NiMh Question

vontresc

vontresc

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Well I have an old Icom Ic-A22 handheld I bought years ago as a backup, that I never really used on a regular basis. Now that I am getting my glider rating in a 2-33 without a radio I use the radio on a regular basis.

Here is my problem. I basically let the rechargable battery pack sit for long periods of time, and charge it up from time to time (6 months between charges if that). Now the thing won't hold hardly any charge anymore. I'll probably end up buying a new battery, but are there any tricks to reviving a NiMh battery? Also what is the best way to get good life on these things.

Pete
 
vontresc said:
...
Here is my problem. I basically let the rechargable battery pack sit for long periods of time, and charge it up from time to time (6 months between charges if that). Now the thing won't hold hardly any charge anymore. I'll probably end up buying a new battery, but are there any tricks to reviving a NiMh battery? Also what is the best way to get good life on these things.
Click to expand...

The battery can't be revived. There are places that will replace the cells, or you can try it yourself, but the cost will be within 20% of just buying a new battery pack.

I have a lot of NiCad and NiMh battery power stuff that always ends up discharged or dead, dead.

Get an alkaline battery pack if you can. That's what I got for my Yeasu. Alkalines are more suited to having a long shelf life AND a long life when used and of course, replacing them is cheap and easy. You buy a big pack of AAs at Home Depot or Costco and keep a few dozen in the plane.
 
Get an alkaline battery pack if you can.
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That's the conclusion I came to, as well. For many of us, a handheld is something that sits, never used, but needs to be ready when the time comes, and I don't think there's any rechargeable battery technology that fits that bill as well as regular, old alkaline batteries.

By the way, I'm surprised an old A-22 has nimh batteries. My old A-22 was nicad (and it's dead, too).
-harry
 
When I bought it I got the Icom Alkaline pack, and an aftermarket (Kendoo I think) MiMh battery.

Pete
 
Look up Garden State Battery in NJ. I used them and sold them when I was selling aviation radios. They put out a great product. Prices are half that of OEM.
 
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NiMH has a shelf life of a few years. It is very likely that your battery is dead and beyond revival. You will need to order a new one. Check any one of the myriad of ham stores such as AESham.com or http://www.hamradio.com/, etc. as the batter in the A22 is also used in lots of ham gear. Shop around for the best price, they will vary.
 
mikea said:
The battery can't be revived. There are places that will replace the cells, or you can try it yourself, but the cost will be within 20% of just buying a new battery pack.

I have a lot of NiCad and NiMh battery power stuff that always ends up discharged or dead, dead.

Get an alkaline battery pack if you can. That's what I got for my Yeasu. Alkalines are more suited to having a long shelf life AND a long life when used and of course, replacing them is cheap and easy. You buy a big pack of AAs at Home Depot or Costco and keep a few dozen in the plane.
Click to expand...

Alkalines are fine for an emergency radio, but for one that's used regularly, rechargables are far more economical. I think that use as a #1 comm in a glider would qualify for that. I use a rechargable pack in both my handhelds. For the one I carry as a backup in the Baron I also have an alkaline pack, because without regular use and charging you never know when the rechargeable will keel over, except that per Murphy that will happen when you need the radio to work.
 
Pete,

Try this if you have the time.

Bob
 

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smigaldi said:
I have sen NiCADs blow up when people try this stuff. Really, just buy a new battery
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I'll second this. If the cells are over charged they will vent. The second time they are over charged and try to vent, pressure builds and they have a tendency to explode if the vent sticks.

Vents sticking is a very common failure mode. They have a tendency to stick after the first venting.

This is a common problem with NiMh & NiCads......be careful.

I use to work for DeWalt Power Tools and have heard of dozens of cases where this occurred. Fortunately there were no serious injuries but it could quickly become a fire hazard.
 
