[okieman]

This ain't exactly a home construction question, but it does involve the use of the Ni-Cd batteries used in tools. I've had trouble finding a forum on the Web that might answer this...

I just bought a Radio Shack scanner that uses a pack of four AA Ni-Cds for power. To charge the pack, you turn the scanner off and plugin the AC/DC 9-volt "wall wart." Seems simple. However, the chart in the owner's manual only provides two suggested charge scenarios:
Current Charge Time
600 mAh 6 hours
850 mAh 8 hours
That's not real helpful to me, because the only information I have are the wall wart specs saying its output is 1 amp (1,000 ma). It's confusing, because their chart suggests it takes longer to charge the Ni-Cds if more current is being pumped into them. I found an online calculator that suggested I charge for 3 hours at 1 amp, but my research says it's bad to charge Ni-Cds quickly. What do I do; put a resistor between the charger and the battery pack so that it will trickle charge?

 

[a7ecorsair]

The 600 and 850 mAh is referring to the size of the battery in the pack. The larger pack takes longer to charge. 4 batteries in series only be 4.8 volts so I don't understand the 9V output from the wart.
A one amp output seems high for Ni-Cd charging. Did this wart come with the scanner?

 

[okieman]

The charger was sold separately from the scanner. I didn't ask many questions at the time of purchase, because I've dealt with this clerk in the past, and seems to be knowledgeable about a wide variety of the products. I also thought 1 amp seemed like a lot. Wall warts of this size I've used in the past generally would only produce half that much current or even less. What a pain in the neck. Maybe I just need to ask her if a lot of customers have used this setup with success. I doubt that they would, if it's pumping out an amp. An even better idea might be to return the wall wart and buy one of these chargers sold by Amazon.com that either offer a trickle charge option or auto-detect the need...
http://www.amazon.com/ReVIVE-REFRES...?s=electronics&ie=UTF8&qid=1308886374&sr=1-13

http://www.amazon.com/Tenergy-T-119...3?s=electronics&ie=UTF8&qid=1308886374&sr=1-3

 

[a7ecorsair]

Is the wart classified as a NI-Cd charger or is it just an AC to DC converter power supply with a 9 volt - 1 amp rating?
BTW, what scanner did you buy?

 

[Speedy Petey]

If you read forums like RadioReference.com, you'll see that charging in a scanner is a REALLY bad idea. There have been more than a few literal melt downs in some pretty expensive units. One of mine is a PRO-106 and several guys reported bad things with this same unit. Pretty lame for a $400 hand held scanner to go nuclear over the internal charging circuitry.


I have a MAHA MH-C9000 intelligent charger for all my AA and AAA NiMh's and it will also do NiCd's I believe. I have to say, if you are still running NiCd's it is time to step up to some quality NiMh's.

 

[susee]

i would go in to r/c web sites . i build and fly r/c planes . some of my n. m. h are 5 years old and i quick charg them every time i take them out to the field . i have not hade a problem in a long time

 

[okieman]

Is the wart classified as a NI-Cd charger or is it just an AC to DC converter power supply with a 9 volt - 1 amp rating?
BTW, what scanner did you buy?

It's a 9-volt converter with a 1-amp rating. Apparently it's supposed to charge the Ni-Cds in the scanner, a Radio Shack Pro-404. I've done some research and recharging inside the scanner does not have a good reputation.

Your thoughts?

 

[okieman]

I have a MAHA MH-C9000 intelligent charger for all my AA and AAA NiMh's and it will also do NiCd's I believe. I have to say, if you are still running NiCd's it is time to step up to some quality NiMh's.[/quote]

Where's a good place to shop for NiMhs and the appropriate charger? Amazon.com?

 

[Speedy Petey]

I got mine here: http://www.thomasdistributing.com/

 

[a7ecorsair]

You owner's manual say rechargeable batteries have to be installed in the Yellow battery holder.
It also says to use a 9V 400 mA external power source:

Charging Rechargeable Batteries
1. Install rechargeable batteries using the yellow
battery holder.
2. Connect an external power source to the PWR DC
9V jack using a 9V 400mA AC/DC adapter (not
supplied). The average charging times are listed
below.
Battery Current Charge Time
Ni-MH 1600 mAh 16 hours
Ni-Cd 600 mAh 6 hours
Ni-Cd 850 mAh 8 hours

I thought that one amp was high:yes:
You can buy a package deal at just about any store which will include 4 batteries and a charger. Get at least 2500 mAh NiMH batteries.

 

[okieman]

Well I missed the 400 mA detail, and the clerk apparently didn't know any better. I'm assuming I can still use the 1A AC/DC whenever I'm without battery power, or am conserving battery power.

I'm shopping now for a medium priced intelligent charger for NiMh batteries. Thanks for all the help.