.... Another self-build van wiring quandary...

[Samwise-100]

Hi everyone!

I've just bought a van to convert and it came with quite a lot equipment which i plan to use in my camper (previous owner had intention of converting and made a bit of a start, but i'm starting again).

I'm currently studying the electric system and have found loads of information all over the internet, lots of people asking 'similar' questions to me. I'm working on a wiring diagram based on the info i've gathered so far. However, would just like a bit of advice or feedback from any of you more knowledgeable folk to let me know whether i'm on the right lines.

Attached (or below) is my first draught sketch, and to follow is a summary of what i have so far, along with a couple of questions:

• Firstly, i have 2 x 100AH or 110AH (identical but i can't quite recall what capacity they are) leisure batteries, which i plan to link in parallel, so i understand this is simply 1+ to 2+, and 1- to 2-, my question is, does it matter whether run battery 1- to earth, as shown, or should it be 2-, or doesn't it matter?
• I plan on using a VSR split charge relay to charge my leisure batteries, linked from van+ to leisure 1+, with a link to earth, as shown.
• I also have 1 x 250w solar panel running through a 20amp 'dual' battery controller, with outputs for 2 x batteries. Question is, would i benefit from linking the controller to both my leisure batteries? Or should i just run in to my primary leisure 1 battery as i've shown? I assume that there would be no point running the second output to the van battery as this is charged off the alternator? Please advise.
• Would this setup mean the leisure batteries would be charged by BOTH the alternator/van battery AND the solar panel, simultaneously? Is this ok?
• I've read and been told not to bother running the fridge (12v Thetford T1090 compressor fridge) through the PMS3 power management unit, instead, running it straight from the the battery? Not sure exactly why this is, would anyone concur or advise against that?

Sorry for the bombardment but would love to hear what anyone has to say on any of this, currently enjoying the learning curve!

Thanks in advance

Sam

 

[andy63]

Hi Sam.. and welcome..
Try and take your points in order..
The supy and charging connections to your batteries connected in parallel should be off the positive of say battery one and the negative of battery two..

If you use a voltage sensing relay to connect the start and leisure batteries get a high current rated one..they are usually dual sensing so will work both ways..

It's generally OK to have more than one charging source connected to a battery..



If you have a dual solar charge controler link the two leisure batteries to one output...and your start battery to the other..

I would run the compressor fridge off the batteries with an online switch ..they are heavy users and its good to be able to manually isolate them say through the night when the door is seldom been opened..Thats if you need to conserve power..

Hope that helps
Andy..

 

[Jake vE]

Firstly, its nice to see a picture for it to make sense!

I can't comment on the fridge but to balance the batteries you need to move either the group of grounds or the positives across to the other battery as shown in the picture below if that makes sense?

You may not have drawn them in but make sure you have the positive connections all fused as close to the battery as possible.

There shouldn't be an issue running solar and alternator charge together but if you wanted you could put in a switch for the solar to isolate it if you ever needed too.

Hope that helps and good luck!

 

[TheBig1]

You are going to need an extra way to charge the batteries through winter months when solar power is reduced this far north of the equator. Modern vans have a lot of electronics that cause parasitic drain on the van battery. Even with some solar it sometimes struggles to keep up with discharge. A multi stage charger will fix this if you can hook up to power occasionally. Heating or cooling anything is always power hungry

 

[Lenny HB]

With only two batteries close together it is not important where you take the load connections from, only becomes necessary if you have a larger battery bank or the batteries are some distance apart.

Do not use a VSR relay for the split charge, use a conventional relay switched by the D+ feed from the alternator.
You are using a dual output solar regulator, If you use VSR for the split charge when the engine battery voltage rises with the solar input the relay will turn on.

I wouldn't switch the fridge off at night there are bound to be times when you forget to switch it back on in the morning, no one wants warm beer.
Most compressor fridges have a night setting now days.
With a compressor fridge might be wise to fit more than 200a/h of batteries and 250 Watts of solar.

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[Samwise-100]

Thanks ever so much for your replies guys. I've updated my plan taking heed of your advice (also jiggled it around to be somewhat representative of the van layout) so think this should be better.

My leisure batteries will be sat next to each other but, whether necessary or not, it's an easy enough fix to link them as advised, so went for that.

Regarding the second solar output going to van battery (Andy)... sorry if this is a daft question but... would i benefit from having it also charge my van battery, or would this be a 'waste' of the solar energy generated? Wouldn't all the energy generated from solar be better spent charging my leisure batteries? I thought the van battery might be 'self sufficient' charging off the alternator?

Regards the relay, i'd read about the alternative HD relays so have swapped the VSR out for one of those, as advised, i'll take a 12v trigger from my rear brake light as i need to access this anyway to fit a reversing camera.

And regarding Big1's comment about battery charging capacity... i've read quite a lot of conflicting info about the PMS3's ability to charge my leisure batteries when hooked up to shore power. The unit literature and quite a few forum posters say it will charge my batteries, but one or two people who sound really clued up say it won't. I'm kind of thinking i'll just see what happens with it, as long as i get it all set up correctly.

Also, duly noted about fuses and isolation switches, will ensure they're all fitted to everything. Provided this 'charging' part of the set-up is ok, everything else which is just 12v outputs (lights, diesel heater, water pump etc) will come from the PMS3 and, i think, should be relatively straightforward.

Thanks again guys, any more feedback or anything else to add would be much appreciated.

