)

trevskoda said:


> China now sell a small electric car under £1000, duel seat and 33mph with 2/25 mile range and self assembly.View attachment 103354


Self assembly . Like the first LED calculator. Full circle


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## colinm (Nov 5, 2021)

The Chinese have a big EV market and whilst there are quite a few dirt cheap which would only sell as novelties in the UK, they are starting to up the numbers of 'quality' cars on sale all across Europe, hopefully this will drive down the prices to sensible levels, unless mainstream manufacturers get their act together soon they will loose out big time.


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## TJBi (Nov 6, 2021)

trevskoda said:


> China now sell a small electric car under £1000, duel seat and 33mph with 2/25 mile range and self assembly.View attachment 103354


What use is 2/25 mile range? That's 0.08 mile or about 129 metres.


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## Markd (Nov 6, 2021)

That is a bit short!
However given the average journey length is much much less than the 300 miles deemed essential by the manufacturers (or more accurately users) means that EVs are far too big and heavy.


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## TJBi (Nov 6, 2021)

Markd said:


> That is a bit short!
> However given the average journey length is much much less than the 300 miles deemed essential by the manufacturers (or more accurately users) means that EVs are far too big and heavy.


I would certainly deem 300 miles range essential. I have driven that distance in what would effectively be a single journey. I'm not aware of charging facilities on board ferries! Cut down the maximum range available and you will thereby almost certainly reduce the average journey length. (It is, after all, the average!) Keep going like that and you might well end up with a range of a few hundred metres!


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## wildebus (Nov 6, 2021)

TJBi said:


> I would certainly deem 300 miles range essential. I have driven that distance in what would effectively be a single journey. I'm not aware of charging facilities on board ferries! Cut down the maximum range available and you will thereby almost certainly reduce the average journey length. (It is, after all, the average!) Keep going like that and you might well end up with a range of a few hundred metres!


The kind of use we have for the car, an Electric Car would be totally perfect, with short journeys generally of 10 miles or less.
However, the kind of use we have for the car means an Electric Car would sit unused for most of the time and would be an very expensive lump of motoring compared to a petrol car.
This is the problem currently ... the people for whom they suit best are the same people where it makes no financial sense as their  small spend on fuel means there is no real ROI for electric and so no incentive to change.  (and 'saving the planet' is no incentive either as there is more pollution created in making a brand new car than just running an existing one)


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## Markd (Nov 6, 2021)

Great description of the conundrum.
I do lots of twice a day 5 miles each way journeys but I also do 300 mile journeys fairly often.
We might swap one of our cars for a runabout electric of it was more expensive than a second hand diesel.
Or should we keep the diesel Passat for short local journeys and get a £40k Tesla for visiting family?


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## trevskoda (Nov 6, 2021)

Most cars here go about 2/3 miles at most to shops and school run in a day, girls may also be able to master parking in one, I said maybe.


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## colinm (Nov 7, 2021)

wildebus said:


> The kind of use we have for the car, an Electric Car would be totally perfect, with short journeys generally of 10 miles or less.
> However, the kind of use we have for the car means an Electric Car would sit unused for most of the time and would be an very expensive lump of motoring compared to a petrol car.
> This is the problem currently ... the people for whom they suit best are the same people where it makes no financial sense as their  small spend on fuel means there is no real ROI for electric and so no incentive to change.  (and 'saving the planet' is no incentive either as there is more pollution created in making a brand new car than just running an existing one)


A few years back gf drove the 'works pool' Zoe, she was so impressed wanted to buy one, at that time the batteries where rented, and the cost per month was higher than she paid for petrol, added to what was an expensive car to buy it was a none runner.
There are cheaper BEV's coming which should shake up the market, but the thing that interests me is V2G or V2H, at the moment debatable if it makes economic sense, but has the potential to make use of an expensive investment which for the vast majority of people spends 90% of it's time doing bugger all.


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## Markd (Nov 7, 2021)

Only 90% stood?
At least with a motorhome standing time is 'productive' when we're out and about.


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## trevskoda (Nov 7, 2021)

When electric cars come down to around £10 I may buy one if there is at least 15 years left in it like my last car.


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