TOPBAND LIFEPO4 made in USA ?

[curtis]

I have been extensively researching LIFEPO4 cells and full packs. See ( ali express LIFEPO4 packs)

I got a lot of good advice to steer clear of ali express LIFEPO$ packs.

After extensive research and looking at Youtube videos I found a video that tests 25 Ah LIFEPO4 cells.

Here is the results.

48V 25Ah LiFePO4 E-bike Battery w/ Navitas cells-How far can I go? DIY your own battery, it's fun!!!​

Looking at placing the order on the third. The company is based out of Illinois.

The shipping is reasonable as it is not that far from me. Illinois is close to the center of the USA making shipping prices reasonable all over the USA.

I still will need a BMS but if that video is correct and accurate stating > 30 miles on a charge then I might be able to run them up to 20 miles safely without a BMS. I could wire up a multi meter to my handle bars which will give me total pack voltage. With a 5S active balancer that should do the trick as I wont need to monitor each cell.

Total weight is > 23 pounds and < 24 pounds. Looking at 25 pounds total with hardware / wiring and enclosure.

Please let me know what you all think about those and please watch the video.

Thanks.

Curtis out.

 

[DieselTech]

My friend talked me in to trying them type cells for a ebike build. When I get to that point I plan on using them. I'm not sure where to get a bms thou.

 

[curtis]

They have them on e bay as well as Amazon. Daly makes Bluetooth BMSs. They run around $80 to $90 for a 16S - 80 amp. A 60 amp could be about $60 or $70.

Brand new prismatic cells rated at 25 Ah should all be about the same voltage and capacity. I am going with active balancers. 1,2 amp should even work. Then get a multimeter and mount on the dash where you can see it when running your bike,

Doing the math. 16 * 3.45V (around 90% capacity for LIFEPO4. = 55.2V. FULL.

3.1V * 16 = 49.6V

I would not run it below 50V as LIFEPO4 can drop in voltage very quickly below 3.2V. Just keep an eye on it. Voltage will SAG under load. It should not go below 50V with zero load. Therefore take the measurements when not touching the throttle to see where you are at.

I have a 15 amp 900W - 54.6V - 15S - LIFEPO4 charger that will work for 16S. 54.6 / 16 = 3.4V. I might get a second 2 or 3 amp 58.8V charger for overnight charging but the 15S charger will work when out on the road to get the pack up to around 80% quickly.

I could get second 5 amp 58.8V charger to get it full. The 15S charger will just save time up to about 80% The 15S charger was > $120 so not looking to spend much more than $30 for a 16S LFP charger.

25 Ah is probably good for about 30 to 35 miles so if you don't go much over 20 miles there should be no worries. It might be ok just charging to 80%. We will see.

Thanks for posting.

Curtis out.

 

[DieselTech]

They have them on e bay as well as Amazon. Daly makes Bluetooth BMSs. They run around $80 ti $90 for a 16S - 80 amp. A 60 amp could be about $60 or $70.

Brand new prismatic cells rated at 25 Ah should all be about the same voltage and capacity. I am going with active balancers. 1,2 amp should even work. Then get a multimeter and mount on the dash where you can see it when running your bike,

Doing the math. 16 * 3.45V (around 90% capacity for LIFEPO4. = 55.2V. FULL.

3.1V * 16 = 49.6V

I would not run it below 50V as LIFEPO4 can drop in voltage very quickly below 3.2V. Just keep an eye on it. Voltage will SAG under load. It should not go below 50V with zero load. Therefore take the measurements when not touching the throttle to see where you are at.

What are these active balancers you speak of? Is it something used instead of the bms balancer circuit. Thanks.

 

[curtis]

http://mocha-java.uccs.edu/ECE5720/ECE5720-Notes05.pdf

Looks like passive balancing should only work during charging.

There will not be too much charge when discharging.

Then an active balancer works all the time. HOWEVER ! wont protect against over discharge. defiantly NOT recommended with lower capacity packs < 20 Ah.

Brand new cells should be at least 95% after full charge and not drop voltage. Their capacity should be very close as well. It wont require 5 amp balancing so 1.2 amp active balancers should be ok and much cheaper. Multimeter absolutely required.

The fact is if you run LIFEPO4 too low by accident with an active balancer it could catch the balancer on fire if it cells reverse polarity. I believe 5 or 10 amp fuses could protect the balancer from a fire but bottom line don't run too low.

I did have a little fire with misused Headway cells awhile back. 12S - 2P. The balancer started smoking and a couple blocks later caught on fire. Now I install a fuse after each balance wire coming from the cells. It was a 1.2 amp active balancer. I ran the pack hard that day two full cycles and did not give the pack enough time out to properly equalize. A 5 amp active balancer may have prevented the calamity.

I will think of the multi meter as a gas tank. Otherwise get a good Bluetooth BMS. You can run an active balancer with a BMS. I think most BMSs are passive balancing but not sure. A BMS with active balancing sounds like the best bet if you have the $$$$$
I know I don't have the $$$ so that option is off the table.
Thanks.

Curtis out.

 

[HumanPerson]

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