RC Lipo pack inspection, series/parallel charging, and lifespan/safety tips

[neptronix]

I wanted to give you guys a little update on what is going on with my lipo usage since i wrote this tutorial.

I still have a 10S pack. It is 4 years old with around 300 cycles on it and is still giving good capacity and staying in balance. Cherry picking the 20C 5AH packs out of 10 packs that i bought has worked out very well for me.

I made a big 12S pack from 15C Zippy lipo 2 years ago ( 30AH ). One of the packs had a slightly wonky cell in it. I left the battery discharged over the winter and the slightly wonky cell went bad, puffing up a little and leaking electrolyte. Lame! the other cells in the battery were down to about 2.9v on average. I took out the bad pack, slowly charged the rest of the packs 3.8 at 0.1A and made a 25AH pack out of what was left.

I hope to upgrade to the turnigy multistar packs in the near future. These 15-100C batteries are generally 150whrs/kg whereas the multistar are 190whrs/kg. I can fit 25ah into this triangle now, but with multistars, i can fit 30-40ah... that's rockin!

The same lipo advice i've given correlates with what you should do with Turnigy multistars. The discharge curve looks to be identical.

More threads by me on that topic:

Turnigy multistar VS. allcell comparison:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=62932&start=25

Maximum battery that can fit into a triangle bag:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=67485&p=1016496

 

[longwise_suck]

thats a real nice bike is that a mac on the back wheel?

 

[neptronix]

No. I no longer have a mac. I am running a leafmotor. ( read my signature for the build link )

 

[Anveshsameer]

HI ya.... Last week I got stuff from HK and, last night I was charging the batteries.....
Here is the info
2x5s lipo
5000mah
I charger 1010b+
during my 1st charge I charged them upto 3.7v each
And next time when I left the charger to charge for 4.15 each, charger shows 4.2 v on each cell in the display and beeps indicating charging is completed.
When I check the voltage pack by a multimeter, it only shows 34 volts on total and 3.4v on each cell.
I had only discharged to 3.2volts on my first ride.
Any idea what's happening? I went through manual several times and also through forums, but couldn't find anything regarding the issue..
Help guys!

 

[wesnewell]

Timer? Now edit your post and delete all the quoted part which is 99% of your post.

 

[Anveshsameer]

Timer? Now edit your post and delete all the quoted part which is 99% of your post.

what i actually see on the charger is

But, when i check the individual voltage of each cell, it is 3.1v i know it must be some changing in settings, that is what i was expecting from the readers ifthey had some experience with this JUNSI 1010B+ charger.
BTW sorry for quoting that long post,i wouldnt have drawn your attention if i hadnt done that!
Maybe i should read more about TIMER settings.

 

[longwise_suck]

Have you balance charged?

 

[MrDude_1]

Timer? Now edit your post and delete all the quoted part which is 99% of your post.

what i actually see on the charger is

But, when i check the individual voltage of each cell, it is 3.1v i know it must be some changing in settings, that is what i was expecting from the readers ifthey had some experience with this JUNSI 1010B+ charger.
BTW sorry for quoting that long post,i wouldnt have drawn your attention if i hadnt done that!
Maybe i should read more about TIMER settings.

you probably are attempting a normal charge or a fast charge.
when you see that, you need to do a BALANCE charge.. or a discharge run.... so it can discharge the high cell and bring everything closer...

 

[longwise_suck]

Those cells are new you need to balance charge them and cycle them a few times before they behave, I'm hoping you understand lipos?

 

[Anveshsameer]

Have you balance charged?

yes, i balance charged them at 2 AMPS..
All i found on the charger during charging is

 

[longwise_suck]

I think you need to re-read this post some what carefully, you have one cell out of balance and it is at 4.2 volts ok what are the others at?

 

[Anveshsameer]

I think you need to re-read this post some what carefully, you have one cell out of balance and it is at 4.2 volts ok what are the others at?

BNBR longwise_suck...
I think you better re-read my question i had quoted at the start.I had some basic knowledge on lipos and well experienced with Formula student Electric from past 2 Years, and I'm not that dumb to leave a cell to get charged to 4.2V, I had quoted my problem saying that i had issues with wrong reading on the charger.
Now coming to the issue, there is no cell in the pack even charged to 3.2V !!
But the Charger shows around or greater than 4.1v on each cell.

 

[MrDude_1]

I think you need to re-read this post some what carefully, you have one cell out of balance and it is at 4.2 volts ok what are the others at?

BNBR longwise_suck...
I think you better re-read my question i had quoted at the start.I had some basic knowledge on lipos and well experienced with Formula student Electric from past 2 Years, and I'm not that dumb to leave a cell to get charged to 4.2V, I had quoted my problem saying that i had issues with wrong reading on the charger.
Now coming to the issue, there is no cell in the pack even charged to 3.2V !!
But the Charger shows around or greater than 4.1v on each cell.

looks like your charger is screwed up. can you setup a power supply as a 1s setup, and test it?

 

[dnmun]

the guy who posted the picture of the yellow voltmeter is measuring the full pack voltage of a 10S pack and not the individual cell voltages it appears.

but what is most obvious is that the battery is dead on his DVM so his measurements are totally useless.

 

[Anveshsameer]

I think you need to re-read this post some what carefully, you have one cell out of balance and it is at 4.2 volts ok what are the others at?

