Building A Ludicrous 14s2p SPIM08hp battery

[thorlancaster328]

Looks like these cells don't like the cold at all. After storage in the garage overnight (overnight low about -8°c), the pack measures an abysmal 193 milliohms, even worse than my old recycled 18650 battery pack. Hopefully the internal resistance is a lot lower at 30°c.

[DogDipstick]

Looks like these cells don't like the cold at all. After storage in the garage overnight (overnight low about -8°c), the pack measures an abysmal 193 milliohms, even worse than my old recycled 18650 battery pack. Hopefully the internal resistance is a lot lower at 30°c.

Gotta be a fluke measurement.

Like I said I got 24 of these cells comming in the mail from Tom and gonna do some Powerlab testing.

I try to baseline all my testing at 59*.

Edit they here.

[john61ct]

That sort of cold radically impacts every LI chemistry.

Only LTO is OK charging at normal say 0.2C rates there, not sure about discharge rates

[thorlancaster328]

After heating the batteries with a box and a hair dryer set on low until the internal 10k thermistor I put in the pack read a steady 29°c, I did another test of the battery's internal resistance. Hooking up a load (subwoofer) that drew 27 amps, I measured a whole-pack voltage drop of only 0.5 volts after 3-4 seconds.
That's 18.5 milliohms for the WHOLE PACK.
Eighteen. Point. Five. Milliohms.
Holy cow! That's really, really really good. 1.3 milliohms per cell group on average. Can't wait to finish the pack and take it for a test ride.

The extreme temperature sensitivity of these cells (-5°c to 29°c cuts the IR by a factor of TEN) is likely the reason people are getting wildly varying results on these when they measure the IR. Bet you'll have loads of fun with your BatteryHookup pack as well as long as you keep it warm.

[john61ct]

Are we sure that ESR vs temp variation is unusual?

[thorlancaster328]

My pack of Samsung 30q doesn't sag near this bad, even when it's really cold. My 12s12p 30Q pack only sags about 5 volts when drawing 60ish amps after being stored in similar temperature conditions. The 30q is a more advanced cell than these old dinosaurs, cold affects them a bit but not near as bad as these old SPIM08HP cells.

[SteveHare]

How did the pack work out for you?
I am going to build a pack with these cells for a dirt bike build I am working on.
I want to do a 20S6P pack for the bike and will only be drawing 150 amp max with the controller I ordered.
Are thesee cells capable of 3c with no significant issues or sag?

[Balmorhea]

My pack of Samsung 30q doesn't sag near this bad, even when it's really cold. My 12s12p 30Q pack only sags about 5 volts when drawing 60ish amps after being stored in similar temperature conditions. The 30q is a more advanced cell than these old dinosaurs, cold affects them a bit but not near as bad as these old SPIM08HP cells.

How does the Wh/$ compare for those Samsung cells?

I thought so.

[--Oz--]

here he shows these cells to be 30milliohm, that is quite high imo, specially for the size/capacity, but there is so many factors in testing IR, so who knows if that number is correct

I have 1800mha lipo cells under 3milliohm, 5x less capacity, and 10x less resistance, seems like these spim08hp cells are junk at higher loads? When I parallel charge 10x lipo 1300mah cells (13AH total), I am seeing 0.2 milliohm, and these are 30?

https://www.youtube.com/watch?v=9nmDj0Ykn-c

[DogDipstick]

here he shows these cells to be 30milliohm, that is quite high imo, specially for the size/capacity, but there is so many factors in testing IR, so who knows if that number is correct

I have 1800mha lipo cells under 3milliohm, 5x less capacity, and 10x less resistance, seems like these spim08hp cells are junk at higher loads? When I parallel charge 10x lipo 1300mah cells (13AH total), I am seeing 0.2 milliohm, and these are 30?

https://www.youtube.com/watch?v=9nmDj0Ykn-c

He is wrong. Here is my empirical test of a random cell I bought off Battery Hook Up a year ago ( 3/31/19). Two cycles, reliable result, at room temp. This was the lowest test: but did not get much deviation from that. Who the F knows how Jehu measured that IR. Quotes more than one fallacy in that vid. Talks all kind of shit cause he is paid. Some question about the older cells: but the ones I just got look great. Like the featured build here in the thread.

SPIM08IR.PNG (95.93 KiB) Viewed 621 times

This is not the new batch that Battery Hook Up has, they look much better: I am testing those now. I'll post result when it gets a little warmer out its cold yet here. IR of 24 cells in 24 tests... over a minimum 48 cycles total... for reliable measurement. Lol. Second screenshot is the same graph but zoomed in.

[--Oz--]

@ Dogdipstick
thanks for the reply.

The FET in your signature I wish I would of found for my high rpm project a year ago, the inductive kick was beating my fets up (mostly irfz44/46). You can see the kickback voltage being clamped by the poor fet (top blue trace in the scope shots shows around 75V clamping fron fet avalanching). I did try a couple different snubbers (D, RD, R, zenner) across the inductor, while it helped the avalanche issue, but it slowed my rpm.
3,808,800 RPM, 63,480 RPS, 1338mph, 2153kph, 24.3M G's
[youtube]https://www.youtube.com/watch?v=ZQE05T-3680[/youtube]

[Frank]

I bought two of these cells to evaluate and am measuring Ir from 2.2 -> 3.0 mOhm with my PowerLab6. The cells I bought are in the holder. I did a 40A discharge and the cell only got a little bit warm.

