If I may, I would like to add some of my experiences with Lipo.;
SO6S/LCD-3 sine wave controller/display on 12S-
I tried several times, but never could get the system glitch free. I never did figure things out and just went back to a square wave controller. My "gut" feeling was, the sine wave did not like the odd Voltage values of the Lipo.
10S-
I was vacationing at the beach and riding on the broadwalk, so I wanted to lower the 3-speed range of my system to make it more versatile at low speeds. I ended up going to 9S, to better match the 31V LVC of my 36V controller. That's a little low, as cell Voltage @ end of discharge was ion the 3.20V to 3.30V range. Top speed with a mid-speed motor was around 15 to 16 mph.
Charging-
It really is best to avoid "breaking" the pack to charge. The chances of making a mistake are too high. At one time, there were three 12S-14S balance chargers available in the States, but now we are down to one, the Thunder 1430C, but with a Power supply, it's over $200US. I am currently bulk charging using a Industrial LED lighting PS, the Mean Well HLG-320H-50A or HLG-320H-54A;
http://www.mouser.com/ds/2/260/HLG-320H-spec-226092.pdf
Here is a short review;
"It is, in effect, a poor man's Satiator(Grin Cycle) in the way it works and what it can do.
The first thing that is noticed is it's weight, It no lite weight, due, no doubt, to to it's robust construction and the fact that is fully potted. I have not used it as an on board charger yet, but would have no qualms doing so. It is very slim and I'll take on some extra weight if it means the charger is vibration and weather proof(Designed for outdoor installations).
Here are some of it's features;
Auto adj. AC input, 115V or 220V.
95% effcicency
Short circuit/over-current/over-Voltage/over-temp. protection.
Voltage adjustable(42-53V for HLG-320H-48A, 48-59V for HLG-320H-54A)via internal potentiometer reached from the outside though a port(see pic).
Constant Current level(0-6.75A) adjustable via internal potentiometer.
How it works;
First off, unlike some balance chargers, it makes no difference on the order of how it is connected.
I plug in the AC cord first and the mini Voltmeter I added reads the final out-put Voltage(For example, I set it to 48V for an end-of-charge storage Voltage of 4.00V/cell).
Then I plug it into the pack(I never get a spark doing this) and the mini meter reads the pack's state of charge Voltage.
It starts charging immediately and silently and it is fast.
Unlike balance chargers, it does not interupt the charging, to cycle though, to read cell Voltages.
Just a constant 320 Watts(the Satiator does 380W).
As it approachs the end-of-charge value, the Constant Current mode attenuates to current to the shut-down point, at which the current is just a trickle and a soft internal switching relay can be heard.
It is safe to leave it this way, but since we are talking Lipo, the charging process should not be left unattended anyhow. A timer on the AC input could be installed to turn it off completly(reports from other users, report that is only a very small drain when the pack is left connected w/ no AC input).
I may add something to read Volts and current, but so far, I just leave the current adj. to max.
Words cannot describe how nice this unit is to use. It makes my old Thunder 1220 seem like a PInto compared to a Caddy.
Since it is designed for industrial use, it is much better quality that any of the chargers designed for RC use.
It might seem expensive at $135, but w/ a 5 year warrenty, I would say it's a bargin and one of the best Ebike purchases I have made."
I use Battery Medics to check/balance. The thing about Battery Medics is, there are so many clones of them, care must be taken when ordering them as some don't work well. The ones from Hobby Kings are, strangely, among the worst. The Ebay ones are OK, but the genuine Battery Medics, which I get from hobby suppliers are the best.
Lipo Quality- I have used both Zippy and Turnigy Lipo and am of the opinion the Turnigy lasts longer.
Even with all the new versions of Lipo that have hit the market recently, I still think the Turnigy 20C 6S, 5000 mAh are the best value.
Lipo and controller LVC-
Most 48V controllers will have a LVC of 42V. This matchs 12S perfectly, with an end of discharge cell Voltage of 3.65V, just at the point where the cell Voltages are starting to stray.
