Would splicing existing wires (from charge controller to battery) to connect an inverter work, and is it safe?

Question

I'm trying to add an inverter in my travel trailer, but wanted to figure out the best way to do it. Because I'm not that familiar with the electrical setup of the trailer, I was only able to access the electrical components of the charge controller; the rest are wired under the trailer somewhere.

I just want to know if it'd be safe to splice the wires going from the charge controller to the batteries, to hook up the inverter. I know that the ideal way to do this is go straight from the battery to the inverter, and not piggy back on any existing wiring; but the wires from the batteries all go under the trailer, and I'm not sure how it's all wired together.

Apologies for the amateur question(s).

Answer 1

May I ask what are you using the inverter for? If you want to draw power from the battery to power anything, it wouldn't be safe to splice the wires. The charge controller takes care of the system, ensuring that the battery doesn't get over charged and goes through the proper charge cycles. Some charge controllers will have a terminal for a load and can be programmed to power that load at certain times of the day. So if you want to power a device from the battery, go through the charge controller. I have previously used blue sky controllers. If you are planning on splicing to have another means of charging your battery, it is definitely a bad idea. Some charge controllers have a master-slave capability, this allows you to hook up another charge controller that is a "slave" to the current charge controller and works in unison with the master to charge the battery. So I guess my overall consensus is to stay away from splicing. If you would simply like to monitor your battery health with some measuring tool, then that would be the only case I would encourage probing the battery terminals, but still avoid splicing. Hope that helps, let me know if you need me to clarify anything. Good luck! - Josh

Answer 2

I would wire the inverter directly to the batteries with large enough wire to handle the inverter's full load.

If the solar panel and charge controller can only handle 60 watts, I'd expect the wiring between the controller and batteries to be no larger than #12, if that.

Consult the inverter specs to see what wire size it recommends for the cable length you will be using. If the inverter is a "plug into a lighter outlet" type, the existing wire may be adequate, but if it is intended to be hard-wired to the battery (probable for inverters capable of 300 watts or more) you should wire it directly to the battery, using the recommended wire size (which will vary, depending on the wire length between battery and inverter).