Odyssey PC 680 Expansion

While doing some routine maintenance today I noticed that my Odyssey PC680 battery is seriously bulging. The battery is literally bulging out of the lightening holes I cut in the standard Vans battery box (it is a sight to see). It also bulged the whole bottom of the battery box out. Voltage across the terminals reads normal and the battery charges fine with my alternator. Anybody have any idea what is going on? Have others seen this? I have a dual battery, dual alternator setup and my other battery is just fine.

Jason

I would remove and replace IMMEDIATELY. Or you may lose your airplane.

Sounds like what happened to another guy's battery when he overcharged it.

Definitely replace it

Noticed this same condition on my bird several years ago. RV-8, mounted right side on the firewall, bare battery w/o box. Scared the **** out of me when I saw it. Unknown cause... supposed it to be from heat. Ordered a replacement with the steel jacket and no further problems.

Possible overcharging. What kind of charger have you used? Should be nothing more than 2-4 amps and autoshut off when done. A Battery Minder is a good choice.

The danger of battery box lightening holes

jrouault said:

While doing some routine maintenance today I noticed that my Odyssey PC680 battery is seriously bulging. The battery is literally bulging out of the lightening holes I cut in the standard Vans battery box (it is a sight to see).
Jason

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The Odyssey PC680 has two temperature operating ranges. With the Odyssey metal jacket it is -40 C to +80 C. Without the metal jacket it is -40 C to +45 C.

The "battery box" that Vans supplies is actually an Odyssey manufactured steel metal jacket for the 680 battery. It is a very snug fit.

The reason the temp range is higher with the metal jacket is because the steel jacket prevents the walls of the battery from bulging outwards as the polymer walls soften with increased temperature.

Odyssey do not recommend that large holes be cut into the Odyssey 680 steel jacket (read RV battery box) in operating temperatures above +45 C (and we may presume that temps under an RV cowl will significantly exceed +45 C).

Therefore when Vans suggest that "lightening holes" can be cut into the Odyssey steel jacket (read RV battery box) they are giving advice that conflicts with the battery manufacturer's recommendations.

The best solution for RV builders is to leave the 680 battery box intact rather than attempting to save an ounce of weight and compromise the battery. Of course leaving the battery box intact will also leave the powdercoat intact as well thus minimising the potential for corrosion of the steel.

New battery box???

I had a PC 680 that I had sitting around for many years until I needed it. When I started to use it last year it would not hold a charge. I left a car battery charger on it (outside of the airplane) to try to get a good charge and it bulged as you stated. I was able to find a PC 680 with metal jacket locally. It was easy to remove the metal jacket so that it would fit into the battery mount.

Once the battery bulged it never returned back to the original shape. If your battery is bulged inside the battery box I doubt you will be able to get it out. If you get a battery with a full metal jacket you will could remove the brackets from the old box and attach them to the new box.

If the root cause of why the battery failed is not found it can happen again at a very inappropriate time. If from overcharging, it may be due to a problem with your voltage regulator or alternator.

Frank Smidler said:

Once the battery bulged it never returned back to the original shape. If your battery is bulged inside the battery box I doubt you will be able to get it out.

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This is probably another good reason not to cut "lightening" holes in the PC680 metal jacket (RV battery box). If the battery bulges out into the lightening holes it may not be possible to remove the battery from the box (jacket). That would mean not only replacing the battery but fabricating a new battery box as well.

Geico266 said:

Possible overcharging. What kind of charger have you used? Should be nothing more than 2-4 amps and autoshut off when done. A Battery Minder is a good choice.

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I only use a battery minder system made for the Odyssey PC680. I have never run a charger on the battery.

I cut lightening holes in my steel battery box, I believe Dan C. did as well, and he flies tons more than I do. Four years later, I've not had any signs of battery "swell" in the box, I've had PC-680's in and out a couple of times in the past four years, no problems. Just another data point. I'd look for overcharging as a cause and not lightening holes in the battery box with normal under cowl temperatures we see in these planes...

Battery Placement

Part of the problem may be battery placement. As I stated earlier, I have two batteries. One is mounted on the right side of the firewall very close to Van's recommended location, while the other is mounted on the left. I have a baffle mounted oil cooler on the left side. It is the battery on the left that expanded. Maybe it is picking up excess heat as the air spills out of the oil cooler.

Jason

Heat muff dump

The other thing to consider is the heat muff excess hot air goes to that side of the firewall as wall.