New batt neater will charge

[zrock]

Just got 2 nimh 8.4v 5100 speed pack batteries. Tryed to charge them one is only charging to around 220mah and the other is going to 510mah. Charging is taking less than 10 min. My other 8.4 packs are charging fine to their 3000mah. The charger is new. I guess it's possible I got a bad set of batteries? I tryed running a cycle discharge/charge on one but that also stopped after 15min.

 

[hamz9561]

Try to cycle the batteries through several charge/discharge cycles on the charger.

 

[zrock]

going to do that today.. take them to work with me.. Rand a discharge and charge on them last night and doubled the original charge... Just takes a while at 1 amp discharge rate

 

[Greywolf74]

what rate are you charging them at?

 

[zrock]

I changed the charge to 1 amp and they are taking a charge now. Before I was charging them at 3 amps.

 

[hamz9561]

Usually a lower charge rate is better. I try to charge my batteries, regardless of type, at their rated capacity (3000 mAH=3000 mA or 3 amps).

 

[JoeMAXX]

I like to charge my battery packs at half the MaH level So a NiMH 3000MaH pack I will charge at 1.5 on my charger for example. My receiver packs that are between 1200 to 1400 I will charge them at a rate of .7

Battery packs tend to get hot right at the point they are fully charged if you try to charge them too fast. Some battery charger have an added feature you can purchase for heat detection If you charge them at a lower rate they will not get to hot and generally last longer. Fast charging can cause a False Charge the charger will think the pack is fully charged when it is not. False charging can occour like your battery pack did.

New battery packs will generally take up to 3 to 6 cycles before they will take a full charge and perform properly. this happens in NiMh and LiPo battery packs. I say run them and let it happen while you play. The capacity will build in them while you play.

 

[zrock]

Got one of them to a full charge. The other is being stubborn. It's on the 3rd charge now. Ya I'm using my little girls rustler to drain the pack down.

 

[zrock]

Got them both to 5000 on a 1 amp charge. As soon as I brought the charger back to 4 amps I only got half charge? Gonna try a few at 3 amps see if I get better results

 

[Greywolf74]

I have to charge my 2200mah packs at .5As in order to get them to take their maximum charge without getting so warm that the temp sensors shuts the charger off. I can charge them at a little bit higher rating if I move up the thermal cut off point but i dont like my NiXX cells to get more than 98F while charging.

 

[zrock]

Ya i was hoping i would not have to charge at a lower rate but looks like that's what I'm going to have to do... They were pretty warm when i pulled them off. Miss the old days where you just turned the charger on for 15 - 30 min and hopped all was good..hehe

 

[zrock]

Checked the temp after charging at 2amp they were up around 108. I should do what I did 20 years ago when I first got electric. Made up a long charge cable and would put the packs in the freezer while charging. Always got a good charge doing this.

---------- Post added at 11:20 PM ---------- Previous post was at 11:08 PM ----------

My charger has nimh sensitivity that is set to default and capacity cut off set to 5100 for this pack. Should I change the sensitivity? It gives options of 5mv/cell and up?

 

[Greywolf74]

I use 5mv/cell

 

[zrock]

ill give that a try next...

 

[zrock]

Ok this is now starting to piss me off. Now the batteries at 1 amp are only charging to the full 5100 last time it only went to 3700 and shut down flashing full charge. One thing that is puzzling me is I put the batt back on for another charge and the mah on the charger started back at 0 does this sound right? And every once and a while the amps will drop to 0 then come back up. Charges my 3000mah packs no problem at 4 amps every time.

 

[hamz9561]

It sounds like either a bad cell or a cold solder joint to me. If it's a new pack, try and get it exchanged.

 

[zrock]

Ya they have no problem giving me warranty on it but the cost of shipping is almost the same price as a new batterie.

 

[zrock]

m really starting to think its the charger and not the batteries... Both batteries on 1 amp are only charging to about 3000 and that's in about 2 hours... Put the charger on a cycle charge and it was done in 10 min tried it on all 4 batteries... The safety shut off timer randomly works did about 10 1 amp charges and it never kicked in now its always kicking in until i shut it off..

One thing 1 did not think of when i bought this charger is 1 need 2 batteries to run..Duhhh should have gotten a charger that can do 2 batteries

 

[Greywolf74]

I could only being going to 3000 because thats all the mah thats being pulled out of the pack during discharge. A discharge doesn't drain the batteries of all mah. just a guess. try setting the discharge cut off voltage down a volt or 2 lower than what it is set to right now and see if it charges up and puts more mah back into the pack.

 

[zrock]

That would not explain why I got the packs to charge once to 5100 and the rest are around 3200 or less. When I do a manual discharge it works fine?