# Main Chassis Battery Charging



## G2EWS (May 1, 2006)

Hi Fellow RVers,

I have not used my Winnie since the photography meet and with the electrical work I am doing had to start it up.

I keep the mains permanently connected to charge the 'auxiliary batteries' and this is OK, but I thought that it was also charging the vehicle battery. But it is not!

So the question is this:

On the dashboard I have an 'aux start' switch which is used should the vehicle battery discharge. But I also have an 'aux battery' switch which is described as follows:

AUXILIARY BATTERY SWITCH
The Aux Batt switch disconnects the auxiliary (coach) batteries from the 12 volt system of your coach to avoid long term battery drain by electrical items that are hooked directly to the coach batteries.
Always leave this switch ON except during long storage periods (a month or more)

Now it seems to me that if this switch is ON the vehicle battery will be connected to the auxiliary batteries and if this is the case when they are on charge so should the vehicle battery.

Before I get outside tomorrow with my trusty multi meter does anyone have an opinion on this?

Your assistance as ever wold be most appreciated.

Regards

Chris


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## 98452 (Apr 2, 2006)

I alway switch the chassis power off when not in use. I had a flat battery too! It did start using the double up switch.

I do however leave the coach power on all the time as have electric heater on in the coach but this does only charge the leisure batteries.


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## awr (Jan 11, 2006)

Hi Chris,240 volt plugged in on driveway will charge aux bat ,but not chassis.when no 240 on, switch off aux bat to prevent it draining.bridging switch on dash will allow aux batts to start engine if chassis bat flat or low.just get into habbit of switching off chassis bat when parking up rv....caution=alarmwill not be active with chassis bat switched off. ps look at a battery master for your bat management.
hope this helps Alan.


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## olley (May 1, 2005)

Hi chris I fitted a battery master (van bitz) this keeps the chassis battery topped up when you are on 240v, it simple to connect 1 wire to neg. and 1 wire to each of the positive battery terminals.

I believe the reason for not charging the chassis is because a modern charger might raise the voltage to high and damage some of the engine electronics.

Olley


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## 102786 (Feb 4, 2007)

Hi

New online, just found this forum.

My solution is a 2ft of wire with Croc; clips both ends and a Fuse in the line. atached pos (coach) to pos (chassis) this keeps ALL batts Topped up if you forget to disconect before starting it blows a 5cent fuse. Whilst in principle the charger could give overvoltage to some electronics they are MOSTLY tolerant of some over-volts as your ALTERNATOR will push out 14+ Volts at first after starting, as you require a "pressure" gradient to get Charge INTO a battery. (the old water allegory).

pete (ARVM PeteH)


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## G2EWS (May 1, 2006)

Hi Guys,

Thanks to all of you for your advice. When the temperature rises I will be back outside finishing off the reversing lights and washing her - the Winnie not Claire - ready for next weekend.

Interestingly I was discussing this with my buddy last night and he agrees with you Alan. That is the vehicle battery cannot be connected for charging purposes to the leisure battery as this would risk it being discharged. I will confirm one way or another later on this morning.

My simple method of testing will be too look at the vehicle battery voltage which was a bit low last week then push that there switch and see if it goes up a bit.

Regards

Chris


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## 101411 (Oct 15, 2006)

I bought one of those on dash solar panels. Wont charge your battery if flat but seems to do a great job at keeping the chassis battery topped up and for the few quid they cost the power they deliver is free!!

Also you can change them from vehicle to vehicle and they just plug into the cigarette lighter.

Dazzer


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## eupho (Jun 3, 2005)

Hi,
My solution is a multimate charger connected to the chassis battery.
These are designed to be left on for months if neccessary and will cycle on and off automatically maintaining battery at optimum charge.
Any drain from audio/visual alarm is thereby negated giving peace of mind that alarm will always be operational and vehicle will start without recourse to leisure battery.
I maintain the leisure batteries via the onboard charger which I switch off regularly to allow batteries to rest for a couple of weeks before topping up again.
I also run a couple of greenhouse heaters and a de-humidifier to keep the interior warm and dry.
It goes without saying that the rv is connected to a 240v supply.


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## dangerous (May 1, 2005)

*Chassis battery charging*

I too fitted a Battery Master, this is a little black box which connects aux batteries to chassis battery. Then any excess charge from aux batteries (when they are charging) is transferred to the chassis battery, this works very well on our RV as when in storage the solar panel keeps all batteries servicable, the current only goes one way so no danger of draining chassis battery................very effective.
dangerous.


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## G2EWS (May 1, 2006)

Once again, many thanks for all the advice. I do like the sound of the Battery Master and will most certainly get one in the near future.

I have to say I feel a bit of a chump. Having re read the note I put on from my manual I appear to have completely lost the plot. Somehow I was reading it very differently from how it was written. I now see that all that switch does is switch off the leisure batteries. I seemed to have been under the impression that it would connect all three batteries together!

How foolish of me! No wonder my pal was looking at me last night like I was off my trolley!

He kept trying to explain it in terms of his master switch in his caravan, I just could not get it. Perhaps I just had one too many glasses of wine.

Regards

Chris


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## 88927 (May 10, 2005)

G2EWS said:


> Perhaps I just had one too many glasses of wine.
> 
> Regards
> 
> Chris


Always the best course of action when confusion sets in Chris :lol: :lol: :lol:

Keith

PS Glad you are back on Earth again though now mate :lol:


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## G2EWS (May 1, 2006)

Hi Keith,

Landed and ready to go!

Cannot wait for the weekend, first time out since the photo meet! Going to Setthorns in the New Forest.

As you may have seen elsewhere though I must get the lights sorted! Flashing red and orange at the rear for the time being!

Regards

Chris


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