Sinopoly Cells - Info -

[Burgerman]

I wouldnt order 20. You will just end up with 4 unused...

[sin85]

Yes . Still available .

Will be on holiday to Seoul for a week .

Policy always changing . Have to re-assure shipping when came back.

Hope to get sin85's OPTIMUS a 270Ah block , so he can ride all day long with his grand daughter .

it is my daughter
and yes we would do a tour of croatia

[Furio]

Hi,

Today I took delivery of 8 nos.120ah(?) aluminium shell prismatic cells from the following supplier.

https://www.alibaba.com/product-detail/ ... 6ccawGz4AE

They also provided copper connectors and screws.I am not certain whether these are used/old or new cells.Those were shipped from China around 15 Mar.They said the charge at shipping will be 50%. On receipt, I noted the cell voltage as below.

1. 3.297v
2. 3.295v
3. 3.291v
4. 3.299v
5. 3.292v
6. 3.298v
7. 3.300v
8. 3.290v

I would like to charge/discharge these cells individually to ascertain the real capacity.I need from Burgerman charge/discharge settings for the same. Assembling the cells will take some time as the cells need proper insulation.
Also ideas for best insulation is appreciated.

@snaker. How did you wrap the cells before assembly.

Furio.

[Burgerman]

You wont see the full capacity by discharging them down to a healthy level, of say 2.900V. To measure the remaining capacity means going lower to around 2.5V per cell which from experience can leave you with a cell that has a higher self discharge rate.

So best to discharge down to around 90 to 95 percent as above to compare cells to one another.

You can discharge at 10A max so thats going to take about 12 hours per cell. The highest figure on discharge is when you discharge at around 1C as this warms the cell slightly which makes the cell work better. So you will see a slightly lower figure than this too.

You can charge at 30A or more if you want.

Configured for 30A charge and 10A discharge. Use good cables and ring terminals.

[shirley_hkg]

Fold electrical insulation paper around it , and shrink wrap it.

[snaker]

@Furio: Firstable I insulated the battery box by a 0.5mm amiang sheet. It's very solid and cheap (about $4 for 1m2). Then I wrapped each pair of cells by a 0.5mm silicone sheet and sticky tapes. I note that the silicone is very durable, 0.5mm is already strong more than enough. The sticky tape is specific to wrap lithium cells. It is very special, I see it the first time. It is made of mica, very sticky, thin but solid.

Links to buy silicone sheets and sticky tapes
https://world.tmall.com/item/5244358338 ... 0936362501
https://world.taobao.com/item/387284724 ... bbceJuyQ1E

I wrapped the pack the same way we make our traditional rice cake
https://www.google.com.vn/search?q=goi+ ... 60&bih=702

Here is the final result
https://photos.app.goo.gl/E8tmjESjqjsB3zhZ7

[expresso]

@Furio: Firstable I insulated the battery box by a 0.5mm amiang sheet. It's very solid and cheap (about $4 for 1m2). Then I wrapped each pair of cells by a 0.5mm silicone sheet and sticky tapes. I note that the silicone is very durable, 0.5mm is already strong more than enough. The sticky tape is specific to wrap lithium cells. It is very special, I see it the first time. It is made of mica, very sticky, thin but solid.

Links to buy silicone sheets and sticky tapes
https://world.tmall.com/item/5244358338 ... 0936362501
https://world.taobao.com/item/387284724 ... bbceJuyQ1E

I wrapped the pack the same way we make our traditional rice cake
https://www.google.com.vn/search?q=goi+ ... 60&bih=702

Here is the final result
https://photos.app.goo.gl/E8tmjESjqjsB3zhZ7

You did a nice job there snaker - its a work of art to wrap those rice cakes

[Burgerman]

We are now talking about rice cakes?

[Gnomatic]

Snaker that's a nice 150Ah rice cake!

I hope to make one similar.

[expresso]

https://www.aliexpress.com/item/8pcs-Fa ... a962&tpp=1

maybe these can be used - but not cheap if you need 16 - for 180ah

seems as if they will fit in group 24 MK

[shirley_hkg]

Run a quick trip to find out shipping quote this afternoon ; 35℃ under the mercyless sun.

