A300Driver

A300Driver

Active Member
My battery is mounted in a metal box between the rudder pedals in my RV-4. I've never noticed this - never bothered to check - but my battery box is hot to the touch. It's a Odyssey PC-680 @ 2 years old and I've replaced the voltage regulator through Van's @ 6 months ago.......with no visible problems charging, starting, etc...

So, do you think it's normal for a battery "box" to get hot?

FWIW, I'm writing this before I get out to the hangar to tear apart the instrument panel and visibly inspect the battery........I'm charging my electric screwdriver.

Thanks,

Bob
 
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What is the voltage reading on the alternator? What is it charging at? Should be around 14.2-14.5 volts
 
You sure it isn't heater air getting in there? It would seem if the box is getting that hot, the battery would have melted if it was the source of the heat. Or cooling air from the cowl?
 
In general, when batteries get old and tired, their internal resistance builds up. When charged, some of the charging current is turned into heat resulting in a hot battery. Had one of my two starting batteries go bad on the motorhome. I finally figured out my problem when I found one battery very hot to the touch and the other cool while charging.

I'd try charging your battery on the bench to see if it gets hot.
 
I replaced my Odyssey battery after a failed start. It was giving me plenty of warning so I should have done it sooner ---anyhoo. When I removed the old battery, the stainless allen head screw on the positive side was blue from heat.

Replacing the battery also cured a problem I was having where I would hear an intermittent tick in the radio and the fuel gauges jump in concert with the tick sound. I had assumed that this problem was due to an intermittent ground or loose connection somewhere. Score!

I got away with something that could have bitten me hard. I check the positive terminal as part of my preflight now. Changing batteries is cheap insurance IMHO. Good luck.

Hugh
 
All great points - thanks. Battery checked "good" today, appearance, connections and amp draw w/the master ON. It didn't heat up with just the master ON so I ruled out a grounding issue - thanks Joe.

Bob
 
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Here's a possibility- the heat is not coming from the battery at all, but is being conducted from the firewall (which can get quite warm) and possibly the bottom skins near the exhaust pipes (which can get quite warm.)

Just a thought. Might not have anything to do with the battery.

FWIW- there is no need to mount an Odyssey battery in a box. They are sealed RG, they do not vent or leak.
 
Had the same thought as Jeff. I have a -4 also with an oddesey battery and with my typical voltage of 13.9 it does not get warm. I do not have the battery just sitting on the bottom skin. I put down two layers of 1/8" Fiberfax insulation and covered that with a sheet of 1/16" alumin. The battery sits on top of that. Also have the inside of the firewall pretty well insulated. Seem to run pretty cool.

Warren Moore
RV-4, 200hrs.
 
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