Second leisure battery debate / challenge.

[JonnoR]

Hi All,
Still fairly new to the MH/CV way of life and tbh loving it.

I have a quandary, so just returned from a two week trip around the highlands and islands of Scotland. TBH I am struggling with the leisure battery life (the van and battery are brand new). We want to go off grid for a few days (2-3 tops) at a time and the highlands lend themselves well to this.

However I was finding that the LB (110Ah) would not give us sufficient life. We have a 100W 650wh solar panel but for the first three days in Glen Coe all we saw was rain and no sun, so the LB would never get sufficient to keep it charged up. We even had to resort to driving around for an hr to try and out some juice back into the battery from the engine, but it never really got back up to full strength until we attached it to the EHU for a couple of days. Even longer 2-3 hr drives never saw it back to 13v.

I have asked the coachbuilder who fitted out the van (Peugeot Boxer) to add a second battery but it seems there is no space and they are telling me this cannot be done.

The fridge is the biggest consumer of electric, its a 12v with a tech sheet quoted 3.8A draw, we have LED lights and a Truma - I guess, water pump. Just doing the simple calcs the battery if receiving little or no solar would only last a max of 28hrs (taking it down to dangerous charge levels - which I am not prepared to do) and that is just the fridge alone. We ended up on a few occasions decanting water into water bottles and using torches for light at night. So may as well go back to camping.

Is there anything I am doing wrong OR am I missing something with respect to the charge. I have to say that the van is at home on my drive and the LB charge sitting at 13.4v today with a sunny day.

What are the other solutions available to me to give me extra off grid life. Not really looking to go down the generator route.

Thoughts please.

Many thanks
Jon

 

[r4dent]

However I was finding that the LB (110Ah) would not give us sufficient life.

Only about 50% of this nominal capacity is available (i.e. 55 ah) before the battery is flat.

We have a 100W 650wh solar panel but for the first three days in Glen Coe all we saw was rain and no sun, so the LB would never get sufficient to keep it charged up.

The effectiveness of solar depends on the amount of sun; the time of year; and how far North you are.

The document in this thread has a table to help you estimate how much power you will get in Scotland in September.

I have asked the coachbuilder who fitted out the van (Peugeot Boxer) to add a second battery but it seems there is no space and they are telling me this cannot be done.

What are the other solutions available to me to give me extra off grid life. Not really looking to go down the generator route.

You will get many suggestions for other battery types and "power stations" which provide more power in a given physical volume.
Read them carefully before spending cash
If upgrading to two (or more) lead batteries they should be the same make / model / capacity / age. In effect this means throwing your current on away.

The fridge is the biggest consumer of electric, its a 12v with a tech sheet quoted 3.8A draw,

Wrong. The fridge only works on 12v when the engine is running and then is powered by the alternator and so doesn't use any battery capacity.
In practice the biggest users of 12v power are:
a) TV
b) Use of 230v appliances via an inverter (e.g.230v hair dryer)
c) Any 12v heating device (e.g. 12v hair dryer)

Some of your comments do indicate that you are still in a learning curve about electricity in MoHos.
This document was written to help a member who asked why his microwave didn't work when he stopped for lunch in a lay-by.
I recommend you have a read. it. https://wildcamping.co.uk/threads/electricity-in-your-motor-home-for-dummies.74748/#post-1000246
.

 

[mistericeman]

Wrong. The fridge only works on 12v when the engine is running and then is powered by the alternator and so doesn't use any battery capacity.

.

If its a absorbtion type ....that's true ...

However most absorbtion types I've dealt with pull more than 4 amps ....(more like 6-8 )

 

[wildebus]

The fridge is probably a Compressor Fridge and while it may use 3.8A when on (probably will be more in reality), when the fridge is not running (about half the time or more), the draw is zero A - so the average per day - which is the important thing, will be around 30Ah or so (again probably more in reality).

So you are using less from the fridge then you think, but even so a 100Ah battery is borderline with a compressor fridge. Everyone who claims their battery 100AH battery lasts a whole weekend and they have a compressor fridge also have a common MO .... they turn off the fridge overnight and they don't use it on a Sunday as they have a) run out of food and b) run out of beer. So their "whole weekend" is more like less than a full day.

