Assembled Hi-Power LiPo battery packs - any interest?

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DanGT86   10 kW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by DanGT86 » May 16 2019 12:41pm

I love the "Heavy" sticker as if a pallet of anything that size would be tempting for a person to lift by themselves. :lol:

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jonescg   1.21 GW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by jonescg » May 16 2019 8:29pm

I know hey - it's hard enough to get stuff delivered by pallet trolley.

These cells are from a chap in Canberra who wants me to build a racecar battery (16 kWh). Unfortunately, every single cell he sent across was individually wrapped, boxed and packaged inside dozens of individually wrapped and packaged boxes... There's at least a full day's worth of unboxing alone :evil:

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jonescg   1.21 GW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by jonescg » May 27 2019 12:17am

Related to battery building - I finally got the mezzanine built in my shed, so I can have a bit of a clean-er space for building batteries. The shelving will help me manage jobs as they progress too.
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I need to get some lights installed fairly soon though. Might even put a sheet of clear polycarb sheeting in place of one of of the wall sheets to let daylight through.

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jonescg   1.21 GW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by jonescg » Jun 09 2019 9:56pm

My new battery building jig has provision for better compression at assembly. You end up with a perfectly square battery pack which fits snugly inside the enclosure.
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jonescg   1.21 GW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by jonescg » Jun 30 2019 9:16am

I finally knocked these packs off my bench. They are destined to power a cool electric dirt bike in Tasmania.
Each pack is 3 kWh 100 V nominal, 30 Ah (28s6p) and will form the basis of a hot-swappable arrangement.
Also built a 28s3p battery (literally half the height) for the same customer. Ultralight trail bike pack.

3 kWh packs:
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1.5 kWh pack:
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BMS is an EV-Power system which uses IsoSPI as the communications bus. Its a pretty simple yet robust BMS.

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jonescg   1.21 GW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by jonescg » Jul 14 2019 5:27am

Well this pack came together fairly quickly, but that just means most evenings and all weekend. Now that it's finished I can get back to the Prelude conversion...

96s9p of 5000 mAh, 40C cells (customer supplied). So all up a 360 V nominal, 45 Ah, 16 kWh battery pack for a race car. Should be good for over 1200 A bursts. Each module is 24s, so they are linked with a pair of busbars from one module to the next. The brass nuts are so the customer can mount some Batrium modules on each cell, except for the last cell of each module which needs to go outside the pack or something. It will be powering a Le Mans style hill climb race car with a Tesla drive unit.
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Last edited by jonescg on Jul 14 2019 8:51am, edited 1 time in total.

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spinningmagnets   100 GW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by spinningmagnets » Jul 14 2019 8:02am

Awesome work, mate!

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by DogDipstick » Jul 14 2019 8:38am

I have always wondered. Why do you build with such small cells (...5Ah), when 15, 24 or even 50Ah cells are readily available? Why parallel (9)cells when one can do the same with one cell strings, or two, cells running in parallel? There are powerful enough NMC I do believe, or am I wrong?

My NMC EV 15Ah cells have a IR of 1.2-1.4mOh best. All my high end RC lipos are all higher, in the 2-4mOh range (or more?). I calculated 274+ amps with one of my used NMc 15 ah cells... continuous max C-rate... Burst should be able to do 3x that? Isnt that enough C rate to do... anything? I would think for simplicity paralleling two 24 Ah cells would be easier, longer lasting, and more powerful than nine 5 Ah cells ... for ~45 Ah. C rate doesnt change ?

I know you said customer supplied.. Also, there is a Typo in the above post.. you said the are 5000Ah cells.. I would assume they are 5,ooo mAh, not Ah.. but what are they? 5Ah @ 40C is 200 amps.. Did you test the IR? What is it? Are they name brand? If I paralleled (3) 15Ah Chevy cells there you have your 45Ah., I would feel safe with 750 amps contin... and over 2000A burst. (If only I had something that needed 2KA).
Last edited by DogDipstick on Jul 14 2019 8:50am, edited 2 times in total.
Allota Watts @ 84v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. ( BTW; ...it will hurt you... :? )... (retired the Ol' BD BBS02 Motobecane).

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jonescg   1.21 GW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by jonescg » Jul 14 2019 8:51am

DogDipstick wrote:
Jul 14 2019 8:38am
I have always wondered. Why do you build with such small cells (...5Ah), when 15, 24 or even 50Ah cells are readily available? Why parallel (9)cells when one can do the same with one cell strings, or two, cells running in parallel? There are powerful enough NMC I do believe, or am I wrong?

My NMC EV 15Ah cells have a IR of 1.2-1.4mOh best. All my high end RC lipos are all higher, in the 2-4mOh range (or more?). I calculated 274+ amps with one of my used NMc 15 ah cells... continuous max C-rate... Burst should be able to do 3x that? Isnt that enough C rate to do... anything? I would think for simplicity paralleling two 24 Ah cells would be easier, longer lasting, and more powerful than nine 5 Ah cells ... for ~45 Ah. C rate doesnt change ?
It's mainly due to the volume limitations of the project at hand. There may be 20 Ah pouches out there, but they would invariably be too tall. Also, the versatility of the smaller size means if we had the space to fit say, 55 Ah in the same spot, we could. But if you went with a higher capacity cell, it's either 40 Ah or 60 Ah. In this case, the customer happened to have ~870 of these cells. So that's what we went with.

The DCIR of these cells is about 1.6 mOhm, which is pretty powerful. It's a good compromise on energy density and power. More energy density means less power, so 16 kWh in a 115 kg battery is good for the application.

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Rix   100 GW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by Rix » Jul 21 2019 9:06am

Subscribed, lots and lots of good stuff here.

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DogDipstick   10 W

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by DogDipstick » Jul 22 2019 6:09pm

Mr. Jones: Let me ask you this, in your 10yrs of experience, have you ever seen an internal short in a large pouch cell lipo?

I never have.
Allota Watts @ 84v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. ( BTW; ...it will hurt you... :? )... (retired the Ol' BD BBS02 Motobecane).

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jonescg   1.21 GW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by jonescg » Jul 22 2019 7:54pm

DogDipstick wrote:
Jul 22 2019 6:09pm
Mr. Jones: Let me ask you this, in your 10yrs of experience, have you ever seen an internal short in a large pouch cell lipo?

I never have.
Nope, me neither. I have seen cells self-discharge to zero, usually before I put them into a battery pack. One battery I'd built a long time back had a paralleled cell group drop to zero volts - its resistance went up, resulting in low terminal voltage, prompting the user to check what was going on. But never had one internally short.

999zip999   100 GW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by 999zip999 » Jul 23 2019 9:53pm

What is the grey stuff on the outer edge of the cells. A glue ? Or ?

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jonescg   1.21 GW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by jonescg » Jul 23 2019 9:56pm

Yep - polyurethane glue.

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jonescg   1.21 GW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by jonescg » Oct 15 2019 8:34pm

Another 24s4p battery pack using the high discharge cells:

The EV Power BMS works reasonably well with these packs, given their small size and universal application. Unfortunately the screen cycle time is painfully slow, but the safety features work immediately at least.
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With 100 volts and a couple of terminal posts right next to each other, a divider is a good idea :)

This pack will be going into a small road going motorcycle. The TC charger is about 1600-1700 W which makes for a ~1 hour charge.

litespeed   100 kW

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Re: Assembled Hi-Power LiPo battery packs - any interest?

Post by litespeed » Oct 16 2019 6:48am

Your packs/builds are always top shelf.

Very nice!

Tom
I'm married so you know I'm no stranger to pain!

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