dead battery

[Lungcookie]

Thanks for putting up with me guys.
Looks like the BMS was 20a/1000w...more dummy move on my part.
(Can upgrade to 1500w) which I didn't do. dumb dumb.
I didn't know that 1000w for me was not enough...first eBike.


I got addicted to the amps...and need more!

I started running at 10a, felt like I was riding a resistance exercise machine. My mom could have ridden this no problem.
Turned it up to 20a, that was ok but not really what I was looking for.
Turned it to 30a, I liked it and that's where it stayed. Would have scared my mom.(she is not athletic nor a speed demon)
I would have turned it to 40a but I was thinking the MP3 controller was only good to 1500w.

I used to play with R/C stuff back in the late 80's early 90's.
I was all-ways pushing stuff faster, past its intended application.
One electric boat I had (still have) would de-solder the wires right off the motor, but man was it fast! Then you went for a swim.
I could hardly drive my buggies and trucks because I would gear them up so much. One truck I could launch over a 6ft fence.
Looks like I haven't changed.
Man those NiCads could take some abuse.

Stared crashing R/C helis a few years ago, the trend continued. Replaced with faster motor more aggressive blades.
Now cooking eBikes on a forum near you!

Thanks again for holding my hand thru this. kevyleven007,cannonball2.
Live and learn, from my mistakes...when I make them you (forum members) wont have to.

 

[paul]

if you have the built in controller for you magic pie 3 they are limited to 30a, it will take the higher settings however it will still only upload up to 30a on your controller. I just realized that the other day when playing with mine. so mine is set at 30a and max 70a. also make sure throttle is set to 100%. that makes a big difference.

 

[Lungcookie]

if you have the built in controller for you magic pie 3 they are limited to 30a, it will take the higher settings however it will still only upload up to 30a on your controller. I just realized that the other day when playing with mine. so mine is set at 30a and max 70a. also make sure throttle is set to 100%. that makes a big difference.

Yup, that's what I was running however my BMS (battery management system) was only rated for 20a, that what cooked.
Now I cant find a BMS in north America for under $100. All the rest are over seas with 3+ weeks shipping.
I am getting the notion to break this battery into 4, so I can charge it with my R/C balance charger, use the CA for LVC...but then It turns into a hassle to charge./sigh it was so nice and easy.

 

[motortriker]

A rc balance charger will give you more feedback about what is going on with the cells and is the best way to troubleshoot a battery pack.

One hooked to a computer display will really show what is going on.

This really opened my eyes to li ion batteries.

http://www.hobbyking.com/hobbyking/store/__7348__imax_software_kit_.html

I now use a Hyperion 1420 hooked to a display.

A bms will sometimes mask battery pack problems that a balance charger will show right away.

Once you get the pack to charge right with a balance charger ( a good pack does not take long to balance ) then put a bms on it.

Use a fuse to prevent over discharging the pack. I would not count on the cheap mosfets. They tend to short out when they fail.

Lipo alarms for lvc.

http://www.ebay.com/sch/i.html?_trk...lipo+alarm&_nkw=lipo+alarm&_sacat=0&_from=R40

Try and solder the loose cells fast like this.

http://www.youtube.com/watch?v=vkDgoXikI_8

 

[cannonball2]

Im in the middle of this battery build still waiting on the rest of the cells. It is constructed so that it consists of 7.4 cells that are modular. I can charge them on my R/C charger individually to balance them. Wont do it this way every charge but as is needed to attain balance. Checking balance is easy with a voltmeter. It has no BMS to limit draw, my controller does that. I didn't have a very good experience with my BMS, so really am trying to operate with out one. If I maintain balance and the controller limits amperage I don't see the need, just something else to fail. Posted this incase you decide to break up your pack. Also I can add more modules if I want to up the voltage in the future. http://motorbicycling.com/showpost.php?p=552242&postcount=5

 

[Lungcookie]

More fun with batteries!
Pulled this pack apart, 4, 12v bricks.
Tested each cell, all but 3 cells where about +3.31v.
3 cells read .792v! WTH
So I am thinking 3 cells are bad.

Then after looking for batteries I came across this trick. Combo of a MB members recent battery build thread and a R/C forum.

I am NOT saying DO THIS to fix your battery.
This seems to have pulled these cells back from the grave...so far.
May have been related to the BMS failure?

This is using a B6AC+ SkyCharger.
Batteries read 'low voltage' when in LiFe and wont charge.

Set charger to NIMH manual mode.
Charge at 0.5a.
Watch screen, stop at 2.5+v (LifePo).
Change to LiFe mode.
Charge as normal.

