PINNED - Lithium battery conversion/info

[FJC10]

You need to measure cell impedance, and cell self discharge rates individually. Not just capacity to see that all are similar and low. That alone will take a month sat to test.

And not promising.. photos. DALY BMS shown has an unbelievably low balance current capabilty of around 30mA... So while it looks pretty. It is actualy pretty useless. Even if he had a clue how to configure it. So I would certainly test.

I understand, wouldn't you buy it? Everything you see in the photos is sold to me for 750€ shipping included. Do you think the risk/benefit/"speed of delivery" is justified?

[shirley_hkg]

These EVE -105 cells are difficult to deal with , especially those use 4mm threaded terminals .

Go for CATL. They are good , even used stuffs .

[Burgerman]

I would agree.

[FJC10]

These EVE -105 cells are difficult to deal with , especially those use 4mm threaded terminals .

Go for CATL. They are good , even used stuffs .

They are LiitoKala, I don't know if you also call them EVE.

What exactly do you mean by "difficult to deal with"?

He sells that whole set for 750€ shipping included, and I think it is a very good price. And I only really need 8 cells, because with 105 Ah I have enough, I have now 108 Ah Headway and I have enough, but I want to reduce weight and make the assembly easier and safer than with the 72 Headway cells that I have and these prismatic cells weigh half as much for the same energy or twice as much energy for the same weight and many fewer connections and points where they can fail, I think. A cleaner assembly.

I would sell my Headways and 8 prismatic cells and the rest of BMS and solar station battery pack and I think I would get everything at a very good price, unless you say that these LiitoKala are very bad and will give me more problems than the Headway.

Where can I buy quality CATL at a good price in Europe?

[Burgerman]

Headway cells are 10C rated. And high quality. So you can safely pull half that from them with no real problems. With the flat prismatic cells which are more energy dense, but much lower C rate you really need all 16 cells. Or will probably have problems. They are much less electrically "strong".

When shirley says difficult to deal with he means they have a very short small thread drilled into the terminal. Which was very problematic. Many on here fave stripped them without using much force or found them to have pulled out or come loose causing balancing issues or worse.

[FJC10]

Headway cells are 10C rated. And high quality. So you can safely pull half that from them with no real problems. With the flat prismatic cells which are more energy dense, but much lower C rate you really need all 16 cells. Or will probably have problems. They are much less electrically "strong".

When shirley says difficult to deal with he means they have a very short small thread drilled into the terminal. Which was very problematic. Many on here fave stripped them without using much force or found them to have pulled out or come loose causing balancing issues or worse.

Is 8x 230Ah CATL better or would I also have lower C rate problems or something?

8x 230Ah CATL batteries will also fit in the wheelchair slot, cleanly and without many connections

[Burgerman]

The more Ah you have the less c rating is needed. Because with double the battery Ah you take less Amps from each Ah.

[shirley_hkg]

I bought 100 cells and they seemed perfect , but some cells got high IR for no reason (just during storage).

Go to pages 160, 163, 203 of this thread.


I now use CATL .
https://www.wheelchairdriver.com/board/ ... start=6270
and next page .

[steves1977uk]

Boy, charging these EVE-LF105 cells for saker98 is a PITA . Some cells read 50+ mOhms which I fear are the weaker ones. I only have 18 of these and if 3 or more are bad then I guess I'll have to look for replacement ones.

I've also noticed some cells seem to lose their charge quicker and the PL8 errors out with No Cells Add Up error. Melissa helped me to charge up the weaker cells by connecting them singly to the PL8, but when building the 8S pack the PL8 charges them for about 30-60mins before erroring out.

Any advice on what to do in this situation?

Steve

[shirley_hkg]

If you used thread lock (Loctite), play attention that it will diffuse over the terminals , so you get high resistance when you've done the connections . Clean it with the edge of a cutter.

[shirley_hkg]

Boy, charging these EVE-LF105 cells for saker98 is a PITA . Some cells read 50+ mOhms
Steve

Where did you get these IR, directly at battery terminals or through the ring terminals ?

[Burgerman]

Probably the PL8?

Sounds like they are all toast. Unless bad connection.

Some cells read 50+ mOhms

Do you have one of those chinesium 4 pin impedance testers? Should be super low.

[steves1977uk]

Shirley, I get the reading from the PL8 which isn't the best way I know. It maybe the ring terminals needs resoldering too. I haven't used any loctite yet until all the cells are charged and balanced properly.

Steve

[steves1977uk]

Probably the PL8?

Sounds like they are all toast. Unless bad connection.

Some cells read 50+ mOhms

Do you have one of those chinesium 4 pin impedance testers? Should be super low.

Tried two different PL8's, same problem. I don't have a impedance tester, I'll have to buy one. Strangely the first cell reads 0.9mOhms which is what I would expect. Cells 2,3,7 and 8 are in the 2mOhm range but 4,5 and 6 are significantly higher.

