PINNED - 230Ah (245Ah certified) A grade cells Amy, Docan

[Burgerman]

Hello John

Thanks for your fast reply, please check the quote:
Grade A EVE 230Ah LiFePO4 cell with laser welded M6 studs Unit Price: US$55/each*8pcs=US$440
DDP sea shipping cost: US$180
Subtotal: US$620

Payment Options:Goods and service fees (PayPal/CC/Visa, etc.) is 5%, Alternatively, bank transfer with a bank fee of approximately $48-$100 per payment
Details:
*Free Gifts:One copper bus bar and two nuts per battery & epoxy boards between battery cells
*DDP International Sea Shipping: All-inclusive fees. No VAT, duty, or taxes.
Reliable 50-70 days delivery via DDP sea shipping. Local delivery to your door with truck, DPD, FedEx, or UPS.

Warm Regards
Amy Zheng
Docan Tech
http://www.docanpower.com

So in pounds thats:
inc delivery, to my door, 620 US dollars. And that according to paypal is at todays 1.27 doolar to pound rate £474.22 UK pounds.

The current price of say one MK gel 74Ah battery I can find that wont charge VAT is £328 each. So £656 for a set. So that makes the230Ah EVE grade A cells about 2/3rds the cost of a set of MK decent lead bricks.

That 74Ah lead battery can only do 40Ah before it is used up in a power chair. Tested. At this point you stop after a real world 16 miles at best.
That makes lead £656 div by 40Ah = £16.40 per Ah.
The 230Ah USABLE from lithium gives 474.22 div 230 = £2.06 per Ah more than EIGHT TIMES cheaper per Ah!!!
Then they last maybe 2 decades before replacement compared to 10 to 18 months.

So under 2/3rds the initial outlay.
5X the range or better.
8X (more) cheaper per Ah.
4X the calender life, typically 25 years +
10 to 30x the cycle life. And charge weekly...

Who in their right mind can afford or want lead?
Downside? £30 and a few hours to make up a charge cable/balance lead. (Or a BMS if you wanted )
Hobby grade charger, and a little knowledge needed rather than an overpriced dumb mobility charger that kills your lead bricks.

Getting up in a morning, looking at a perfectly balanced and charged 100 mile capable battery on the laptop screen, starts the day off nicely! Knwing that it doesent matter how far or where you wander off to that you can always get back. I dont have 230Ah yet, I have a bunch of different lithiu chairs all using headways etc. But that great range is even true with 120Ah that my green chairs battery has for e.g. That has 3x the range of lead already. And its almost enough for endless roaming without considering range of battery meters. 230Ah is even better.

[fishinjunky]

wow they have really come down in price thats half what I paid just over 2 years ago for 200ah grade a cells! Ill be getting a new chair next winter an putting a 230ah pack in it for sure I could never go back to lead bricks .
I think some people over complicate building a pack an get stuck in the weeds trying to understand everything in a hurry and some will never fully understand the chemistry or the technical details. But if those people could just slow down an take a step back they could be directed how to build a pack. Im an example I have maybe average intelligence but with your guidance and others on this forum my mom and I were able to build a pack charge it and install it without any problems or complications it was much easier than we expected.

[Burgerman]

If you want cells that are 50mm or 53mm thick, then order sometime soon. The 230Ah ones are being replaced everywhere by 280 or 308Ah. Those are 70mm thick and wont fit...

Right now docan is the best deal and probably the best supplier. So grab em while price is reduced and still available.

Then they will JUST fit if you use this layout:

[Burgerman]

Bill...
Thats £475.23 delivered.

[shirley_hkg]

Doing a maintenance charge cycle to the Gel pair, that powered me along streets of LONDON last Sept.

Pretty strong still.

They are @ £100 / pair.

[Burgerman]

But 68Ah back on lead means that you only took about 58Ah out...
And you cant even do that in a chair while rolling as its voltage falls too low, resistance goes too high, and you run out of steam after about 55% of the capacity.

[Burgerman]

Ordered today.
A GRADE 230Ah EVE cells, for £475, thats much cheaper even than a set of decent Gel batteries like MK. And over 5x the range, 20x the lifespan. Thats quite mad.

These 230Ah cells, and this is amy showing them, in 2022:
https://www.youtube.com/watch?v=-jXogB3736A&t=21s

This is Amy testing one and showing details:
https://www.youtube.com/watch?v=PlLr-XzYpyA&t=29s

I think that I trust Docan as they are one of the largest and oldest sellers of these lifepo4 cells. And they are happy to give the lowest prices, garanteed A grade brand new stock, complete with traceable and manufacturer genuine bar code stickers and even have a way for you to test and check these on the site. They also supply the manufacturers test data to match each individual cell/barcode if you ask for it. I will do. But garanteed to be 237Ah or greater and very low impedance. She says she welcomes any testing and wishes me to post the results on their social media sites. And with PayPal how can you go wrong?
Especially at 475 delivered! They have stores and staffed distribution and stock in China, South Africa, EU and the USA.


