THREE (3) PMNN4547A batteries crapped out on me

[mbnv992]

So - I have not one- but three of the 8000H Hazlock 4547 batteries and all of them stopped taking a charge. Granted - they haven’t been used in about 5-6 months but still - I figured at least they would recondition themselves and then take a charge again. Hell - I have 10+ year old XTS batteries that I’ve had off chargers for almost a year and they fire up just fine.

Any suggestions besides buying new ones ? Haha

As of now - I go to put the batteries on my Impres charger and it just flashes red. I tried putting them on my gang charger, an Impres 2 charger, and I get the same thing - flashing red. Prior to this these batteries haven’t even had 10 charge cycles on them. True they are from 2020 and are getting up there in age but I expect a LOT more from these batteries.

Anyone else having issues with these 4547 batteries or even APX batteries in general like these issues ?

 

[n3obl]

Try using a low current variable voltage power supply and feed some current from top terminals.

 

[G7RUX]

The flashing red is just telling you the charger is not happy with the state of charge of the battery. Give each one a bit of charge with a limited supply (bench PSU set to 10V with current limit set at 200-250 mA) for a few minutes and it should come up in a way the charger likes. Take it off the PSU and drop it in the charger and see if it comes up.

Stored Lithium batteries tend to self-discharge to a point where most half-decent chargers won't try to dump a load of current into them. Stored NiMH/NiCd also self discharge but the chargers tend to be a bit simpler and don't throw a wobbly at low terminal voltage.

 

[nokones]

Impress batteries should service you at least 10 years if they are maintained properly with an Impress Charger. Just put the batteries back in the Impress Charger and leave them in the slots and see if they will reset and wake up on their own from a deep sleep. If you try anything else but what the charger could do might damage and fatal the batteries.

 

[G7RUX]

Impress batteries should service you at least 10 years if they are maintained properly with an Impress Charger. Just put the batteries back in the Impress Charger and leave them in the slots and see if they will reset and wake up on their own from a deep sleep. If you try anything else but what the charger could do might damage and fatal the batteries.

All the charger does is provide constant current until the terminal voltage reaches cutoff, perhaps tapering down as the voltage rises. The red light is triggered by the terminal voltage being outside the "good" range, here likely due to excessive self-discharge; putting a little current in for perhaps 5-10 minutes will bring the terminal voltage up and will make the drop-in charger much happier. I have done this with dozens of units on Moto handies.
Neither the Impress chargers nor the compatible batteries are particularly clever.

 

[PACNWDude]

I have had a batch of Motorola PMNN4547A batteries that have failed after only a couple of years of use....but they were taken out of sleep mode on a Motorola IMPRES2 charger, then condition/charged on a Cadex system. Suspect a batch of batteries in our case, they all have the same 2022 date code.

These are used on APX6000XE radios in this case, with IMPRES2 chargers. One issue I have had to keep stressing on the firefighters is to put the batteries in use, do not store them for 6 months, expecting them to work fine once you eventually put them back into service. They do self discharge, and the chip needs to keep a certain voltage to work properly.

 

[mbnv992]

All the charger does is provide constant current until the terminal voltage reaches cutoff, perhaps tapering down as the voltage rises. The red light is triggered by the terminal voltage being outside the "good" range, here likely due to excessive self-discharge; putting a little current in for perhaps 5-10 minutes will bring the terminal voltage up and will make the drop-in charger much happier. I have done this with dozens of units on Moto handies.
Neither the Impress chargers nor the compatible batteries are particularly clever.

I have one of the Chinese Li-Ion Visar plug in wall wart charger I hear these are also good for zapping a battery back to life. Stupid question but - what terminal do I need to use to zap the battery with ? There’s 3 terminals on the top ( -, blank and + ) and the 4 charging terminals on the bottom.

Never had to “zap” a battery back to life before but I’d much rather try this than try and source all new batteries for my 8000H. Also - threw it on my Impres 2 charger before I left for work today ( still flashing red obviously ) so I’ll see what happens when I get home off shift. Probably still flashing red I’d guess.

 

[wgbecks]

Try using a low current variable voltage power supply and feed some current from top terminals.