Avoid slowing down as far as possible , but only get average speed 15.5km an hour .

Best I can do .

Hat off to snaker , who ran 8 hours non-stop.

[shirley_hkg]

Air freight : £6.75 / kg to UK ; custom fee included . No more extra at all . That's what I've been told.

EVE-LF90 , Rated --- 3C (5C max) ; IR @ 0.5mΩ .

90Ah cell , 2017/8/31 NOS @£27.50

* * * * unknow batch NOS @£18.80

Any guinea pig ? ? ?

[expresso]

hey shirley - maybe i take a shot at them since i havnt ordered any yet for an ADD ON i want to do -

i noticed one cell has the size i can use - 185 x 130 x 30 68ah ? if i am correct - if the total height is no more than 185mm for real - i can use it - 30mm thick is perfect also and up to 145mm wide i can do

if i can get connectors and screws etc, all the hardware - i take a chance and try them - if you dont mind ?


if so - i can use 8 of them

[expresso]

https://sc01.alicdn.com/kf/HTB1UyhGa.z. ... 0nFXaq.jpg

i finally got one seller to set it up for me and final cost would be $631 with shipping - 8 cells with connectors -

is that a good price you think Shirley ?

its 36mm thick which is max i can do - i would have liked 30mm like yours - gives me more

what would it cost if getting the 8 from you ?

[expresso]

quick question -

the C rate of a Cell - lets say its 150A constant discharge rate -

if using 8 Cells - would that mean its 150A x 8 for the total discharge rate for the Pack ?

trying to understand so when i check specs etc, i have a better idea of what Cells to consider - i assume the pack of 8 spreads the load when in use - so in theory a Cell that has a 150A constant discharge rate is suffice to use ?

i know if its higher - its always better - headways 5C -

will using a Cell thats 150A discharge rate be Ok or at least good enough - 8 Cells taking the load - lets say the chair Rnet is using 240A All the time - which it dosnt but even if it did - if 150 x 8 gives you 1200A total - which 240A gets spread out between all 8 Cells when in use ?

is that correct or if not - correct me so i understand

thanks

[Gnomatic]

quick question -

the C rate of a Cell - lets say its 150A constant discharge rate -

if using 8 Cells - would that mean its 150A x 8 for the total discharge rate for the Pack ?

is that correct or if not - correct me so i understand

thanks

Lets say you have 8 x 75Ah cells rated at 2C constant discharge. That's 150A/cell discharge. If you wired all of them together in parallel(+ to +, - to - ...), your pack would be only 3.2v, but would be 600Ah. At 2C for the pack, thats 1200A continuous discharge.(assuming specs are accurate) But again, only a 3.2v pack.

Now, if you wire those same cells together in series(+ to -, + tp - ...), as we need to do for our chairs so the pack has the right voltage, you'd have a 75Ah pack, @24v. The voltage we need. At 2C, that means the pack could sustain 150A discharge.

[Burgerman]

But the higher you go, towards the max discharge the less cycles you will get.

When a pack is rated for say 2000 cycles, it is at anything from 0.1C to 1C depending on tests.
At 2C discharge you may lose half of that, get 1000 cycles. At 3C you may get 500 cycles.

So taking 2C from a 10C pack? Safe!
Taking 2C from a 3C pack, not so clever... $£$£$£$£

This is especially important on a addon, as its small, so you are taking a higher C rate from its cells.

[expresso]

I see. I got it wrong then. Ok bottom line now is. The cell I found is 3C. Says 180 A. Discharge the link I posted above. Is that Ok ?

[Burgerman]

Depends. As an addon? Or as a part of a bigger pack?

It will WORK in both cases. As an addon its OK just about only because its big, at 60Ah, so 3c max? is 3x 60Ah, or 180 max. But those cells wont like it much. They are happier at low dicharge rates.

The headways are 5C continuous, 10C peak.
So a smaller 36Ah headway pack is good for 36Ah x 5 = 180A cont, or 360A peak. So thats safer!

