Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 11, 2025 ...

Power conveter.

April 29, 2017, 05:16:46 pm

Hello fellow Foretravelers,
I have a 1989 U 300. The old girls uses a separate converter/charger and inverter. My power converter fan would go to it's higher speed mode ( assuming more demand) if I had all the 12 lighting on inside the coach. Lately it comes on every few minutes with nothing on. The house batteries are 3 years old and read a constant 12.8 volts even with the power converter turned off for a few hours.
The fan coming on thing happened right before I had to travel for work so I shut off the power converter and any thing else that would suffer if the house batteries went dead. I do have some solar panels to charge house battles as well (not sure of the output) so I think I'll be alright.
I guess my question is this. My power converter is 28 years old. After speaking with Randy at best converters who suggested a Boondocker 1280 I think I'm just going to order one so its there when I get back from working away. Is the fan running a sign of the converter getting tired? I assume they wear out. Although it's only been 28 years.. Even if it turns out to be bad batteries or an unseen draw on the system, Is my current power converter on borrowed time? Or is rushing to just replace it foolish.
As always thanks in advance for you always spot on advice.
Andy

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Re: Power conveter.

Reply #1 – April 29, 2017, 06:57:49 pm

The fan comes on by the temp. of the inverter. If the bay is hot it could come on without making power.

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Reply #2 – April 29, 2017, 07:11:01 pm

Andy, Converter's job is to supply 12.6 or so volts to power RV things like lights and pump, but converters are not a very good battery charger.  But most battery chargers will do both quite well, so replacing with a battery charger may be a bettery choice.
If you have sealed batteries, you should charge them with a 'smart' battery charger.  12.8 is a good converter output voltage, but not a good battery charge voltage especially for wet cells.  12.8 also implies the converter is working fine, just has a loud fan.
More than likely the fan is controlled by a temperature switch, which sound like it has gone bad, indicating that there is no problem with converter, just the switch.
If you want to keep on using your converter, just replace the switch or fan and/or put a 2nd 12volt computer/muffin fan on the converter's air intake grill.  Computer fans are quite quiet and can run all day without using much power.
Does not seem logical to me to put money in a new converter.

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Re: Power conveter.

Reply #3 – April 29, 2017, 07:48:06 pm

Andy, could it be that the bearings are going out the on fan and you are just noticing the failing bearing noise now?

I sent my old converter to the dumpster years ago when I blamed a cooked battery on it.  It could have been a false conviction but I didn't want to chance another battery with it.  I see the Boondocker has a built-in desulfation cycle: that's a nice feature.

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Reply #4 – April 29, 2017, 07:49:53 pm

Bulged countless battery with that converter back then.....

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Reply #5 – April 29, 2017, 07:51:02 pm

Another possibility is that the convertor might actually be getting hot enough for the fan to come on maybe due to contacts etc getting old and or dirty. You could check the temp of the convertor.

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Re: Power conveter.

Reply #6 – April 29, 2017, 08:06:19 pm

Those converters ruined many batteries as they tended to overcharge them. I would recommend replacing it.

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