Battery pack made from several small modem packs.

[goatman]

Like I said in my previous post my test of these cells is looking promising. 20p in my case is working out to be around 53.5ah. I suppose if I need to I can change my final build to 13s30p for 70ish ah. I don't expect to pull crazy Amps from this pack, I have lipos for that.

max discharge of this cell is 5amps from 5c to 40c? Amberwolf has the data listed above, cant remember exactly

0.2c is 500mah but isn't that just how it was tested? and nothing to do with a recommended discharge rate

 

[Sidotian]

Ignore the max discharge rateing you want to pay more attention to the continuous discharge rateing. Don't pull more than one amp a cell for example if you have a 20p pack keep the amps under 20 amps. Don't forget even a controller rated at 20 amps could spike well over that for a few seconds. But keep the discharge under 1amp per cell period.

 

[john61ct]

C-rate and resistance related info from datasheets is usually very suspect if not pure fiction.

Read the reviews from trusted members and related discussion threads for more reliable data.

 

[goatman]

C-rate and resistance related info from datasheets is usually very suspect if not pure fiction.

Read the reviews from trusted members and related discussion threads for more reliable data.

hey john, I was hoping youd chime in, if they recommend charging this cell at 0.5c/1250mah why cant you discharge this pack at a max of 0.4c/1000 mah

 

[john61ct]

Nobody says you can't.

That sure isn't a high bar, for someone shooting for fast and light would not be suitable.

And you won't actually know until you try, get objective data hands on.

 

[goatman]

sidotian is doing the testing

yes, I like fast and light but im still learning so topics like this I consider as a test question, I read it and see if I get the answer right. I think the answer is , if the max discharge rate of the designed pack is lower than the recommended charge rate then whats wrong with sidotians pack, hasn't sidotian just built a pack that you would recommend building?

I know you prefer brand new quality cells like a 50E although it only has a standard discharge rate of 0.2c/980mah

 

[john61ct]

I'm not checking your answers man but most cells considered decent around here, 5C is low peak many seem to want much higher.

Personally I'm a low C-rate guy.

And yes would not consider secondhand cells unless they were thoroughly tested verified "as new" by someone I trusted.

 

[dogman dan]

Pretty much what I keep saying,, they will work fine in a 50 ah pack.

But 50 ah is a lot of battery to carry on a normal bike. Maybe you are doing something else? but this is the bike section, sooo…

I did build a custom frame that could easily carry 80 ah, but that does not mean it was going to ride nice with 60 pounds of battery on board. It did fine though, with about 38 ah on board.

So if you can carry 50 pounds without having a bike that wobbles above 10 mph, great. my custom frame was crazy stiff, much stiffer than any normal cargo bike frame.