jedi.mind.trick

I have just bought a new rx battery, it is a Venom 6v NiMH 1600mAH hump pack and my charger is a Venom Pro Charger.
I have set the capacity cut off to 1600mah, Delta peak is on Default, in the NiMh profile the charge current is set to 1.6A - Min discharge voltage is set to 4.5v (.9v per cell), I also have the temp sensor (set to 110°F/43°C) hooked up..just for good measure..

As soon as I ripped it out of the packet I set it to charge, it took about 14min to finish & report as FULL and the screen read: 0362mA - voltage: 7.54v

Then I did a few discharge > charge cycles, it finished with:
1 - DCG - 0189
1 - CHG - 1339

2 - DCG - 0879
2 - CHG - 1048

3 - DCG - 0907
3 - CHG - 1043

4 - DCG - 0886
4 - CHG - 1046


Anyone know whats going on? Am I doing something wrong? Could it be delta peak settings I need to adjust? if so, what setting should I change it to? I can set it from 5mV - 20mV per CELL

I just charged my glow plug ignitor (nicd) and set it to 2A and it finished at 2000mAH like perfect..

Now, this is the second battery I just bought, the same one, but on the first battery I "accidentally" set the min discharge voltage to .9v for the entire pack, I cycled it a few times before I realized and changed it to 4.5v, the battery works but I was still getting similar charging/discharge results and I thought that was the reason and I damaged it so I bought another and it's still happening..I even tried just setting it to charge over n over again a few times..then did a cycle..but similar results.

Any help will be greatly appreciated.
Thanks

EDIT:
Just tried with 5mv delta peak..same thing.. DCHG: 0905mah CHG:1073mah

I just tried with capacity cutoff turned off, discharge rate of .1A and charge rate of 1A, and it was a little better, just over 1200mah

Tried charge rates of .7A and .5A and delta peak from 5mv to 20mv - No better

chuckk2

This may or may not apply and help. (From an older post) There were a lot of complaints about Venom Pro Chargers several years ago.
The manual is not clear on how to set NIMH to auto charge. This is how to do it which I got from another model which this one is probably rebadged as:
browse to program select HiMH BATT and enter. Press enter and the set current will start flashing. Now press the decrease and increase buttons together and it will change to Aut (you just do the same to change it back to manual mode) and set current will change to current limit. I usually set this to 1C to be on the safe side but you probably could go higher. Then hold start for 3 seconds to start the charge. It will stop when battery is full and beep.
A possibility is also that you may have gotten "old stock" NMIH batteries.

jedi.mind.trick

It wont go down to auto, I know what you mean but it just goes all the way to .1A it always says MAN on top right on screen but I can't set it to auto, I can do it for discharge but not in the charge section.. ill have to buy another battery and if that's ok then i guess it's the batteries, if not the charger.

Rodney

On any new (or one that has set unused for a month or more) Nixx battery, it is always best to charge it at 0.1C for 16 hours. You do not have to discharge it to any degree prior to doing this for the first slow charge. This will insure that all cells reach full charge without harming the cells which reach full charge first as the heat build up will not be sufficient to hurt those cells. It may take 3 cycles of this with discharging at not more than 0.33C rate down to 1 volt/cell between charges to bring the battery to full capacity. This is called a forming charge and is required on all NiMh or NiCad cells to get maximum capacity. Back when most of us used NiCad's, this was pretty common knowledge but has seemed to slip into obscurity with the advent of Lixx batteries.

jedi.mind.trick

interesting, does this mean I will never get to full capacity because I didn't do this from the start?

thailazer

I normally characterize a new NiCd or Metal Hydride battery set and then check it every few months with a given load such as 70 mA or so. Checking voltages before and after you fly is very good practice, and doing a profile of the discharge curve gives you more insight into how the battery is doing. I have found that older batteries will have a steeper discharge curve than new, and at some point, it is just too different to keep in a plane. I like to see the steep drop off at the end, at least for NiCd batteries.

049flyer

My Feedback: (18)

Many Nimh batteries do mot respond well to quick charging. Try charging at the 1/10C rate for 12 to 15 hours then discharge, I'll bet you get better results.