GhostTown

I'll probably get laughed off the forum, but here goes....

I've been out of the hobby for 13 years. Looking to get back in and doing the research on everything needed. I never got rid of my old stuff, including all of my (back in the day) high dollar matched cell nicads.

Is there a way to recondition these packs at all so they can be used for, well, anything? Some practice laps?

I still have a Novak Millennium Pro charger. Could that do anything?

Otherwise, recycle bin I suppose?

Thanks.

GerryH

iTrader: (26)

Might as well try before you recycle them.

I've had some success with nickle based batteries using this method. You'll need to trickle charge them to about 150% capacity. I've used a 9v wall transformer with a low output, something like 250ma. I make sure I set my charge time buy taking the batteries capacity divided by the charger output to get hours then add 50%. So a 2000mah battery pack would normally take 8 hours to get full (2000/250=8) then bump that up to 12 hours.

The usual recommendation is even a lower rate charge, 1/20C, but couldn't find anything that puts out 10-20ma.

Then I give them a 1c or less discharge to .9v/cell. Then a 1c charge/discharge cycle.

Hopefully on the last discharge cycle you get something better than a couple hundred mah out if it.

Good luck

GhostTown

Thanks for the response. I'll see if my LHS has a charger like that.

MarkA

iTrader: (21)

If you're going to buy anything specifically to try it - don't. The worst new pack you can get today will be better than a resurrected pack from more than a decade ago. If you can get them to come back to life at all, the performance will still almost certainly be abysmal.

disaster999

iTrader: (1)

Any of the modern lipo charger would charge nicad or nimh just fine, the high dollar ones might do 0.01v increments but depends if its necessary.

I have a pack of old matched nimh that I thought ill try with my new charger for shit and giggles and wouldnt hold more than a few hundred mah. After a few charge/discharge cycles I was able to bring the pack closer to its rated (2600 out of 3000mah) capacity.

Mark is right tho, if your just going to buy a charger just to resurrect your packs, then dont bother, Might as well get some modern batteries while your at and stick those in your old cars.

2uzferunner03

I'm my experience you can get them to hold near rated mah with a bunch of cycles on them but they won't have any amps to push.

Basically the rc moves for about 5 seconds then they're dead. Seen this with about twenty or so roughly 10 year old nimh/nicd pro matched batts.

Are you trying to run old rc's with brushed electronics? If so there's a guy on ebay that makes matched nimh packs. If your using new brushless equipment just invest in a charger and some lipos. You can pick up an accucel 6 lipo charger on hobbyking for about $30 with the power supply plus shipping. That charger does lipo, nimh, nicd and even lead acid. That same website has really nice and affordable zippy or turnigy Nano tech lipo batteries.

30Tooth

iTrader: (1)

Last year got 6 1700SCE packs, some are holding voltage others not. The ones that hold voltage are the ones you are focusing your attention, this is going to last several days but in the end you'll have some packs to run.
Slowly charge the packs with a high(normal is around 12mv/cell so 14 should be a good start) delta peak, if the cells have information about slow charge printed go with that. Normally the first charge will have lots of false peaks. Amperage should be at least 0.1A because you don't want it to be so slow that creates large crystals nor so fast that doesn't activates all the electrolyte.
Check if the packs are getting warm to touch, if all the cells seem to be warming up at the same time it's good because it means there's little voltage unbalance. Once they are warmer(a bit over ambient temp) stop the charging process record the amps that went into the pack, let it rest at least 1 hour before slowly discharging to 1.0v per cell, write amps the pack gave and let it rest. Proceed to the next pack and repeat above steps if you have more packs to restore. Next round increase the charging amps to double of what it was until there's no increase in amps the pack gave, again stop when pack is warm(and now you can change delta peak to a lower value if the charger doesn't stop when the pack is warm or increase delta peak if the pack is cold). Always record amps that went in and went out of the pack and their respective charging/discharging amperage. This is a tedious process but I liked it and my charger helped me big time because of graph output and cycle memory.
With this method I restored:
-GP3000(that gives around 1700mah @ 20A!)
-1800 NiMH(again 1400@10A)
-several SCE packs, can't remember numbers but two have good numbers.

One thing to remember, they will want to be exercised almost everyday or they will drop off. Charge them almost full the first times after conditioning.

Any question just ask.

GhostTown

30Tooth, that is excellent info. Thank you very much. I will attempt that process just to see what I get.

I don't plan on racing with these packs. I simply pulled out my old stuff and thought I might see if there is a way to resurrect more than $500 in old packs before sending them to the recycler. If I can use even 2 of them as test packs then I would see it as a success.

Thanks again.

30Tooth

iTrader: (1)

No problem, that was just my personal findings. You will find so much contradictions out there concerning nicad charging it's not even funny.

rc car freak

what i did was use a hobbico 910 charger to force charge the packs since it doesnt have peak detection

30Tooth

iTrader: (1)

That's a charger intended for 15 minute charging and then 0.1A of trickle charge so it won't work. A constant 0.3A trickle charging would work really well.

GerryH

iTrader: (26)

And that's why I suggested the wall power adapter. If you're like me, you have a box of these sitting around the house. Just need to solder a proper battery connection on it or some alligator clips.

The problem with most RC chargers is they have peak detection, which you don't want since these packs might false peak and they usually have some sort of safety timer, which might be turned off.

GhostTown

I may have to try this next, since I am getting false peaks.

Just have to watch the temps close, right?

Could I discharge with just a couple bulbs? Old school style?

30Tooth

iTrader: (1)

Important issue there, the wall charger is rated for 0.3A @ something volts but it's not constant(like 0.3A @ 7v, anything bellow is capped at 0.3A and anything above will diminish until the charger can't supply more amps), a proper charger will supply constant 0.3A which is what you want(my old SCE peak at more than 10v so a wall charger wouldn't charge those correctly). Usually the false peaks happen in the first 10-15 minutes of charging, my charger features a delta peak lock and it's been set up at 10 minutes most of my recondition attempts.

My charger arrived, it's currently charging a couple of 1700SC and GP3000 @ 0.5C(half nominal capacity), everything fine.