Thread: Discussion Hobby City's EPO 3d-Hawk
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Old Aug 24, 2010, 01:24 AM
retiredbri is offline
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United Kingdom, England, Saffron Walden
Joined May 2008
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Quote:
Originally Posted by Micro Fly View Post
.... 850mah 25-45C batteries .... They can be charged at up to 5C charge rates and the extra discharge rate should provide the punch needed for the electronics on this plane. I'm just wondering how well it will fly with the added weight of the larger battery pack? ....

I've got a feeling that the ESC is limited to 10A (approx). The 450mah was a 20C so was being pushed to deliver 10.19A. For the 20C, 800maH battery the battery was well within the C rating and there was very little voltage drop but even so, WOT only drew 11.31A.

I time the flights and then see what the charger puts back in. This gives me the maH used per second of flying time. With the stock 8x4 the 450maH gives about 4.5 mins agressive flying burning about 1.5 maH per sec. The best "gentle" flying is 0.95 maH per sec. I haven't calibrated the 800mah batteries yet.

I try to keep the charge rate down to 1C (for longer battery life) and use parallel charging to get low charge currents with short charge times. It connects up to 8 batteries, of different capacties in parallel (with the balance connectors also connected in parallel). This means eight batteries are charged in about 1 hour (1C rating). The only stipulation is that I check the dischaged voltage of all batteries and only connect them in parallel if they are within 0.1V of each other.

The idea came from http://www.rcgroups.com/forums/showthread.php?t=1139916. Start at thread 1. The article has 2 ways of doing things, charging through the balance connector or charging through the battery lead with the balance connectors seperate. Post 10 of the article shows this latter arrangement for four 3S batteries that use Deans plugs.

I made mine, the pics show the two parts, charging leads and balancing leads. I also made one for charging six 1S helicotor 100maH batteries at the same time.

I'm not an expert and only copied the article. Please use only the data in the article and decide for yourself if you want to use this method.


retiredbri
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Last edited by retiredbri; Aug 24, 2010 at 01:35 AM. Reason: To emphasize the warning.
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