APX Battery/Charger Issues/Mystery

[portroyalbirdy]

My fire department got our radios (APX6000's) back in 2013 when our "new then" system went live. Due to age and not wanting to have issues, in September of 2023 I replaced all 18 of them (with PMNN4485A)

Over the course of time, I've had batteries go "bad" (Be dead, go to charge them, then the IMPRES red blink them, even upon taking them out and reseating in the charger.

For about 2 or 3 of them I've RMA'd them through where I bought them for my department (local Moto Dealer) because the lady said Moto's pretty good on warranty) I thought okay, maybe bad batch. After a recent incident/our one member said he put the 2 Brush radios in the Tanker gang to charge up, and same issue, red blink, lockout. I've asked AI, and I know it's not always 100% but it's thinking a low voltage lockout? My question is what do I do? The chargers we have are IMPRES I (2 "Gang" NNTN7064B) 1 on our Engine, 1 on our Tanker, and a few "singles" NNTN7079A for our "Officer" portables but it says that IMPRES II batteries can charge on those fine.

I know the brush truck ones are likely dead from sitting in the back seat, no charger, which I know you're not to run them "dead dead" but I've even had some do the red lockout on a APX gang in the engine or tanker, never moved! I'm just lost! And half wishing I didn't ditch my old ones!

Sorry if this is long winded, and I do have a phone call in to a tech at my dealer and I'm waiting for a call back to see what they say. But I also wanted to ask in here, to see if anyone else may have ran into the same issue! I can't keep having the radios "die" on the fireground or keep RMA ing them! Heck, now even some of the ones I've RMA'd already are doing it again!

Thanks in advance, and I'll update to what the dealer/tech may say, albeit good or BS! Haha!

 

[K2NEC]

I've had nothing but problems with the PMNN4485 batteries. We bought a batch of them with our 6000s also, back in 2018. They were doing fine for a few years and suddenly I started getting dead battery complaints consistently. I ended up having probably close to 200-250 of these batteries that were totally dead, blink red on the charger, and 0.0v with a multimeter, but due to them being out of warranty period there wasnt anything I could do. I just chalked it up to being bad cells in the batteries and just bought the PMNN4486 batteries instead. Besides looking "cool" and being flush with the front of the radio, they provided 0 benefit to anyone over the 4486

 

[shockhazard69]

Best practice I have found is to throw them on the charger monthly (or even every couple months) if you aren't using them. This keeps the batteries from getting completely dead.

There is a way you can recover these dead batteries. Take a power supply set to the correct voltage (or another charged battery) and jump the positive pin to the positive pin and negative to negative. Be sure not to short it out. Hold that for a minute or two and then immediately put on the charger.

 

[PACNWDude]

Had this same issue as many firefighters like to hoard batteries in storage, which is not advised any longer.....see thread above for the drama. We have had luck with recovering many by using the power supply method above as well.

Motorola has also changed chips in the batteries for their APX6000/7000/8000 series radios. We used to use one battery for all three models, but a 2018 Motorola Technical Notice (MTN-0080-18-NA) said that you may see "Wrong Battery" on your radio if the chip does not match the model number of radio it is to be used with. I did not experience this until 2025 though.

What works for us: get new battery and take it out of "sleep mode" by charging, condition charge battery, then Cadex and labelling, put into service and rotate through charger/use on radio, at least once every other month. If a battery flashes red or red/green, zap it with a DC power supply at 7.5 volts forward and reverse voltage - immediately place onto charger, and it might be salvaged.

APX6000XE use PMNN4486A or PMNN4494A

APX7000 use PMNN4486A, PMNN4487A, or PMNN4494A

APX8000XE use PMNN4505A or PMNN4504A

 

[K2NEC]

Jump starting batteries is great for personal use, but I highly recommend against putting a known faulty battery that you just frankensteined into a IDLH environment.

 

[2wayfreq]

If you have any Impres 2 Chargers, try it in that.

 

[portroyalbirdy]

Best practice I have found is to throw them on the charger monthly (or even every couple months) if you aren't using them. This keeps the batteries from getting completely dead.

My Brush and Officer ones I can see that with, but even the ones that are sitting in the gang(s) have done/are doing it!

 

[portroyalbirdy]

APX6000XE use PMNN4486A or PMNN4494A

APX7000 use PMNN4486A, PMNN4487A, or PMNN4494A

APX8000XE use PMNN4505A or PMNN4504A

My original 2013's were PMNN4403 and my dealer said that the PMNN4485 were it's replacements.

