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I have a Joysway 28 in Bullet with a 50 amp water cooled ESC. I'm running it on a 3c 35a 2200 mah lipo. The boat ran great on the 1st run. I charged the battery and took it out for a second run and started loosing power, kind of like the battery was dead, then after letting the boat sit a second or two the power would return for a few minutes only to happen again. I wanted to add that it took roughly 45 minutes to charge the battery. What could cause this type of behavior?
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You mean 3s, 35C, 2200 mah.
Is the battery in good condition?
How long was your 1st run? Did you check where the voltage was when you ended the session?
How many Mah did you put back to the lipo. You are supposed to leave 20% reserve, 440mah should have remained. 1760 mah theoretically should go back. Lipo batteries do not react kindly when over discharged, not saying you did it, just asking.Too many boats, not enough time...
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The battery is brand new. I didn't check the voltage when I ended the session. The 1st session was roughly 20 min.Comment
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Man, 20 min is way too long, I have a feeling your battery is done. It drops its voltage under load and that is what you are seeing. There is an amp draw formula here, you can calculate how many mah you have dumped in 20 min.
Sent from my D6708 using TapatalkToo many boats, not enough time...Comment
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I can't believe you made it 20 minutes on a 2200mah pack in a 28" boat........? There obviously must not have been any low voltage cutoff in the esc, or perhaps it was set for 2s.
I am guessing you killed the battery.My private off road rc track
https://www.youtube.com/watch?v=XC3H...yaNZNA&index=8Comment
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I did think there was a low voltage cutoff and maybe it is set wrong. I ruined the battery that came with the boat which I replaced with the same type. The reason I replaced the battery was because the old one was swollen when I removed it from the boat. This one did the same thing and it was extremely hot when I removed it. I thought the original battery did this because it got wet.
I'm new to the rc boat hobby. I have experience with rc cars and lipo, but haven't had this sort of thing happen before.
I know know I can purchase a gadget to test the battery for voltage, but how do I make sure that the esc cutoff is set properly?Comment
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I don't see the amp draw formula, I did a search but came up empty.Comment
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I don't know what esc it is, so can't comment on setting it. Also, what type of charger are you using? I would run the boat for say, 3 minutes, then charge it and see how many mah go back into it. Most chargers also have the option to see the voltage, even on individual cells.
Fwiw, lipos don't really mind getting wet with fresh water. Obviously we do our best to keep them dry, but it's not that big a deal. Saltwater on the other hand is bad.
Sent from my SM-G920V using TapatalkMy private off road rc track
https://www.youtube.com/watch?v=XC3H...yaNZNA&index=8Comment
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Thanks for the info on the lipo getting wet kevin, all unnecessary worry is put to rest.Comment
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I have a Joysway esc that came in the boat when I purchased it. I have a Tenergy charger and the display does tell me how many mah are being put into the battery.Comment
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The formulas you looking for might be this one?
http://www.offshoreelectrics.com/conversion.htm
I think if you give the guys more details on your ESC such as Amps and chargers watts etc would help? and what readings you are getting at charging the batteries!Comment
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I purchased a voltage tester/alarm and the voltage on the battery is testing good. 3.83 on all cells. I also looked up the manual for my boat and downloaded it, the download has way more info than the one that came with the boat. I set the esc to low voltage cutoff at 3 volts. Should I set the alarm for the same value or would you recommend setting it a little higher?Comment
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If the battery is good, can you think of any other reason that I would be getting the power fluctuation as described in my original post?Comment
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