Flat Batteries on my Motorhome

wildebus

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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)
 

r4dent

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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.
 

Markd

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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

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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.
 

wildebus

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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.
 

Markd

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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.
 

wildebus

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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?
 

Markd

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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

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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.
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.
 

Markd

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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 😀
 

trevskoda

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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.
 

Markd

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

colinm

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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.
 

trevskoda

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

colinm

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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.
 

Markd

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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.
 

TJBi

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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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