 

[ambulancekidd]

 

[andy63]

Regarding the second solar output going to van battery (Andy)... sorry if this is a daft question but... would i benefit from having it also charge my van battery, or would this be a 'waste' of the solar energy generated? Wouldn't all the energy generated from solar be better spent charging my leisure batteries?

hi, what I was meaning is if you have a dual solar charge controller then you could connect one of the battery outlets to your two leisure batteries and the second to your start battery.. if it is a dual charger then you can prioritise the way in which the charge is split between the two batteries... thats as far as I know.. I don't actually have a dual solar charge controller..

if you go down the route of a split charge relay to charge the leisure battery from the alternator , rather than the vsr. then its usual to trigger the relay from an engine run signal.. not sure what your reference is to the brake light circuit..
Andy

 

[mitzimad]

you cant trigger the split charge from the brake lights you need a d plus signal so the relay makes when there is out put
from alternator if you cant find a d plus then use a smartcome vsr to trigger the relay this can connect to any live feed

 

[Raul]

Just to add, a compressor 50L will consume in average 30ah a day with a 20C deg ambient temperature outside. A bit less in winter and a bit more in summer. With that said you will likely add 20-30ah for the rest of the loads. So round up a 55ah daily requirement. Because the charging and discharging round trip efficiency of around 75% at best, you will need to put back 68-70ah. Can you do that? Is your solar beef enough to harvest 70ah a day? If not, then make sure you have additional charging sources. With the split charge relay you could put that back in 2hrs drive. With a mains charger needs to deliver a minimum 20a to meet the demand of your 200ah bank. If the pms3 can’t do that, you need a charger man enough, wired directly to the batteries.

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[BasherBaz]

Thanks ever so much for your replies guys. I've updated my plan taking heed of your advice (also jiggled it around to be somewhat representative of the van layout) so think this should be better.

My leisure batteries will be sat next to each other but, whether necessary or not, it's an easy enough fix to link them as advised, so went for that.

Regarding the second solar output going to van battery (Andy)... sorry if this is a daft question but... would i benefit from having it also charge my van battery, or would this be a 'waste' of the solar energy generated? Wouldn't all the energy generated from solar be better spent charging my leisure batteries? I thought the van battery might be 'self sufficient' charging off the alternator?

Regards the relay, i'd read about the alternative HD relays so have swapped the VSR out for one of those, as advised, i'll take a 12v trigger from my rear brake light as i need to access this anyway to fit a reversing camera.

And regarding Big1's comment about battery charging capacity... i've read quite a lot of conflicting info about the PMS3's ability to charge my leisure batteries when hooked up to shore power. The unit literature and quite a few forum posters say it will charge my batteries, but one or two people who sound really clued up say it won't. I'm kind of thinking i'll just see what happens with it, as long as i get it all set up correctly.

Also, duly noted about fuses and isolation switches, will ensure they're all fitted to everything. Provided this 'charging' part of the set-up is ok, everything else which is just 12v outputs (lights, diesel heater, water pump etc) will come from the PMS3 and, i think, should be relatively straightforward.

Thanks again guys, any more feedback or anything else to add would be much appreciated.


View attachment 468983

I have been using this Votronic Duo solar charger for over 2 years no problem.
<Broken link removed>

As the article says it puts just 1 amp/h into your starter battery. This is what I wanted to keep up with the drain from the vehicle tracker when parked up for weeks when at home/working. The insurance companies insist on having the tracker on the starter battery rather than leisure batteries. Its also helpful if your listening to the vehicle radio for hours whilst camping and not moving and saves installing a separate radio or alternative leisure battery supply.

Hope this helps

 

[Samwise-100]

Thanks for your comments guys, I'm back after plenty of studying with an updated wiring plan using an ignition switched relay taking a feed from alternator D+ (still need to figure out exactly how to do this).

Duly noted about the fridge battery drain and question about the charging capability of the PMS3, we'll be mostly camping on sites with hookup, with maybe the occasional off-grid night here and there so think i'm just going to have to see how we get on with that one...

I've done this plan showing the diesel heater wired straight to the battery because i've read elsewhere that it should always be powered to allow it to shut down properly after use and burn off any combustion remnants (ie unable to be switched off anywhere other than the controller). Can anyone verify this is correct?

The 12v ports i'm using on the PMS3 are Pump, Lights and 2 x Aux ports.

For the pump, i want to link an extractor fan to come on at the same time. I've read the fuse sizes should be 7A for the pump and 3A for the fan. I've shown individual fuses for each of these, but the PMS3 has an inbuilt fuse for the pump output... Would it be right to put a 10A fuse in there to cover both 7A and 3A for pump and fan?

Similarly, there are 2 Aux outputs and i will be using one for the fan and one for the cooker ignition, both of which need 5A fuses. But, the unit only has a single built-in fuse for Aux... I assume this is for both outputs combined, so as i have 2 x 5A fuses, is it right to put a 10A fuse in here, same as above?

Any feedback, info and/or advice would be greatly appreciated.

Cheers

 

[68c]

I would not use a single 10amp fuse. Fuses are there to protect the wiring, if the wiring can only carry 5amp each may cause problems as you will have effectively fused it at 10 amp. Also having two Fuses makes fault finding easier, you can also isolate one at a time by pulling the fuse. However, if you want to use one outlet from from your PMS3 for both you can fit a 10 amp fuse if you then split the supply through two 5 amp fuses, bit messy and increases the resistance of the circuit.