15 or 20 Ah ?

[Treasurer]

My father bought the eBike 24 Volt Comfort electric bicycle with no batteries. It has the 400 watts motor.
I need some advice if the 15 Ah battery would be strong enough or we need the 20 Ah's?
We are in contact with Li Ping, he suggested to buy the 20 Ah stronger one.
Please help us with your experience!
Thanks,
Treasurer

 

[Battboy]

It's very hard to give you any advice because there are many differences in Cells no matter if they are 14Ah or 30Ah. Would have to know what you expect out of this bke?

Don Harmon

 

[Lessss]

More amp hours equals longer drive time.
What you really need to know is how many amps the motor/controller needs - - then you need batteries that will deliver that C rate.

 

[dumbass]

Personally I would consider the Thunder Sky 20ah cells (packs) at http://elitepowersolutions.com/products/index.php?cPath=16&osCsid=26af044c24272b20635b69ce1c1a16c2 For the money I think they are a better deal then Pings packs. And if you have any problem they are warantied in the USA not in China like Ping's cells are.

Bob

 

[Treasurer]

It's very hard to give you any advice because there are many differences in Cells no matter if they are 14Ah or 30Ah. Would have to know what you expect out of this bke? Don Harmon

My dad working at a pizza place, which is about 7 miles from our house. He would like to use it to go to work.

 

[Treasurer]

Personally I would consider the Thunder Sky 20ah cells (packs) at http://elitepowersolutions.com/products/index.php?cPath=16&osCsid=26af044c24272b20635b69ce1c1a16c2 For the money I think they are a better deal then Pings packs. And if you have any problem they are warantied in the USA not in China like Ping's cells are. Bob

Thank you for the link Bob! I will check them out. I see that they have a distributor less than 50 miles from us in St. Pete (we are in Sarasota, FL).

Thanks again to all of you for the quick replies!

 

[Lessss]

7 miles - - your laughing
10AH on a scooter style bike ( motor does all the work) will easily do that.

 

[dogman dan]

Yes, 10 ah will be plenty of range. But pings last longer when the average discharge rate in amps equals the pack size in amp hours. ( 1c discharge rate) So I wouldn't advise a 10 ah ping.

so 400 watts divided by 28v = about 15 amps. So while the motor may pull more than 400 watts on a start, it's likely that the pull when cruising full throttle will be 400 watts or less. So a 15 ah ping would be getting discharged mostly at no more than 1c rate. A 20 ah would give more range of course which is good. So the TS 20 ah or ping 20 ah would be better. And the c rate would be even less which is also good.

 

[dumbass]

Yes, 10 ah will be plenty of range. But pings last longer when the average discharge rate in amps equals the pack size in amp hours. ( 1c discharge rate) So I wouldn't advise a 10 ah ping.

so 400 watts divided by 28v = about 15 amps. So while the motor may pull more than 400 watts on a start, it's likely that the pull when cruising full throttle will be 400 watts or less. So a 15 ah ping would be getting discharged mostly at no more than 1c rate. A 20 ah would give more range of course which is good. So the TS 20 ah or ping 20 ah would be better. And the c rate would be even less which is also good.

Of course we don't really know that that motor is going to draw 400w max. It would depend a lot on the size of the controller which is unknown. I have yet to own an ebike that didn't double the rated wattage draw when at a high load at full throttle (like starting from a stand still or climbing a hill). So that motor could easily draw 800+w under load. I like to use a packs 3.2v per cell rating so I'll just say at 800w/26v=about 31a at max load. In my thinking a 20ah with 2c rating is more of a must then luxury.

I hear different things about the C rating of Ping packs from .5c to 3.0c. Never having one I don't know what is correct. Are they different for different size modern cells (from what I've heard older cells had a lower c rating)?

 

[dumbass]

Personally I would consider the Thunder Sky 20ah cells (packs) at http://elitepowersolutions.com/products/index.php?cPath=16&osCsid=26af044c24272b20635b69ce1c1a16c2 For the money I think they are a better deal then Pings packs. And if you have any problem they are warantied in the USA not in China like Ping's cells are. Bob

Thank you for the link Bob! I will check them out. I see that they have a distributor less than 50 miles from us in St. Pete (we are in Sarasota, FL).

Thanks again to all of you for the quick replies!

I'm glade they are so close to you. Most people with TS packs will speak very highly of them but if something should go wrong it would be easy for you to return them. What distributor is so close to you? I think Elite Power Solutions is in Phoenix, Az. If you choose to go with TS cells watch out for the pricing. I have seen those same 20ah pack ranging from $120 (W/O balancers) to $260. They are great packs at $120 but I wouldn't pay $260 for them. Of course you could always show them the EPS site price and they may match it.

Bob

 

[dogman dan]

Yes, without a wattmeter on that motor we are all guessing what it's real draw is. No doubt there will be an amp spike much higher than 400 watts on start up, or climbing a long steep hill.

But I doubt the controller is over 20 amps or they'd call it a 600 watt. I still wouldn't hesitate to use a 20 amp controller with a 15 ah ping provided the use wasn't climbing hills constantly or pulling a trailer. There is a pretty good track record of pings in the 15 ah size handling 20 amp controllers. Typicaly a few short higher watt discharges do no harm if the battery gets to enjoy a cruising wattage that is a lot less.

But for sure, except for the size and weight of it, a 48v 20 ah battery is much better to have than a 48v 15 ah. Any cell is happier with the lower c rate of discharge you get when you increase the size of the battery.