Dumbing down an IMPRES charger to charge a too-low voltage battery

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EindhovenOne
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Dumbing down an IMPRES charger to charge a too-low voltage battery

Post by EindhovenOne »

Hi, everyone. I've got some NOS NNTN6034A batteries that are apparently so low in voltage that the IMPRES charger won't actually initialize them. I've tried a bunch of times so far but each of the batteries goes from steady flashing yellow for a few minutes to rapid flashing red. I've read that if I were to get a small amount of charge on these in a non-IMPRES charger I could then use the IMPRES to recondition and do its thing, but I don't have any non-IMPRES chargers. Is there any way I could tape off one of the leads/contacts on my IMPRES charger to dumb it down and brute force charge the battery for a bit?
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fineshot1
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Re: Dumbing down an IMPRES charger to charge a too-low voltage battery

Post by fineshot1 »

EindhovenOne wrote:
Mon Aug 30, 2021 6:55 am
Hi, everyone. I've got some NOS NNTN6034A batteries that are apparently so low in voltage that the IMPRES charger won't actually initialize them. I've tried a bunch of times so far but each of the batteries goes from steady flashing yellow for a few minutes to rapid flashing red. I've read that if I were to get a small amount of charge on these in a non-IMPRES charger I could then use the IMPRES to recondition and do its thing, but I don't have any non-IMPRES chargers. Is there any way I could tape off one of the leads/contacts on my IMPRES charger to dumb it down and brute force charge the battery for a bit?
You could at least mention your impress charger model number so we could complete research for you.
When you leave information out of your request it dumbs down your question.
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fineshot1
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Re: Dumbing down an IMPRES charger to charge a too-low voltage battery

Post by fineshot1 »

I could not find any online info regarding impress charger charging contacts so I disassembled my
only impress charger and the contacts were labeled on the pcb " B+ TH CD B-" so I suspect that
the one labeled as CD stands for charge data which would be the data read from the battery by
the chargers intelligence battery interrigation so the one labeled as "CD" is probably the one you
are looking for if your charger is similar. PS: I measured between B+ and B- 12.42VDC and suspect
that TH is the thermal data read from the battery.
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Re: Dumbing down an IMPRES charger to charge a too-low voltage battery

Post by N4KVE »

I just stab them with 12 volts for a few seconds from the closest Astron PS. Then the Impres charger can properly charge them. GARY.
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fineshot1
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Re: Dumbing down an IMPRES charger to charge a too-low voltage battery

Post by fineshot1 »

N4KVE wrote:
Tue Aug 31, 2021 7:11 pm
I just stab them with 12 volts for a few seconds from the closest Astron PS. Then the Impres charger can properly charge them. GARY.
That may not be such a good idea Gary. These impress batteries contain charge rate electronics that may be damaged by doing
that. Many years ago with regular nicad batteries i used to do that also and in some cases it helped revive them if they were
on the way to the recycling box.
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Re: Dumbing down an IMPRES charger to charge a too-low voltage battery

Post by N4KVE »

fineshot1 wrote:
Thu Sep 02, 2021 4:18 am
N4KVE wrote:
Tue Aug 31, 2021 7:11 pm
I just stab them with 12 volts for a few seconds from the closest Astron PS. Then the Impres charger can properly charge them. GARY.
That may not be such a good idea Gary. These impress batteries contain charge rate electronics that may be damaged by doing
that. Many years ago with regular nicad batteries i used to do that also and in some cases it helped revive them if they were
on the way to the recycling box.
I realize that, but it hasn’t happened yet. It was that, or throw them in the trash, so I had nothing to lose. One particular stubborn battery that sat for months without being used needed jolting 10 times before the Impress charger would work. It’s been perfect for 2 years now. GARY.
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fineshot1
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Re: Dumbing down an IMPRES charger to charge a too-low voltage battery

Post by fineshot1 »

N4KVE wrote:
Thu Sep 02, 2021 5:33 am
fineshot1 wrote:
Thu Sep 02, 2021 4:18 am
N4KVE wrote:
Tue Aug 31, 2021 7:11 pm
I just stab them with 12 volts for a few seconds from the closest Astron PS. Then the Impres charger can properly charge them. GARY.
That may not be such a good idea Gary. These impress batteries contain charge rate electronics that may be damaged by doing
that. Many years ago with regular nicad batteries i used to do that also and in some cases it helped revive them if they were
on the way to the recycling box.
I realize that, but it hasn’t happened yet. It was that, or throw them in the trash, so I had nothing to lose. One particular stubborn battery that sat for months without being used needed jolting 10 times before the Impress charger would work. It’s been perfect for 2 years now. GARY.
OK Gary - if that has been your experience then you should wright up a short explanation about this and post it under "mods and
out of the box solutions " forum instead of holding out on the rest of us hams and professional moto users - seems like a good
fit for that forum.
fineshot1
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Re: Dumbing down an IMPRES charger to charge a too-low voltage battery

Post by N4KVE »

fineshot1 wrote:
Thu Sep 02, 2021 9:08 am
N4KVE wrote:
Thu Sep 02, 2021 5:33 am
fineshot1 wrote:
Thu Sep 02, 2021 4:18 am


That may not be such a good idea Gary. These impress batteries contain charge rate electronics that may be damaged by doing
that. Many years ago with regular nicad batteries i used to do that also and in some cases it helped revive them if they were
on the way to the recycling box.
I realize that, but it hasn’t happened yet. It was that, or throw them in the trash, so I had nothing to lose. One particular stubborn battery that sat for months without being used needed jolting 10 times before the Impress charger would work. It’s been perfect for 2 years now. GARY.
OK Gary - if that has been your experience then you should wright up a short explanation about this and post it under "mods and
out of the box solutions " forum instead of holding out on the rest of us hams and professional moto users - seems like a good
fit for that forum.
Good idea, & done. It’s like seeing a guy asking a question on a forum, & after getting a few suggestions, he replies “problem solved” without posting the solution. So now it’s posted where you suggested. Of course I only do this with batteries where the warranty is long expired. GARY
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Re: Dumbing down an IMPRES charger to charge a too-low voltage battery

Post by Jim202 »

I always use a variable supply where I can control the current going into the battery.

Plus I have a low Ohm resistor of about 2.5 Ohms I made out of some wire wound resistors connected in parallel. This give you some surge protection of the battery under test.

Put a volt meter on the battery side of the resister to monitor it's voltage. I have a current meter on my supply, so I can monitor the current going to the battery. With a volt meter on the battery you can see just what is going on with the battery between both meters. You want to keep the current below 1 Ampere while your trying to bring the battery back to life.

Make sure you monitor the battery temp if you keep it connected very long with high current. It will heat up and you want to keep this heating to a minimum.

This is not a sure fix for all portable radio batteries. You will run into a battery that just won't un-short it's cells. You can try a higher current, but keep an eye on the battery temp while doing this.

Don't connect it up with a current above an Ampere and walk away. You could end up with a big bang or a loud hiss which you don't want either of.
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