My experience bulk charging lipo with BMS 400w charger

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My experience bulk charging lipo with BMS 400w charger

Postby atom1025 » Tue Feb 21, 2012 9:12 pm

So I recently invested into bulk charging. I purchased the necessary cell protection from Methods and purchased two 400w chargers from BMS. One charger at work one at home.

I chose 4.10v per cell so 61.5v output at ~3amps. I only use 5amps to and fro so charging takes about two hours.

Been running this for a week now and love the plug and play charging.

So my concern. The resting voltage after charge reads 61.05v (4.07per cell)on the 101wattmeter. The resting voltage after commute is around 54-55v roughly 3.6 per cell.

So it appears I am only using the lower spectrum of my pack. Obviously power is down a hair on the way home. So my question to ya all is.... Do you think using the lower end causes more abuse to the pack then say using the upper?

So I am kinda thinking bout getting a new charger with 62v output. 4.13 per cell. Put me more into the upper mid range.... might try and modify these chargers, myself since they are paperweights if replaced...
Bashed Synergy Cycle runs
1800w peak, 31mph tops.

2004 Cannondale Jekyll with a MAC 10
15s 8ah lipo (2100w peak) 31mph tops.
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Re: My experience bulk charging lipo with BMS 400w charger

Postby neptronix » Tue Feb 21, 2012 9:17 pm

4.15v would provide you a decent amount of additional power, remember that these are normally charged to 4.2v/cell. So 4.15v/cell is still conservative.

3.6v is about where they are ready to start diving for 0v.. i usually stop at 3.45v/cell, anything lower than that, and the internal resistance rises to the point where the cells can actually disbalance themselves & start heating up.

( we're talking about RC Lipo ( lico ), i take it )

Image

^-- turnigy 20S 5AH pack being discharged.
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Pro-tips for noobs: Avoid BMS Battery like the plague | Charge RC Lipos to 4.15v, stop discharging at 3.5-3.6v | Use torque plates/arms! | Rear mounted hubs are always best
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Re: My experience bulk charging lipo with BMS 400w charger

Postby wesnewell » Wed Feb 22, 2012 2:47 am

I'm pretty sure you can adjust the voltage on those chargers so there's no need to order another one. Just adjust the voltage up to 62V.
Mongoose 26" FS MTB bike $99, yescomusa.com 48V 1000W rear hub kit $276, Hua Tong 72V 40A controller $35, 10ah 24s lipo $275=40+mph, range=45 miles @20mph
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Re: My experience bulk charging lipo with BMS 400w charger

Postby miuan » Wed Feb 22, 2012 3:18 am

Theres a lone blue pot inside, at the corner of the board, that adjusts voltage. Take a thin screwdriver, turn it to get the desired voltage, as easy as that.
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Re: My experience bulk charging lipo with BMS 400w charger

Postby atom1025 » Thu Feb 23, 2012 9:46 pm

miuan wrote:Theres a lone blue pot inside, at the corner of the board, that adjusts voltage. Take a thin screwdriver, turn it to get the desired voltage, as easy as that.


Hells yeah! Easy peazy!

I adjusted up to 62v. The charger cutoff when pack reached 61.5v. So I adjusted it up to 62.5v and I hope it cuts off at 62v. I'm staring at it now monitoring temps and volts.
Bashed Synergy Cycle runs
1800w peak, 31mph tops.

2004 Cannondale Jekyll with a MAC 10
15s 8ah lipo (2100w peak) 31mph tops.
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Re: My experience bulk charging lipo with BMS 400w charger

Postby atom1025 » Thu Feb 23, 2012 10:11 pm

The charger cutoff @ 62.1v( measured at the pack leads) with the output voltage set at 62.5v.

It is indeed the blue stand alone pot in the corner by the fuse. Turn it counter clockwise to turn voltage up.
Bashed Synergy Cycle runs
1800w peak, 31mph tops.

2004 Cannondale Jekyll with a MAC 10
15s 8ah lipo (2100w peak) 31mph tops.
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Re: My experience bulk charging lipo with BMS 400w charger

Postby Scottyf » Thu Mar 01, 2012 4:05 am

Just wondering if the smaller 240w bulk chargers also have a pot in them if anyone else know's?
I have a feeling their not but would be interested to know.

Might have to buy another bulk charger for my needs as there quite a bit simpler for charging 9 lipo bricks...

Just wondering as the 240w charger has the same case as the 400w. That obviously means its not garanteed to be the same. But it would be nice to know.
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Re: My experience bulk charging lipo with BMS 400w charger

Postby docnjoj » Thu Mar 01, 2012 3:57 pm

Even my old Ping 2 amp charger has a voltage adjust pot. I had to cut it open to find it, but it works fine to adjust the voltage from 61 volts for a 48 volt pack to 45 volts for a 36 volt pack. Both have BMS that need the higher voltage to balance in these Signal lab BMS's.
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