T350 lwb van conversion 2nd battery (1 Viewer)

[Jasvan1]

Hi everyone

I am starting a van conversion project and have kit left from the old owner including an inverter kit that runs from cigarette lighter or battery terminals... And also a relay Kit to isolate a 2nd battery

My question is that I already have a 2nd battery in the van which is the aux battery linked to the starter battery next to it..

To run van electrics... (water heater/fridge) Would I Need a 3rd separate battery as an isolated leisure battery and connect the relay from main battery to the new leisure battery or could I use the existing aux battery as the leisure battery and connect a relay between the starter and existing aux battery and then connect. van electrics to the existing aux battery?
Hope that is explained well enough!

I am. Also hoping to get a solar panel which would connect somewhere in the mix?

Thanks for any advice..

Jas

 

[autorouter]

I think there is probably a minimalist method of using the aux battery as the leisure battery - surely there is already some method of charging it from the engine, no need for a relay I think.

However if it were my van I'd go for a separate 3rd battery. It's very easy to leave something switched on and run the battery flat, and you don't want to be unable to start the engine if that happens.

You don't say what the relay kit contains. If it's one that switches from a 12V coil signal (ie not a VSR - Voltage-Sensitive Relay ) then make sure you trigger it from the D+ rather than the ignition, so that it doesn't come on until the starter motor has finished and the engine is running.

If it's a VSR, think twice about using it. They are OK for simple systems, but when you add solar and/or mains charger and a method of trickle-charging the starter battery they can throw up problems. Triggering from the D+ is better, but more trouble initially to instal.

If constructing a space for the battery, allow for a second one to fit in alongside in the future, it's a very popular upgrade.

Also there's a Self-Build Motorhomes forum on this site where this kind of thing is discussed in detail.

 

[Jasvan1]

Hi. Thanks you very much for this. Really helpful .. I am. Not sure what D+ related to?... Yes it seems to be the vsr.. I was hoping to link it between one of the 2 existing batterys and then connect the solar panel and the inverter which is a 1500w DC ac inverter.... I would like the electrics for the fridge and water heater and probable not much else... Does this seem doable?.

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[Itsmcb]

This thread might help a bit. A fairly long read and quite technical in places but some interesting information for you

Ford Transit Under Cab Seat Twin Batteries

Bought a MK7 2010 Ford Tranny Van to Use as a Work Van with some Creature Comforts. Never owned a Tranny Van before. I will be using it as a self-employed work van. Before I start waffling My question is:- Under the driver's seat there are 2 batteries. I want to add a 20A dual solar charge...

www.motorhomefun.co.uk

 

[Jasvan1]

Thank you. I saw this one and it's got some really good tips... My last remaining question now is .. Does it sound like a good way to use... the vsr relay between the aux battery and a 3rd leisure battery.. Then connect the solar panel and av inverter to the new leisure batter and power the electrics from that..?.... Sound OK?..

 

[Jasvan1]

Ac not av.

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[autorouter]

Yes that looks OK. I'd keep wires A and D as short as possible (300mm or less), and it's a good idea to keep the VSR quite close to the leisure battery, to keep the new 12V electrics all in one place. The solar panel/controller and inverter will each need a fuse.

The solar controller can be connected straight to the leisure battery (via a fuse of course).

The inverter will need a fuse of 150A, and it is a bit optimistic to expect a single 100Ah battery to provide that power - two's not really enough, and three is better. If you only use lower-powered appliances like a fridge it should be OK. In reality to power that kind of inverter you need to think about the maximum amps from each battery, and a good way of recharging the batteries when the inverter discharges them.

Those fuses that came with the VSR kit are Midi fuses (30mm between bolt centres) I think. If not they are Mega fuses (51mm between centres), obtainable from automotive electrics suppliers like Altec or 12VoltPlanet.

 

[Jasvan1]

Thank you.. Really helpful...i currently only have the crocodile clip connections to connect inverter to the 3rd new leisure battery.. So maybe the is a way to connect inverter to the new leisure battery and the 2nd.(van aux) battery at the same time so that I can use the 2 batteries to power the inverter in tandem?... As you say I would like to use the batteries via the inverter and fuse!) to run a water heater and the fridge..

If one leisure battery is enough to power that
. I will keep it simple as connect the inverter directly to the 3rd battery..

I am learning this as a I go along.. o so your advice is invaluable .. Thank you.

 

[Itsmcb]

Nice idea to put the new leisure battery (s) under the passenger seat I think. Possibly room for the inverter either under there as well or behind the seat base? That would keep the 12v cables to the inverter really short which is good . Just a thought, should you be taking the split charge power for the new leisure battery from the starter battery rather than the auxiliary battery as the starter battery gets charged directly by the alternator? I think I've read somewhere that the auxiliary battery is already being charged by a split charge device, will it be receiving sufficient charge to pass on to the new leisure battery? Hope that makes sense?

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[Itsmcb]

Thank you.. Really helpful...i currently only have the crocodile clip connections to connect inverter to the 3rd new leisure battery.. So maybe the is a way to connect inverter to the new leisure battery and the 2nd.(van aux) battery at the same time so that I can use the 2 batteries to power the inverter in tandem?... As you say I would like to use the batteries via the inverter and fuse!) to run a water heater and the fridge..

If one leisure battery is enough to power that
. I will keep it simple as connect the inverter directly to the 3rd battery..

I am learning this as a I go along.. o so your advice is invaluable .. Thank you.

The auxiliary battery powers all the cab electrics so connecting that to your inverter is maybe not the best idea.

 

[Itsmcb]

Any idea what you plan to plug into the inverter? I've just done a search and the one you have may not be as powerful as you think. I suspect it's 1500watts maximum just for a few seconds, probably only able to supply a maximum of half that at best for any sustained period. It's also not a pure sine wave inverter so won't run lots of sensitive items like laptops.

 

[autorouter]

As you say I would like to use the batteries via the inverter and fuse!) to run a water heater and the fridge..

Just to avoid any confusion - when you say water heater, I take it you mean a gas or diesel powered water heater, that has its controls, ignition etc running from 12V. There's no way an actual 240V electric water heater can run through an inverter from a single 100Ah battery.