# Thread: Li-Po Lithium Ion batteries for electric handcycles.....

1. ## Li-Po Lithium Ion batteries for electric handcycles.....

So far it's just been Sealed Lead Acid batteries. These things are great, but they are heavy. Well, now e-bikekit has started selling Lithium Ion batteries and I wanted to put the prices out there.

As you can see they are pricey. However, I just sold one of my customers the 48v 13ah battery so we will see how he gets on.

• Sealed Lead Acid: 36v 12ah = \$204
• Li-Po: 36v 15ah = \$644
• Li-Po: 36v 20ah = \$844
• Li-Po: 48v 13ah = \$624
The weights for the Li-Po's is about 1/3 of the SLA. The SLA quoted above weights about 25lbs.

I have not tried the Li-Po's myself, but I hope to have a go soon.

Personally, my feelings at this point is to stick with the SLA's. I like that they are "cheap". I do not worry about the extra weight, since you cannot really feel the weight when you are up to speed.

But I am glad that the Li-Po's are out there, and I hope they will come down in price one day.

2. Thanks Mark for the update on the lithium battery. I look forward to reading a report from your customer who is using one now.

3. What current draw is involved with an electric handcycle?

4. Originally Posted by Andy
What current draw is involved with an electric handcycle?
Good question. I will take a guess*

W=IV

W = Watts/Power
I = current
V = volts

I = W/V

I = 500/48 = 10.4 Amps

HOWEVER. With the 48v option the power output can max out at 1000W. This would equate to 20 watts.

The battery would not last so long at this output though...!

* - WARNING high school physics ahead, take with pinch of salt

5. Originally Posted by MarkB701
Good question. I will take a guess*

W=IV

W = Watts/Power
I = current
V = volts

I = W/V

I = 500/48 = 10.4 Amps

HOWEVER. With the 48v option the power output can max out at 1000W. This would equate to 20 watts.

The battery would not last so long at this output though...!

* - WARNING high school physics ahead, take with pinch of salt
Lipo would be light years ahead on this application just on the weight aspect itself. 1000W is childs play for good cells. Ok, the 48V 13Ah battery, if it is of a common 30C cell generation, it is capable of 30 times 13Ah discharge for 390 Amps, multiplied by the voltage gives 18720 watts, convert to HP gives 25HP support...subtract for motor efficiency, lets use 80%... about 20 horses o' fun. This is assuming the handcycle is using a brushless design (usually 3 phase).

Now somehow I suspect that a brushless controller of this output and a handcycle are economically on other sides of the spectrum though...what sort of motor are these using?

Longevity-wise...Lipos of good quality can handle around 100 cycles, more if they are not run down to excess keeping the temperatures cool. Also, if they are not running at full constant output, they can run at a slow discharge rate just fine like a lead acid battery, but at a closer level to its rated voltage until the capacity is used up...then the voltage drops quickly (and if continued to be used, possibly damaged due to letting the cells get below their stable voltage level).

Did I mention that the 30C constant battery can handle short burst of double that...like 60X capacity for 780 amps...I think you'll need some 0 guage cable for that, lol. And they make 60C batteries lately .

Out of curiousity, those 48V 13ah batteries...do you have a size and weight spec on those assembled cells?

6. Any other advantages on the Li-Po batteries other than weight savings?

7. Originally Posted by DaleB
Any other advantages on the Li-Po batteries other than weight savings?
Power output. I did some rough calcs...given the right motor/technology setup...how's a reliable 20 horspower handcycle sound to you?

8. Originally Posted by Andy
Power output. I did some rough calcs...given the right motor/technology setup...how's a reliable 20 horspower handcycle sound to you?
Absolutely, incredibly, and in all other ways: FUN!

For my money, I'd be after extended range before speed, I think.

I'd have to be in to hand cycling, first, of course.

9. Originally Posted by DaleB
Absolutely, incredibly, and in all other ways: FUN!

For my money, I'd be after extended range before speed, I think.

I'd have to be in to hand cycling, first, of course.

It is so much FUN Dale. This is the first innovation to come along that really levels the playing field. Rather than a/b cyclists slowing down for me, They can either draft behind me at 18t mph or I have to slow down for them.

If a person can backpedal to work the brake and push the throttle switch up and down, they can ride again or for the first time.

I've always loved handcycling, it's what keeps me sane. The last few years has been a challenge with worn out shoulders etc. The PP has brought the fun back into it bigtime.

I'm stickin' with my SLA batteries mainly because of the quick dropoff in juice with a LiPo. I'm getting ready to buy another 12vlt battery to bring it up to 48vlt so I can do an extra 15 or so mile. I have the 15ah 36vlt for that little bit of extra juice and the new 12vlt will be 18ah.

10. Originally Posted by DaleB
Any other advantages on the Li-Po batteries other than weight savings?
The disadvantage of the Li-Po is that they don't discharge slowly like the SLA's. They go from full power to no power in a very short time while the SLA's decrease more slowly before full discharge.

Is the 48vlt 13ah one battery or four like the SLA's? Will have to check them out.

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