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want to know the do's and donts of lipos

want to know the do's and donts of lipos

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Old 05-15-2010, 09:07 AM
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Cool want to know the do's and donts of lipos

I keep geting dead cells and why do people dicharge lipos my lipos seem to also loose there power
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Old 05-15-2010, 09:48 AM
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Dont make multiple threads on the same thing just because no one answers in your other thread. I'm not going to give a seminar on what I know about lipo's, if someone else wants to, good for them. I'll go as far as giving you a link and
then you can read everything you need to know about lipo's.
Google is really good for that.

http://www.rchelicopterfun.com/rc-lipo-batteries.html
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Old 05-15-2010, 01:43 PM
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Simple and fairly short answer

Never let the voltage of any cell go over 4.2 volts or under 3.0 volts. Using a proper charger and a low voltage cutoff in the car shuld take care of 90% of that. Do not discharge LiPo's, store them in a mid charge state. The exact point is not a big deal, just somewhere around 3.7 volts per cell is good. This way they will not exceed the safe limits if the temperature changes.

Finer points, use a balancer when charging, or even better, a balance type charger. The reason for balancing is to get all the cells to the came voltage, usually 4.2 per cell at the end of the charge. If the cells are not perfectly matched, and they rarely are, they will go out of balance as they discharge. For this reason, I like to set the LVC in the car abit higher than 3.0 volts per cell. I go to 3.3 or 3.4 to allow for some imbalance so the lowest cells at the end of a run is still over 3.0 volts. If you run to the LVC, it is a good idea to charger it part way up before storing it.

I also don't like charging any faster than 1C. Sme cells and packs are rated for more, but the faster you charge, the harder it is to keep the cells in balance.

Hope that helps.
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Old 05-15-2010, 01:59 PM
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thanks for the help and as for doing 2 thread sorry i could not find the old one not to good at computers and could not find the old one
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Old 05-15-2010, 05:28 PM
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Do:
- use a balence charger and connect the balencer during charging for extra safety during charging
-be careful not to run too long
-Hobbcity.com Turnigy hardcases
-leave in the sun to legally warm your batteries without breaking Roars (and most tracks) "don't warm your batteries" rule.
-use the proper C rating but don't overdo it.

Don't:
-lick the ouput connector on a 6S battery
-dent, smash the lipo
- buy fancy brand battieries that cost 3 times too much and are actually , IMO&IME, much worse than the generics from China.
- use as an ignition source for C4.
- overload the packs with monster 1/8th scale motors.
-forget to balence
- leave them charged overnight
-jellybeans!
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Old 05-15-2010, 05:53 PM
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Best thing to do if you dont have a low voltage cutoff is when you very first start to notice the vehicle slowing down, pull it immediately and charge, I cant tell you how many batts ive seen die from new people treating them like nimh and running them in the car till almost dead.
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Old 05-15-2010, 06:32 PM
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Originally Posted by VenturaDC View Post
Best thing to do if you dont have a low voltage cutoff is when you very first start to notice the vehicle slowing down, pull it immediately and charge, I cant tell you how many batts ive seen die from new people treating them like nimh and running them in the car till almost dead.
Even this is a bad idea. On my cars, the LVC seems to come on as the car was running rock solid only a lap earlier. So I did a little test. I had my LVC set up at 3.3 volts per cell, and when it cut in, it went from a fast lap, clearing the triple, to stopped on the back section. I checked the pack, and sure enough, it was right at 3.3 per cell. I knew it would not hurt anything, so I dialed it down to 3.0 lvc. And guess what, the car had rock solid power again, and did about 3 laps, clearing the triple and all. Then the lvc cut in again, and shut it down. Later I was running one of my crappier 4S packs in my 1/8. 4S is tricky for LVC as a weak 4S could be as low as 12 volts, where a full charged 3S could be as high as 12.6 volts. Well, I ran to a 3.2 volt per cell lvc cutoff and pulled the car. When I got back to my pic, I deciuded to turn it on to run the fans a bit as the motor was quite warm. I use the "auto LiPo" feature on the Mamba Max Pro and when I turned it on, it only beeped off 3 times. It thought my dead 4S was a full charged 3S. This pack was very low, down to 12.5 volts total. For the heck of it, I dropped it on the track and ghave it a puch, It had plenty of punch, and again, easilly cleared the triple jump. I only did 2 laps, cause I didn't want to hurt it. I knew it was low. The pack was down to under 3.0 volts per cell, and was still very quick.

My point is, you can't depend on seeing it go slow and think your safe. LiPo's will easilly crank out huge current and great acceleration to well below 3.0 volts per cell, but they are destroying themselves when they do it. Use a low voltage protection device. The only way I would try running without is if I knew for sure I had 10 minutes of race run time before going to 3.0, and I was running a timed 5 minute race. But even that is risky. Noone drives exactly the same, and a little binding in the car can suck a pack faster than you expected.
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