Critique my leisure battery setup please

[AHPP]

Plan is to use van for overnights/weekends away climbing etc.

Would want to power:
240v AC - phone charger, laptop, lamp
12v DC - LED lights, fridge maybe

Plan is to buy a leisure battery and an intelligent split charge relay (I don't want to wire into alternator or ignition wires).
I already have a 70W inverter.

Not being electrically minded, my main worry is frying myself. Secondary worry is flattening the main battery. Does my setup look safe and workable? In particular, does the black wire from leisure battery negative to crank battery negative safely earth everything (or do I have to run leisure battery negative to the chassis itself?)?
Please also make suggestions about wire thickness, fuse strength and location etc.

[duvet]

get phone and laptop 12v chargers...... and a 12v lamp?

[Honey monster]

What van have you got as some have split charge already in.

[Tom2023]

That's a very basic schematic.

Fuses either side of the split charger relay - 70amp (you'll need fuse holders too!)

You could do with a Master Switch on the +ve output of the leisure battery. This would completely isolate your battery should any faults develop in your 12v system.

From a master switch I would have a 20 amp fuse to a 12v fuse box

No idea what current your inverter will draw but that needs a fuse between it and the Master Switch.

Personally i wouldn't have the inverter, I'd have everything 12v.

Wire; From the crank battery to the leisure battery - (315/0.40mm) 40mm2 - might be over the top but readily available.

From the leisure battery to the 12v fuse box (80/0.40mm) 10mm2

You'd need tinned ring terminals for those 40mm & 10mm cables to fit them on to the Batteries, fuse holders, split charger & 12v fuse box.

I'd dump the manual swith to give the crank battery extra boost.

If you need any parts you could do worse than go to http://www.vehicle-wiring-products.eu/VWP-onlinestore/battconns/batttermls.php


I'd also have a Mains in and a couple of double sockets. These would come in handy if you had to book into a campsite to carry out repairs.

A little mains powered battery charger would be handy then too.

[AHPP]

get phone and laptop 12v chargers...... and a 12v lamp?

I know they're available and I've heard they're more efficient but the convenience of plugging in stuff I already have wins the day. I'd have maybe thought about it harder if I didn't already have the inverter.

[AHPP]

What van have you got as some have split charge already in.

2001 MK6 SWB 280

[AHPP]

That's a very basic schematic.

Fuses either side of the split charger relay - 70amp (you'll need fuse holders too!)

You could do with a Master Switch on the +ve output of the leisure battery. This would completely isolate your battery should any faults develop in your 12v system.

From a master switch I would have a 20 amp fuse to a 12v fuse box

No idea what current your inverter will draw but that needs a fuse between it and the Master Switch.

Personally i wouldn't have the inverter, I'd have everything 12v.

Wire; From the crank battery to the leisure battery - (315/0.40mm) 40mm2 - might be over the top but readily available.

From the leisure battery to the 12v fuse box (80/0.40mm) 10mm2

You'd need tinned ring terminals for those 40mm & 10mm cables to fit them on to the Batteries, fuse holders, split charger & 12v fuse box.

I'd dump the manual swith to give the crank battery extra boost.

If you need any parts you could do worse than go to http://www.vehicle-wiring-products.eu/VWP-onlinestore/battconns/batttermls.php


I'd also have a Mains in and a couple of double sockets. These would come in handy if you had to book into a campsite to carry out repairs.

A little mains powered battery charger would be handy then too.

Thanks very much for that. Very helpful post.
I got the crank battery boost idea from reading on here. There's already a switch (red plastic key job) set into the underseat battery compartment - thought I might as well use it!

[AHPP]

Is the earth good?

[duvet]

get phone and laptop 12v chargers...... and a 12v lamp?

I know they're available and I've heard they're more efficient but the convenience of plugging in stuff I already have wins the day. I'd have maybe thought about it harder if I didn't already have the inverter.

thing about inverters is I think they have a drain even if not powering something???

and the power loss in converting 240 and back is stupid.

have the inverter by all means but also have 3 or 4 12v and a USB socket.

[n8rbos]

The earth from leisureto main battery is ok but if theres bodysteel close to battery earth it there, get a smartcom splitcharger kit off ebay £17 +£1.50 p&p, comes complete with fuses etc , fit and forget, i have fitted a few of these and can recommend.

[bortaf]

Unless it a dedicated 12V compressor fridge forget running it on the battery, 3 way fridges draw a HUGE amount on 12V, so do compressor ones but they switch off and on so use less over time.
If the 2nd battery is a propper leasure battery forget using it to boost the starter, A it wont have any cranking amps worth talking about and B it will kill the leasure battery (plates in them are thinner and NOT designed fro cranking) and i'd also forget the inverter and get everything 12V, you loose ennergy converting from 12V to 240 then back again to 12V to charge items that are 12V to start with

[n8rbos]

I use a 3 way fridge, 12v whilst driving and if only nipping out for 5 mins, gas for any longer stationary, 230v before leaving home.

The chances am you will be using ' cheap' leisure batteries, these are really no more than a starter battery and would be ok to use as supplementary power for the starter battery . Expensive proper leisure batteries would be as said above.

I too use an inverter, but only plugged into the cigarette lighter whilst driving only or 10/15 mins bursts from the leisure batteries (220amps) i have an ammeter in the dash to tell me the output of my alternator and starter battery and one in my switch panel to tell me what voltage my leisure batteries are,that they are charging when the engine is running and the draw off the items i have on.

Fit additional cigarette sockets in the dash area or an adapter so you can charge all your 12v items up whilst driving.