HT1000 Rapid Charger Problem

[slatecom]

Hopefully this will be the last of my problems, seems like I've been having nothing but them!

I bought a new aftermarket battery for my HT1000 and I've been having some trouble charging it. When I pop it in the charger (NTN7209A), it shows "charging" for about 15 minutes and then turns to complete, even when the battery is extremely low. The voltage was dropping to around 6 volts at that time, which I don't think seems too abnormal but I do know it was definitely losing capacity as the radio kept restarting after transmitting for less than a second. I know that the charger does work properly when it is charging but I can't really tell if it still charges after the "complete" light as there is little to no heat emitted at that point.

What exactly happens when it says "complete"? Does it just stop charging altogether or does it trickle charge the battery at that point?

I just don't know if I have a defective battery, defective charger or if this is a "normal" problem with the charger. I left it in the charger overnight so today I will see if there is any improvement.

Thanks!

[escomm]

What chemistry is your battery and what leads you to believe the problem is with the charger. Your charger is NiCD slow rate only. There is no way it can charge a good battery in 15 minutes.

[slatecom]

What chemistry is your battery and what leads you to believe the problem is with the charger. Your charger is NiCD slow rate only. There is no way it can charge a good battery in 15 minutes.

I am using a NiMH battery. What leads me to believe the problem is with the charger is that there are quite a few other articles about people having a similar issue (battery charges perfectly fine in other chargers but has problems with the light turning green very early with this model) but none that have resolved it or have figured out what causes the problem, since it happens even with original Motorola batteries of the NiCD type.

Not sure if this is what you mean but the charger is for both NiMH and NiCD and doesn't have any labels that indicate it charges a particular way for a particular type of battery, some people think the charger is only for NiCD but the label says "charge only 7.5v niCD or NiMH batteries".

The battery itself in my experience is perfectly fine, holds and has held a very good charge, the only problem could be with the charger, more specifically the charger's electronics. I'm going to take a peek inside the charger and see if anything looks out of the normal.

[escomm]

My notes say it's a NiCD only charger. This is a shoe charger correct? Is there another part number on the label?

[slatecom]

My notes say it's a NiCD only charger. This is a shoe charger correct? Is there another part number on the label?

Yes, I'd call it a "shoe charger". The only other numbers I found on the bottom on the bottom are 'MODEL AA16740" and a manufacturing date of 9909 C2 REV 05. There is no Motorola logo on the bottom but there is one on the front.

[KG4INW]

The NTN7209A is just the charger itself but with a US power cord is known as the NTN1168A, if that helps escomm. It is suppose to be bi-chemistry even the older ones that said Ni-Cd only. It does trickle charge after the light goes green but it's not suppose to change so quickly.

[slatecom]

The NTN7209A is just the charger itself but with a US power cord is known as the NTN1168A, if that helps escomm. It is suppose to be bi-chemistry even the older ones that said Ni-Cd only. It does trickle charge after the light goes green but it's not suppose to change so quickly.

Thanks for clearing that up. I left it to charge overnight and it looks like the battery has been charged properly as it's been working for over 6 hours so far. I'm thinking if I do a couple of cycles the charger might "learn" the status of the battery.

[escomm]

I would be worried if the battery does not get warm after a charge cycle that starts from a full discharge. NiMH doesn't work well with trickle charging and it sounds like this thing may be trickling only. Maybe the voltage on the battery was too high for the charger. If the battery doesn't get warm during the next charge cycle some more investigation would be warranted

[slatecom]

I have a feeling you may be right. The battery, last time I checked was 8 volts rather than the 7.5 it should be as listed on the label. I know that some batteries may contain a slightly higher voltage when charged, but .5 volts seems a bit high to me. Would 8 volts be within proper operating range or is it way too high?

I also noticed that my battery's voltage went up from 6.5 volts up to 8 volts in about half an hour or so, it's possibly why the charger thinks the charge is finished.

I will give the battery a few charge/discharge cycles to see if it stabilizes it.

Thanks for the response!

[MTS2000des]

I've got several 7209's in service, and they are indeed Nicad and NiMH only (no LiON) chargers, made by Astec corporation (same people who build computer power supplies). They are very sensitive to the values in the battery circuit itself that instruct it what charge rate to send, and use a negative Delta -V method, so if it doesn't get the right result after the first 10 minutes of charging, it reverts to trickle mode. Seems only to be affected when used with cheaper aftermarket batteries. The ones I have work great with OEM NiCD and NiMH Jedi and XTS batteries.

[slatecom]

MTS2000des, thank you for the info! Is it worth keeping this charger as a trickle charger until I purchase a different battery or the problem goes away (which I think it might after a few cycles, and it cost the same amount!), selling it and buying a different charger or could it be a defective battery in some way that I should exchange?

Here is another topic (old) in which someone had the same problem even with Motorola batteries. I think this could possibly be just an issue with getting the batteries to charge properly the first few tries but should even out in the long run.

http://batboard.batlabs.com/viewtopic.p ... 34&start=0

Thanks everyone for the help!