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  1. #1
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    lipo discharge question

    kinda new to the hole electric world here have had my share of nitro trucks but i just got into electric in past few months after buying a friends slash 4x4 and e revo from him but i was informed i need to store my batteries a certain way when im not using them and the charger i ended up getting from my buddy dosnt have a discharge option at all ..so i was wondering what it is i do is there a way around it other then goin and buying a new charger.. the one i got is a Primal multi chemistry ac balance charger its kinda a cheepo starter charger it seems but i mean if its worth just going and buying a good one i will ig but if i can work around it that be grate to id use money to make one of my trucks better instead

  2. #2
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    I have been using my lipos for years and don't bother doing anything but charging them when I run them. I try to keep them full so I don't have to wait when I get a chance to run it. I too have a basic charger/balancer (Dynamite Passport) works well for me.

  3. #3
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    u dont notice then die down over time or anything doing that ? and i mean i use them at least once a week so its not like they sit to long longest is few days... and i mean it kinda makes seance what u say because i use the new millwaukee brushless drills at work and we keep them batteries fully charge at all times and they dont lose any power ...that was actually how we where told to store them

  4. #4
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    Proper lipo care says to store them at 50% charge, it does make a difference on the longevity of the battery and its performance. So 3.85 volts per cell.

    There really only is one way to discharge them and thats to load them. If you have a good charger most come with a storage feature and will charge or discharge them to obtain the storage voltage. If you dont then the only option is to run them down then charge them back up and watch the voltage and stop the charge when it get of 3.85 or there abouts. Even a 24 period is considered storage. Millwaukee batterys are lithium ion not lithium polymer, a bit of a difference.

  5. #5
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    DO NOT store lipos with a full charge. it damages them over time. Pack life can be reduced by years when doing this. You want to store lipos at 3.8v per cell. Thats how all lipos come from the factory and they can be stored like that for years.

    If you want to get the most life out of your packs never let them sit charged for more than 12 hours. I still have my first lipo i ever bought from April of 2010 because i followed these rules. And that pack still has the punch it had when it was new.

    Storing them full can also create a fire hazard. If the temp rises more than a few degrees from when you charged them, the voltage of the pack will increase and the lipo WILL puff and could start on fire. Either way, the pack is done.

  6. #6
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    Quote Originally Posted by WJ Jeep Guy View Post
    DO NOT store lipos with a full charge. it damages them over time. Pack life can be reduced by years when doing this. You want to store lipos at 3.8v per cell. Thats how all lipos come from the factory and they can be stored like that for years.

    If you want to get the most life out of your packs never let them sit charged for more than 12 hours. I still have my first lipo i ever bought from April of 2010 because i followed these rules. And that pack still has the punch it had when it was new.

    Storing them full can also create a fire hazard. If the temp rises more than a few degrees from when you charged them, the voltage of the pack will increase and the lipo WILL puff and could start on fire. Either way, the pack is done.
    Where did you get this information? It is a lipo battery the same as the one in you tablet, cell phone, cordless phone, etc

  7. #7
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    actually most phones, tablets, laptops, etc, are lithium ion batteries. and those have a much different chemisty. And thats also a different situation. Those batteries are constantly in use which is what lithium batteries need to have a long life. Sitting in general damages them. A lithium battery that is used often will last much longer than a lithium battery that sits. Meaning you will get more cycles out of it before the internal resistance is too high, and capacity is lost.

    I have all of this information from the companies themselves and many years of experience.

    For example, at our LHS they keep the RC helicopter batteries charged all the time ready to give demos. They have to replace those every 6 months because they dont have enough power to get the heli off the ground. I have the same batteries and helis, i keep them at 3.8v when i store them, and those batteries are 3 years old now. Those are the same type of batteries that we are using, and ive seen the same thing with airplane packs and car packs.

  8. #8
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    And back to what the jordankeis originally asked: you dont need to get a new chargers to drain the lipos. The most simple way is to just run the trucks for a bit and run the packs down. The other way is to make a light discharger, you get some automotive taillight bulbs, like 4 of them, solder them together and put a battery plug on the wire. Then those will discharge the battery. I know a lot of people that do this, and i have one for the times i dont have time to drive the cars. However with lipos you have to be very careful doing this. If the lipo is drained too far (past 3v per cell) it will be damaged. So if you go this route you will need a multimeter to monitor the voltage. Or a cell checker/ balancer would work as well. So run the pack down to 3.7v per cell and remove from the discharger.

    heres a cell checker that works good: http://www3.towerhobbies.com/cgi-bin...?&I=LXAEPR&P=7

    the cell checker is good to have in your pit box anyways, its also a balancer.

  9. #9
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    would i need to get anything els to make that cell checker work ? i differently would like to be able to store them the right way and see where the cells are at.... but do they make chargers that can discharge and tell u what cells are at ? and if so how much would something like that run about i mean if i buy a new charger i guess i wont be to mad because i am sure id get sick of mine one way or another being that it only charges 1 at a time and kinda makes for long wait time if i play with my revo ..kinda why i haven't been playing with that one so much

  10. #10
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    oo and one other question if im using the batteries at least once every 3 days is it ok to leave them sit full then ? or is that even bad ?

  11. #11
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    the cell checker just plugs right into the balance port on the lipo. so no changes need to be made.

    If you want a charger that discharges you can get a dynamite passport ultra. it only charges 1 battery at a time but its a great charger.

    Even leaving them charged for 3 days isnt good. I dont like to let mine sit overnight. Although i dont worry too much about that. Ill only do that if i know I'll be running the truck the next day. If they need to sit for a few days i run them down.

  12. #12
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    mm ok good to know ... so for now in mean time till i got some spending cash what would be best thing for me to do ....can i just go run the battery till it trips the esc cut of and be good or is that to low even? and for the charger u mentioned are u talking about the 150w or the 200w ? i went on ebay typed it in and get a few different ones
    Last edited by jordankeis; 01-14-2013 at 08:42 PM.

  13. #13
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    you can run the pack all the way down, but you dont have to. if you do just throw it on the charger until it gets to 3.8v per cell then stop it. Otherwise just run the truck for a while and stop. and if its close to 3.8v per cell just leave it. It'll be fine for a few days. Just dont store them empty or full, both are bad.

    heres the charger I'm talking about: http://www.horizonhobby.com/products...cycler-DYN4064

  14. #14
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    Quote Originally Posted by jordankeis View Post
    would i need to get anything els to make that cell checker work ? i differently would like to be able to store them the right way and see where the cells are at.... but do they make chargers that can discharge and tell u what cells are at ? and if so how much would something like that run about i mean if i buy a new charger i guess i wont be to mad because i am sure id get sick of mine one way or another being that it only charges 1 at a time and kinda makes for long wait time if i play with my revo ..kinda why i haven't been playing with that one so much
    There are plenty of chargers on the market that have the storage function and will charge or discharge as necessary to obtain the 3.85V/cell. They do come with a cost though but if you are going to invest in it may as well do it right and save yourself the guess work. You can expect to spend $175-$250 for a good one. I run the Hitech X2 400W/channel that will charge the batteries at 20 amps per channel. Takes me 12 minutes from storage charge to full charge with 2 of them charging. For a power supply I use a 1300W converted server power supply, cost me $16.99 shipped on ebay and another $15 in wire and a binding post etc to convert it. Commercially made power supplies specific to RC use with this much power run in the $200+ range.

    When Im done I plug the batteries into the charger and cycle to storage charge and it does its thing. If they are too high it dischages them, if too low it charges them. When its done it beeps and I put them to bed.

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