You need more battery capacity.

 

[r4dent]

The fridge is probably a Compressor Fridge and while it may use 3.8A when on

Yep, hadn't thought about that. With the base vehicle being a Boxer I just assumed a standard factory Motor Home, most which are absorption.
Assume ..makes an ASS out of U & ME but in this case just ME!

You need more battery capacity.

Agreed.

Thoughts please.

Is the fridge Compressor (Electric only) or absorption (selectable between battery / gas / mains) ?
If you don't know ..what is the make & model?

 

[colinm]

I have asked the coachbuilder who fitted out the van (Peugeot Boxer) to add a second battery but it seems there is no space and they are telling me this cannot be done.

This is the thing you need to sort out, and it depends how the van has been fitted out. If the battery has been fitted under one of the cab seats then two 90Ah batteries can usually be fitted, as an example we have two 75Ah batteries under the drivers seat and there was enough space to also fit an invertor. Another option might be to fit a Lithium battery which can be discharged to lower levels, so effectively is a bigger battery.

 

[Canalsman]

If you don't have a battery to battery charger fitted, this is an option well worth considering.

These devices provide a much higher charge rate than the basic split charge relay system which in effect connects the leisure battery in parallel with the starter battery when the engine is running.

A B2B would maximise the ability to recharge the leisure battery even if you are driving for a relatively short time.

 

[merl]

Hi All,
Still fairly new to the MH/CV way of life and tbh loving it.

I have a quandary, so just returned from a two week trip around the highlands and islands of Scotland. TBH I am struggling with the leisure battery life (the van and battery are brand new). We want to go off grid for a few days (2-3 tops) at a time and the highlands lend themselves well to this.

However I was finding that the LB (110Ah) would not give us sufficient life. We have a 100W 650wh solar panel but for the first three days in Glen Coe all we saw was rain and no sun, so the LB would never get sufficient to keep it charged up. We even had to resort to driving around for an hr to try and out some juice back into the battery from the engine, but it never really got back up to full strength until we attached it to the EHU for a couple of days. Even longer 2-3 hr drives never saw it back to 13v.

I have asked the coachbuilder who fitted out the van (Peugeot Boxer) to add a second battery but it seems there is no space and they are telling me this cannot be done.

The fridge is the biggest consumer of electric, its a 12v with a tech sheet quoted 3.8A draw, we have LED lights and a Truma - I guess, water pump. Just doing the simple calcs the battery if receiving little or no solar would only last a max of 28hrs (taking it down to dangerous charge levels - which I am not prepared to do) and that is just the fridge alone. We ended up on a few occasions decanting water into water bottles and using torches for light at night. So may as well go back to camping.

Is there anything I am doing wrong OR am I missing something with respect to the charge. I have to say that the van is at home on my drive and the LB charge sitting at 13.4v today with a sunny day.

What are the other solutions available to me to give me extra off grid life. Not really looking to go down the generator route.

Thoughts please.

Many thanks
Jon

Agree with most of the above and you deffo need more than 110Ah if you're off grid for more than a day or so. The battery will age quite quickly (because you're hammering it with deep discharges) so very soon it wont be 110Ah any more and subsequently you'll hammer it harder and harder as it gets weaker and weaker, it's a vicious circle.
You need more storage for sure, get a second opinion from someone who knows what they're doing about the available battery space because you're going to need that space for sure. If you're north of the border then PM Wildbus for sure.
Obviously I/we dont know the exact details of your MH but check If the converter has used a simple off the shelf control panel wired back to the alternator, if so the charge time while driving will be slow (especially if you've got a modern chassis with a smart alternator). Fitting a B2B charger will be the obvious way forward if so, you'll then re-charge the leisure batteries much faster while driving.