A 60Ah headway could do 5x 60Ah continuous, thats 300A. 600 peak for limited periods. So that keeps us further away from the max they can do, so last longer. This is why the bigger a battery is, the better!

[expresso]

Depends. As an addon? Or as a part of a bigger pack?

It will WORK in both cases. As an addon its OK just about only because its big, at 60Ah, so 3c max? is 3x 60Ah, or 180 max. But those cells wont like it much. They are happier at low dicharge rates.

The headways are 5C continuous, 10C peak.
So a smaller 36Ah headway pack is good for 36Ah x 5 = 180A cont, or 360A peak. So thats safer!

A 60Ah headway could do 5x 60Ah continuous, thats 300A. 600 peak for limited periods. So that keeps us further away from the max they can do, so last longer. This is why the bigger a battery is, the better!

this would be or an ADD ON - to replace the 36ah i had before - now its on Quickiee's chair - i got a price of about 630 for 8 cells shipped - fedex so about 2 weeks if i go for it - - going with headways would give me 45ah max. and alot more money - with shipping etc, -

i did want to try this kind - size wise - makes it easier to build - 8 cells etc, -

Shirley been getting over 5 years with his ADD ON's i believe if not more - cant be to bad ?

[Burgerman]

Should be OK, the lead helps too.

[expresso]

Should be OK, the lead helps too.

ok - i am ready to act on this one - i did email this seller back to ask for a 5C Cell if she can find one -

GTK - i found this one which says 5C BUT if you look at the picture - its the same Cell the Frey which says 3C - its very tricky how they post pictures and specs - cant be sure what i would get if ordered these instead

i know for sure the Frey model is 3C - brand new - with connectors etc, - shes been very nice and got it all ready for me to just click buy and pay - i did ask just in case if she can get this GTK model if its really 5C - i am warry and cost would be more unless i want it by boat

the quote i got was for Fedex shipping in 2 weeks - isnt bad at all i dont think


https://www.aliexpress.com/item/1pc-Lif ... 2e0ekqdatW

lead i got new and never used it alone always had the ADD ON - now i dont want to use it with out an ADD ON - it wont be used much since i am expecting a new chair in a few months - - i got approved for the boulder - like it or not - with lithium 100ah - and thinking of adding an ADD ON there also

[shirley_hkg]

goodpost Air freight : £6.75 / kg to UK ; custom fee included . No more extra at all . That's what I've been told.

EVE-LF90 , Rated --- 3C (5C max) ; IR @ 0.5mΩ .

90Ah cell , 2017/8/31 NOS @£27.50

* * * * unknow batch NOS @£18.80

Not interested at all ? John .

[Burgerman]

Yes but cant do it right now... £££

[shirley_hkg]

Can bill you later .

[Burgerman]

Right now I have a list...
I had a leak. 3 large carpets, decorate and renew woodwork and plaster, new sofa etc.
New motor on BM3...
And many smaller things!
Like gas, electric, water...
And I am on bed with a stupid bladder infection.

But thanks anyway!

[shirley_hkg]

One way to ease your worry about over-stressing a low C add-on is to put a diode in its discharge path .

-0.6V will match the discharge platform of MK gel perfectly .

Didn't you hear BM mentioned before ?

[expresso]

i have no idea if i heard BM say it before or not - i am not that tech. to do all kinds of things like you are -

Shirley what do you think of those Cells i found ?

the ones you found - how much would it cost US dollars for 8 - 68ah model ?

i was ready when i got response for the others Frey model -

[Gnomatic]

Hi shirley.

Can you still get cells like this

https://item.taobao.com/item.htm?spm=a2 ... =14#detail

or this?

https://item.taobao.com/item.htm?spm=a2 ... =14#detail


I'm interested if so, and can still ship to US.

[Burgerman]

Yes a 100/200A heavy diode in series with the lifepo4 cable saves the lithium, and uses more lead. So you dont just lean on the add-on most of the time. Also means the battery meter will make more sense.

Say 2x these in parallel, would do it. They will drop .7V approx, so your lithium will be 25.6 less .7 = 24.9V most of the day.
https://www.ebay.com/p/50-X-Vishay-Powe ... 1021668224