Tied the warning lamp to the “Gen” lamp on dash, so I get early warning of potential issues.
SOC output is connect to fuel gauge on dash, so I get 20%-100% aligned to E – F on the gauge. Never want to go below 20% SoC, but nice to know I have a couple of “limp” miles even at E.
My legacy BMS (Home brew) is being upgraded – same principle but using Raspberry Pi reading the serial port of the Lithiumate.
2 years of lead abuse and I’m down to probably 10 miles max range. Arriving at the office/home with major voltage sag <110v… 🙁 The batteries were at least 3 years old when I brought them, and in my original plan “buy a cheap set and run them into the ground” so I was expecting not to get this much out of them. In the mean time lithium packs have really started to look really good, very stable, very long life and best of all much lighter. So my plan for the second set is purchase a brand new lithium pack.
Specification
Current pack is 12 x 12v/138Ah Lead Acid weighing in at healthy 1200 lbs in total.
Per my EV calc model that gives me a 43.6 miles @ 30 mph, 25.7 miles @ 60 mph range.
The actual should be somewhere in between two (for commuting).
Experience has taught me 36 miles was the best range I ever got, and still arriving 80%, so it within the range.
For the purpose of comparison the relative range is the key factor, as long as the Li pack is equal or better we should be in good shape.
Cells
Volts/Cell
Pack
Capacity
Total
Weight
30 mph
60 mph
12
12v
144v
138 Ah
19.9 kWh
1200 lbs
43.6 miles
25.7 miles
48
3.2v
153.6v
100 Ah
15.3 kWh
370 lbs
48.5 miles
29.0 miles
48
3.2v
153.6v
160 Ah
24.6 kWh
571 lbs
74.0 miles
45.0 miles
48
3.2v
153.6v
200 Ah
30.6 kWh
686 lbs
90.5 miles
56.1 miles
So the 100Ah option should be equivalent to my existing Lead set up, two major factors here:
1, My research indicates that LiFEPO4 do not suffer that same Puekert effect that Lead so a Li pack of 60-70% stated capacity of a Lead pack should have the same performance – that checks out.
2. It weights 1/3 of the weight
The cost is more or less linear from 100Ah to 200Ah, and although it would be nice to have 80 mile range, my commute does not require it, so the more cost effective route is best for right now. As new battery technologies develop and as commercial offering expand I expect to be able to extend/replace the pack.
Weight
335lbs of Li vs 1200lbs of Lead… this can only be better me thinks…
Volume
Li 100Ah cell: W 7.1 x D 2.5 x H 8.6
Rear battery rack is:-
Each battery is W 13.57 x D 6.63 x H 10.93
Total size is 13.57 x 39.78 x 10.93 = 5900.17 cu in.
Li Pack = 7327.2 cu in. (62% of lead pack)
Lead Pack = 11800.3 cu in.
Will try and fit complete pack under back seat, so can re-purpose the table for cables/tools and behind the driver for a sub… maybe…
Purchased complete battery and BMS from evolve electics, based in Colorado.
Batteries
GBS 100Ah, come pre-strapped in blocks of 4 (12.8v), so 12 blocks of 4.
Written by chivey on June 1, 2021 Tags: Battery, GBS
Range testing today ended probably the only way was going too… randomly loosing power to the control circuit just as we pulled into the liquor store… then dropping dead about a mile from home with a load sensor error. A sketchy tow home and now for some more diagnostics… current actual range is 25miles… that is about half the calculated range? Hmmm… To cap it off while chucking the ball for Bentley, somehow managed to hit the antenna and snap it clean off… bugger!
Written by chivey on May 20, 2021 Tags: Battery, GBS
Removed the troublesome cells 40 and 44⦠rejigged the pack, adjusted settings on Soliton and BMS⦠Running much better! Have upgraded the monitoring system to automatically log data for offline analysis⦠and got the inspection done!!! Yayâ¦
