Cobra 18M LiPO malfunction?

[KDirk]

I'm going to have to open a support ticket with Cobra, but wondered if anyone and seen this before. Have an 18M with rechargable battery option already installed, that I purchased second hand in very clean, lightly used condition about 3 years ago. Last year prior to the 4th, when on the charger the red LED would blink rapidly (noticeably more so than any of my other modules) and while it would attain full charge, the LED never went solid. I make a point of charging my modules quarterly when not in use to maintain the batteries. I just pulled them out last week and found that module won't charge at all, the red LED never lights irrespective of which charger I try (and I tested with several).

Should I suspect a bad battery, or a failed charger board? And if the latter, does Cobra's lifetime warranty typically cover the cost of a new/repaired board? I've used this module twice since purchase, and it's odd it has failed in this fashion, since it was apparently barely used (judging by the condition it is in). Just curious to see if anyone has encountered the same symptom, and what the resolution was.

[jdels]

If the battery is puffed at all it's toast. Swap one in from a different module and see if it will charge.

[displayfireworks1]

I am not a battery expert and I can not speak for Cobra. For LiPo batteries from what I am reading, it is not recommended to store them at full charge. I remember with older battery technology it was recommended to always keep them fully charged in storage. However, with these Lithium-ion batteries I use on my camcorders it recommends to charge them the day before you use them. For my Cobra modules I have them setup for standard 9-volt replaceable batteries. I personally think this is good for periodic use. If you have a periodic big important display, just purchase new batteries. In your situation I suspect you need to replace your rechargeable batteries, partially when you see one of them swollen.
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On a side note, I once heard Bill Gates talk about his investment in battery technology. He said he was not impressed with the progress. That told me a lot. LOL I personally can’t figure it out sometimes. My camcorder rechargeable Lithium batteries need replaced once yearly, and even then, do not perform the way I expect. Then there is this Black and Decker rechargeable screw drive I purchased 20 years ago with an internal non replaceable battery that has and continues to consistently perform excellent. At 20 years, It can still maintain great torque and performance. Over the time I owned it I never over charged it or just left it unattended in the charger.

[KDirk]

True, Lithium Ion batteries are best not stored long periods at full charge. But neither do I want to have them deeply discharge in storage, as these get used once - maybe twice - a year. Typically, it is advised to maintain about 80% charge max I on smart phones to maximize the battery life. I know a swollen ("puffed"} battery is junk, have had this happen on a couple of smart phones.

I guess I'm just wondering if the charge controller board in the Cobra modules is smart enough to detect a shot battery, and refuse to apply charge (or not) since the red charge LED does nothing now when plugged in. I'll contact Cobra after I try swapping both the battery and the board to see if they changed anything. Appreciate the suggestions.

[BMoore]

Remove the bad battery and put it in another module and try to charge it. If it takes a charge you'll know it's an issue with the hardware and I'd expect Cobra to be able to help you out.

I had a battery drain issue on one of my modules and Cobra's advice to me was to charge the Lipos to P5 (50%) and then remove them from the module. It seems Cobra modules have a parasitic drain (at least the 36 and 72M do) and will hold their storage charge much better if physically unplugged from the module.

[KDirk]

Interesting recommendation from Cobra to charge them half way and leave them disconnected. I can see the latter, but surprised storing them at 50% charge is suggested. I guess I'll try swapping the battery on the faulty 18M, and if that doesn't yield a change, will then swap the charge adapter PCB to see if the behavior moves to another module. I just want to narrow down the cause and eliminate anything obvious before I contact them, as I figure they'll want me to try some basic troubleshooting anyway.

[BMoore]

Storing Lipos at a 50% charge is a very common recommendation. Degradation occurs faster the closer you are to fully charged or fully depleted.

[KDirk]

Ok, will keep that in mind going forward.