Dave ,
what charge profile are you going to use ?
177 charging now. Up to 3.36v.
Awesome! (At last I think awesome knowing very little about batteries!).
Stupid question - at 3.5v, should that be 98v for the array of 28 cells?
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On Jul 10, 2019, at 10:05 AM, Inwo via Electric Forum electricforum@discoursemail.com wrote:
July 10Now 88v. After charging to 3.5v (90%) and draining each cell 68ah they are near empty. (10%)
Yes, all test over 70ah @ 10a rate.
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Yes, it is.
This is working perfectly.
10 or so leds came on showing full at 98v.
In cv mode now at 99v 1.5a leds are dimming. Meaning shunts are holding the high cells below 3.65v.
Charger just finished full balance charge in 8 hrs. Threshold must be about 1amp/finish. Over 6hrs at 12 amps. That’s a lot of kwh for “60” ah cells.
All over charge lights are off. 3.38v per cell. 95v total.
This arrangement is so nice and so simple. May have to put these in all my cars.
Shunt balancers rule. We don’t need no stinking BMS. 
Let pack settle over night, test total pack volts, and start discharging for shipment. I hate to part with this one!
A little more work fully testing total pack. Next one I will need to add a couple $100 for a days work.
Is the cutoff voltage adjustable on the shunt boards? Regardless that’s a great setup. At this point I really only plan to use my 28s BMS to easily monitor individual cell voltage and act as a failsafe to protect against overcharging. There doesn’t seem to be much need to balance these LiFePo4 cells.
No there isn’t.
They work perfectly as-is. They never need to do a thing, unless a cell starts to go high.
Monitor is nice to see when battery is low.
The monitor is great when the Bluetooth works. It sucks when BT drops but the app continues to display the old voltage values and you keep driving along thinking life is great only to find your cart is slowing down when you should have plenty of power and then BT reconnects and you realize you’ve got a couple low cells and are now dead on the side of the road. 
I’m lucky to have a tolerant wife and children. Not tolerant in the moment per se but all good eventually, haha.
No drop in voltage overnight. 95.2v this AM.
I will remove the boards for safe shipping.
Time to discharge to a safe level.
12amp load bank.
Oops, my bad. Next time I’ll look.
In any case they should go out tomorrow.
David,
Let me send you the difference in shipping - appreciate all you did to help me out and not right for you to eat that cost.
If I add that all up it is roughly $230 - so shoot you another $130?
Stewart
That would be great.
Totally my fault. I was getting burned out testing and shipping batteries, so I had removed my Ebay listings. After a month off kind of forgot how expensive these were to ship.
Also I shipped in smaller groups this time. UPS treats packages like bowling balls.
I will eat my own mistakes, but I appreciate your understanding.
David,
No worries, and it is my pleasure.
I sincerely appreciate your help in getting an electric-■■■■■ like myself up and running on lithium.
Will send shortly.
Stewart
David,
I see the batteries are in route and should be here on Thursday - so excited to get this up and going!
Two stupid questions - (i) are there any special instructions / best practices for installation of the lithium cells that I should be aware of etc?, and (ii) is it possible to have the existing battery/power monitor in the dash work with this set-up to have an idea of how much charge is left when I am out and about?
Thanks,
Stewart
The newer gem soc meter can be set. A cheap meter on the dash is better.
I forgot that you need a voltage spoof for 28s.
I’ll get one in the mail.
David,
Batteries arrived, as did the charger - so wanted to let you know. Believe you were sending the spoof separately, so will keep my eye out for that.
On installation - anything to watch out for etc, or is this as simple as replacing the existing? You mentioned adding a cheap monitor to the dash rather than using the factory installed one - any specific monitor you would suggest?
On maintenance - what are best practices for maintaining these batteries in the best way? Believe I read Lithium doesn’t like to be stored fully charged?
Stewart