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Old 04-20-2019 | 07:02 AM
  #4261  
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Originally Posted by cHAmpa
Yeah, the 5000mah are nice.. they sold some a few months ago for testing and I've been running them in buggy and truggy making 10-minute mains.
That is great news, I have been looking into something a little smaller than the 7400mah just for racing. I don't see the 5000mah up yet but hopefully soon they will sell them in the states. Heck now looking they don't even have the 7400mah still for sale, that is one of the frustrating things it seems they are always changing what they sell.
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Old 04-21-2019 | 04:49 PM
  #4262  
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Exclamation new lipo battery dead...?

i have a rc car which runs on lipo batteries i have ran the battery for 2 hours for the rc car the rc car is high powered at it was the correct battery but we have tried to charge it and it has not worked we dont know how to fix it any tips?
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Old 04-21-2019 | 05:22 PM
  #4263  
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Do you have a lipo cut off on the RC car?

What are you using for a charger?

Do you know the voltage currently for the battery?
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Old 04-21-2019 | 06:39 PM
  #4264  
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Originally Posted by Mahjik
Do you have a lipo cut off on the RC car?

What are you using for a charger?

Do you know the voltage currently for the battery?

1: not sure what a lipo cutoff is. The car has run before
2: greedy quick charger can with the rtr
3: 1 battery is .8 the other is 8.4
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Old 04-21-2019 | 08:19 PM
  #4265  
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I'm guessing these are 2 cell packs. The .8 volt pack is probably done, it likely has been over discharged.

Lipo cutoff is an esc feature that cuts off the drive voltage when the individual cells drop below a preset voltage, usually in the 3.2-3.5 volt range. The car will either stop running or noticeably slow, they may also flash indicator lights depending on esc brand.

Did you run the 8.4 volt battery or am I mistaken by assuming these are 2 cell packs?
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Old 04-22-2019 | 06:28 AM
  #4266  
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Originally Posted by somedude1212
1: not sure what a lipo cutoff is. The car has run before
2: greedy quick charger can with the rtr
3: 1 battery is .8 the other is 8.4
While this is a drone link, it's a good article about how to care for your Lipo batteries:

https://www.dronetrest.com/t/lipo-ba...batteries/1278
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Old 04-22-2019 | 08:51 AM
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Originally Posted by sweems
I'm guessing these are 2 cell packs. The .8 volt pack is probably done, it likely has been over discharged.

Lipo cutoff is an esc feature that cuts off the drive voltage when the individual cells drop below a preset voltage, usually in the 3.2-3.5 volt range. The car will either stop running or noticeably slow, they may also flash indicator lights depending on esc brand.

Did you run the 8.4 volt battery or am I mistaken by assuming these are 2 cell packs?
Yes both packs have been run and are 2 cell. the one pack at 8.4 is running fine. the .8 volt two cell must be toast as you suggested. Both charged with a balance charger

Regarding the ESC im pretty sure it has a lipo safety feature some sort, The car is a RTR by Associated with all Greedy branding/components.

This seems to be operator error. Im old school regarding batteries. I ran both down then charged them for long term storage (thinking lead acid battery).

So im good if i run battery to 3.x V for storage? Also,

Where would I dispose of a LIPO battery?

and, since i need to buy a battery pack, what are your thoughts on a 3 cell pack? gear the car up? (isnt there some inverse relationship regarding gearing and thermal)?

Fyi, im writing this for my son Andy. This is a learning experience for both of us. Im from the 80's with the grasshopper and other old school cars.

TIA, Andy
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Old 04-22-2019 | 08:54 AM
  #4268  
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Originally Posted by Mahjik
While this is a drone link, it's a good article about how to care for your Lipo batteries:

Thank you for the help. I skimmed this yesterday will reread today.
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Old 04-22-2019 | 10:16 AM
  #4269  
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Originally Posted by somedude1212
So im good if i run battery to 3.x V for storage? Also,
3.0V per cell would be the lowest to take a Lipo. Typically, you should stop running at 3.2V per cell which is when most Lipo cutoffs solutions will happen. Your storage charge should be 3.8 - 3.85V per cell.

If you have a configurable Lipo cutoff, you could set it for 3.8V which would be your storage charge.
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Old 04-22-2019 | 10:57 AM
  #4270  
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The cutoff would be set in your ESC.
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Old 04-24-2019 | 01:24 PM
  #4271  
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so i have run the car until it wont run.

With a new Klien meter I am reading 8.18v for a 2 cell pack rated for 7.2 and the car will NOT run anymore.

The Reedy (sorry for mispelling earlier) ESC is blinking rapidily. Im assuming the esc is shot or battery is discharged at 8.18v and the esc is shutting down.

NOW heres the kicker. The car stopped working right after I hit a curb pretty hard.

1) im still not understanding the correlation of V as a measure of stored energy potential at a given point in time(charge). I get small variances in amp out vs V but storage? seems like a very small V variance to work with. Wouldnt time on charge be a better measure? is there a chart showing V to Amp out correlation. wouldnt that be a better measure of stored capacity than V?

2)im going to charge it up .2V and see if i get a run. There seems to be a memory on these batteries within a VERY small V window.

Am I overthinking something? I have read and reseachered but am missing something

TIA
DMW for APW
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Old 04-24-2019 | 01:56 PM
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What are you using to measure voltage of the battery?
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Old 04-24-2019 | 08:07 PM
  #4273  
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Originally Posted by Mahjik
What are you using to measure voltage of the battery?

Klein Tools MM... one of the best measurement tools available set to 20V DC. Used a cheapie chen-tech meter and both read the same

found out the rapid green blinking is ESC overheat.
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Old 04-25-2019 | 06:16 AM
  #4274  
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Are you reading off the balance lead? It seems extremely odd that you are getting 8V+ for a 7.2V battery. Either it's getting overcharged or something is a miss in how you are getting your readings.

FWIW, there are some easy to use devices that you can use to verify you are getting the correct readings from your multi-meter:

https://www.amainhobbies.com/isdt-bg...d-bg8s/p694594
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Old 04-25-2019 | 06:32 AM
  #4275  
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Originally Posted by Mahjik
Are you reading off the balance lead? It seems extremely odd that you are getting 8V+ for a 7.2V battery. Either it's getting overcharged or something is a miss in how you are getting your readings.
Well most chargers charge the batteries up to 8.4 volts these days so it is not uncommon to see that high of voltage.
For those that don't know, 8.4 volts is the max voltage a person can charge to assuming they are following the rules by the sanctioning bodies.
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