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A battery question

Hello

I just received an 8-cell 1700mAh NiCad battery from AlleRC for my Zagi

400X. The AlleRC instruction sheet that comes with the battery says that the very first charge should be done at 170mA (1/10 of the capacity value), but unfortunately my charger doesn't go lower than 500mA. Of course I can take some steps to get exactly 170mA from it, but first I'd like to know how important it really is to follow this recommendation. Or, more precisely, how much worse it is to use 500mA for the first charge instead of the recommended 170mA. Is it a battery performance issue (including battery life) or rather a safety issue?

For "normal" charges of these batteries I use 1A (per Zagi's instructions).

Interestingly enough, Zagi's instructions don't recommend anything like this for the first charge or the original battery, but then again it is possible that the original battery comes already "broken in".

Reply to
Andrey Tarasevich
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As a general rule the first charge on NiCad and NiMH is done a 1/10 C or 170 ma for your 1700 battery pack. This is usually a 15+ hour slow 'forming' charge. Total capacity and battery life are considered to increase substantially with the first charge being done this way. Your best bet is to educate yourself a little at

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and make your own decision.

remove my-wife to reply :-)

Reply to
Icrashrc

Frankly, I couldn't find anything on rcbatteryclinic.com that would answer my questions. The "Fast Charge ..." article talks about the importance of "forming" cells by says nothing concrete about the charge rate. The "Ni-Cd Life ..." article mentions the 'capacity/10' value but in a completely unrelated context.

BTW, Zagi's instructions say that the original 1700mAh battery should be charged at 1A and that some people even charge it at 2A sometimes. According to rcbatteryclinic.com, this means that original Zagi battery qualifies as "fast charge" battery, which in turn means that it usually comes pre-tested and pre-formed. This probably explains why Zagi's instructions say nothing about "forming" the battery.

AlleRC instructions, on the contrary, suggest that forming should be done by the owner of the battery, which makes me to conclude that the battery is still "raw" and I can't be sure that their battery can be "fast charged" at all. At the same time their Web site literally says that their 1700mah battery is "same as original Zagi pack". Of course, this "same" is always open to interpretations...

Anyway, does anyone have any experience with AlleRC 1700mAh Zagi battery? How do they behave under 1A charging current? What about 2A?

Reply to
Andrey Tarasevich

I believe a 1/10 charge the first time is to allow the cells to equalize. You receive a pack and each cell may be in a different state of charge. The

16-hour slow charge helps them get to a similar state of charge. It is better to do this than do a fast charge on a new pack. I don't know how much worse it is to use 500 mA the first time.

John VB

instructions).

Reply to
jjvb

Sorry, i thought Red had that info on his site. If your pack is made of 1700AE cells like my original Zagi pack then after the first 3 or 4 cycles go ahead and fast charge it. I've been charging mine at 1.7 amps for the last 2 years.

remove my-wife to reply :-)

Reply to
Icrashrc

| I believe a 1/10 charge the first time is to allow the cells to equalize. | You receive a pack and each cell may be in a different state of charge. The | 16-hour slow charge helps them get to a similar state of charge. It is | better to do this than do a fast charge on a new pack. I don't know how | much worse it is to use 500 mA the first time.

I think there's a bit more to it than that, but that's probably some of it.

If your fast charger can't do 170 mA, you could use your transmitter charger which probably puts out 50 mA or so at around 9.6 volts, then do some simple math to realize that it will take 3.4 times as long to do the initial charge.

(Of course, you'll have to improvise a connector, but that's not hard. Just make sure you don't get the polarity reversed and you don't short it.)

500 mA is probably a bit too fast for the first charge.
Reply to
Doug McLaren

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