 

[Steve and Julie]

When we first got our van a swb relay it only had a 110 lead battery and a 12 volt cool box would only last a day. So changed battery to 200ah lithium fitted a 50 litre compressor fridge a 235 w solar panel and a b2b with mppt solar charger and it works perfectly we where away last week for 7 nights and didn't need ehu our solar charger works even if it's raining and we used our inverter most days.i would check what type of b2b and solar charger you have and upgrade if needed as it makes a lot of difference and recommend changing your battery to lithium

 

[Deleted member 86180]

From the symptoms described it sounds like a compressor fridge. A standard lead acid battery and solar panel of the sizes mentioned will struggle after a couple of days given the weather conditions mentioned. Even if you alternate freezer packs from the freezer compartment to the main fridge over night or turn off the fridge during the night, you will struggle.


Sounds like the typical cv20/40 or 80 factory spec, it isn’t enough for the type of use you require (off grid). If you want what you describe and you haven’t ruined the battery by repeated over depletion, you don’t need an awful lot more power or expense to achieve the few days off grid you require (with cold beer!).

The weather will always defeat you from your description because increasing the size of your solar array will be futile in bad weather. A reasonably priced dc to dc charger might be the answer for you? They are very easy to fit. Renogy do a 30 and 50 amp dc to dc/solar controllers combined in one unit for very reasonable money IMHO. Even the smaller 30 amp one may suit your needs (with the Bluetooth module it cost £199.99 and then you can see exactly what is going on) The 16mm2 cabling and fuses required wouldn’t break the bank either.

Since I fit the 50amp option I’ve noticed a one hour drive gives us more than a days requirement because unlike another way more expensive brand we previously chose for another vehicle, it doesn’t over heat and choke the output.

 

[wildebus]

This is the thing you need to sort out, and it depends how the van has been fitted out. If the battery has been fitted under one of the cab seats then two 90Ah batteries can usually be fitted, as an example we have two 75Ah batteries under the drivers seat and there was enough space to also fit an invertor. Another option might be to fit a Lithium battery which can be discharged to lower levels, so effectively is a bigger battery.

This is a very good point. I have seen a pair of 100Ah batteries fitted in a Boxer/Ducato/Relay type van when the installer has removed the rubber trim and foam underlay to drop the effective floor height, so more is possible than maybe thought of?
I know on a VW Transporter T5 (a smaller space than a Boxer for sure), I fitted a pair of 100Ah AGM batteries, a 1500W inverter and a 30A B2B all under a pair of cab seats (and the T5s have a lot of standard wiring under the seats taking up space as well).

 

[RAW]

It's all a bit tricky TBH - I am looking now for a new Van and have been looking at a few. I know a little about Solar and Electrics as I have done some work myself but by no means am I an expert.

Today I saw a Van that had 2 90AH batteries, 400W Solar and a Renology DC/DC with an MPPT built into that. The guy had no shore power input and was fine with that set-up for two weeks in lake District area, not that sunny usually.

So you have two major issues as have been talked about above, not enough battery capacity and IMO not enough Solar capacity either. There may be other considerations to factor in like what sort of charger works from the engine side, is it B2B or a split charge relay because from what I have read up and know you get a better charge, more throughput % better Amps into the leisure side if you have a B2B rather than a SCR. Other factors are cable dimensions, quality of the battery, quality of the solar. There are larger capacity batteries available which may fit in your van set-up or an alternative might be to get something like this https://uk.jackery.com/pages/plus-series-event

Hope that is of some help

 

[Deleted member 86180]

It's all a bit tricky TBH - I am looking now for a new Van and have been looking at a few. I know a little about Solar and Electrics as I have done some work myself but by no means am I an expert.

Today I saw a Van that had 2 90AH batteries, 400W Solar and a Renology DC/DC with an MPPT built into that. The guy had no shore power input and was fine with that set-up for two weeks in lake District area, not that sunny usually.

So you have two major issues as have been talked about above, not enough battery capacity and IMO not enough Solar capacity either. There may be other considerations to factor in like what sort of charger works from the engine side, is it B2B or a split charge relay because from what I have read up and know you get a better charge, more throughput % better Amps into the leisure side if you have a B2B rather than a SCR. Other factors are cable dimensions, quality of the battery, quality of the solar. There are larger capacity batteries available which may fit in your van set-up or an alternative might be to get something like this https://uk.jackery.com/pages/plus-series-event

Hope that is of some help

uncanny!