 

[TampaTyron]

I have done this to hundreds, if not thousands of MOTOTRBO batteries............ I cannot speak for APX batts, but assumed they would be more forgiving (they are not).

TT

 

[portroyalbirdy]

UPDATE 4/22/26:

I didn't talk to a tech, but I talked to the lady/same person I talked to when we had the first round of battery RMA swaps, and described my issue(s) she said I may still have some "bad" ones, even the ones I just swapped. She said to get a total count of the "bad" ones when I'm down at the station tomorrow, and we'll swap again. She claims to let them charge fully up, then take them out for a bit then back in. She doesn't want to really go a different part number/model, because we'll have to basically "re purchase". She claims the charges shouldn't be an issue.

 

[portroyalbirdy]

It also may be worth noting that, after doing some research/homework, my IMPRES 1 chargers are running firmware version 3.9. After doing some Google ing, it says that IMPRES 1 chargers CAN charge IMPRES 2, but should be running firmware version 3.11. I'm also going to try another semi local Motorola dealer for help/insight tomorrow, as I feel like the one I got them from is "giving me the run around/talking in circles".

 

[noderaser]

I'm also using IMPRES 1 single and multi-unit chargers to charge IMPRES 2 batteries... It was an attempted cost saving measure to avoid buying all new chargers; we obtained multi-unit adapters from our vendor, and 3D printed our own single unit adapters. So far, of about 100 IMPRES 2 radios over two years I've had two batteries come back as "bad". They will still charge up, but the IMPRES functionality is disabled, even after charging with a proper IMPRES 2 charger. The few chargers I have that are labeled with their firmware revision are v3.0. I'd very much like to upgrade them, but finding the IMPRES Charger Reprogrammer is nearly impossible these days.

The bigger issue I've encountered, is users who buy aftermarket chargers. They will absolutely cook batteries.

 

[portroyalbirdy]

Update 4/23/26:

I talked to the other Moto shop, who was much more helpful and actually took down my "story" and battery and charger specs. The bench tech said he himself was going to do some digging, and would get back to me either tomorrow or Monday. He too, is thinking what I suspect is a faulty low voltage lockout due to firmware.

 

[portroyalbirdy]

Update 4/30/26:

I talked to the other Moto shop again, and they 98% suspect faulty low voltage lockout due to firmware. He is going to get me an IMPRES 2 single unit charger to "demo" to see if that 100% solves my issues before I/my fire company fully commits to buying new chargers, to end up not solving the problem.

 

[2wayfreq]

Update 4/30/26:

I talked to the other Moto shop again, and they 98% suspect faulty low voltage lockout due to firmware. He is going to get me an IMPRES 2 single unit charger to "demo" to see if that 100% solves my issues before I/my fire company fully commits to buying new chargers, to end up not solving the problem.

From what I remember thats what we did to. Dropped the batteries into an Impres 2 and they started charging.

 

[portroyalbirdy]

From what I remember thats what we did to. Dropped the batteries into an Impres 2 and they started charging.

I'm hoping that's what happens with ours as well! Do I really want to spend $ on new chargers? Not really, but if I have to, I can/will, but I want the issue(s) to be solved!

 

[portroyalbirdy]

Update 5/7/26:

I got the demo charger from Dealer 2, a NNTN8845A on Wednesday (5/6/26) and 4 of the "flagged bad" batteries by the APX IMPRES 1 chargers I could not get the IMPRES 2 to recover those. I plan to either try to "jump" them" or RMA to Dealer 1, unsure yet.

I have/had a "working" battery on a chief's radio (was hanging in locker, unknown last charge time, but it was on one of the IMPRES 1's, either single or 1 of 2 rig gangs).

Put in the IMPRES 2 charger, did a solid amber light for a few minutes, then went solid red for a few hours, then flashing green 90% and eventually solid green full. I took it out/off for a few minutes, and decided to force a recondition. I know it's not good to "force" them all the time, but I had no clue when it's last recondition actually was. That recondition lasted about 4.5 hours. Not sure if that's common behavior, or shows/tells me that the battery was truly "off" due to the old chargers not really knowing what to do.

The game plan for tomorrow is to take a battery out of the current rig gang, and see what it does.

I think I'm going about this the right way, and I'm 99% sure the IMPRES 2 demo is my "smoking gun", but does anyone else have any suggestions, or is my "Homework/testing" pretty much telling me?