[jorhyne]

120 V is a lot for bike judebert, and 300 V is just unnecessary for a motorcycle!

If he was trying to sell batteries for electric cars I would agree, but for electric motorcycles his offerings are in the right range. I emailed him to see what his prices look like.

[TX_Dj]

Originally Posted by jorhyne

300 V is just unnecessary for a motorcycle!

If he was trying to sell batteries for electric cars I would agree, but for electric motorcycles his offerings are in the right range. I emailed him to see what his prices look like.

Bill Dube' and the Killacycle team would disagree with that first statement. That bike runs at 374v.

He is trying to sell batteries for electric cars- this is his third post to the forum on the subject, the other two threads exist elsewhere.

Due to the fact we don't permit cross-posting and duplicate posting of the same subject by the same poster, I'll go ahead and merge all the topics together.

[ElectriCar]

7.71lbs/battery x 41 batteries = 316lbs for a 13Kw pack at 131V. At 3.2V/100ah.

That would be versus 30Kw of my 1375lb lead pack using US 2200 6V batteries weighing 62.5lbs each. The entire Lithium pack would weigh the same as 5 of my batteries!

With a 78% Weight Reduction I'm wondering what Kw pack I would need for the same mileage as my lead pack in my S10 truck. Anyone know how to figure that out?

[madderscience]

Well the two big sources of drag on a car (at steady speed on the level) are aerodynamic drag and Rolling Resistance.

Aerodynamic drag will not be affected by the lighter batteries.

Rolling Resistance is basically a constant proportion of about 1% to 2% of the overall weight of the vehicle, regardless of speed. So if your truck weighs 4000lbs, and your Rolling Resistance coefficient is 1% or 0.01, drag due to Rolling Resistance would be about 40 pounds. If you lose 1000lbs going to a smaller battery, then Rolling Resistance is 30lbs instead.

At 55mph speed for an S-10, aerodynamic drag is roughly 2/3 of the total drag on the vehicle, and Rolling Resistance is the balance. So using these rule-of-thumb numbers, aerodynamic drag would be about 80 pounds of force and rolling is 40lbs, then the change to lighter batteries would drop your overall steady state drag force from 120lbs to 110lbs. Not a big change in that regard.

However hill climbing and accelerating (which take energy that is proportional to either the mass or the square of the mass of the vehicle, I forget my high school physics) then a drop in weight of 1/4 from 4000lbs to 3000lbs again using totally hypothetical numbers could be quite significant.

Keep in mind that the C rating of the LiFePo4 batteries you are looking at may be such that you need to go to a larger amp hour capacity to ensure that you don't overload the batteries with too much current draw.

[ElectriCar]

I'm in the foothills of mountains so it's pretty hilly. Not steep but seldom flat. Lots of stop & go often which is why I'm building this thing. I'm using it for travel to work and work errands around town. No need for a 4 door diesel truck for such trips. I'm expecting a savings around $3000-3500/year on fuel only.

I've already purchased my lead pack but when it goes, I'm replacing it with Li. Prices should be down significantly by then.

I'm just wondering if I have a 30Kw 1375lb lead pack with a range of 60 miles, what Kw pack would I need to get the same mileage with Lithium. To date I've not really found out a way to calculate that. You're 4000 lb gross is very close to what it will be.

[Technologic]

These prices are about as low as I've seen anywhere, but the pack I want is still 2700 dollars.

Even with my ground up 500-600lb tandum 2 seater, all carbonfiber/aluminum/fiberglass car I'm currently designing, I don't see how I can get below a Cd of 0.1. 4kwh is about the minimum I'd want even with solar panels as there won't be any regen.

I'll have to mull over my financial books on this one.

[Uncle Joseph]

Using their 48V 100Ah pack on ebay as a price example, a 144V pack would be roughly $8400USD.

If these batteries are the correct spec and have BMS and charger, this is by far the best deal going, from what I've found. They offer a full refund if you return the batteries within 7 days...probably not possible if you don't live in China. However, if the 1-year warranty is worth anything, these again could be decent. Free shipping too...almost worth the risk!

With the language barrier, I'm worried about the discharge spec. I'm considering ordering 4 100Ah cells to test. Don't know if I can make EV discharge/amp draw/etc. conclusions from a 12 volt test pack though.

[frodus]

Originally Posted by Uncle Joseph

Using their 48V 100Ah pack on ebay as a price example, a 144V pack would be roughly $8400USD.

If these batteries are the correct spec and have BMS and charger, this is by far the best deal going, from what I've found. They offer a full refund if you return the batteries within 7 days...probably not possible if you don't live in China. However, if the 1-year warranty is worth anything, these again could be decent. Free shipping too...almost worth the risk!

With the language barrier, I'm worried about the discharge spec. I'm considering ordering 4 100Ah cells to test. Don't know if I can make EV discharge/amp draw/etc. conclusions from a 12 volt test pack though.

Its not bad at all...

has me reconsidering.

[chamilun]

as these include the bms & charger (plus one year warranty??), a 144 system breaks down this way:

3 48V 100ah systems = 8394

I was planning on using a t1275 or equivalent:
$218/pc * 12 = 2616 + $900 charger = $3500 (excluding tax & shipping). plus no bms on the fla batts

so, this lithium pack is 2x more expensive, but 3x+ the life cycles.

I havent determined the price on a 200 ah pack (wish there was a 150ah option)

is my math right?

[Uncle Joseph]

Originally Posted by chamilun

is my math right?

That's how I calculated the cost for a 144V 100Ah system. There are probably a few things I haven't considered that will adjust the price slightly. One of the things he shows in the eBay listing is that the chargers have a built-in BMS. To my understanding, for that to work properly with a LiFePO4 pack, you'd need a charger for each battery...one BMS will not work for a series-wired pack. So, for the 48-volt pack, does that mean they're shipping 16 chargers?

Still a little cloudy on the specifications of their packs...particularly stable discharge rates. I just sent him an email asking for a price quote on 4 - 100Ah cells with BMS & charger for testing purposes.