Elektroblock 252 solar connection question - cable sizing

[richierni]

Hi all, my first question.

My van has an EBL 252 and I've just added a renogy 175W solar panel.
I'm bought a Renogy DCC30S (30A) combined DC to DC charger and solar controller, as I plan to upgrade to Lithium soon, but for now I'm just going to use the solar controller part to help charge the existing lead acid batteries via the handy EBL connection.

The EBL has a 20A fuse on the solar input. I don't expect my 175W panel and DCC30S to generate 20A, but I will also fuse the panel to controller (15A breaker) and controller to EBL (20A breaker) just for convenience and safety. I believe I can also limit the output of the Renogy controller to 20A via a bluetooth app.

My question is with regard to the connection from the solar controller to the EBL which is via a Mate N Lok connector which I believe will only take up to a 2mm cable, which seems very light for a possible 20A. The solar panel to the solar controller is 4mm cable.

Is a 2mm cable really ok between the controller and EBL? And if not, what can I do given EBL's choice to use this connector?

 

[Lenny HB]

Always best to bypass the EBL and connect the controller direct to the batteries.

 

[richierni]

As this is a temporary solution I'd prefer the simplicity of doing it via the EBL if possible. I imagine it keeps my voltage monitor accurate too.

If I did choose to bypass, where would I connect the outputs of the Renogy controller to exactly? Simply into the leisure battery/negative connectors into the back of the EBL? I don't think there are any handy common connection blocks in my electrics compartment.

 

[Lenny HB]

Going through the EBL you will lose about 5%.
You can just connect both neg and pos direct to the leisure battery (fuse inline with poss). Won't affect the voltage readout on the panel.
If you have a panel with an LCD display that shows current it will effect that.

 

[richierni]

Thanks for the info, that's useful. I'm not too worried about the efficiency as this is a temporary solution, more about the convenience. Connecting direct to the bateries themselves wouldn't be convenient, they're under the driver/passenger seats and the electrics compartment is in the middle of the van. And as I mentioned there don't seem to be be any handy terminal blocks for the leisure batteries in the electrics compartment.
So, for a direct connection, if the wires fit, is it acceptable to connect the controller (fused) into the terminals on the back on the EBL where the leisure battery is connected into it?

And returning to my original question, I'm interested if anyone knows why EBL woud have used this connector which takes a 2mm wire on a path that their manual says "max 20A". Seems to make no sense so I suspect I'm making some basic error. I do know they make their own 18A (LR1218) solar controller that comes with wiring to connect directly into the EBL solar port, anyone know what size wires that comes with? Even 18A sounds a lot for 2mm wires.

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