converter fan

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kportra

Well-known member
Joined
Jun 12, 2017
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224
Location
Montana
Hey all,
Getting ready for our first outing of the season (late I know, but it's still snowing in the mountains here).  When we hooked up the batteries and plugged in the trailer, we noticed a hum coming from the electrical box area.  I'm thinking it's the converter fan.  It doesn't shut off, but does change speeds.  Also, the breaker labeled GFI makes the noise stop.  What does that breaker do?

Any help will be appreciated.
 
Sounds like the breaker is a dedicated circuit for the converter. The fan will be on when the converter gets overheated from charging the battery. How old is your battery and was it fully charged when you put it in?
 
Assuming you just connected the batteries and that they are in need of charge, the converter would be charging the batteries. The fan offers cooling to the converter and will cycle based on temperatures detected during the battery charging cycle. A two speed fan would offer different levels of cooling as needed. The fan will normally cycle at different speeds as the internal temperatures of the converter change.

The breaker is probably the breaker to the converter. When you turn the breaker off, power to the converter is turned off and the charging of the batteries is discontinued.
 
The batteries were new last year.  I will be soooo mad if they went bad over the winter.  We had them on a tender all winter.  I don't have a tester but think I might need one.  The tender seemed to be working as when I would switch the charge from one battery to the other (bi-weekly) the red light would come on for a few hours and then change to green.  This is the tender we used:  Deltran Battery Tender Plus 1.25A.  We don't leave until Thursday, so I guess tonight as I'm cleaning, etc. I will listen for the fan.  Batteries should have been fully charged, however we did do some things on battery before bringing the trailer to the driveway and getting it plugged in.  Fingers crossed.
 
Henry J Fate said:
Assuming you just connected the batteries and that they are in need of charge, the converter would be charging the batteries. The fan offers cooling to the converter and will cycle based on temperatures detected during the battery charging cycle. A two speed fan would offer different levels of cooling as needed. The fan will normally cycle at different speeds as the internal temperatures of the converter change.

The breaker is probably the breaker to the converter. When you turn the breaker off, power to the converter is turned off and the charging of the batteries is discontinued.

That's exactly what I said but yours sounded better.  :)) :)) :)) :D ;)
 
I wouldn't expect new batteries to be bad in a years time but it is possible. Maybe the batteries were not fully charged when you installed them or maybe something in the trailer is drawing current and the converter is doing its job.

After 24 hours, I would be looking at things a little closer if the converter hasn't settled down.
 
The converter fan did settle down - although I don't know if it ever really shut off.  Hubby got a voltage tester and the batteries test at 12.5 or so (it jumps around) after I unplugged and turned on a light.  So I'm thinking we are good - hoping we are good.  I'll really know after the weekend outing.

We'll be off grid for 4 days using a CPAP and charging with suitcase solar (generator for backup).  Wish us luck.  Either way, I am excited to get out there!
 
With the converter operating (shore power connected), the battery voltage should be in the 13.3-14.4 range.  If it is 12.5-12.6 with the converter on, the converter is not charging. Once shore power is removed, the battery will fall back to its stored charge state and 12.6v is a full battery (100% charge). That is measured with no loads on. Even a single light will cause a small battery voltage drop when shore power is not present.
 
Gary,
Thanks - we did unplug from shore power before testing, so I think/hope that 12.4 or 12.5 with one light on shows me we have good batteries.  I turned the light on to get rid of the surface charge - I had read that somewhere.  Probably from you!
 
You do need to wait about an hour after you unplug to let the small residual surface charge dissipate, either that are run a small load like a light bulb for a minute, before you test voltage.
 
In our case, after we plug-in, our inverter/charger always works hard for the first hour - regardless of the voltage at the batteries (our electric panel will show 14 amps for an hour then settle down to 3).  If the weather is warmer the fan runs during this time.  I am a novice in this area (as with most RV stuff) so I chalked it up as normal. 
 
That is a possible sign your batteries are low on electrolyte (water), or that they are at the end of their useful life.  Also it may mean that your alternator is not charging the house batteries while the engine is running, perhaps a problem with your voltage isolator.
 

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