Steve

[shirley_hkg]

I don't have a impedance tester, I'll have to buy one.
Steve

It is worthwhile , so you are not wasting time on those ir-recoverables .

[Burgerman]

Tried two different PL8's, same problem. I don't have a impedance tester, I'll have to buy one. Strangely the first cell reads 0.9mOhms which is what I would expect. Cells 2,3,7 and 8 are in the 2mOhm range but 4,5 and 6 are significantly higher.

Steve

The resistance you are trying to measure can never be accurate with a charger. Because its less that the cable, less than that across a connection or terminal. And it has to do this as DC which means you get ad readings due to offset voltages caused by the DC Battery effect of disimilar metals in connectors etc. This disimilar metals thing affects balance mv readings too. And also occurs in crimps...

Thats why battery resistance is measured as an AC impedance, directly across the terminals. And that needs 2 wires to each terminal.
Sounds like you are dealing with a few damaged cells there though. Even .9mohm is quite high for a lithium cell. And you must test impedance at 50% state of charge for accurate results. Its higher at each end...

[steves1977uk]

That was my fear BM as saker98 had no way of charging them for over a year, although they were kept warm in a insulated shed. When I got them in Oct 2021 they had 3.3xx volts bar one cell which was under 3 volts from memory.

Would any of these impedance testers be worth buying BM?... https://www.amazon.co.uk/s?k=impedance+ ... -doa-p_1_5

Steve

[Burgerman]

I dont know. I bought one of these some years ago, works very well. Seems accurate with everythng inc lead/joints etc. But the price has more than doubled. Mine was £27...

https://www.aliexpress.com/item/1005004991930757.html

Same thing, different case I think.
https://www.aliexpress.com/item/1005001324818641.html

[shirley_hkg]

https://m.aliexpress.com/item/329017491 ... 6156%21rec

[steves1977uk]

Just bought the YR1035+ from Shirley's link, won't be here until 23rd Jan. It'll be useful to have! Probably can get some old lead bricks to do a discharge using the PL8 to take out half the capacity of these EVE-LF105 cells.

Steve

[Burgerman]

With lead, you test capacity at full charge, less 24 hours stood disconected for best accurate readings. With lead, lowest resistance (impedace measurement) is at full charge. As it discarges this increases.

With lithium it should be tested at around half charge. As it increases a little at full and empty ends of the graph.

[steves1977uk]

Thanks BM, that's useful to know.

Steve

[Burgerman]

You also need to watch temp. As it heats up both battery types read lower impedance and perform better. Inc Ah.

[snaker]

I just bought a YR1035+ and tried to measure some batteries:
16850 li-ion cell: 55.8mOhm
1.2v AA chargeable battery: 30.6mOhm
AA non-chargeable battery: 556mOhm

Are they good or bad?

I see a microUSB port on the case. Is it to charge the battery inside YR1035+? If so, can I use a 5V power source for charging?

[shirley_hkg]

Yes . Lithium powered.

As BM said , lithium don't like fully charged. It will be seldom used , so I don't charge it until it is very low.

[Burgerman]

Nmh batts. They vary a lot depending on type and qality. Energiser or eneloop AAs are usually between 25 and 50mOhm. Cheap or old ones can be 200. But not much use for high drain devices. And hard to charge.

This is a good read. https://data.energizer.com/pdfs/nickelm ... appman.pdf

[Burgerman]

For lithium cobalt oxide type 18650 cells again quality branded cells vary. The highest capacity cells above 3000mAh (max possible is 3600mAh) are around 12 to 16mOhm. The lower capacity cells maybe 2Ah may be 7? mOhm but can deliver 20 or 30A instead of 7 to 10. You need to look at the spec sheets.

Like this one for a high capacity branded cell. Sony VTC6 in this case. https://voltaplex.com/media/whitepapers ... Sheet2.pdf

As for ebay chinese cells, forget it they are all junk. With false crazy claims. And fake batteries where they are "branded". Many claims of sony, molicell, panasonic, LG, etc but they are not!

Buy from places that sell genuine branded cells. Yes not cheap. https://www.vapeclub.co.uk/vape-batteries/18650-size/

How to know if fake?? Measure capacity at low C rate, and impedance and compare to tech sheet. Also check age...

And even the claimed specs. 3000mAh in a 35A cell is not possible by any of the genuine market leaders... https://www.amazon.co.uk/Battery-Plasti ... 56&sr=8-14
So has to be a fake bullshit claim.

[shirley_hkg]

Grap another set (3rd) of CATL 230AH , IR @0.3mΩ .

Price is already 30% more expensive since last July.

Beware of so-called "good deal" at unreasonable low price tag.

[Burgerman]

Any link?

[shirley_hkg]

He does local delivery only.