I'm seriously considering a switch from FLA to a Li battery pack. Can
anyone recommend a good supplier in the Pacific NW (Oregon) area?
My current 114V pack of T-125 batteries is on its way out, and with the
replacements @ $145/ea ($2,755) I'm hoping I can find a Li pack that lasts
at least 5 years for maybe 2x the price. I'm hesitant to purchase another
lead pack as a bridge near me will be closing for a while, adding 10 miles
to my standard 15 mile trip (which I can barely make now). Even with a new
pack I could only get 25-28 miles (in the summer) before voltage sag
became an issue.
114V, 100AHr equates to 36 cells.
CALB = $4860
TS = $4500
Add $500 for a mini-BMS system to prevent overcharge/discharge and the
total is $5360. The only big question is: Will they last 4-5 years???
-Adrian
RUMORS I've heard:
- TS strapping hardware is better built than that of CALB
- CALB cells are a bit stronger (electrically/chemically) than TS
- The "other" brand of large format Li cells is junk
- Kokam and other name brand cells are $$$$ or impossible to get
- Watering floodies sucks (OK, that's not a rumor)
- All battery salesmen are out to cheat you
The MATH:
1987 VW Cabriolet @ 114V. 3,600 pound curb weight. Zilla 1K-LV controller.
A typical 14 mile trip uses ~4KWHr (measured with a Kill-A-Watt meter).
Typical recharge time is ~2.5 hours with a PFC-20. Timeout after reaching
charge voltage is 30 mins, so approx. 2 hours @ 20A for the bulk charge.
4,000 WHr/14miles = 285 WHr/mile
20A * 2Hr * 114V = 4560WHr 2560WHr/14miles = 326 WHr/mile
Call it 300WHr/mile for typical driving - 30-40MPH, hilly roads, final
drive home is 45 seconds of 200A from the batteries to climb a moderate
hill.
To make 24 miles (standard 14 plus the extra 10 while the bridge is
closed) I'd need 300WHr/mile * 24miles or 7.2KWHr of energy. Limiting to
70% DOD makes that 10.3KWHr, or 90AHr cells @ 114V. Alternatively that
would be 71 AHr @ 144V.
My car currently cruises at 50-120A depending on speed and grade, and
takes 150-200A for "normal" acceleration. I have one short hill that
requires 250A to maintain 15MPH. I almost never hit 300A unless I know I'm
doing a short 6 mile run for groceries.
Using this data, 100AHr cells should function nicely. Typical 0.5C to 1.3C
discharge, with < 1 minute bursts of 2C. For 114V I'd use 36 cells @ 3.2V
nominal. I could go to 144V (46 cells) with a change of DC/DC and heater
relays. Absolute limit would be ~200V/3.6V = 55 cells (176V) based on the
"nominal" 156V rating of the Zilla-LV.
A 114V pack would drop my curb weight by 980 pounds to ~2617 pounds (2687
pounds @ 144V)! I assume that will have a very positive effect on
acceleration and current draw going up hills... Is the era of Li finally
here?
_______________________________________________
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anyone recommend a good supplier in the Pacific NW (Oregon) area?
My current 114V pack of T-125 batteries is on its way out, and with the
replacements @ $145/ea ($2,755) I'm hoping I can find a Li pack that lasts
at least 5 years for maybe 2x the price. I'm hesitant to purchase another
lead pack as a bridge near me will be closing for a while, adding 10 miles
to my standard 15 mile trip (which I can barely make now). Even with a new
pack I could only get 25-28 miles (in the summer) before voltage sag
became an issue.
114V, 100AHr equates to 36 cells.
CALB = $4860
TS = $4500
Add $500 for a mini-BMS system to prevent overcharge/discharge and the
total is $5360. The only big question is: Will they last 4-5 years???
-Adrian
RUMORS I've heard:
- TS strapping hardware is better built than that of CALB
- CALB cells are a bit stronger (electrically/chemically) than TS
- The "other" brand of large format Li cells is junk
- Kokam and other name brand cells are $$$$ or impossible to get
- Watering floodies sucks (OK, that's not a rumor)
- All battery salesmen are out to cheat you
The MATH:
1987 VW Cabriolet @ 114V. 3,600 pound curb weight. Zilla 1K-LV controller.
A typical 14 mile trip uses ~4KWHr (measured with a Kill-A-Watt meter).
Typical recharge time is ~2.5 hours with a PFC-20. Timeout after reaching
charge voltage is 30 mins, so approx. 2 hours @ 20A for the bulk charge.
4,000 WHr/14miles = 285 WHr/mile
20A * 2Hr * 114V = 4560WHr 2560WHr/14miles = 326 WHr/mile
Call it 300WHr/mile for typical driving - 30-40MPH, hilly roads, final
drive home is 45 seconds of 200A from the batteries to climb a moderate
hill.
To make 24 miles (standard 14 plus the extra 10 while the bridge is
closed) I'd need 300WHr/mile * 24miles or 7.2KWHr of energy. Limiting to
70% DOD makes that 10.3KWHr, or 90AHr cells @ 114V. Alternatively that
would be 71 AHr @ 144V.
My car currently cruises at 50-120A depending on speed and grade, and
takes 150-200A for "normal" acceleration. I have one short hill that
requires 250A to maintain 15MPH. I almost never hit 300A unless I know I'm
doing a short 6 mile run for groceries.
Using this data, 100AHr cells should function nicely. Typical 0.5C to 1.3C
discharge, with < 1 minute bursts of 2C. For 114V I'd use 36 cells @ 3.2V
nominal. I could go to 144V (46 cells) with a change of DC/DC and heater
relays. Absolute limit would be ~200V/3.6V = 55 cells (176V) based on the
"nominal" 156V rating of the Zilla-LV.
A 114V pack would drop my curb weight by 980 pounds to ~2617 pounds (2687
pounds @ 144V)! I assume that will have a very positive effect on
acceleration and current draw going up hills... Is the era of Li finally
here?
_______________________________________________
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
