How to Charge 12 Volt Trailer Battery

Updated 06/06/2017 | Published 06/04/2017

Question:

Hi! I just hooked up a 12v 33ah battery to my trailer for the purpose of running some low draw led lights. I also have a rocker switch panel that has a 12v plug for a cigarette lighter style power source for charging phones, etc. it also have a voltage meter. I have the battery grounded to the frame of the trailer and the 12V from the 7 pin plug wired to the + terminal. Onisolator yet, as I just unplug when not in use. The battery started out reading 12.9 V on the merger and after several hours of lighting, a couple phone charge ups and charging of two large drone batteries over the weekend it ended up reading 11.7V. I assumed after driving it home for 7 hours the battery would charge back up and read 12 + V. Where did I go wrong? It still says 11.7. Thanks!

asked by: Jake

Expert Reply:

The power that the 12 volt battery on your trailer receives from the 7-way connector is enough to maintain its charge, however it will not be sufficient for charging the battery back up after use. The voltage drop you experienced from charging your phones and drone batteries was simply maintained on during your drive home.

To be able to fully charge the trailer battery, I recommend using the CTEK Multi US 7002 12-Volt Universal Battery Charger # CTEK56353. This can be used to fully charge the battery, and then you can just maintain the charge using the vehicle's system.

I have attached a video demonstration and the instruction manual on this product for you to check out.

expert reply by: Chris R