Pete;

Trot on down to the local Hobby Shop or the local R/C club. NiMh batts are what most all Tx and Rx are using now (except for the E-flyers that use LiPo's :rofl: ) I'm sure you'll find someone with not only a good working knowlege of these batteries but with a cycler that can revive your old pack if it is indeed revivable. The hobby is very dependant on batteries and so these Guys (and Gals) are an excellent source of info.
By the By;
Don't charge an NiMh pack with a Nicad charger...the voltage sensing controller(s) are very different and will either "short charge" the cells ( not bad except you don't get much power out of 'em) or blow right past the "peak" charge and vent the battery cells (this is bad).

Chris
R/C Heli pilot since 1977:D
 
kgruber said:
I'd recommend alkyline.
http://tinyurl.com/24qsb2
Click to expand...

Alkaline is expensive and wasteful for the application that he is going to use his hand held for.

Alkalines are great if you do not expect to use the radio each flight and it will be sitting in your flight bag as that type of battery has a long shelf life and little self discharge. But if you are using the device a lot, rechargeables are the way to go.
 
Already have the alkaline pack.... I opened up the battery pack last night, and I think I have 2 dead cells. 2 of the cells read 0V when I put the multimeter (best 30 bucks I ever spent at radio shack) to it, the rest read at least 1.2V. I may just try to replace the dead cells for now, and if that don't work I can always buy a new pack.

Pete
 
With the question being answered, I'd like to take this a different direction-

What's the best way to discharge NiMH down quickly without damaging them?

I have devices that use 2, 4, or 6 batteries, so I have batteries in different states of discharge. Not trusting the charging circuits to sense one battery is more charged than the others and adjusting accordingly, I'd like to discharge a set then charge them up.

Thanks much!
-->Jack
 
Cap'n Jack said:
With the question being answered, I'd like to take this a different direction-

What's the best way to discharge NiMH down quickly without damaging them?

I have devices that use 2, 4, or 6 batteries, so I have batteries in different states of discharge. Not trusting the charging circuits to sense one battery is more charged than the others and adjusting accordingly, I'd like to discharge a set then charge them up.

Thanks much!
-->Jack
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Here's something I found on the web:

http://www.techspot.com/vb/all/windows/t-7397-How-can-I-discharge-NIMH-battery-safely.html

This guy is recommending against fully discharging nickel-metal batteries. It's also mentioned that memory is not an issue which I've heard frequently. That also applies to lithium-ion batteries.
 
KennyFlys said:
It's also mentioned that memory is not an issue which I've heard frequently. That also applies to lithium-ion batteries.
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"memory" is not an issue in NiMH, LiION or NICADS!

What is termed 'memory' is really voltage sag and was a condition that affected NiCads but no longer affects modern NiCads. A bigger problem is over voltage which can cause problem internal to the battery that would make it incapable of holding a full charge.

As for the original OP question about discharging NiMH, most of the good chargers for that type of battery will condition the battery for you as a function of the charge cycle. Now if you a cheap charger that may not occur and then discharging the batteries may help. But the NiMH chemistries have been around now for about a decade and they have proven themselves to be pretty robust. I don't bother with all the extra work, I just bought a good charger and let it do it stuff.
 
smigaldi said:
"memory" is not an issue in NiMH, LiION or NICADS!

What is termed 'memory' is really voltage sag and was a condition that affected NiCads but no longer affects modern NiCads. A bigger problem is over voltage which can cause problem internal to the battery that would make it incapable of holding a full charge.

As for the original OP question about discharging NiMH, most of the good chargers for that type of battery will condition the battery for you as a function of the charge cycle. Now if you a cheap charger that may not occur and then discharging the batteries may help. But the NiMH chemistries have been around now for about a decade and they have proven themselves to be pretty robust. I don't bother with all the extra work, I just bought a good charger and let it do it stuff.
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I am a fan of NiMh batteries. I have built a lot of my own r/c power packs and I have had great luck with them. I used off the shelf, retail batteries, (and chargers), and did the solder work myself.

They've proven very reliable for me and they are more robust than Li-ion batteries. That being said, having a set of alkaline batteries for backup isn't a bad idea either.
 
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