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Old 01-15-2009, 08:29 AM   #1
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Default HV Pro & Lipo Cutoff question

John, quick couple of questions.

Last night I ran the RC8e over at Pegasus, I was running 2 2S 4000 packs, put it on the track, and ran for 19 minutes before I pulled it off, kinda got tired of standing.

I pulled batteries, let them cool down, they were a little warm, but nothing to extreme.

After they cooled down, I plugged them in and charged them up, when they finished, they took 3200mah, and 3400mah. They were charged on a Hyperion Duo, in Sync Mode.

Does that not seem right? I think the Lipo Cutoff should have kicked in at some point before a 19min run.

I'm running 44/13 for gearing.

HV Pro w/ 6.5 Running in a RC8, Novak conversion kit.
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Old 01-15-2009, 10:41 AM   #2
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This has been stated many times before (check the Novak 1/8th scale conversion thread) by me and others: If you use two separate 2S packs you need to use a 2S smart stop on the control input battery (the one that lets you turn the speed control on if you only have one battery plugged in at a time).

The HV ESC draws more current from the control input pack because that is used to power the BEC which runs the RX, servos and fans. If you don't have the 2S cutoff on just the control input battery you risk over-discharging it and ruining it.

People have complained that Novak never mentions this. True, they don't. Live with it or rewire your ESC to use a single 4S pack and get a separate BEC. Either way, if you plan to run down to the cutoff, you need extra stuff. If you are running fixed length races and never get near the cutoff, then this is not an issue. Just be careful during practice sessions - best to time them.
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Old 01-15-2009, 11:33 AM   #3
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Thanks for that information. That does suck it's not mentioned in the documentation.

Generally should my run times be 10min or so on a 4000mah pack?
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Old 01-15-2009, 07:20 PM   #4
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Quote:
Originally Posted by JGruber View Post
Thanks for that information. That does suck it's not mentioned in the documentation.

Generally should my run times be 10min or so on a 4000mah pack?
My 6.5 HV averaged about 18 amp current draw for a 10 minute run. So from that I figured I could run 13+ minutes on a 400 pack. But that was 10 minutes of running with the watch stopped for the crashes. Also, current draw (thus runtime) will vary a lot depending on the track and driver.

I'm running a Neu 1512 2.5D/F now and that averages about 14 amps and about even, speed wise, with the Novak 6.5.
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