Motorhome Vehicle Battery Charge (1 Viewer)

martincath

Free Member
Mar 8, 2023
4
4
South Yorkshire, UK
Funster No
94,462
MH
Swift Escape
Exp
Tuggers for 15 years now trying MH
Hi all
I am new member, thanks for letting us join. Recently bought a new Fiat swift escape. I had a Phantom alarm fitted for insurance purposes so can see the voltage of my vehicle battery on my phone and was alarmed to see it going down to 11.9 volts over a 2 week period. I have contacted my supplying dealer and they say with the technology on the new Fiats the batteries are flat after about 3 weeks if not used. I store under cover so the solar panel is not producing any charge, no access to mains either. I can't take the battery off every few weeks to charge it as it make my insurance invalid so have come up with the idea of having a slave battery connected to the van battery so that I can take it away and charge it when the voltage gets low and then it will equalise the two batteries when reconnected and put power into the van battery. Is this a good plan or what are the pitfalls and any other ideas??
Thanks
 
Apr 3, 2018
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1995-2004 & 2017》
Hi all
I am new member, thanks for letting us join. Recently bought a new Fiat swift escape. I had a Phantom alarm fitted for insurance purposes so can see the voltage of my vehicle battery on my phone and was alarmed to see it going down to 11.9 volts over a 2 week period. I have contacted my supplying dealer and they say with the technology on the new Fiats the batteries are flat after about 3 weeks if not used. I store under cover so the solar panel is not producing any charge, no access to mains either. I can't take the battery off every few weeks to charge it as it make my insurance invalid so have come up with the idea of having a slave battery connected to the van battery so that I can take it away and charge it when the voltage gets low and then it will equalise the two batteries when reconnected and put power into the van battery. Is this a good plan or what are the pitfalls and any other ideas??
Thanks
What sort of leisure battery's do you have?
Just a thought, would a Battery Master fitted work.
Sorry not finished typing... that would prolong the charge in your vehicle battery and if still in storage when getting near flat, you could remove leisure battery and recharge it...
Possibly one solution.👍👍
 
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Sep 10, 2017
653
727
North Brum
Funster No
50,425
MH
A Class
This Jobbie here may work for you with the extra BT module. https://www.wildebus.com/product/ablemail-amt-12-battery-maintainer/
Through the app you can control what voltage your leisure battery will drop to whilst "charging" the engine battery. You can also set what voltage the cab battery drops to before it gets charged off the leisure battery.
EG: When cab battery drops to 12.4V the leisure battery will charge till it gets to 12.85v and then stop. Leisure battery won't charge the Cab battery if it's voltage drops below 12.2V.
So a fully charged leisure battery can do a LOT of trickle charging to the cab battery over several if not many weeks whilst the van is in storage.
The tracker / alarm drain should also be less than about 80ma so maybe something else in the van is pulling it down? Worth using a clamp multimeter if you know what you are doing with one to see if you have any other parasite drain on the cab battery. And is the cab battery "healthy"?
The Ablemail stuff is very good and pretty much all options are covered.

 
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OP
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martincath

Free Member
Mar 8, 2023
4
4
South Yorkshire, UK
Funster No
94,462
MH
Swift Escape
Exp
Tuggers for 15 years now trying MH
Hi
That sounds like a good option, I was going for the extra battery option as I was concerned about getting at either battery to take home and charge. I think the leisure battery is only a 85 amp one fitted as standard. the vehicle battery seems to start at about 12.6 volts and go down from there, should it be reading higher than that when I first park it up?
 
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Lenny HB

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Oct 18, 2007
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Hymer B678 DL
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Since 2008 & many years tugging
the vehicle battery seems to start at about 12.6 volts and go down from there, should it be reading higher than that when I first park it up?
With smart alternators they often only charge to 80% which is not good for a LA battery.

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Sep 10, 2017
653
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Hi
That sounds like a good option, I was going for the extra battery option as I was concerned about getting at either battery to take home and charge. I think the leisure battery is only a 85 amp one fitted as standard. the vehicle battery seems to start at about 12.6 volts and go down from there, should it be reading higher than that when I first park it up?
From memory when a cab battery is charged and "at rest" it should be about 12.5-12.7v
85ah lead / gel battery should be good for 50% discharge without issue so 40ah is a fair bit of top up. Maybe add a battery or change to lithium if in storage for a very long time with the added benefit of more power when on site?
 
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pappajohn

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Aug 26, 2007
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Instead of charging a second battery and connecting to the existing battery you could charge the second battery at home the swap for the battery on the van and take that home to charge.
You'd probably only need to do it every 10 days to two weeks.
 
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pappajohn

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From memory when a cab battery is charged and "at rest" it should be about 12.5-12.7v
85ah lead / gel battery should be good for 50% discharge without issue so 40ah is a fair bit of top up. Maybe add a battery or change to lithium if in storage for a very long time with the added benefit of more power when on site?
Problem.......how can you fit a second starter battery where there's no room for a second.
fit a lithium.......and a lithium alternator !!!!
 
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Sep 10, 2017
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Problem.......how can you fit a second starter battery where there's no room for a second.
fit a lithium.......and a lithium alternator !!!!
A second leisure battery not another cab battery, sorry I wasn't clear about that. With the Ablemail unit you can configure all kinds of parameters to suit the battery type and how discharged you want them to be. Obvs a lithium is happy going to an extended discharge of 90% or so vs 50% of lead acid versions. You generally don't need to change the alternator when fitting lithium but a B2B is always a good idea for max charging on a lithium is the common thinking.

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eddie

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Oct 4, 2007
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540
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RV
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since 1989

Tens of thousand sold
 
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pappajohn

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Aug 26, 2007
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If the starter battery is flat after 3 weeks and if the vans in storage for say 12 weeks....over winter.
Will the BM keep the battery charged for 12 weeks?
 
