Is a Current Limiter Circuit Breaker Needed for a Battery Charge Line

Updated 12/11/2018 | Published 12/09/2018

Products Featured in This Question

Redarc In-Vehicle BCDC Battery Charger - Dual Input - DC to DC - 12V/24V - 40 Amp

(88)

$620.00

Roadmaster Battery Charge Line Kit for Towed Vehicles

(1333)

$36.90

Question:

Re-wiring a trailer, that is towed behind an RV. I suspect that the charge circuit from the RV is simply connected to chassis battery positive. I dont believe that this is current limited. The trailer has an 625A deep cycle battery that powers everything, and a breakaway switch connected between that battery and the brakes. Power to the breakaway switch is on a 20A breaker. Do I need to add a current limiter to the charge line? If so, link and cost for this unit? Can I instead disconnect the charge line and a tow charger between the charge line and the 625A battery? Is there a DC to DC tow charger that can charge that battery, that isn't $? Hoping for $ or less. Thanks!

asked by: Craig

Expert Reply:

It sounds like you have a charge line ran from the RV's battery to the trailer's battery. If this is the case then yes, you will need a current limiter (circuit breaker) in between the two in order to prevent any spikes that could in turn damage either battery. In the charge line kits we offer like the Roadmaster Battery Charge Line Kit part # RM-156-25, they come with a 15 amp circuit breaker so that is what I recommend you use. However, this battery charge line is only going to provide your trailer's battery with a maintenance (trickle) charge. If you need an actual full charge then you would need to use a DC to DC battery charger like you mentioned. Unfortunately, a DC to DC battery charger that is going to be sufficient for a 625 amp deep cycle battery is not going to be exactly cost effective. The most cost effective one we offer for this is the Redarc BCDC Dual Battery Charger part # 331-BCDC1240D.

Also, a breakaway system cannot receive power from an auxiliary battery. It will need to have its own separate battery which is a law in nearly every state. Therefore, I must first recommend that you replace the breakaway system you have now and how its wired with a system that has an integrated battery like the Pro Series Push to Test Breakaway Kit with Premium Integrated Charger part # 50-85-315. You would then want to use the 12 volt hot lead on the 7-way to charge this battery.

expert reply by: Conner L