PINNED - Lithium battery conversion/info

[Scooterman]

This lets me make lots of jokes about my 'cordless' drill that runs off my chair....

ex-Gooserider

Ditto... I too have a cordless drill.Now its corded. It runs better off the chair. Or the van. Or the lawnmower. Or the solar system. Or any of my power supplies or reserve battery. Or wherever I happen to need it. And its always "charged".


Hacksaw, black epoxy, soldering iron. Much cheaper than a new battery. When I say everything has an anderson on it I mean it!

Wow!

Did you expoxy the anderson in the bottom?

[Burgerman]

Yep...

[Burgerman]

You will need to look at 150Ah approx, to get them shorter. Grp34 is the same as grp24 except 1 inch shorter in height.

[wheelerx]

last night I discovered grp 34 as well. I'm thinking about keeping it simple for now and just going with that. easy to update later. Thanks

[ex-Gooserider]

This lets me make lots of jokes about my 'cordless' drill that runs off my chair....

ex-Gooserider

Ditto... I too have a cordless drill.Now its corded. It runs better off the chair. Or the van. Or the lawnmower. Or the solar system. Or any of my power supplies or reserve battery. Or wherever I happen to need it. And its always "charged".


Hacksaw, black epoxy, soldering iron. Much cheaper than a new battery. When I say everything has an anderson on it I mean it!

Wow!

Did you expoxy the anderson in the bottom?

I didn't put the Anderson in the drill, as I didn't want to take it apart to solder the connections. Instead I gutted the battery pack, and soldered a power cord to the contacts in it, then just stuck the empty pack back in the drill. I also use the smaller PP-15/30/45 Anderson power poles on everything except the chair charging cable, and for that I use the PP-75's instead of the SB-50's on the chair since the chair has 4 contacts. The van still uses the SB-50's for it's dual contact plugs.

Electrically it's the same as what BM does, but IMHO it's a bit neater and more compact.

ex-Gooserider

[steves1977uk]

Can anyone shed some light on why I'm having issues charging 8S EVE-LF105 cells?

Melissa helped me to create a wiring harness to allow me to charge 8 cells using a PL8 balance extension cable with terminal rings crimped and soldered on. Testing the pack with my Fluke 289, it reads 26.xx volts with 8 cells in series. But if we measure each pin on the balance plug we get the following...

Code: Select all

Cell 1... 3.xx volts Positive
Cell 2... 6.xx volts
Cell 3... 10.xx volts
Cell 4... 13.xx volts
Cell 5... 16.xx volts
Cell 6... 20.xx volts
Cell 7... 23.xx volts
Cell 8... 19.xx volts Negative

The PL8 throws a Bad pack error, as it only detects 4 cells. All screws are put in with the same 3Nm Torque setting with my Bosch powered screwdriver and all cables pass the continuity test.

Even removing 4 cells, the PL8 detects 3 cells. Help!

Two of my PL8's do the same thing, but works fine with my chair's pack.

Steve

[LROBBINS]

It's hard to see all of the connections in that photo, but the wiring does not seem to be correct. For one thing, you have the black balance lead connected to the + end of the pack and there doesn't seem to be any balance lead at all at the - end. Here's the diagram from the PL8 manual:

BLACK bal lead to pack -, RED to pack +, and the white leads in the order shown. Cell voltages should be measured with voltmeter negative (or common) lead to the pack -, and all values should be positive and close to what's shown in the diagram.

[woodygb]

As Lenny says ...the balance wires are bit of a mess and out of order.

Start again .

[steves1977uk]

Lenny, the top cell (Cell 1) has the black negative balance wire connected to the negative terminal plus the first node 1 white wire on the positive terminal. Cells 2-7 have nodes 2-7 white wires are on the positive terminals, and the red node wire is on the positive terminal on Cell 8 (bottom cell). I believe this is the right order? The main power cables are on Cell 1 and Cell 8 which I get 26.xx volts from.

But yes Woody, Me & Melissa will start again with the wiring.

[Burgerman]

You dont appear to have a balance wire on the negative wire.

[LROBBINS]

What is the negative pole of cell 8 connected to? You may have mixed up some of the power jumpers as well - cell 8+ should go to the battery not to cell 7 -, cell 8 - should go to cell 7 +, cell 7 - to cell 6 + and so on.

[Burgerman]

It is possible to damage the charger if you get these wrong. So care needed.

[steves1977uk]

The wiring was the same as this setup, which in theory should work...

I double checked Melissa had put the balance wires in the correct place.

Steve

[steves1977uk]

I'm a fool, I spotted my error! The black and red balance wires need to be on the same terminals as the main charge cables. I feel stupid now!!!

Steve

[woodygb]

The wiring was the same as this setup, which in theory should work...

8s.jpg

I double checked Melissa had put the balance wires in the correct place.

Steve

Steve ...A good start would be having the red and black balance wires going to the correct terminals at each end of the pack....I.E. The main Positive and Negative power terminals.

Edit ...Ah you spotted that ...BUT swapping them over is NOT the whole story....I suspect that ALL the balance wires need to be reordered.

