Solar & Split Charger combined help needed please

Thef1man

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Hi all
It may seem a cautious question but I currently have a solar panel on the roof of my van which goes through a duel PWR output to 2 separate and independent leisure batteries, HB 800's from Halfords.
I am now about to fit A Split Relay also just as a precaution and was wondering if there anything I should know other that what's covered in the instructions. I want to get it right and not damage the set up that I currently have.
(y)
 
Appears to be a bit of an odd setup, why are the hab batteries seperate?

Normally with a dual output regulator you wire the second output to the starter battery and this output only supplies a small percentage of the charge to the starter battery .

What relay as you looking at using?
 
Hi Lenny,
To be honest I have only just noticed that the it was a duel. I previously had the 2 batteries in parallel set up.
I thought I would use the 2 out puts as follows:
Battery 1 set to 70% .....only suppling diesel heater in back of the van
Battery 2 set to 30% .....Supplying lights

My theory is that I would rather be warm in the dark with no telly than the alternative haha
 
Please if anyone knows a better setup that would be very helpful 🙂
 
Hi Lenny,
To be honest I have only just noticed that the it was a duel. I previously had the 2 batteries in parallel set up.
I thought I would use the 2 out puts as follows:
Battery 1 set to 70% .....only suppling diesel heater in back of the van
Battery 2 set to 30% .....Supplying lights

My theory is that I would rather be warm in the dark with no telly than the alternative haha
I can see the logic of it but I would think you would be better with the batteries in parallel as that would double the current avaliable as the diesel heater takes high current on startup.

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Thanks Lenny
I that that on board and will revert back to parallel set up. Would you then put the positive on 1 battery and the neutral on the other from the controller. Also how would the wires from the relay connect? Would that be the same connections as per the regulator.
If all that makes sense lol
 
If its the controller I think it is you connect 1 to the positive on the hab batteries and 2 to the starter battery positive and you shouldn't need the relay. Normally to have the hab battery set to 99% & starter to 10%.
 
As Lenny HB has suggested a solar duel controller normally would be set up for it to charge the leisure battery/ batteries from one output and the starter battery from the other (lower power) output.
Not sure what the relay is being used for ?
 
My idea was to have the starter battery completely independent from the habitat batteries. The relay would only be relevant whilst driving to the venue then the solar would just top up whilst I am away, hope this explains my theory haha
 
The starter battery would still be independent ,apart from receiving a small solar charge, using the duel controller , a split charge relay ,if this is what is being fitted, would not be effected by this set up.

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Last edited:
Not sure what the relay is being used for ?
As I read the OP, there is no existing means of charging the leisure batteries from the alternator & this is what the split charge relay would be for.

It is the traditional, cheap & moderately effective way of doing it. A more effective, but more expensive way is to use a battery to battery charger, which would give as good a charge as plugging into a mains charger.
 
As I read the OP, there is no existing means of charging the leisure batteries from the alternator & this is what the split charge relay would be for.

It is the traditional, cheap & moderately effective way of doing it. A more effective, but more expensive way is to use a battery to battery charger, which would give as good a charge as plugging into a mains charger.
Because of the way the OP worded his original post I thought he wanted the relay to charge the starter battery from the solar.
 
Hi and thanks for the input,
Sorry for any confusion, I merely wish for the relay to charge the leasure batteries whilst driving to the venue then the solar panels will top up whilst away.
Hope this explains it more clearly (y)(y)
 
Hi and thanks for the input,
Sorry for any confusion, I merely wish for the relay to charge the leasure batteries whilst driving to the venue then the solar panels will top up whilst away.
Hope this explains it more clearly (y)(y)
Use a relay switched by the D+ terminal of the alternator, voltage sensing relays aren't suitable with solar charging as they turn on when the battery voltage rises from the solar input.
 
Cheers Lenny,
That was my concern to a point. I'm not sure what tou mean by the d connection at the alternator but will do more research ro make sue I get it right. Thank you

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Solar Setup.jpg
 
Firstly I would like to thank the people for their input on this query last evening
I am old school (hence the picture) so apologies in advance.
This is the set up I have currently and I am hoping to connect the relay to charge the habitat batteries whilst on the move then allow the solar panel to top things up. Also if I am away for a few cloudy days I could just start the van and the relay will kick in and top up the habitat batteries.

