Garmin 696 battery question

[DBone]

I've had my 696 mounted in the panel powered by the avionics bus for 7 years now, and it has worked flawlessly. I pulled it out to update the software and maps, and the battery can't keep the thing on for longer than a few seconds. I think it came with an AC adapter, which solves the immediate problem. But this unit serves as emergency backup instruments in the event of power loss during flight, so 5 seconds of battery usage probably isn't going to be enough to get me on the ground safely.

Garmin wants $200 for a new battery. I don't know what the life expectancy of these batteries are, but I wanted to see if anybody else has experienced similar problems.

[DaleB]

Originally Posted by DBone

I've had my 696 mounted in the panel powered by the avionics bus for 7 years now, and it has worked flawlessly. I pulled it out to update the software and maps, and the battery can't keep the thing on for longer than a few seconds. I think it came with an AC adapter, which solves the immediate problem. But this unit serves as emergency backup instruments in the event of power loss during flight, so 5 seconds of battery usage probably isn't going to be enough to get me on the ground safely.

Garmin wants $200 for a new battery. I don't know what the life expectancy of these batteries are, but I wanted to see if anybody else has experienced similar problems.

I bought one with a "bad" battery that would last a minute or less. I found that it had two problems, a dead battery pack and a bad battery connector. The previous owner had, I think, always used it connected to external power. The battery pack never got charged, so the NiCD cells were deeply discharged. The battery pack has an internal charge control circuit, which refused to even attempt to charge the cells.

So... step 1 was to split the pack and test the cells. All were very low, well under half a volt, but they were all identical. None were reversed or internally shorted. I un-soldered the cells from the charge control board. Fifteen minutes on a NiCD charger had enough of a charge on them that the pack would charge. Perfect! The pack was good. I re-soldered the cells in. If they had been bad, those cells are available... they're an uncommon size, but not unobtainable.

The next issue was the bad connector. The 696 battery connector uses spring loaded pins to contact bare pads on the battery pack. The spring on one of the pogo pins was weak, and one was completely broken. The pack would charge, maybe, until you bumped or squeezed it. I ended up disassembling the 696, finding a suitable replacement and replacing the connector. It's a surface mount part, and the replacement I found is functionally equivalent but mounts slightly differently. Anyway, it worked. It's a twitchy repair in a very tight area of a pretty expensive board, so I definitely would not recommend it if you're not comfortable with some "interesting" SMT repair work.

After the repairs the battery would charge just fine, and would last over 4 hours consistently, with XM playing.

[schristo@mac.com]

I suspect that this is a very common issue... one of the internal spring contacts on mine never worked well and I had to fill the void with a piece of safety wire to make a contact. Garmin gave me a replacement battery years ago that would hold a charge for a bit but the performance has degraded to the point that I disconnected it.

A NiMH replacement would be nice.

DaleB, do you have any photos or additional details on the repair?

[DaleB]

Originally Posted by schristo@mac.com

I suspect that this is a very common issue... one of the internal spring contacts on mine never worked well and I had to fill the void with a piece of safety wire to make a contact. Garmin gave me a replacement battery years ago that would hold a charge for a bit but the performance has degraded to the point that I disconnected it.

A NiMH replacement would be nice.

DaleB, do you have any photos or additional details on the repair?

No, I didn't get any pictures. It's fairly straightforward if you have some experience with SMT work, other than the fact that I couldn't find an exact match for the spring confacts. I actually had to tack the plastic body in place with super glue, then solder it. If you're going to tackle the job I could look up the part number I used.

[straill]

Wondering if you could rebuild my battery for me too, since you did such a great job on yours? I actually have a couple that need rebuilding. Let me know, thanks

[rolivi]

This thread got me thinking so I tested it...

I got 01+40 when I disconnected external power to my 696.

I think that's good. I'll probably test it every 6 months.

My 6A has dual electronic ignition, so if I lose the alternator I'm going to be back on the ground within 30 mins. The 696 battery will do that. I'll also endurance test the D-100 battery to make sure I'm good there.

Good food for thought.