auto electricians

[jonsy]

I have an ex welfare bus that ive converted and it has 2 batteries under the bonnet . Well ive just been to an auto electrician and asked that as ive taken the wheelchair lift off and isolated the feed can i use that battery in unison with the main battery to power my 12v lighting and cooler box . Well he told me i had to take the feed for the 2nd battery and wire it into my internal lighting system and if they were to do it would cost me an arm and a leg . Now please tell me if im a bit thick , but im trying to make this as easy as possible and would one of those split charging thingies do the same job . In that the main battery powers the lighting and cooler box and a fully charged 2nd battery is there for back up . Maybe im missing the point , can anyone help please .

 

[sasquatch]

I would do it the other way round keep the main battery soley for the engine starting and use the other batteries for domestic use lights cooler etc. Put the split charger between the engine and 2nd batteries. are the batteries all the same size physically and electrically? If the 2nd batteries are you can connect them in parallel and they will appear as one large battery,the split charger will then charge up the engine one when runnibg and then charge the leisure batts. It may alsobe advisable to install a Battery Master which is an 'intelligent' split charger,it manages the loads for you.
If the lift has been removed carefully you will be able to sell it and use that money to have the work done. Look up tail lift companies they buy them for spares or to fit.

 

[jonsy]

Thanks for that sasquatch , the main battery is the biggest being 75 ah and the smaller one is 55ah i think but both are almost brand new . thank you

 

[AndyC]

I have an ex welfare bus that ive converted and it has 2 batteries under the bonnet . Well ive just been to an auto electrician and asked that as ive taken the wheelchair lift off and isolated the feed can i use that battery in unison with the main battery to power my 12v lighting and cooler box . Well he told me i had to take the feed for the 2nd battery and wire it into my internal lighting system and if they were to do it would cost me an arm and a leg . Now please tell me if im a bit thick , but im trying to make this as easy as possible and would one of those split charging thingies do the same job . In that the main battery powers the lighting and cooler box and a fully charged 2nd battery is there for back up . Maybe im missing the point , can anyone help please .

I'm not 100% clear on your existing setup. What are the 2 batteries under the bonnet and do you already have another (3rd) battery powering your lighting and coolbox?

AndyC

 

[jonsy]

one battery for starting and internal lights and the other was for the disabled tail lift which i have now removed . Have now isolated 2nd battery .

 

[ian81]

If as you seem to describe the two batteries were kept separate one to power the vehicle electrics and the other the lift it would seem fairly simple to take the wire from the smaller battery that was powering the lift via a fuse box to all your coolbox and any other habitation electrics.

If the tail lift battery was installed correctly it probably has a split charge relay to separate it from the main battery when the engine is running. Suggest you check out how this battery connects to the alternator. One way is to measure both battery voltages when the vehicle has been at rest possibly putting an electrical load on one. If the voltages are different then there will be separation between the batteries. Restarting the vehicle and measuring the battery voltages both should be the same.

 

[AndyC]

Yes, follow Ian81's advice, it's spot on.

AndyC

 

[NorfolkanGood]

If you only need to use your 2nd battery for lights, and only for a few days at a time. ... maybe a long weekend. Then you can use keep it isolated from everything else and just charge it from a normal cheap Halfords battery charger when needed.

We only use a second battery for 12 v lights. Everything else inc. fridge runs off gas or mains.
Our 2nd battery (just a large car battery) is in a compartment under one of the bench seats in the back, sitting along side the Halfords charger. It runs 4x 12v strip lights, when needed.
We have never managed to flatten it yet despite using it for up to a week at a time. We fully charge it before leaving home, and when on a mains pitch I just give it an extra charge.
I think for most of us who are occasional travellers (never more than a few days away from a mains point) there is a temptation to go overboard on expensive 12v electrical systems. But you don't need to.

 

[ian81]

I think for most of us who are occasional travellers (never more than a few days away from a mains point) there is a temptation to go overboard on expensive 12v electrical systems. But you don't need to.

The addition of a split charge relay plus some cabling and fuses will (should) cost less than a battery charger and that ensures that the battery will receive charge when the engine is running. Adding fancy units, like a ZIG, I agree for this type of vehicle is an unjustified expense.