Battery current Output??

[EV_dub]

I'm looking to size up a battery pack for motorcycle project.

Will be running a lynch D135 RAG with alltrax 7245 .

Ok, so the controller will be limited to 400amps peak and 200amps continuous to suit the motor.


The LiFePo4 batteries from Hipower China have a 200amp max draw, and 120amp continuous (40AH X C3)

I need to choose the correct BMS to suit this application.

???

[timpootle]

Are you sure you can run 40Ah HiPower cells at 3C continuous?

I bought 200Ah HiPower cells, and was advised not to run them above C/3 continuous, or 60A. I know Russ Sciville runs his Elise on 40Ah cells at 40A continuous, or 1C, but this is against the advice of the manufacturer.

[retepsnikrep]

I agree with Tim. I have 50 x 40ah Hipower in my phev hybrid and they don't see more than 100A max drain for short periods. Mostly I run at under 1C. IMO they will not deliver the power you are looking at. They will sag to very low levels at anything approaching 200A

They are good cells for more modest drain though.

You might be better looking at Lifebatt cells or A123 pouch cells 15-20ah.

Just another option I have ben looking at over last few days.

A123 Cells

Model: AHP 70165227 Model: AHP 68150211
Capacity: 20Ah or Capacity: 15Ah
Size: 7.0X 166X227mm Size: 6.8X 150X211mm
Weight: 480g Weight: 400g

Endless-sphere.com • View topic - 2.5USD per Ah for 15Ah and 20Ah 30C cells

I had a quote from the supplier on the forum.

Price breakdown to UK is as follows:
50 * 20Ah cell = 2500USD
shipping = 280USD
paypal commission, 3.4% = 95USD
Total = 2875USD or £1775

The basic specs for the cells are phenomenal and the Insight will hardly touch their charge/discharge C ratings. 30C discharge!

I'm tempted!

[GregsGarage]

My experience with the Hipower cells is they shouldn't be discharged above 1C average current. 2C and even 3C are o.k. for brief acceleration. When looking at battery manufactures specs, concentrate on "average discharge rate" rather than maximum or burst rates. you will find that most if not all of the prismatic cells average discharge rate is around 0.3C to 0.5C. These are fine if your vehicle is going to have over 1 hours driving time. If you need only need half hours driving time then you need to find cells with average discharge of at least 2C. Also LiFePo4 may not be the best choice for a bike with limited room for batteries. Lipo cells are smaller for a given ah capacity and you need fewer of them due to their higher voltage of 3.7 volts. The winning bike in last years ttxgp used kokam lipo cells. This meant the bike had more fuel and so could go faster around the course. Have a good look on the EV photo album for similair bikes to yours. This should give you some idea of current draw.

[EV_dub]

Just another option I have ben looking at over last few days.

A123 Cells

Price breakdown to UK is as follows:
50 * 20Ah cell = 2500USD
shipping = 280USD
paypal commission, 3.4% = 95USD
Total = 2875USD or £1775

The basic specs for the cells are phenomenal and the Insight will hardly touch their charge/discharge C ratings. 30C discharge!

I'm tempted!

Wow 30C!

I had a look through the topic conversation. Has anyone on here tried these batteries?
and are they avaliable as a pack ready to go with BMS?

[retepsnikrep]

I think the ansswer is no & no.

You could try our own home grown BMS on here if you want a cheap but quite reasonable option.

There are many BMS to choose from. but not all are suitable for this type of pouch cells.

[EV_dub]

Anyone familiar with the Hipower cylindrical batteries.

Apparently they can deliver 5C continuous and 10C Max current

[timpootle]

No, I'm not at all familiar with cylindrical HiPower cells. Is that what you have? Peter, Greg and myself all bought prismatic cells.

[GregsGarage]

Order a few samples and then test them and see if they can do what you need. I wouldn't order a pack just on manufactures specs alone.

[retepsnikrep]

I have some (50) new Lifebatt 8ah cyclindrical cells that might be available, they can deliver upto 200A without issue. Max regen/charge is 32A

What voltage is your system? They can make a 144v 8Ah (200A max) pack or a 72v 16Ah (400A max) pack.