[NSRCA-discussion] Kavan starter with Li-Po battery

[JShulman]

I had the same thing happen to mine with a 4S set-up. The first warning sign was the starter had gotten really hot. The second, and
final sign, was the starter locked-up. I think it's a combination of the higher voltage and, for me, the longer time running it
trying to start the motor (setting and fine tuning), maybe.

Regards,
Jason
www.jasonshulman.com
www.shulmanaviation.com
www.composite-arf.com

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of
adriancwong at earthlink.net
Sent: Friday, August 22, 2008 3:26 AM
To: NSRCA-discussion at lists.nsrca.org
Subject: [NSRCA-discussion] Kavan starter with Li-Po battery


To all,

I have been using a Kavan starter with a 10 cell, 12V, 2.2A ni-cd pack for many years with good results. However, ever since the
1400DZ came out, it required more cranking power from the starter and one charge would normally only last for two weekends of
flying. By the time the 160Z came along, I've switched to a 12 cell, 14.4V, 2.2A ni-cd. Again, it performs flawlessly. However, as
you are aware, the 12 cell pack is really heavy.

At the beginning of this year, I have switched to two li-po packs - 2 cell, 7.4V, 2100 mAh with 15C continuous, 20C burst on each
pack. The first starter lasted for 6 months until it stopped working after normal wear and tear. The second one stopped working -
frozen solid - after about 2 months - I could tell this one had some strange noise to began with, like something was rubbing inside.
Therefore, I wasn't surprise that it stopped working only after two months.

The third starter I rigged up was relatively new, and has been working perfectly, until this afternoon. After the first flight, it
was frozen solid again. Like the second starter, it didn't give any warning sign whatsoever - slowing down, getting hot on either
the starter or the battery.

My question:-

1) Am I using the wrong battery pack?

2) Too high of a discharge rate because it's a li-po instead of ni-cd?

3) Once the starter is frozen, is there a way to fix it? Sure hate to keep tossing away starters.


Any advice or suggestion from you electric gurus are greatly appreciated.

Thanks in advance,

Adrian


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