What @n3obl said. It's not necessary to try and completely recharge the battery. Just apply approximately 7.5 VDC to the top
terminals while you insert battery into the Impress charger. That should be enough to power on the electronics within the battery
that in essences biases on a switch in the path to the charger terminals.

You may have to repeat this operation a couple of times but this method has served me well. Do remove the temporary power
applied to the top of the battery as soon as the charger begins doing its thing. It won't hurt to cycle the battery a couple of times
once recovered.

Good luck!

 

[PACNWDude]

Have "zapped" the batteries as well, usually the outer top battery contacts......and 7.5 volts then reverse the positive and negative and do that a few times, then place on an IMPRES charger.....old trick that has worked on many batteries, not just Motorola.

Often gets a bit of life/usefulness back. Gets the internal chip some voltage and then the charger can take over.

 

[n3obl]

Its been notable to have issues ever since motorola switched to Impres2 setup vs original impres.

 

[G7RUX]

What @n3obl said. It's not necessary to try and completely recharge the battery. Just apply approximately 7.5 VDC to the top
terminals while you insert battery into the Impress charger. That should be enough to power on the electronics within the battery
that in essences biases on a switch in the path to the charger terminals.

You may have to repeat this operation a couple of times but this method has served me well. Do remove the temporary power
applied to the top of the battery as soon as the charger begins doing its thing. It won't hurt to cycle the battery a couple of times
once recovered.

Good luck!

Do not do it while you put the battery in the Impres charger…justpush some current in for a few minutes, disconnect it and *then* drop it in the charger.

 

[n3obl]

I prefer to use a small bench power supply that I can both regulate current and voltage etc..

 

[mbnv992]

Whelp - I left all three batteries on the gang charger all day while I was at work and came home to them all still flashing red 14 hours later. Also tried to “zap” them with my 7.5V wall wart charger plug to the top terminals of the batteries and still nothing.

If anyone wants to check these out for me and see if they can zap them back to life I’d gladly pay someone. Rather do that than A - toss them in the can, and B spend almost $200 a pop on 3 new ones.

 

[G7RUX]

Whelp - I left all three batteries on the gang charger all day while I was at work and came home to them all still flashing red 14 hours later. Also tried to “zap” them with my 7.5V wall wart charger plug to the top terminals of the batteries and still nothing.

If anyone wants to check these out for me and see if they can zap them back to life I’d gladly pay someone. Rather do that than A - toss them in the can, and B spend almost $200 a pop on 3 new ones.

You need to use a bench supply with variable voltage and current limit. Set the current limit to a couple of hundred milliamps and set the voltage to somewhere above ten volts; don’t worry, the current limit will prevent anything untoward happening. Connect to the terminals and observe the current. If some is flowing then leave it running for ten to fifteen minutes and then give the drop in charger a go again.

 

[devicelab]

This is probably not your issue but it's relatively easy to update the IMPRES charger firmware too. You can buy the cable from Motorola's online store. I have this issue with an older TRBO charger. The newer charger works fine but the older charger will not work.

IMPRES 2 charger reprogramming cable

Programming cable required to reprogram IMPRES 2 single unit chargers

shop.motorolasolutions.com

 

[wgbecks]

Whelp - I left all three batteries on the gang charger all day while I was at work and came home to them all still flashing red 14 hours later. Also tried to “zap” them with my 7.5V wall wart charger plug to the top terminals of the batteries and still nothing.

It's possible the cells inside the battery are toast. However, a 7.5 VDC wall wart is incapable of producing "too much" current to be of
concern or to mandate current limiting. Just attached the wall wart power supply to the top battery terminals, observing correct polarity,
then insert the battery into the Impress2 charger.

The idea is to apply power long enough to turn on the internal switching circuit to the charger terminals, and whereby the charger should
give a steady red lamp indication. Remove the wall wart at this point from the top of the battery and allow the charger to do its thing.

I've done this successfully many times, especially on my own 4547 Impres2 batteries that sat idle too long to the point they discharged
below the level required to initiate internal electronics of the battery when inserting them into the charger.