BNBR longwise_suck...
I think you better re-read my question i had quoted at the start.I had some basic knowledge on lipos and well experienced with Formula student Electric from past 2 Years, and I'm not that dumb to leave a cell to get charged to 4.2V, I had quoted my problem saying that i had issues with wrong reading on the charger.
Now coming to the issue, there is no cell in the pack even charged to 3.2V !!
But the Charger shows around or greater than 4.1v on each cell.

looks like your charger is screwed up. can you setup a power supply as a 1s setup, and test it?

Ok...looks like i have overcharged one of my cell, but when i try to discharge my pack through the balancer, charger keeps on displaying "BALANCE PORT CELL HIGH VOL"
what should i do?

 

[BShady]

Got another qu!

Is it bad for the batteries to charge it in parts ( 1 hour increments) or should I charge the whole battery at one time (3 hours straight)?

 

[longwise_suck]

i charge mine in one go, i have the same charger as you i use the temp sensor jammed in the middle of the pack and touch wood so far never had a problem, the problems with these chargers always seems to be when your discharging

 

[geosped]

Advice needed: I'd like to make a 12S LiPo 10,000mah battery.

My charger has limitiations. I can only charge a 6S to 5,000mah

I'd like to utilize the two Turnigy Accucell-6 charger that I currently own. Should I just buy 4 6S 5000mah batteries and wire two of them up in Parallel then in series? OR

Is there an inexpensive charger from Hobby King or other that would charge up to a 12S 10,000mah battery? This would be better as I would have more options as opposed to sticking a bunch of batteries together.

Goal= 12S 1000mah 44-48v battery= 4 6S 5000mah 2 in parallel 2 in series correct??
Purpose= Offroad mountain biking hilly terrain. Tracks are no longer than 4-5 miles.

 

[longwise_suck]

I use the charger above, it only charges 6s but at 10 amps an hour i use a balancing board to charge, the battery set up your are aiming for is exactly what I'm using on the flat running around the town just 25 - 30 kph i get almost 40 kilometres

 

[DrInnovation]

Advice needed: I'd like to make a 12S LiPo 10,000mah battery.

My charger has limitiations. I can only charge a 6S to 5,000mah

I'd like to utilize the two Turnigy Accucell-6 charger that I currently own. Should I just buy 4 6S 5000mah batteries and wire two of them up in Parallel then in series? OR

Is there an inexpensive charger from Hobby King or other that would charge up to a 12S 10,000mah battery? This would be better as I would have more options as opposed to sticking a bunch of batteries together.

Goal= 12S 1000mah 44-48v battery= 4 6S 5000mah 2 in parallel 2 in series correct??
Purpose= Offroad mountain biking hilly terrain. Tracks are no longer than 4-5 miles.

Lipos need constant care and feeding to stay healthy.

The 12s packs I've seen (e.g. Spider have a break out for 2x6s balance leads.

Your charger should be able to charge two 6s in parallel, it will just take longer as it will only output 125 watts so it will take twice as long to charge the parallel pack.

If you are doing standard Lipo in 2S 2P 6S packs (which may be 2p or 3p in each 6S pack depending on manufacturer) you should balance charge the packs then connect their main power leads in parallel (e.g if using Deans T) then connect balance wires in parallel with something like this which will keep the 2p groups balanced while in use and also allow you to group charge them/check them. Then connect parallel power leads in series..

But for every day (I commute) I bulk charge my lipos with a modified Meanwell, and checked regularly with a celllog for blance and took it apart to charge the groups when needed. I also did not push the voltage, generally charging only to 4.05 average and only 4.2 when i knew I'd need more power. I did that for a year and just finally added a BMS so I don't ahve to keep taking it apart to balance charge.

 

[amberwolf]

My charger has limitiations. I can only charge a 6S to 5,000mah

Already told ya how to fix that in one of your various threads.

 

[neptronix]

Cheap RC Balance chargers such as the ones that hobbyking rebrands and sells have a place - in the garbage can.

Get a name brand unit that receives good ratings and has a company that stands behind it. They will have more features than you know what to do with, and be so accurate that you'd need a very expensive multimeter to see any variation in how well they balance the cells.

When you are playing with the most dangerous battery chemistry you can buy, you do NOT want to cheap out on some charger that is not well built. Inaccuracy of many cheap balancing chargers makes a dangerous battery chemistry even more dangerous to handle.

http://hobbyking.com/hobbyking/store/__6792__iCharger_106B_plus_250W_6s_Balance_Charger.html
This is the cheapest charger that i can personally recommend buying - the entry level into the iCharger brand. They also have a 10S model.

http://www.progressiverc.com/charge...ID=smpvgvor9thn29ipa3k153phv1#page=1&top=684&
This is how much high end, well built chargers generally end up costing.

 

[longwise_suck]

hello, does anyone have a clue why one of my packs jumps out of balance at every discharge? 3 are perfect but this one pack 2s2p will point blank refuse to stay balanced and it is never the same cells in the same small packs, it makes me want to pull my hair out, the other 3 are set up exactly the same and always run perfectly..im at a loss, any tips would be warmly received

 

[MrDude_1]

hello, does anyone have a clue why one of my packs jumps out of balance at every discharge? 3 are perfect but this one pack 2s2p will point blank refuse to stay balanced and it is never the same cells in the same small packs, it makes me want to pull my hair out, the other 3 are set up exactly the same and always run perfectly..im at a loss, any tips would be warmly received

there are only two reasons:

1. they see a different load/charge -- check all connections for starters. recheck circuit design. make sure nothing is pulling from one set without the others.
2. cells are going bad.

 

[longwise_suck]

this is what drives me nuts its the same set up as all the others!! maybe somehow i got all the crap cells together in one pack