As the Hub Motor Turns and the LiPo Fire Burns.

curtis

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Oct 19, 2021
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I understand the safety of batteries. I watch Lipo/Lion fires on youtube. I see the mistakes.

In my opinion, if you want a safer battery you switch to a better chemistry.

You will sacrifice with a lot more weight and bulk plus energy density for almost endless charging cycles and 100% more safety.

40V - LTO = 32 pounds. 50V = 40 pounds.

LFP or LIFEPO4 is about 40% lighter but 1/10 the charge cycles. LTO is like 30 to 50K. LIFE - 5 to 10K and lion < 1K. - SLA. 300 to 500.

I have built and run 20S and 16S - LTO. I have 8 e bikes and only one 20" that rides good with 40 pounds of LTO. I want the tradeoff for lfp or LIFE. Why I am doing cell recovery.

The Skycharger proved to be worthless charging 3.3V Headway cells. Just piss poor for LFP in general. My 400W Megacharger does the trick though so can utilize the Skycharger for discharge/capacity testing.

Building a huge parallel charging station.

Cell recovery is fun. I got 168 - A123 - 26650 cells and over 30 of the Headway as well. Spending the winter just building safer e bike batteries. Sparks were flying cutting those tabs with snippers so got me a Dremel kit with all the attachments for < $20 at Wall Fart.

Also cells are glued in so prying will tear and damage cell wrappers. Why I buy extra electric tape and plenty of red so no screw ups parallel charging. These cells are no joke and will move a sick amount of amps quick.

Like to finish a decent 15 Ah - 12S AND 15S. I might use both Headway and A123 cells for both packs. Parallel is magic to those cells. Cells with a high self discharge rate will be separated however. Might be useful for 12V lighting 1 or 2 amp load but not for e bike motors.

I bought Two LFP chargers when I got the 24 - Lishen LTOs and LFP cells. a 12S - 43.6V - dedicated 600W - 10 amp LIFEPO4 charger last year for $90 and a 15S - 900W 15 amp for $130.

43.8V / 12S - LFP = 3.65V. 43.8V / 16 = 2.73V.

54.6V / 15 = 3.64V. LFP.

LTO = 54.6 / 20 = 2.73V per cell. 2.8V maximum charging voltage for LTO.

I run active balancers induction instead of wimpy BMSs. 60 or 80 amp fuses.

Probably have run100 cycles with 16S - LTO and maybe 20 with 20S. I run 12S - Headway twice I think since building that pack.

15S - LIFE = 20S - LTO in charging voltage.

Lot of work ahead of me.

I am not an expert. An undergraduate in electrical technology at a community college. I have background in audio technology and some computer skills

As far as motors I have two posts on Custom e bikes.

The 1,800W and 3 Kilowatt chain and the direct drive and geared hub motor post.

Anyone who wishes to share their e bike building experience on a technical level or who just wants to learn about e bikes in general please tune in to " As the Hub Motor Turns and the LiPo Fire Burns"

Thanks.

Curtis out.

Got 168 A123 - 3.2 Ah cells. Building three 5S - 8P in those plastic storage boxes from Hyper Tough. IMG_20221221_054546895.jpgIMG_20221221_054528905.jpgIMG_20221221_052003993.jpgIMG_20221221_051800227.jpgIMG_20221221_051749420.jpgIMG_20221221_051715502.jpgIMG_20221221_051645935 (1).jpgIMG_20221216_200912126.jpgIMG_20221221_055705687.jpgIMG_20221221_055649449.jpg
 
Just Stay Safe curtis!!

I want to see your project flying all over the city ;)

Happy Holidays & Stay Safe! :cool:

HP
 
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