The cells sitting over night read 3.31v, 3.31v,3.30v.
I am in the process of charge/discharge cycles, I will see what happens.

I was trying to over think some single cell holder.
Still probably overkill, 2 magnets could hold the charger leads.
Ended up putting a rubber-band on the cell to hold the strips, 2 strips of copper slip on next and small bar clamp to hold the strips solid. Clamp gives a nice handle for a burning battery. Charger has a temp probe so hopefully no fires. Batteries are not even getting warm.



Learning and re-learning as I go.

 

[Stoney]

What ever came of you battery.

 

[Lungcookie]

Turns out I had 1 dead cell, just constantly lost voltage.
Found similar battery(cells) from a California seller, $20/4cells.
They are 3200mh where as the cells in the original pack should be 3300mh.
I will see if it works out.

The entire pack got torn down to single cell then rebuilt with 10gauge solid copper wire.

 

[cannonball2]

Nice work!

 

[snellemin]

Nice work Lungcookie.

 

[Stoney]

I have a codd power 48v 20ah pack as well that died as well. I took it out of the white box then removed all the tape which happened to un connect 2 of the tab welds thro6gh out the pack. Now every row is 3.31 then the next row 3.32 in each 12 cell group. EXCEPT on one row within the 12 cell group all 6 cells read .33.
What do ya'll suggest?
I am so impressed with what cannonball and you have done. On endless sphere they make it seem that it is impossible to solder cells and both of you have done it with success. So hopefully I will add to the group!
I have a stokemonkey mid drive on a sun atlas cargo bike. It is great so I want to get back to riding as soon as possible. The controller will run on 36v or 48v. So I don't mind running it on 36v (designed to actually run on 36v and is capable of carrying over 600lbs up the steepest san fransisco hills with the motor not even warm. It is a pretty impressive set up).
So what should I do. This is what I have- 48v 6ah charger that came with battery, 24v 1.5 ah lifepo charger for my 24v 6.5ah currie newlife battery (a123 cells), 3- 24v 1.5ah sla chargers, a volt meter, a 17w (I believe) solder iron.
I will buy what ever necessary. Now I will shut up and listen...

 

[cannonball2]

Basic advice would be to dismantle the pack and find all the weak cells. You could still run it as a 48v(preferable to 36) but maybe at a lower ah rating. If so many cells are bad then maybe voltage dropping would be necessary. 20ah is a big pack, so there should be plenty of cells to salvage. You didnt mention a BMS. If there is one then rebuilding @48v would be easiest.

 

[Lungcookie]

Sorry I was a bit light in details in that last post...In my case it was a row of 3 cells (10ah battery) and 1 cell was killing the row.
So I would guess 1 cell maybe killing your 6.
You would have to pull that row apart and charge each cell at 3.2v-3.3v. Use that trick as per post #26.
Let them sit for a couple days then test voltage, hopefully most will read about 3.31v.
The bad cell/cells will just keep loosing juice.
I am not sure any of the chargers you listed will work(for testing) but you can get a R/C lipo balance charger for about $20.
Watch out for that tin strip, it is very sharp. Looked like I had a fight with a cat when I was done.

If you build them into 12v bricks like the way I did you can run them in any configuration you like, series or parallel to get different voltage or Amp hour.
You could use your lipo chargers.

I was using a 40w solder iron, flux paste, tinner and 60/40 solder.
Keep your iron clean(tinner and sponge and wire brush if needed). Rough up the cell.
Put a small dab of flux on the cell, touch solder to iron then touch iron to cell.
I hot glued 3 cells together before soldering.
Next, Flux on wire place wire on cells hold in place with skewer, touch iron to solder, place iron on wire and cell.
A little goes a long way with the flux and solder.

I used a piece of bamboo skewer to hold the wire in place.
The wire I used was from housing electrical 10awg/3, I had a roll in the garage had to pull insulation off.

Happy to help if I can, I am learning as I go.
Good luck!

 

[Stoney]

Thanks,

can you give me a link to the rc balance charger that you recomend? And Is this the same thing that you are using to charge your pack when ever you charge or you are using another one.
I like your set up and I think I will copy yours.
cannnonball
yes, it has a bms but maybe thats why it went south. I don't know. I think I may run w/o one like you 2.
I am a total noob. I don't even know what flux paste is. So I will write this stuff down bring oit to home depot or where ever and say I need this.

