bob8619

What might cause a battery to rapidly discharge and the appear to not want to charge back up, then randomly charge and hold its charge as if nothing ever happened?

I thought I fried my battery by plugging it into a charger improperly but yesterday I attempted to charge it again and this time it charged up and seems to be working fine.

RCKen

My Feedback: (9)

I don't know what is causing your issues with the battery, but if the battery was in my radio and it acted flaky like you describe I would replace it immediately. The cost of Ni-mh's has come down it's not worth risking losing a plane over a battery that you can't trust any longer.

Hope this helps

Ken

j.duncker

My Feedback: (2)

I will second Ken on this. Time for a new battery. When you get it I would cycle it through on the same kit that you have been using in case there is something else going sour on you.

I had a weird problem which turned out to be a switch alternately going high resistance then partial short.

bob8619

Yeah I have a new one ordered. Just my curiosity here.

Rodney

Sounds more like a charger or harness problem than a battery problem. Check for bad connections solder joint on both the battery, charger and any inter connections.

WI53072

Replace the battery Bob. You wouldn't want to lose a plane or one of your cars because of faulty equipment. Your new P47 is not worth risking over a few dollars.

JPMacG

My Feedback: (2)

I'm with you, Bob8619. I would want to find exactly what is going wrong. Otherwise, how would I know I had fixed the problem?

Rodney

I would want to know for sure where the problem is. It might not be the battery and if not, then the problem is waiting in the wings to bite you again on another battery. The problem definitely appears to be a connector problem but where? In the battery between cells or output leads, in the charger harness, in the charger or was it just a human error that can no longer be verified as it disappeared when the cables were rearranged or changed? If the battery still acts up when checked a second time and all other batteries charge okay under the same conditions then, yes, blame the battery and fix or junk it. If the battery will charge okay on another charger or now on the same old one, you have more detective work to do.

bob8619

The battery was getting real hot just after few hours charging if that means anything

Rodney

What current were you charging at? Did you do a discharge test after the charge at about 0.3C down to 0.9 volts/cell? If so, what were the results? To compare a Nixx battery to factory specs, you would first charge it at 0.1C for about 16 hours and then discharge at 0.33C down to 0.9 volts per cell. The milliampere hours measured should be withing 80% of the manufacturer's stated capacity if it is okay to use in a critical application. Charging at the rate of 0.1C will not raise the temperature much at all, not enough to feel by touch unless you are exceptionally sensitive to temperatures. I have to use an infrared thermometer to measure the temp rise when charging at such low rates.

bob8619

No that's all Greek to me. I think the spektrum charger charges at 100 or 150mA

JPMacG

My Feedback: (2)

If you have a 4 or 5 cell NiMH pack with AA sized cells and it is getting -HOT- not just mildly warm when charging at 100 or 150 mA then I would say it is likely that you have a bad charger.

bob8619

We will see what happens with the new lipo. It should be here tomorrow

skeeter_ca

Remember you will have to use a different charger to charge the lipo battery. You can not use the wal-wart that came with the transmitter.

skeeter

bob8619

The manual says you use the same wall charger. Just gotta change the setting in the transmitter to 7.4v

JPMacG

My Feedback: (2)

I guess that means that the charging circuit is built into the transmitter. So possibly it is not the wall wart but the transmitter that is malfunctioning on the NiMH packs.

bikerbc

I am not sure if this is a DX8 that you are having difficulty with but if it is the charger is built into the radio and it is multi -chemistry charger designed to charge 4-cell NiMH and 2-cell LiPo batteries at a charge rate of 200 mAh . The thing that looks like a charger and plugs into your radio is actually a 12 volt power supply ..To change your radio over from charging the included NiMh pac over to charging the optional 2-Cell LiPo Pac You must change some settings in your transmitter ..Any charging that is done must of course be done thru the transmitter ..

bikerbc

By the way this is all covered on page 7 of your DX8 Manual and it is Critical because you can cause irreversible damage to your transmitter if you try charging with anything other than the 12 volt power supply ..there is no way your battery should be getting hot.. It is possible to start a fire and again that thing that looks like a charger that comes with the DX8 is not a Charger . It is a 12 volt power supply ..The actual charger is inside the transmitter.. This is only on the DX8 as far as I know .. I like the feature because I can upgrade my battery pack and now I only need to charge my transmitter about once a month ..

bafflerback

My Feedback: (6)

I had a problem like this with a JR radio. It turned out to be a problem with the charger plug. If you look at the end of the plug there is a black plastic insulator between the inner charger terminal and the outer charger terminal. Mine was cracked. On occasion when you plugged the charger in it would short the positive and negative together and when I came back to check on the battery it would be completely dead. I'd unplug the connector and replug and the battery would recharge. I found it quite by accident. One night I went to charge the transmitter and it shorted bad enough to blow the fuse. By then the insulator had broken bad enough it was easy to see. Changing the end fixed the problem.

skeeter_ca

Well i'll be jiggered.

skeeter

scale only 4 me

My Feedback: (158)

Those batteries must have an on board balancer,, I only see two wires???