e-flight22

Hey everyone,

I have used Nicad packs for many years and just bought my first 1800mah High Rate NiMH pack thats at 9.6v. I am using it in a Zagi Tazz which worked well for its maiden flight. I charged it at 1.5 amps till it peaked and then flew it and it worked fine for 1 flight. Then the next day i charged it at 1.5amps again...and it seems to be peaking at 11.89 and wouldnt go any higher, whats wrong???

i never did any "form" charging/discharging before hand and am wondering if thats the reason its not peaking right or what do u think might be going on/wrong???

I thought that a pack of this size would be able to get to about 14.00-15.00 somewhere around there. Any ideas or recommendations as to what might be wrong would be great? Any help would be appreciated.

The chargers im using are: MRC Super Brain 959 AC/DC delta peak charger ....and..... Astro Model 110D DC/DC digital peak charger

Thanks in advance for taking the time to respond and read my post. Any help would be great.


e-flight22

mGerben

Hi,

What do you mean 'charged it untill it peaked' ?
Did you measure this yourself? Did you not use a 'smart' charger?

If you use a smart charger it is not your concern at which voltage it peaks. The charger takes care of that. When the charger says it's full, it's full.
You can't charge manually at 1.5 amps and get it right.

Having said that, NiMHs take a couple of times to reach full capacity. First few times won't be 100% yet.

soarhead-RCU

EF-22
To form your nimh pack you need to charge at around 180ma (c1/10) for 14 to 16 hours. This balances all the individual cell together in voltage and capacity. The way I do it is to pull the pack down to 1.1v per cell and then trickle charge it with a wall wort type of charger. I also do this every 15 or so cycles and they seem to hold max capacity through there lifetime.
Good Luck
Bob

jooNorway

Did you expect 15Volt from a 8-cell NiMh-pack??? 12-13 Volt is appr max.
As mentioned it should have been charged at 1/10C for the first time... and also sometimes inbetween all the fastcharging.
Also some NiMh`s need a slowcharge and some cykles when they have been stored for a long period to "wake up" again.
They also perform best if they are used immediately after charging.

kihei11

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I usually trickle charge my new packs after frying a few and limiting their duration try cycling battery a few times I brought a few packs back to life