Includes nuts, fibre seperator plates, and plated link plates. And they package these very very well! Take a look on the website. They do appear to be the real deal. We will see!

Ordered. But unfortunately, 30 to 60 days by sea/then on land so I am now waiting!!!
Docan site and amy sent me a link that allows us to check out the codes on the batteries we buy anywhere.
https://www.docanpower.com/index.php?ro ... tion_id=12

[Burgerman]

Remember that you will need a lot more power in order to efficiently charge these. At least if you discharge them a lot. This may be because of a long distance or just because you decided to charge weekly. And that will be OK for some users.

At 230Ah it would take your typical 8 Amp mobility charger 230Ah div by 8A = 28 hours! Not including balance and CV stage. Because you are actually charging the equivelent of 5x the range. Or if you prefer the equivelent of 10 complete MK gel batteries!

I will be using the 40 Amp hobby grade PL8 charger to charge mine as I already do with many other lithium batteries. That can charge a huge 5x faster than a 8A mobility charger. So it will take 5.7 hours to put back around 80 to 100 miles of range. Or about 20 miles returned for every hour. Plus a few mins to balance and end CV. Definitely under 6 hours for a full recharge.

That will allow me to go 5x (plus some in reserve) further than a set of MK gel batteries.
It will go the same distance as if you had TEN of those MK gel batteries on board.

If your chair literature claims 20 mile range" then it will now do 100. (20m x5 = 100m). And have some left.
If it claims 16 miles, as mine does, it will now be 80 miles and a little in reserve.

And last much longer than the chair will...

[shirley_hkg]

AND you even saved 1/3 the price of a pair of MK Gel.

That's ridiculous.

[Burgerman]

Lithium just keeps getting cheaper. And lead gets dearer!

I expect that there will be a newer version of the 173 x 54 x 206 cells, maybe even bigger than the 230Ah we have now. Sooner or later. But I cant use 230Ah in a day anyway, and at these prices its just a no brainer. A new size may not be as cheap. These ones are already 3500 cycles at 100% discharge level. At 0.5C. The newer 280 and 310 Ah ones with the hex shaped terminals are 6000 cycles at 100% discharge...

But these 230Ah ones will already outlive me because of the low duty cycle/size etc as it is. So not concerned!

Cheaper than lead. but same range as TEN+ lead bricks

The only real differnce is the weight.

An MK gel is 23KG two is 46KG. A 230Ah EVE x 8 pack is 33.3KG. So its 13KG less. That shouldnt be an issue? It actually improves performance, range, and even speed because slightly higher voltage. Not much but better than NOT having it!

I am tempted to order another set when the 1st lot arrive if all is good. While they are available. That physical size may dissapear.

[foghornleghorn]

What is the overall height including the welded on posts?

[shirley_hkg]

220mm

[Burgerman]

A bit less once I chop off 6mm or more from each one with my dremel... 214mm or less. If required.

You only need enough for a ring terminal, a balance wire terminal, and a thin washer + thin nut. = about 9mm total.

To shorten a terminal NEATLY and accurately add 2 ring terminals, a thin washer, and an ADDITIONAL washer as spacer, and nut. Cut off with dremel flush with nut and grind nice and flat. UNSCREW nut, and gently debur the edge of the thread with a debur tool. Then you will have just 1mm of extra thread unused.


Tech full spec PDF here:
https://www.docanpower.com/index.php?ro ... load_id=15

[Burgerman]

For those struggling for height, the 160Ah cells, are the current best alternative. So for difficult chairs like permobil etc.

These like the 230Ah ones show OUT OF STOCK but email Amy, and you will find hat they are not. They have plenty. But wont be getting new stock when these are gone.

https://www.docanpower.com/index.php?ro ... uct_id=453

Thats not quite as good.
But when you consider that you get 45Ah at beast from lead, these will stil alow you to get 3.5x the range. So your 18 miles becomes 63 miles. Say 50 real world with a safe 13 miles in reserve.

And just about big enough to deliver the current needed without causing problems long term. Same exact width and length as the 230Ah ones. Just shorter in height.

