backstop my safety please! Before I kill anyone!

[Cult Hero]

Finishing up my solar build and although I want to keep it simple, I also want to make sure I am not missing out on any particularly dangerous safety points.

Two 12v 55ah batteries wired in parallel, connected via a breaker and switch to my pure sine wave inverter. The batteries are connected to my solar controller that runs to my panels.

I plan on anderson connectors to run to the solar panel and also want to put anderson connectors off the battery on my truck so if need be I can use my alternator to charge my solar batteries, or use the solar panel to charge the truck battery.

I presume the solar controller will regulate the charge from the batteries, but would it be better to run the connectors straight to the alternator and bypass the battery? I know the alternator is voltage regulated, but wanted to check.

 

[dwh]

The solar controller is a voltage regulator. Run it to the battery and let it regulate the voltage from the solar.

Let the truck's voltage regulator handle regulating the alternator.

 

[Cult Hero]

wait what? Run the controller directly to the truck batteries if I want to charge the solar batteries? It will adequately regulate the power from solar or alternator / battery?

I want to be able to charge my portable power with truck power (via the batteries and alternator) and solar, just change the connection from solar to truck.

Any other safety concerns?

 

[rayra]

Yep, just run another line from the solar charge controller to your starter battery, and put a switch in the line if you want to focus all the solar power on your battery bank.. If your controller can feed two banks, just wire it that way.
It it only has one hookup terminal to feed your batteries, then put a diode in the starter battery line to electrically isolate its stored power from your battery bank.


Another option for 'desperate measures' is building in a heavy cable from your battery bank to your starter, interrupted by a marine-style rotary cutoff. That way you can self-jump if you have to, if you can't wait for your panels to do the job.

There's lots of ways to do it, just have to avoid turning it into a railway switching yard.

 

[dwh]

wait what? Run the controller directly to the truck batteries if I want to charge the solar batteries? It will adequately regulate the power from solar or alternator / battery?

No, i thought you were talking about using the solar to charge the truck battery. For that, just run the solar charge controller's output straight to the truck battery.

You mentioned using the truck's voltage regulator. Forget it, don't need to mess with that.

I want to be able to charge my portable power with truck power (via the batteries and alternator) and solar, just change the connection from solar to truck.

For the solar, just connect the charge controller to whichever battery you want to charge.

How were you planning to charge the portable from the truck?

 

[dwh]

Okay, I get it.

Anderson straight to truck battery, another to portable battery. Plug solar into whichever you want to charge.

For truck to portable just run a jumper between the truck's battery and the portable battery. Anderson to Anderson.

It'll work, but while connecting different size batteries during charging is fine, leaving them connected when the engine is off is going to shorten the life of all batteries involved. So you'll have to make sure you disconnect the portable whenever the engine is off.

 

[MichelleKiwi]

I'm just wondering, Would it be possible to run wires between both batteries, and the charge controller through a standard 5 pin automotive relay. Where one battery is connected to the Commonly Open, the other battery is connected to the Commonly Closed and the output of the solar controller is connected to Common. And then control which battery is charged by activating the relay using a switch.

Instead of unplugging and plugging the Anderson plugs every time you want to change when a battery is charged.

 

[dwh]

This would work if the relay contacts are adequate ampacity.
Then decide which of the batteries will energize the relaycoil. Remember unless its mechanical latching relay, its coil will be a constant load when energised.

A SPDT switch may be a better choice.

Further, if switching only one battery lead from the solar controller, be cautious no "sneak circuit" will be created.
Many solar controllers are positive common/ground configuration.

This.

 

[naz4x4]

Personally use a switch such as the Blue Sea 4 position unit.