Walkie Talkie battery replacement

I bought a set of Uniden GMR2240-2CK walkie talkies for a song on Ebay, and at first everything looked perfect. But later one of the radios refused to transmit, and showed a low battery indicator, earlier than it should have. I switched the batteries between the radios, recharged both, and tested again. The shutdown happened again, but the good news is the problem followed the battery to the other radio. Well, the date code is 2211, so I think it's time.

I see that I can buy a set of two replacement EBL brand battery packs (BP40) on Ebay for under $8 delivered for the pair. I've always had good luck with generic batteries, but I know others haven't. Has anyone here had experience with these? Genuine Uniden replacements would be about $40.

And just to check my logic, it does make sense, doesn't it, that if the problem follows the battery, then the battery is the problem, not the radio? The thing that's curious is that if I wait a while after the shutdown, I can fire up the radio again, and it shows a full battery indicator, and the thing will run in listening mode for another hour or two. Maybe it's a heat related connection issue inside the battery pack. I further assume that at these prices for replacements, it makes no sense to try to replace the NiMH AAA cells in the pack, particularly since I don't know for sure that the problem isn't in the electronics inside the battery pack.

Reply to
Peabody
Loading thread data ...

Probably there's an internal battery connection that's gone faulty. Internal faults account for lots of flaky battery behavior, usually there's just a bit of electrode material slightly loose against a crimped-in cap.

It's not age related, but it IS very very annoying. You might be able to get two good cells from a 3-cell pack, though, if it's worth the trouble of doing a pack disassembly.

Reply to
whit3rd

Yep. It's probably the battery. However, if both BP40 battery packs are the same age, it's likely the working battery pack will soon fail. Buy a replacement BP40 for both radios.

I usually don't have any problems with NiCd or in this case NiMH battery packs. You're probably safe at buying the cheapest. However, LiIon batteries and packs are another story, which are full of counterfeits and defective cells.

NiMH cells come in different capacities varying from 500 to 1000 ma-hr capacity. For example, the BP38 battery is rated at 4.8v 700 ma-hr, while the BP40 is rated at 550 ma-hr. For a dollar more, the BP38 seems like a better deal. The problem is with no-name pre-packaged battery packs, you don't really know what capacity you're getting until it arrives.

If this were my radio, I would buy 4ea AAA NiMH LSD (low self discharge) cells, such as Eneloop cells, and weld them into a replacement battery pack. The ability to charge the battery and know that it will be mostly at full charge months later, is worthwhile. Be sure to check the charge current to make sure that you're not overcharging or quick charging the Eneloop batteries.

One of the NiMH failure modes is accellerated self discharge. It will charge up to normal terminal voltage, but rapidly discharge itself (without a load). It also acts like a battery with much lower capacity than might be expected. I think that's what you're seeing.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
 Click to see the full signature
Reply to
Jeff Liebermann

A totally different battery, but my cellphone battery was getting real weak, The phone is a basic phone, not a smartphone, and the whole phone cost me $20. I went to "Batteries Plus". I was shocked when he quoted me $50 for a battery. I was gonna just buy another phone, but first I went to Ebay. Bought a battery on ebay for $5 shipped. It lasted well over 2 years, until the phone needed to be updated/replaced. I still have that battery, because the new phone uses the same. That way I have a spare.

Reply to
oldschool

snipped-for-privacy@tubes.com wrote on 10/16/2017 3:37 AM:

I used to be on a pay by the minute cell plan and it costs $30 for a minutes card. Or I could buy a new phone and get a $30 minutes card with it for

Reply to
rickman

I did that. One of the big suppliers of generic BP40s also runs auctions from time to time, with a starting bid of $.01 plus $5.39 shipping for a pair. One of those was ending as I was about to buy, so I bid a penny and won the auction. So $5.40 for two BP40s. They claim to be 700 mAh, but of course there's no way to know about that for sure. But I think not a bad gamble overall.

I've always used Eneloops in my speedlights, and am a big fan. But the charging setup here is very strange. The charging cradle appears to put out a minimum of 7V to each radio, sometimes 12.5V, and it loods like the BP40 has some smarts built into it that actually controls the charging. So if I used Eneloops, I would have to take them out of the radios to charge them. So for the moment I'm going to stick with the BP40s and use the charging cradle.

The charging contacts on the BP40 are not directly connected to the outside battery terminals of the 4-pack. So there's some circuitry in there. When the new ones arrive, I may take the old bad one apart and see what's in there besides the cells.

Reply to
Peabody

I thought I was the only one.

Reply to
Peabody

I'm still using a Nokia flip (and trying to treat it very carefully...).

I really don't want to have to use a smartphone (well I actually have a couple but don't use them as phones.)

--
Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
 Click to see the full signature
Reply to
~misfit~

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.