Fluke battery restore

[Gordo]

At work we have a Fluke DSP-SR Smart Remote that runs off of a Fluke BP7217 (Ni-Cd 1700mAh/7.2V). The batteries will no longer charge. I was hoping to attempt to analyse them and if possible to recondition. Also there is a volunteer fire dept. that has Motorola radios with several un-recharagable batteries.
After reading here and at the battery university I have a general idea as to what is needed but not a specific idea.

What would it take equipment and time wise?
Is this something that is going to be cost effective?

 

[alpg88]

you could try zapping them, i do it on my power tool batteries, it does work, thou if your batts, beyond dead it wont, but still worth a try,

this is one way of doing it. you can use car charger at 10amps for zapping.
http://www.instructables.com/id/Revive-Nicad-Batteries-by-Zapping-with-a-Welder/

there are other ways, just google reviving old nicd batteries, and you'll get lots of results

 

[VidPro]

What would it take equipment and time wise?
Is this something that is going to be cost effective?

soldering gun , charger that can check the cells once before assembly, a reliable battery dealer , screwdriver or torqes set.
its cost effective big time to replace Just cells in a unit, if you dont include Paying the human doing the work :ironic:

most of the stuff you can replace, you can get Tabbed cells, or packs made up AT the battery dealer before shipping, for minor additional costs, tabeed cells are proper, fit better the original location and better than soldering, although soldering done Perfectally is just fine too.

 

[Gordo]

Is there a rule about zap current/voltage and the battery voltage?
Like, my tool batter is 18-v but the Fluke is 7.2-v, and I don't know what the Motorola battery is but will a 10-amp car battery charger work for all?

 

[VidPro]

Is there a rule about zap current/voltage and the battery voltage?
Like, my tool batter is 18-v but the Fluke is 7.2-v, and I don't know what the Motorola battery is but will a 10-amp car battery charger work for all?

uhh yes, or less even 10 amp is pretty harsh when pushed to the 7.2v, it could slam in 20 amps surge. generally zapping is a last resort thing, you have nothing to lose of course you dont do it while connected to anything. and it is a Manuel operation with the user in control at all times, and checking with a meter in between zaps. the reason a "Car" charger is convienient, is becuase most of them have a breaker, and hefty linear transformers, and big diode items. so when you slam everything and it overloads, it can cope with it somewhat.

big TIP, put a old incan bulb in series with it, like an old blinker bulb will give you about 2amps max, and an old headlight will give you about 5amp max. with the incan bulb in there as a buffer, there wont be a direct short, and you can control the total current easily. a resister will do the same thing (of course), but with a bulb you can see many more things, and bulbs are designed with the resister heater in there all hanging out in space. put the bulb in Seires, and Zap away, then you can see almost everything that happens without a meter, then meter it after each zap to see where you are.

 

[alpg88]

Is there a rule about zap current/voltage and the battery voltage?
Like, my tool batter is 18-v but the Fluke is 7.2-v, and I don't know what the Motorola battery is but will a 10-amp car battery charger work for all?

good question, i assume you could read that , on pages that describe prosedure, they use welder it is more than 10 amps.

i revive my power tools batts, in a bit different way, i use flash circit from disposable camera, it has few thousands volts, and very little current, i take batts out of the housing, and use 2 sharp nails attached to wires, to zap individual cell, i leave batts attached, just poke holes thru insulaton to zap each one separatly 3 times. of course you should watch polarity when zapping, negative lead i solder to negative capacitor pin, capactor is maked.

i was given few batts, that were dead, and took so little charge that, in 1 min of drill opperation, they just died, now they work fine, not as good as brand new, but hundreds of times better than before i zapped them.

 

[J_C]

Best long term solution is probably to just buy the new tabbed cells and rebuild the packs. Zapping can work for awhile but you're fighting aginst a dying battery pack when a few cells aren't that expensive... and money well spent when it's a fire dept.

So far as what to use to zap, I've used tons of things from a car battery to a battery charger to a wall wart, computer PSU, etc. Usually I just use a 12V wall wart as I've plenty of spare ones I end up throwing away every now and then, zapping individual cells with the pack open instead of through all of them in series. One word of caution, last time I put my multimeter leads in series to measure the current out of curiosity, it burnt through the wire internally where it had frayed a little internally from reoetutuve bending right before the strain relief at the handle. Thought I blew a fuse on the meter for a moment...

On the other hand, if the pack is practically completely drained it can help to hook a higher voltage wall wart up to the pack (if the charger refuses to even try to charge the pack) for a small number of minutes, just to get some charge into the cells that aren't shorted so you can individually measure them next to determine which are shorted... though it's not really necessary, so long as you keep positive probe on positive battery contact then a continuity meter check will indicate which are shorted (reverse the leads with negative meter probe on positive battery terminal and it may give a false positive for a short).