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

[Pete Cosky]

Good point. Are the lipo packs in series or parallel?

I can't think of a reason why you would be seeing a failure unless you are 
running them in parallel. As the voltage goes down the amperage demand will 
increase and you may simply be pulling more current than it was designed to 
handle.

----- Original Message ----- 
From: "Kevin Sung" <kysung at comcast.net>
To: <adriancwong at earthlink.net>; "General pattern discussion" 
<nsrca-discussion at lists.nsrca.org>
Sent: Friday, August 22, 2008 10:50 AM
Subject: Re: [NSRCA-discussion] Kavan starter with Li-Po battery


> Hi Adrian,
>
> I am not an electric guru but have use the same set up like yours except 
> the
> lipo being a 4 cell pack since last year, and it has been working fine, so
> the set up works.  Perhaps the starter has some problem?  Meanwhile, I
> assume that you are using two 2-cell lipo packs in parallel.
>
> Kevin
>
>
> -----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 12:26 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
>
>
> _______________________________________________
> NSRCA-discussion mailing list
> NSRCA-discussion at lists.nsrca.org
> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>
> _______________________________________________
> NSRCA-discussion mailing list
> NSRCA-discussion at lists.nsrca.org
> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>