Why Does Battery for Trailer Jack Keep Dying

Updated 06/23/2015 | Published 06/21/2015

Question:

We have a sundowner 4 horse trailer with equalizer hydraulic jack on the front. The trailer is over 5 years old and I doubt the TAP breakaway battery has ever been replace or tested. It seems that I have to keep charging the battery for the hydraulic Jack every few months it seems something is draining it down when its sitting. All of the lights, fans and switches for the trailer are off I dont know what keeps draining the battery? My question is this. If the Breakaway battery is bad will it keep draining the deep cycle battery that powers the hydraulic jack?

asked by: Brian

Expert Reply:

The breakaway battery would usually be maintained from the 12-volt circuit coming off the 7-way trailer connector. You can test the battery with a volt meter to see if it's still good. It's unlikely that the breakaway battery would deplete the battery for the trailer jack.

It's not unusual that you need to recharge the battery for the jack every once in awhile, because the power wire form the 7-way does NOT have enough grunt to recharge the battery once it's depleted. It can maintain a battery such as the break away battery, but once the trailer mounted battery is depleted the vehicle battery is too far away, the alternator isn't powerful enough and the wire feeding the 12-volt pin on the trailer connector is too small to deliver the kind of power necessary to charge that battery when it gets low. Therefore, it's not unusual at all that you'd need to recharge it using shore power from time to time.

expert reply by: Mike L