12-17-2017, 08:56 PM | #1 |
RCC Addict Join Date: Feb 2017 Location: Surprise
Posts: 1,762
| How a lipo drains
So I'm running my HP 3 cell 1500mah battery, climbing up hitting the throttle , then , boom , its like the battery went from a 3 cell to a 2 cell, the speed changed, so my question is, do lipos discharge equally, or at one at a time ? I've never witness that before or just didn't pay attention till now . |
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12-17-2017, 10:27 PM | #2 |
Quarry Creeper Join Date: Aug 2016 Location: British Columbia
Posts: 466
| Re: How a lipo drains
Buy a lipo battery checker and find out if it is the battery, an individual cell, or not. https://www.venompower.com/products/...lipo-batteries |
12-17-2017, 11:28 PM | #3 |
RCC Addict Join Date: Feb 2016 Location: Santa Maria, CA
Posts: 1,751
| Re: How a lipo drains
The cells should be discharging equally as they are wired in series. If it surges like that, your motor is probably pulling more amperage than that particular battery can supply and it may only keep up for a couple seconds (that is what a batteries "burst" rating is about.) What motor and esc are you using, and what is the C rating of your battery?
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12-18-2017, 12:29 AM | #4 |
I wanna be Dave Join Date: Feb 2013 Location: NW Indiana
Posts: 3,196
| Re: How a lipo drains
Are you sure your ESC isnt cutting back as it nears its low voltage cutoff? Some do that before shutting down completely
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12-18-2017, 01:02 PM | #5 | |
RCC Addict Join Date: Feb 2017 Location: Surprise
Posts: 1,762
| Re: How a lipo drains Quote:
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12-18-2017, 01:03 PM | #6 | |
RCC Addict Join Date: Feb 2017 Location: Surprise
Posts: 1,762
| Re: How a lipo drains Quote:
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12-18-2017, 01:04 PM | #7 |
RCC Addict Join Date: Feb 2017 Location: Surprise
Posts: 1,762
| Re: How a lipo drains |
12-18-2017, 01:05 PM | #8 |
RCC Addict Join Date: Feb 2017 Location: Surprise
Posts: 1,762
| Re: How a lipo drains |
12-18-2017, 01:12 PM | #9 |
Rock Crawler Join Date: Mar 2016 Location: Zagreb, Croatia
Posts: 747
| Re: How a lipo drains
Those batteries are rated at 30A discharge. Not much, def not enough for a 550 can... The esc probably went into limp mode (reduced power) due to voltage sag.
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12-18-2017, 02:04 PM | #10 |
owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down!
Posts: 20,290
| Re: How a lipo drains
Lipos dump really fast. One second it seems like they are just fine and the next they are pretty much dead feeling. Nothing out of the ordinary.
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12-20-2017, 05:45 PM | #11 | |
RCC Addict Join Date: Feb 2017 Location: Surprise
Posts: 1,762
| Re: How a lipo drains Quote:
Limp mode ,lol that's funny hearing that for a esc. | |
12-20-2017, 05:50 PM | #12 |
RCC Addict Join Date: Feb 2017 Location: Surprise
Posts: 1,762
| Re: How a lipo drains Pretty much a dead feeling is what I got, sure felt like that...! Good to know nothing out of the ordinary with lipos...lol
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12-21-2017, 09:54 AM | #13 |
Rock Crawler Join Date: May 2016 Location: SoWIs
Posts: 618
| Re: How a lipo drains
First off, the batt checker that tells you anything relevant will show internal resistance. Resting voltage doesn't mean much unless one cell is noticeably lower than the others after charging or discharging. Second if you are discharging them to the point where voltage drops quickly, you're damaging your batteries. It's not like hitting it with a hammer, but you could go from 500+ charge cycles to under 50. The following pic gives you an idea. A lipo will still have "juice" for a crawler under 3.5v, usually down past 3.0v, but it internal resistance increases PERMANENTLY. If funds are an issue, then you can double your battery's life by discharging no farther than 3.7v & even more if you charge to 4.1v. Only Chuck Norris can get away with discharging a lipo past 3.0v. But then again he only has to stare at it for a second to get it charged back to 5v/cell... |
12-21-2017, 12:59 PM | #14 | |
RCC Addict Join Date: Feb 2017 Location: Surprise
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| Re: How a lipo drains Quote:
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12-21-2017, 10:39 PM | #15 |
Rock Crawler Join Date: Mar 2016 Location: Zagreb, Croatia
Posts: 747
| Re: How a lipo drains
I like my packs at storage voltage when I'm done driving. Unfortunately, not many ESCs have such a high cutoff. But with a 5Ah pack I rarely end up below 3.8 anyway.
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