Moto IMPRES XPR Batteries blinking red and won't charge

[Soul_Eater]

Hey all, just walked into a job and inherited about 15 XPR 7550e radios that won't charge. They've been boxed up for a few years, and about ten of them refuse to charge. They flash red on the charger when inserted, and no amount of cleaning or wiggling will make them take a charge. Really don't wanna tell my boss first thing that he needs to shell out serious cash to replace them. Anybody have any ideas?

 

[mbnv992]

Blinking red - time for a new battery 🔋

 

[jeepsandradios]

IF you can find a non impress trickle charger you may be able to get them to come back after a short charge. Most likely all need replaced.

 

[N4KVE]

My friend had that problem with a 7550 that sat unused for a few years. He connected a 12 volt Astron to the battery contacts that power the radio for a few seconds, & it blasted the battery back to life & then it was able to charge from the drop in charger. One particular time the battery was very stubborn, & needed to be blasted 5 times for 5 seconds each time before the charger would work. The battery is fine now, but I told him to recondition them every few months whether he uses them, or not.

 

[merlin]

Usually such batteries are end of life. I have had fair luck rejuvenating using methods above.
I stick them on a current limiting bench supply set over 10 volts.
Set current to the battery rating and let it sit a while. you will see the voltage drop to like 9.1 volts
then put the current to 50 Ma and let sit overnight.
The battery will get quite warm but should not be hot to touch.
This is what the impress chargers do, but you are forcing the charge here.
After that, the impress charger should work. If not, the battery is a gonner.

 

[K2NEC]

I've bought a box of Impres batteries that were fairly new date code wise but absolutely dead when tried to put it in the charger. I took a 12v power supply, hit the battery contacts for a few seconds, and it was sort of a way to "defibrillate" the battery. It seemed to be just enough for the Impres charger to recognize it and decide to charge.

Sometimes it may take multiple attempts to convince the battery that it needs to take a charge. If after numerous failed attempts, I'd call it a day.

 

[Rahel]

For such a case there are two options

Firstly, the battery is end of life.
Secondly, the battery didn't take a charge for a long time mean that, it didn't take calibration/Recondition mode at all

You try to put the battery on IMPRES multi unit charger for 2-3 hours and let it be blinking red.... after that will back to calibration/recondition mode then the LED will change to Steady red.

 

[Soul_Eater]

Apologize about not posting my resolution, time got away from me. Took your advice about leaving them on the charger for extended periods, seems like removing the batteries out of the radios made a difference (thankfully I didn't have to break out a power supply to jump them, I probably would have fried myself). A few stubborn ones just wouldn't take, but I found another tip on here about polishing the battery contacts with an eraser. That got the rest of them up to speed, thanks for your all your help fellas.

 

[Anderegg]

Isn't there a trick taping over certain battery contacts to turn the battery "dumb" and force some charge into it?

Paul