First thing i need is a charger - correct
please feel free to give me any additional advise remember I am a noob so there is no such thing as too much details - I AM STUPID - treat me that way please
Lungcookie your explanation is the type of breakdown I am looking for
thanks in advance you 2 and everyone else on this forum!!!

 

[cannonball2]

We are kinda jacking Lungcookies thread here I hope its ok with him. Im not first hand famiilar with this battery chemistry, but have read the specs. It seems 3.65 is a max charge voltage where as Li based batteries max at 4.2. Unless the R/C charger has a setting for these batteries(mine are older and dont)there would be a mismatch in voltages. Pack voltage is based on the cells rated voltage Lis are 3.7. If these batteries are 3.3 then there is no proper voltage of a lipo charger to charge bricks to. I charge with a common SLA charger and just monitor the voltages. When I cell balance I use the r/c charger on the individual bricks. If the newer chargers have a setting for these batteries then forget the above.
I like running with out a BMS where the pack is built in balance able cells. The controller limits the amperage, and controls the LVC for standard voltages. Theres one less thing to fail.
Lungcookies build method is a good one, very nice work. One thing to remember dont use acid core/flux on electrical soldering. Rosin is the type. Avoid the newer no lead solders they dont solder as well. I trash canned a $14 roll from the Depot.
Hang in there and have fun. Once you build a pack, buying one is jut no fun and $$$.

 

[Lungcookie]

No worries on the hi-jack, sounds like its the same issue I had.
I am using a Skycharger B6AC+.
Looks like most of them now are the IMAX B6AC charger, google or Ebay for best price or whatever you shop. Looks like closer to $35.
Cool little charger, it will charge NiCd/NiMH, Li-ion, LiPo, LiFe, and PB(Lead-acid) batteries. 1-15cell NiCd/NiMH and 1-6cell Li-ion/Poly.
It has build in auto cutoff for high and low voltage per battery chemistry and cell count.
The only real drawback is the max charging voltage is 20v, so its only good for one 12v battery at a time.
On a thread over on endless-sphere someone suggested using a cell phone charger to put some volts into the low cells.

I plan to use the 48v 6amp CODD charger for bulk charge. However I have not done this, that charger is putting out 59.9v. Kevyleven007 said something about turning down the voltage so... I am not sure on that one. Seems like it should work to me but like I said I haven't tried it yet.
-edit-Bought a 4x charger, can balance and monitor cell health.

Flux paste is a metal cleaner and helps the solder to flow.
You may not need it but it helps.
If you cant find any try in a plumbing store for joining copper tube.
It leaves a residue I cleaned off with Q-tips and isopropyl alcohol.
Like cannonball2 said on the solder, tin/lead rosin core.


If you have never soldered anything before I don't recommend practicing on your batteries those cells are $5-7 each.

If anything blows up just blame it on cannonball2! j/k
He started all this with his battery build.
THANK YOU cannonball2, saved me some money!

 

[Lungcookie]

Wanted to add that these 12v batteries are in fact 13.5v, so x4 54v.
Couple more pics, ignore the copper wire, I used 12gauge and hammered it flat then found some 10 gauge and rebuilt my rebuilt packs!

 

[Lungcookie]

So far so good.
Had to figure out a battery holder, .30 cal ammo can worked perfect.
Seeing as how I didn't need a new battery, I splurged on a 4x charger.
After 11 miles the battery reads 52v and used almost 5Ah, mostly flat pavement, 3 miles gravel road. Pedaling more than half the time just cruising 20mph.

 

[cannonball2]

Really nice work LC! Great idea on flattening the wire! Love the ammo box. Dont know what motor/controller set up you are running but if it will tolerate 60+v, add some cells. The difference is pretty cool on speed. Not sure with the cells you are using but my 59v pack charges to 62.5v. Its a lot of fun in the first several miles. Cool thing about modular batteries, just keep adding modules for either ah/voltage or both.

 

[Lungcookie]

cannonball2 strikes again.

I had 3 extra cells, the ammo box will fit 6 more...maybe
Made a little single pack out of the 3 and hooked it up.
Now its a 56v ammo can.

I was not sure a couple extra volts would be noticeable but it is a bit faster top speed.
Charges to just over 59v, the Magic Pie 3 is 60v-63v, I think. Seems like I saw somewhere.
So it right at the edge, but it didn't blow up!

Not to sure about this new charger, it keeps giving an over voltage alarm balance charging. It is taking 1 cell to 3.68v, in a 4 cell pack, then the alarm sounds. One more thing to figure out.
The Skycharger B6AC balances to 3.59v-3.60v every time.

This has been a good lesson for me, I know I will build the next battery I need.