48V 18650 configuration

[kje]

I've been using a 13s9p 18650 pack for my Bafang BBS02 750W motor on my folding bike for several months now. I live in Austin, which makes Oslo look flat. If you watch your gearing, high amps is only about 18amps, on a 20 degree hill in 1st gear. Normal biking conditions, the battery is pushing ~10 amps to get to speed, and if I don't watch it my peak will max at 25a for a fraction of a second if I forget to drop gears before a hill. So you should be fine.

Sorry I wrote wrong, I meant 7p!
I wonder if 7p is enough for BBS02 750W with used laptop cells. Average capacity is 1.5A for each cell after testing. (Both voltage sag and capacity test) So the battery pack will be about 10.5A. Is 10.5A enough?

The reason I ask is limited space in the middle of my bike. ☺

 

[kje]

If you build your pack with some additional Jst plugs on the balance wires, you still can speed balance the pack using 1s charge or discharge mode. And perhaps even better, you can use those plugs to monitor how well it's balanced, or when it's 90% charged.

What I mean is the balance wires that lead to the bms will have a Y splice, so you have wires to the bms, and wires to jst plugs. Definitely do that if you are building your own pack. Watching a cellog 8 as your pack charges can show you the bms is working, which cell fills first, which one the bms is discharging, etc. Great info to have.

How do I speed balance the pack using 1s charge or discharge mode? What jst plugs do I use? Two 6s plugs and one 2s plug? How do I connect this to the charger and what charger do I use for this? My Imax B6 or my 48V power supply?

 

[kje]

Anyone?

 

[kje]

I connected this Adjustable MeanWell type 48V power supply to my 13s battery pack with a meter between that measured 7A for a second and then the adjustable power supply died.

Any idea why it just died?

http://www.ebay.com/itm/271852793055?_t ... EBIDX%3AIT

 

[999zip999]

A cellog is just to check cell voltage and balance. I never leave my battery plugged in to anything no bms. But I use A123 20ah cells 16ah at most and discharge the pack at 50amps and 780 cycles. But who wants the weight of lifepo4.
Use high quality cells, don't waste your time with used laptop cells.

 

[wesnewell]

Could have something to do with pulling 7A from a 3A rated supply.

 

[kje]

Could have something to do with pulling 7A from a 3A rated supply.

Shouldn't the power supply limit the current by itself?

 

[DrkAngel]

If you bought a charger ... yes.
Cheap power supplies will output unregulated amps and quickly burn up.
Even MeanWell quality power supplies will output beyond rated and burn up. They can briefly output beyond rated to satisfy surges or starting demands. Usually regulated at ~130% of rated amps.
The MeanWell models I specified are capable of modding to precisely regulate amps.

 

[DrkAngel]

Moved from MeanWell thread.

I bought this 7.5A 360W 48V power supply. (As my last 3A 150W 48V fried)

http://www.ebay.com/itm/311001005100?_trksid=p2057872.m2749.l2649&var=610293600576&ssPageName=STRK%3AMEBIDX%3AIT

Can I Remove R33 & R38 and replace with a .5k (500ohm - 500B) pot? Will this allow ~0A to 5.4A adjustment?

Only the specific models of genuine MeanWell brand power supplies are guaranteed to use those specific components for that specific function.
Some, unidentified, clones might have copied identically?

400w 48V clone is available with mods documented.
See - Meanwell clone- AD488.3-400W power supply mods

Can I solder inn this 5w 22ohm resistor in series between my 7.5A 360W 48V power supply and the battery pack? Will it reduce the amps while charging?

http://www.ebay.com/itm/400552119082?redirect=mobile

Adding a resistor in line will reduce current.

Reduction is dependent on resistor size and value.
Current restriction is for entire range and more effective dependent on voltage differential.

But ... running 350w through a 5w resistor might severely restrict amps with resultant extreme heat production.

 

[DrkAngel]

Recommend you use your iMax in series with 48V 350w PS.
Adjust PS to 42V.
Rig in series with iMax set to 3s Lipo ≤5A (dependent on iMax capability)
42V + 12.6V = 54.6V (13s x 4.20V = 54.6V)
Drop PS voltage if safer cell voltage desired ...
53.95V - 12.6V = 41.35 (13s x 4.15V = 53.95V)
53.3V - 12.6V = 40.7V (13s x 4.10V = 53.3V)
etc.

Important! Confirm electrical isolation between PS and iMax.
No continuity from PS DC neg and iMax DC neg.
No continuity between PS housing and iMax housing.

 

[kje]

I have this 7.5A 360W 48V power supply. I will charge my 13s pack with 54.6V. Can I solder in a resistor in R35?

A 220 ohm resistor will be 54.6V / 220 ohm = 0.248 A?

Sounds like I should have a smaller resistor like 10 ohm? 54.6V / 10 ohm = 5.46A?

And what wattage should it be? (The resistors physical size determine the wattage)

 

[DrkAngel]

I'm guessing, that for some unknown reason, you believe R35 in this power supply controls amp output?

Circuit board does not compare to power supply that uses R35 for such function!
Component layout is similar ... but different!

Obtain circuit schematic from manufacturer?
or
Take additional picture of underside of circuit board so R35 function might, possibly, have a chance of being determined?

 

[kje]

Is R35 reducing the amps on this board?

 

[kje]

I've taken additional picture of underside of circuit board so R35 function might, possibly, have a chance of being determined?
Does R35 in this power supply controls amp output?