dead battery

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 said:

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.

Click to expand...

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.

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.

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.

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!

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!

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!

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 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.