Optima to LiPo Conversion

[Kingfish]

Greetings –

My Machinist has this really cool ol’ Chevy Love PU that he recently converted to electric drive. Under the hood, it reminds me of White Zombie, but only briefly 8)

Anyways – his truck is powered by Optima D34 batteries, QTY-10 in series for an operating voltage of 120VDC. Because of the weight he can’t put too much more into the truck, and because of capacity he can only go about 20 hilly miles; good enough to take to work and back but not much else.

I was thinking that if he converted to LiPo the weight would go way down and he could add back more capacity. The problem is that I cannot clearly see how to figure the capacity of the D34 in order to predict a proper replacement.

What would you use and why.
Thanks, KF

 

[fizzit]

Well the reserve for a battery is the minutes it lasts at 25a I believe and that one is 25a for 120 minutes so 50ah at a 2hr rate. For a replacement, 50ah of lipo should last at least a little bit longer and weigh a lot less, I think!

The rough cost of that would be:
$55/6s5ah brick shipped to our area

120v/22.2v = 5.4
5.4 packs in series * 10 parallel * $55 = $2970

 

[Kingfish]

Well the reserve for a battery is the minutes it lasts at 25a I believe and that one is 25a for 120 minutes so 50ah at a 2hr rate. For a replacement, 50ah of lipo should last at least a little bit longer and weigh a lot less, I think!

The rough cost of that would be:
$55/6s5ah brick shipped to our area

120v/22.2v = 5.4
5.4 packs in series * 10 parallel * $55 = $2970

Mucho thanks for that explanation. The reason he didn't go Lithium was that someone quoted him $12k USD for like-capacity

Calculating weight:
D34 = 42.9 lbs each x 10 = 429 lbs.
Zippy 6S1P 15C = 1.58 lbs each x 5.4 x 10 = 85.12 lbs. Yeez I could carry it on my back!

Whatcha think, 15C be good enough? Or should we get nanoized?

OK, so let's take $12k / $2970 roughly equals 4, so for about $12k he could get 4X capacity (80 miles) and still weigh less at 341 lbs.

That's pretty neat. Means he can make a run into Seattle and back. <sigh> He'll prolly pay for it off my machining work :lol:

Cool thanks, KF

 

[wesnewell]

Looks to me like th D34 is a 55ah battery. About 25ah of lipo would get the same or more range. 50ah of lipo should more than double his current range. His 10 batteries fully charge to 135V @ 2.25V per cell (the voltage of a good sla cell). So 36s lipo would be his best bet @151.2V fully charged. Using 15C lipo @25ah would provide 375A continuous with 625A burst output power. Double both of those if you went with 50ah. Should be way more than enough. He should know the max draw of his controller. Cost for 25ah @$45 per 6s pack would be $1350. I have no idea what shipping would be for 30 6s packs, but can get a discount off the regular $45 price for sure. He'd also have to spend a bit for charger equipment.

 

[dogman dan]

Some big Thundersky or equivilant lifepo4 cells would be my choice. It's not for a race, and you want max cycle life. Yeah, you can get a lot of cycles from well cared for lipo, but lifepo4 treated similar would be even more cycles.

Big bux. I haven't calculated it in years, but it was about 15 grand when I was looking at a truck or car with about 70 mile range in lifepo4.

 

[neptronix]

I've thought about doing a lipo car conversion, but i am not at that level of insanity yet
Too many friggin' wires imho. Imagine wiring up about 10kWh of that stuff.
Imagine worrying about 10kWh of that stuff going up in smoke!!
Maybe if you can keep it low volt and high amps, like 76v/20S or so. Then it would be way easier to monitor and live with than say, 200v+..

Thunder skys are like the pings of the car cell world.
GBS are interesting, a bit higher discharge C, and still fairly affordable i think.