# Solar Panels Wiring with Split Charge Relay



## garvin (Jun 22, 2014)

Could someone please help me?

For my van I phave put 6 100 watt 10 amp solar panels on roof, this is wired in parallel to a 60 amp charge controller. This is then wired to my starter battery, which i then wired a split charge (earthed) relay to 2 leisure batteries (earthed). Finally my inverter connects to leisure batteries.

Firstly is this correct?

I have a diagram :

http://www.printernational.co.uk/garvin/Solar_panels_wiring_with_split_charge_relay.pdf

Genarally, the system works, running a small fridge and laptop PC, as i frequently drive, so alternator gives power aswell, however a few bugs worry me.

Does the charge controller (60 Tri Strar), which is fully connected to the starter battery (with positive and negative), only charge the starter battery to the point of 100% and then stop over charging?

I think 6 solar panels is a considerable amount, which cover the whole roof. The Charge controller is expensive at 60 amps. 

I once overused the storage of the 2 leisure batteries by heating water on an electrix hob, to the point the inverters continiously beeped and i turned of the inverter.

With the flat leisure batteries, i then discovered the next day upon the sun coming , that i could turn on the inverters again, so turned on the fridge and PC. When the sun left, by midnight the beeps returned so i switched off ther inverter again. That day I did not drive, so the alternator was not charging anything.

I guess i needed to charge the batteries more that day. Its the peak of summer so light is great.

I guess from what i can see is that the split charge relay is giving some power to the leisure batteries.

But i thought it should be more, as they ran out that night. Could this be that the charge controller is only supply enough power to the starter battery to fill it complete, but not considering the leisure batteries?

Should i wire the charge controller straight to the leisure batteries, and put a bi-directional voltage sensing relay instead of the charge controller?

this is shown here: Victron Cyrix-i 120, 12v or 24v Split Charge System 

Battery Split Charge Relays - www.solar-wind.co.uk

I am told the key to this system is to use a Victron Cyrix split charge relay unit - which charges in both directions. That way if either the starter or domestic banks gets full the Cyrix allows the power to charge the other bank.


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## The Grand Wanderer (Jun 25, 2014)

Interesting set up.
Personally I would have connected the solar panels to the leisure batteries using the split charge relay to top up the engine battery as and when it needed a charge.
I would only use the leisure batteries for powering your habitation appliances.
All the cables between all batteries and from your solar panels should be at least 5-10mm thick as anything less will cause resistance and voltage loss.
I notice that on your wiring diagram you do not show how the power from your alternator enters the system, does it have its own split charge relay?


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