Has anyone built a pack using the holders yet? I don't know if the tabs are close enough together to clamp w/o some sort of intermediate conductor. Thoughts?

[joshuahuang]

I've been pretty busy with college for the past couple days and have finally finished categorizing my battery pack. I will be using 32 cells to make a (mostly) 2S14P pack, with 3 cells on 4 of the parallel groups because they have weaker cells. According to my measurements and calculations, the finished pack should have around 33 mΩ of resistance at 4.1v/20°c. When the battery warms up and isn't fully charged (IR goes down near mid-SOC and higher temperatures during summer riding) I'm expecting the IR to drop into the low 20s of milliohms.

For under $80, a pack that holds 750 watt hours and can put out 180 amps is a total steal even if it only lasts a single season. Given that my bike peaks at 130 and can only do 70 continuous amps, I should get 2 or 3 years out of this pack. Now I'm wishing that I had a beefed-up motor like SpinningMagnets (or LiveForPhysics my battery would probably if I tried to do that much power).

Spreadsheet of cell data: https://docs.google.com/spreadsheets/d/ ... sp=sharing

Docrocket, You're correct about jumping the gun on the voltage cut-off. When I capacity-mapped a random cell (viewtopic.php?f=14&t=54202&start=75), it showed that most of the charge was stored between 3.6-3.8 volts resting. Under a moderate load, you'd lose a TON of capacity if you cut off at 3.6. Personally I'd set the LVC for when the weakest cell hit 3.1v under load. These batteries are rated for discharge to 2.5, so 3.1 won't hurt them a bit.
Regarding your question about balancing, NO, it's not a good idea to not balance, especially if the cells aren't matched to begin with. If you had a pack with 5 strong cells and one weak cell, the weak cell would be way overcharged by the time the strong cell hit 4.1 volts. If you don't have a balance charger or lead, charge only to 4.0 volts/cell and then balance by hand (or put them all in parallel like I did).

aren't these advertised for 0.8mohms? I just bought 70 cells from battery clearing house and the seller told me he checked 10 random cells which were all at 0.8mohms. He only guarantees greater than 70% SOC though.

[thorlancaster328]

With my experience there's no way you'll get 0.8 milliohms unless you hook a flux capacitor in parallel and a unicorn farts on it. The batteries are several years old and LiPo batteries degrade with time, even more than 18650s.

With that being said, you will likely get around 2 milliohms from the better cells if you heat them up a bit - about 30 degrees celsius right before the ride should do it. These cells are heavily dependent on temperature and hate the cold.

[DogDipstick]

I bought two of these cells to evaluate and am measuring Ir from 2.2 -> 3.0 mOhm with my PowerLab6. The cells I bought are in the holder. I did a 40A discharge and the cell only got a little bit warm.

Has anyone built a pack using the holders yet? I don't know if the tabs are close enough together to clamp w/o some sort of intermediate conductor. Thoughts?

I never got so low yoou ust have some good ones. I have had a few in the 2-4 mOh range, but not all of them. Most around 4mOh. On a PL6 and a DPL8.


Like so? (See pics below)

You can tessellate them, gang them up, parallel them, teh copper can take all the amps you need and the aluminum provides clamping force. I use penetrox pasted for good conduction and nickel plated copper only.

I also band the packs into modules then, for strong clamping force holding it all together.

Yeah I been selling them. Those little clamps. These are from BHU. The cells.

aren't these advertised for 0.8mohms? I just bought 70 cells from battery clearing house and the seller told me he checked 10 random cells which were all at 0.8mohms. He only guarantees greater than 70% SOC though.

nah.. I have to pair up a pair of 1.2mOh cells ( different cells) ... and they are BIG BIG powerful cells.. 300A cells +... to get to near 600A.. and that reflects teh power capability of a 0.0005Ohm lipo... group. ( half a milliOhm).... and it can push a huge amount of current. These guys cannot push that much current, no matter whatever any seller states.

These are not near 1mOh.. theya are 2-4mOh by what we see here... and you would have to pair up four of them to make 0.0005 Ohm cell group.. ( half a milliOhm).... Given they are 2mOh (0.002Ohm) and the 4p group would THEN be 0.0005Ohm(1/2milliOhm).. and could push the amps of an intrinsic resistance of (1/2milliOhm).... through a circuit. Do the math. 0.0008Ohms wont add up on a virtual circuit test.. Put in V=IR... do it.. and you will see. They wont push that current.

[Frank]

I like your clamping plates. I don't think I have any pics, but I built a 12S e-bike pack with 3-d printed plastic spacers and just bent some pieces of copper between the cell tabs (using the plastic spacers), then bolted them together. I haven't actually had a chance to ride it yet but at 40A max draw I'm sure it will be fine.

Have you actually measured how much current these cells can deliver (at reasonable sag)? I was thinking about using them for a different project but I'm not sure they could do the job.