 

[trevskoda]

If the fridge is a true 12v alone unit they are the same as boat fridges, they use more power than a 230v triple a unit running through a smart inverter, mine burns 250ma/1/4 amp, not sure what the inverter uses, but i did a bench test before fitting and i can run 24hrs on 2 90ah batteries before they require a charge.
Now for solar, rull is min 100w for a 100ah battery, so if fitting two new batts then i would be going for 200w min or 250w to which some mppt regulators run at max, the votronic do a 250w unit which also has a 1ah charge to the starter battery.
Next batteries, without having to buy fancy chargers and all sorts of expensive goodies i now would tend to go loach lead carbon which are about £200 a pop at 100ah, you will require 2 if wilding, these will dischage down a bit more than standard lead acids and wont sulfer up the plates within, they also have a 1300/1500 cycle life where your old lead acids will at best have 200 cycles before loosing anything from 20% to 50% before dieing.
Wildbus is your man on here with tec stuff, do follow his advice and dont let the wallet open to you read and understand his advice.
One point you say seems strange, battery voltage, under full whack from solar it should hit 14,4 and drop back to a float of about 13.6/7, then when no sun after about an hr the battery should be at 12.7v before any load is on, hope this helps.

 

[rugbyken]

without knowing your set up it’s all conjecture but you can research many options david wildebus on here has helped many of us with knowledge when too far away, but if your feeling flush even the restriction of battery under seat can be overcome with the fogstar 280a designed to fit there with terminals on the side this would give in the region of 5times the available power you have with a lead acid , if your problem is space joy zigzag took out a dead 110 lead acid & replaced it with a 160A lead carbon same footprint just 3” taller again an increase of about 2.4 times the original, then there are the external power scource options so lots of research

 

[RAW]

uncanny!

Should have read the thread a bit more before commenting, what Brand of B2B were you using that overheated ?

I hadn't looked at Renology before, Sterling and Victron look good and I have bought and used Victron gear in other van projects.
Also having an MPPT built into the B2B seems odd, I wouldn't have thought you would get as good an output from both Solar and engine as you would with two separate devices, but maybe I am wrong. Also a single point of failure.

Another van that I looked at, that I am contemplating buying, had a https://www.donrowe.com/KISAE-DMT1250-Abso-50A-DC-DC-Battery-Charger-p/dmt1250.htm and 350 watt Solar, and maybe 300 AH leisure and they had issues with charging, similar to what this thread is about, which seemed odd to me. However, not sure on quality of panels. Do you know anything about those DMT1250 chargers, the brand wasn't Kisae, was something else. but the same unit ?

 

[JonSue]

Why don't you use gas to run the fridge? We always do when wilding.

 

[colinm]

Why don't you use gas to run the fridge? We always do when wilding.

From the op it's a 12v fridge, not a 3way.

 

[molly 2]

How old is the battery it could be under warrenty it sounds like your battery shot or your sollar is not performing I have just done seven nights of grid np problems but fridge on gas ,do you have a way of monitoring battery capacity, your van will have a smart alternator so it will only put a small current to the leisure battery , iff it is impossible to fit a second battery ,,research the benefits of fitting lead carbon about £180 110 amp or a lithiam ,as a guide to L CARBON a leasure lasts about 150 cycles a LC 1500 cycles and a greater discharge capacity watch a few utube videos on fitting a second battery

 

[Nabsim]

How old is the battery it could be under warrenty it sounds like your battery shot or your sollar is not performing I have just done seven nights of grid np problems but fridge on gas ,do you have a way of monitoring battery capacity, your van will have a smart alternator so it will only put a small current to the leisure battery , iff it is impossible to fit a second battery ,,research the benefits of fitting lead carbon about £180 110 amp or a lithiam ,as a guide to L CARBON a leasure lasts about 150 cycles a LC 1500 cycles and a greater discharge capacity watch a few utube videos on fitting a second battery

Warranty doesn’t cover taking battery too low which will have happened here Baz.