[jefferso]

Docan site and amy sent me a link that allows us to check out the codes on the batteries we buy anywhere.
https://www.docanpower.com/index.php?ro ... tion_id=12

All 8 of the 160Ah cells I ordered show:

Manufacturer: EVE Power
Product Type: Battery Cell
Battery Type: LiFePO4
Nominal Capacity: Don't Know Yet
Nominal Voltage: 3.2V
Manufacturer Website: https://www.evebattery.com

Production dates show 2 were slightly older than the others:

1 Production Date: 12/Jan/2024
2 Production Date: 12/Jan/2024
3 Production Date: 05/Mar/2024
4 Production Date: 05/Mar/2024
5 Production Date: 05/Mar/2024
6 Production Date: 05/Mar/2024
7 Production Date: 05/Mar/2024
8 Production Date: 05/Mar/2024

[Burgerman]

Considering that they are good for decades I dont think that matters. But you should really do a capacity test of a random one just to check.
Test from 3.65V down to 2.5V at 25C should give the rated output.

Down to 3V a little less but is what I would do. And at 20C also a little less.

But you get a good idea. Are they pristine and clean and not bulged or anything abnormal?

They should be flat. Or almost completely so.

To take continuous high current out of them you should clamp them between metal plates. But that doesent apply to our usage so dont worry!

[jefferso]

They all seemed to be good, flat, straight sides, no bulges or marks, quite pristine.

https://www.wheelchairdriver.com/board/ ... 60#p202782

[Superchunk]

An MK gel is 23KG two is 46KG. A 230Ah EVE x 8 pack is 33.3KG. So its 13KG less. That shouldnt be an issue? It actually improves performance, range, and even speed because slightly higher voltage. Not much but better than NOT having it!

I was always wondering about this. Is it worth adding weights to the battery box to make up the lead battery weight? Wouldn't the lower weight affect centre of mass and stability?

Test from 3.65V down to 2.5V at 25C should give the rated output.

How do you discharge at 25C? PL8 only does 10A no?

[Burgerman]

Centigrade!

Discharge at 25C rate wouldnt be good! It would destroy your cells.

Unfortunately the PL8 discharges 10A max, so takes a day. Because discharging at 0.2C which is how they test is much more than 10A that warms the cell slightly. Which results in about 3 or 4% more Ah...

As the cell temp increases the more the lithium cells (and lead) are capable of. In regards Ah. But the higher rate you discharge the worse lead gets. So its the opposite to lead. With lead the faster you discharge the less you get. With lithum the fact that it warms the cell a little give you more Ah. No peukert.

-Lead. (At the "gun it from full charge, and cover 16 miles in 2 hours rate) nets you around 50 to 60% of the 20 hour Ah written on the tin. And you stop.

-Lithium, that same 2 hour rate, which is 0.5C actually gives almost the same capacity as the 1C (230Ah) or the 0.1C rate. Theres about a 5% change only. And its better as the cell warms up at higher rates. Up to a point.

[Burgerman]

I was always wondering about this. Is it worth adding weights to the battery box to make up the lead battery weight? Wouldn't the lower weight affect centre of mass and stability?

Well thats all up to YOU and your chair, your preferences, your specific CG etc. So its another compromise to add to all the rest! But its only 16kg difference. Thats about the same low down as having 16kg item like a 36lb toddler or other item on your knee. Is this an issue?

It should make a rear drive chair have a better weight distribution. Unless you already addressed that in which case you may need to un adress it!

Mid drive? Shouldnt matter.

Frot drive? You shouldnt be using one!

[Superchunk]

Thats about the same low down as having 16kg item like a 36lb toddler or other item on your knee.

Shove a baby in my battery box then. Noted

[slomobile]

5% credit card fee or $48-100 bank transfer fee.
$77/cell for 230Ah US stock. Plus shipping.

[Burgerman]

Paypal here. No 5% fee if you send as freinds and family. Your risk.

https://www.wheelchairdriver.com/board/ ... &mode=view

[ex-Gooserider]

If you want cells that are 50mm or 53mm thick, then order sometime soon. The 230Ah ones are being replaced everywhere by 280 or 308Ah. Those are 70mm thick and wont fit...

Right now docan is the best deal and probably the best supplier. So grab em while price is reduced and still available.

Then they will JUST fit if you use this layout:

You might want to edit the drawing - you have TWO cell 8's and no Cell 7....

ex-Gooserider

[Burgerman]

Yes... But that makes it interesting.

[jefferso]

Here's another version of the drawing renumbered and with numbered balance wires drawn in.

[Burgerman]

Good!
What software do you use?

[jefferso]

Good!
What software do you use?

Adobe Illustrator for that one. I set it to use pixels for measurement, then have each pixel scale to 1mm so things should be fairly to scale. That png export is zoomed in a bit so no longer 1px=1mm but the sizes should have the right relationship to each other.

[Burgerman]

I have the latest illustrator 2024 and all the rest. Never used it though. Will give it a try. Do you need the latest version, up to date as of a few days ago?

[jefferso]

Mine is from 2019, seems to be working ok. And it's on the Mac OS, which I'm guessing is not the version you have…

I'm not sure if it will work, but I've attached the .ai file as a zip. It has some extra stuff on the side but the main part might be useful.