Any advice on connecting the relay would be much appreciated.
Lenny did say last night about connecting the relay to the D+ on the alternator but I am still a bit confused, its obviously me hahaha
 
Sorry I forgot to mention:
The relay I am hoping to fit is a HC Cargo VSR a Microprocessor-controlled relay, or would I be better off fitting a smartcome vsr as apparently you don't have to use the D+ connection off the alternator. I wouldn't have a clue where the D+ connection could be made other that from the alternator itself lol
 
A voltage sensitive relay (VSR)turns on when the voltage exceeds the trigger voltage. In simple systems this only happens when the engine is running and the alternator is charging the starter battery.

In more complex systems, the starter battery voltage can rise for other reasons: charging from solar or mains charger for example. Often this is OK but it can cause problems.

Triggering the relay from the ignition sounds a good idea in theory, but there's problems with that too. The relay turns on while the starter motor is running and the starter battery is feeding a huge burst of amps to it. The leisure battery is connected to it, and tries to help supplying the amps. Leisure batteries are not good at supplying heavy current, and are meant to supply moderate current over a longer time.

There is a wire from the alternator called the D+ signal, which is zero volts when the engine is stopped, and jumps up to +12V when the alternator is up to speed, the engine is running and the starter motor has finished its job. This is the best trigger for a split charge relay.

I understand your concern to keep the leisure and starter batteries independent. The last thing you want is to run the leisure battery flat, then discover the starter battery has been drained flat too.

There's a couple of ways to keep the starter battery topped up while you are parked up. A dual output solar controller will keep the batteries separate, sending most of the solar power to the leisure battery but sending a trickle charge to the starter battery.

Alternatively a 'battery maintainer' is a one-way trickle charger from the leisure to starter battery, for example a BatteryMaster.
 
Hello autorouter and thanks for the reply. That does explain quite a lot and makes good sense.
Many thanks.
I will be sure to post an update on here once sorted.

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You can use the smartcom to provide a dplus signal to a normal dumb relay often easier than tring to find a d plus
Smartcoms got a bad name as people used just that as a slit charge.THey are optimistically rated as 30 amp switching and dont handle high current for long but if you use it to switch another relay they work well you can tap off from any live wire set the smartcom to switch above 13 volts
Advantage is you can use a decent relay 80 or 100 amps which come with studs for connections of decent sized cables
 
Hi mitzimad,
Thanks for the info.
That's sounds like a good option as the back of my van is completely boarded and carpeted so the only acces to the d+ would mean a long run from the alternator. The van battery however is a lot closer.
Cheers
 
Hi mitzimad,
Thanks for the info.
That's sounds like a good option as the back of my van is completely boarded and carpeted so the only acces to the d+ would mean a long run from the alternator. The van battery however is a lot closer.
Cheers
You will have a wire from the vehicle battery to the leisure battery's put the dumb relay next to the leisure battery and take the wire for the smartcom from that as well I willl try drawing it and send
 
For best battery life
Connect both batteries in parallel but fit a big fuse in each positive first.
Connect the solar regulator output to charge these batteries as one and if you need to then output 2 to the starter battery. Using two leisure batteries sequentially will give less overall energy.
C.
 
Cheers mitzimad, pictures speak volumes to an old school guy like me lol.

Hi Clive, thanks for the input, I did have the 2 leasure batteries connected independently, 1 for the heater and 1 for the lights and telly, the theory being I'd rather be warm in the dark than cold with the lights on. I have had a couple of failures and been extremely cold hahah. This is the reason for 2 batteries with solar panel and the relay setup, no more cold nights for me lol

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Not the best drawing but you can see its all together fed from the cable from the vehicle battery you need a fuse in the main and trigger circuiting my old ducat i ran a 16mm cable with crimped on rings obviously the trigger sides of the relays only needs small cables but should be fused it was all mounted adjacent to the hab battery
 

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Cheers mitzimad for the pictures, much appreciated.
 

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