Battery Charger / Converter

[Craig D. Thompson]

Folks with electrical system savy,

I am not sure if my questions are specific to the U-Haul battery charger or chargers in general. When I bought the 13’ U-Haul from my parents several years ago there was no battery. The heater and apparently a power monitor / control panel next to the heater were removed and discarded. I installed a deep cycle battery and the charger / converter seemed to be doing it’s job: charging the battery when hooked to shore power and bypass the battery with 12v power. We took a two-week trip and the system seemed to function properly.

I periodically plug into shore power to charge the battery but I have not been checking for proper function. I am getting ready for a short trip next weekend (after more than a year of actually using the trailer, sad but true) and the charger did not seem to recharge the battery and did not supply 12v power to the lights.

With the charger wires disconnected from the battery and turned on, should I be able to measure 12v (or slightly more) from the charger? Turned off I read 0v (no surprise) and on I measure about 4.5v.

By the way, I checked all of the fuses in the charger / converted, none are blown.

The battery did charge up with my car battery charger.

Hoping I don’t need a new charger / converter.

Any thoughts and help are most appreciated.

Craig T.

[Janine]

Right off I'll admit no electrical-savvy-ness, however just logically if your car battery charger works and this'n doesn't, it rules out all but your charger/converter as the problem. Unless there's a way to fix that, which I'd doubt, it's $$-time. Which brings me to the question...why can't you use the car charger and run 12V off your RV battery instead of circumventing it...does it do your battery in to be charged/used as opposed to charged on the side and routed around? I wouldn't think so...but again.

Folks with electrical system savy,

I am not sure if my questions are specific to the U-Haul battery charger or chargers in general. When I bought the 13’ U-Haul from my parents several years ago there was no battery. The heater and apparently a power monitor / control panel next to the heater were removed and discarded. I installed a deep cycle battery and the charger / converter seemed to be doing it’s job: charging the battery when hooked to shore power and bypass the battery with 12v power. We took a two-week trip and the system seemed to function properly.

I periodically plug into shore power to charge the battery but I have not been checking for proper function. I am getting ready for a short trip next weekend (after more than a year of actually using the trailer, sad but true) and the charger did not seem to recharge the battery and did not supply 12v power to the lights.

With the charger wires disconnected from the battery and turned on, should I be able to measure 12v (or slightly more) from the charger? Turned off I read 0v (no surprise) and on I measure about 4.5v.

By the way, I checked all of the fuses in the charger / converted, none are blown.

The battery did charge up with my car battery charger.

Hoping I don’t need a new charger / converter.

Any thoughts and help are most appreciated.

Craig T.

[Frederick L. Simson]

With the charger wires disconnected from the battery and turned on, should I be able to measure 12v (or slightly more) from the charger? Turned off I read 0v (no surprise) and on [b]I measure about 4.5v.

Hoping I don’t need a new charger / converter.

I hate to bust your hopes, but you should be seeing close to 14 volts DC there. Looks to me like it's toast.

sorry.

[Craig D. Thompson]

Thanks for the quick responses.

I was just checking the voltage again and now, with shore power to the charger / converter, the batter master switch off, I am reading 12v from the charger. With the battery master switch on I read 14v.

Is there some circuitry that is evaluating the battery charge state and changing the charger / converter voltage accordingly? I guess I mean to ask when the charger is charging, will it always deliver 14v, turn off when the battery is fully charged, or will the voltage taper off when the battery is almost fully charged? (Thus my reading of 4.5v earlier this morning and now 12v)

As always, thank you all!

Craig T.

[Pete Dumbleton]

Unless you have a very modern converter, with the optional multi-stage charging, it's not likely your converter is doing anything with regard to the battery except putting out a constant charge that will overcharge it in the long run.

The converter's reason for existence is as a 12VDC power supply for the trailer and battery charging runs a very dim second place...