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Sep 10, 2017
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I was referring to a lithium starter battery, if there is such a battery yet, regarding the alternator....again, if there is such a thing.
Not seen a lithium van cab battery yet but lots of motorcycle owners fit smaller ones to save weight. Cranking power needs are different to draining a leisure battery so less of a need for lithium I suppose in a van.

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eddie

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If the starter battery is flat after 3 weeks and if the vans in storage for say 12 weeks....over winter.
Will the BM keep the battery charged for 12 weeks?
No, but it wouldn’t really be a good idea to leave it for three months without starting it, it is after all intended as a delivery van, stop started every day

The Battery Master would probably extend the period to six or seven weeks though
 
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Sep 10, 2017
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No, but it wouldn’t really be a good idea to leave it for three months without starting it, it is after all intended as a delivery van, stop started every day

The Battery Master would probably extend the period to six or seven weeks though
Do you have the specs of what voltage the leisure battery has to be to charge the cab battery? The reason I ask is that the docs say that it works if has solar or hook up? Obviously if the voltage differential is known the amps available / top up to cab battery can be worked out based on that and give a rough time frame for how long the leisure battery will keep the cab battery charged. Ta
 
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Apr 27, 2016
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A class Hymer
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Since the 80s
How easy is it for you to access the storage place? I think there are a few ideas for a solution to your problem.

You could get a 'Power Station' device, which is a battery in a box with a charger and inverter, and produces 240V mains if you want it. A smart charger can be plugged into the inverter, connected to the starter battery. It will charge the battery up to 100% if there is enough chasrge in the power station, but it may take a few hours. Then take the power station back home to recharge it. Probably not worth getting one just for this job, but if you can think of other uses for it as well, it's worth considering. Something like one of these.

Alternatively, if you already have a slave battery and a small smart charger, say 5A or so, you could get a small inverter about 150W, which is small enough to plug into a cigarette-lighter socket. You could charge the battery at home. Then take the battery, inverter and charger to the MH. Connect up to the starter battery and charge until full. You could leave overnight then go back to collect it for recharge. I used this method in the past, before lithium batteries were around, and it worked fine. I used a CTEK MXS5.0 charger, 5A. Small enough to work with a 150W inverter, large enough to fully charge the battery.

Your existing method of connecting a second battery in parallel to share charge works to some extent. It will certainly prevent a flat battery and ensures you can always start the engine. But in the long term a lead-acid battery needs to be taken to 100% every month or so to avoid deterioration due to sulfation, so using an inverter and smart charger will do that.

Another possibility is a CTEK device called the CS Free. It's a jump starter power pack, but it has a lot of extras. The internal lithium battery, like most of these jump start devices, is quite small, about 5Ah. Enough to start the engine, but not big enough to refill an 80Ah battery that's fairly flat. However unlike other jump start packs, this one can be connected to a spare battery such as your slave battery, and will transfer the charge to the target battery. I've not tried this CS Free, but at least one other Funster has one and has used it successfully if a similar situation to yours.
 
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martincath

Free Member
Mar 8, 2023
4
4
South Yorkshire, UK
Funster No
94,462
MH
Swift Escape
Exp
Tuggers for 15 years now trying MH
Hi All
Thanks for all the brilliant replies, this site is a treasure trove of knowledge. Whilst some of the suggestions seem really good but a little complicated, W are not sure how long we will keep this moho first one and all that so we are going to go with the trickle charger between the leisure battery and the vehicle battery. There is the Vanbitz Battery master and the AMT12-2, not sure which is best, the AMT seems to have a stopping point if the leisure battery gets down to a 11.5v. Not sure if the Battery master has that facility. They are both the same price so that is not a deciding factor. Might have to flip a coin!!
 
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Apr 3, 2018
3,763
10,478
Funster No
53,151
MH
PVC
Exp
1995-2004 & 2017》
Hi All
Thanks for all the brilliant replies, this site is a treasure trove of knowledge. Whilst some of the suggestions seem really good but a little complicated, W are not sure how long we will keep this moho first one and all that so we are going to go with the trickle charger between the leisure battery and the vehicle battery. There is the Vanbitz Battery master and the AMT12-2, not sure which is best, the AMT seems to have a stopping point if the leisure battery gets down to a 11.5v. Not sure if the Battery master has that facility. They are both the same price so that is not a deciding factor. Might have to flip a coin!!
Remember you get Fun discount on Battery Master... but you have to mention when ordering.... not after 👍👍

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Oct 8, 2014
1,654
3,061
Wiltshire
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33,737
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Autotrail Excel 600B
Exp
Previous VW Camper + Caravan
Remember you get Fun discount on Battery Master... but you have to mention when ordering.... not after 👍👍
It's still cheaper to buy via the MH Fun shop. I ordered one yesterday!

Scroll right to the bottom of any post and click on MotorhomeFun Shop
 
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Sep 12, 2016
2,280
5,065
Chesterfield England Tellus 3
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45,091
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Lunar Roadstar 800
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6 years
There's a SIMPLE solution

a small solar panel connected direct to the cab battery when not in use you disconnect it when you turn the ignition on but then you store it away until you park up
We bought one as our Lockdown Alarm/Tracker system does drag the battery down this way as long as there's light my battery is full
 
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Apr 3, 2018
3,763
10,478
Funster No
53,151
MH
PVC
Exp
1995-2004 & 2017》
There's a SIMPLE solution

a small solar panel connected direct to the cab battery when not in use you disconnect it when you turn the ignition on but then you store it away until you park up
We bought one as our Lockdown Alarm/Tracker system does drag the battery down this way as long as there's light my battery is full
OP states moho stored under cover.👍
 
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