[steves1977uk]

No, I'm going to get Melissa to remove everything and start over. That's the best thing to do.

Steve

[woodygb]

Note that you have in the pic ,on the top pair of cells , 3 balance wires ( 2 white and one black ) , there should I believe be only 2... Red and one White.

So ...DISCONNECT EVERYTHING AND START AGAIN.

Ha! ...You came to the same conclusion as I was posting.

[shirley_hkg]

You don't appear to have a balance wire on the negative wire.

John is right .

Besides , we all number the cells from the NEGATIVE and up.

The negative end is cell 1
The positive end is cell 8.

BMS uses 8 balance wires only . PL8 has 9

Always start with the first balance lead on the (Negative Terminal) , and then … ALL SUBSEQUENT LEADS TO EACH OF THE 8 CELLS' POSITIVE TERMINALS …accordingly .

Confirm the volts of the JST connector , 0 ,3, 6, 10, 13, 16, 19, 23, 26 , BEFORE hook up PL8.


Woodygb spotted you another mistake too.

Note that you have in the pic ,on the top pair of cells , 3 balance wires ( 2 white and one black ) , there should I believe be only 2... Red and one White..

[steves1977uk]

Me and Melissa redid the wiring, now it looks like this...

The pack is slowly charging at around 1A, the IR of the cells is between 5.1mOhms and 9.0mOhms except cells 4 and 7 which are in the 50's. Melissa said it might be her soldering as it was the first time at it which isn't bad!

What's the best way to discharge a fully charged cell while the others catch up? Would a car bulb work?

Steve

[Scooterman]

Steve - why don’t you put a strip of tape behind the crimp and mark the balance wire number on it? (aka make a tape tag)

[steves1977uk]

SM, I did have some sticky labels that I was going to use but no idea where they've gone!

Steve

[shirley_hkg]

What's the best way to discharge a fully charged cell while the others catch up? Would a car bulb work?

Steve

Yes.

[Burgerman]

I used to use car or 24v truck headlamp bulbs. But I eventually bought a 24V 30A or 12V 15A depending what you connect it to, discharger. The load dump or dump load device.

Its all just ohms law after all.
https://www.calculator.net/ohms-law-calculator.html

[Scooterman]

SM, I did have some sticky labels that I was going to use but no idea where they've gone!

Steve

I often suffer from that too

A guy at work I was apprenticed too, bought me a key fob the size of a saucer cos I was always losing the van keys!

[fishinjunky]

i want to double check is this correct for winter storage?

1. fully charge and balance pack (200ah)
2. discharge 25% of 200ah (remove 50ah)
3. disconnect pack from chair
4. repeat the first 2 steps every 2 or 3 months?

if i dont unplug the pack from the chair how often should i fully charge an balance then discharge 25% ?

[Burgerman]

Every 2 months. f they blance easy try 3 or longer. Not critical. And anything from 30% to around 70% charged is OK. Ideally round 45% charged for long term storage. Again not critical as long as not full or empty!

[FJC10]

I have the opportunity to buy 16 Liitokala 3.2V 105Ah cells like the following:

http://www.aliexpress.com/item/1005001581160612.html

Would those work with my Invacare TDX SP chair?

I have a space in my chair for batteries of the size you will see in the diagram. The connections I should make for those cells I think are also the ones I have put in the diagram, right? That would leave a configuration of 2P8S and a 210 Ah battery. To charge them I would use the Revolectrix Cellpro PowerLab 8 charger that I use for the headways.

https://i.gyazo.com/97f96f927ea3234ce88d688c87a64004.png

Am I correct or am I miss something? The batteries are used, for a home solar station, says the one who sells them to me, that has only been used in 150 cycles, so I would still have many cycles and the price is a little lower and, above all, that I do not have to wait 3 months for them to come from China, because in Europe I do not know of any place to buy them and that they do not take 3 months to arrive to me.

[Burgerman]

ONE incorrect cycle, over or under the limits will kill a cell. So how do yo know they are any good?

[FJC10]

ONE incorrect cycle, over or under the limits will kill a cell. So how do yo know they are any good?

If I charge and discharge them all individually with PL8 to check that it supports the 105 Ah per cell, doesn't it serve as a check that they have not been damaged?

Photos of the home photovoltaic installation:

https://i.gyazo.com/3d4151acf29e8c89ab2ebd9693912986.png

https://i.gyazo.com/e83dbf17154d9228942c68659eab3b6f.png

https://i.gyazo.com/ae8fc943055895aec8f440cc7e1900ff.png

https://i.gyazo.com/4bd0d6377ab06c88c74f5cfeba2437a7.png

And the manufacturing date, according to a cell label, is December 2021.

The seller claims that the cells have only 150 cycles and have not been mistreated, but of course, that's what the seller says.

If any store in europe would sell them and they would arrive in 10 or 15 days, I would buy them new, but I don't know any store that ships so fast.

Do you know any store that sells these cells in europe and ships fast?

[Burgerman]

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.