PINNED - Lithium battery conversion/info

[saker98]

James,

Are they these ones?
https://m.aliexpress.com/item/33054219276.html

In a 8s2p configuration that's 210A continuous, 600A pulse. Which should be fine.

Today's Ali express price delivered is £1128 for 16 cells so if that's for 18 that's a good price (£1178 @ MasterCard fx rate) but check your conversion rate us$ to gbp. Better to get vendor to quote in gbp.

Hi Irving,

Yes, that was fine until Alibaba.com realised that I was an individual and not a company, then shut me out!

I will have to look elsewhere.

But thank you for the configuration information.

Regards
James

[LROBBINS]

I am an individual and have bought from Alibaba and AliExpress many times. Perhaps it's that particular supplier who doesn't want to deal with individuals. Very non-Chinese! The biggest difference between buying non-mass-market things here in Italy and from China is that Italians will fall all over themselves to sell me a full truckload of something, but tell me to get lost if I want one unit, while the Chinese are happy to sell me one whether stock or made-to-order. All I need is patience to out wait the shipping.

[saker98]

Hi Irving,

I can purchase the cells 18@1174gbp to my door.

Link below, do these seem ok?

Https://herculesi.en.alibaba.com/product/60809511666-801647080/Longwise_Lithium_batteries_100_amp_hour_LiFePO4_battery_3_2V_105ah_prismatic_single_cell_for_EV.html?spm=a2700.12243863.0.0.2f5e3e5fPfLCCF

Regards
James

[saker98]

I am an individual and have bought from Alibaba and AliExpress many times. Perhaps it's that particular supplier who doesn't want to deal with individuals. Very non-Chinese! The biggest difference between buying non-mass-market things here in Italy and from China is that Italians will fall all over themselves to sell me a full truckload of something, but tell me to get lost if I want one unit, while the Chinese are happy to sell me one whether stock or made-to-order. All I need is patience to out wait the shipping.

My bad, I got a reply afterwards, it was that I had put my name in company data capture box, and my company did not exist!

Plus time difference to get a message after the error.

Regards
James

[Scooterman]

Saker - Did they tell you how long shipping time is to UK?

[saker98]

Saker - Did they tell you how long shipping time is to UK?

Hi Scooterman,

7-14 days once payment has been made.

Regards
Saker98

[Scooterman]

That's good, quick delivery!

[Burgerman]

Add 10 days going nowhere in customs, waiting for them to rip you off and then being held to ransoe by royal mail who will also add another fee for the privelidge of collection from customs till you pay the bill before they even bother to turn up

[Scooterman]

Add 10 days going nowhere in customs, waiting for them to rip you off and then being held to ransoe by royal mail who will also add another fee for the privelidge of collection from customs till you pay the bill before they even bother to turn up

That's tue, I'd forgotten about that.

Although I was lucky with my cells in that the UPS guy knocked on the door and delivered them like any normal national delivery. No customs, no tax, which saved me a few quid, and as you say 10 days of extra waiting time. Which is infuriating when they're sat in some UK customs centre.

[Burgerman]

Yes the ones that take the piss are royal mail or parcel force ex socialist gov run, and with their entitled attitude. All the rest just deliver and if theres a bill send that later.

[saker98]

Add 10 days going nowhere in customs, waiting for them to rip you off and then being held to ransoe by royal mail who will also add another fee for the privelidge of collection from customs till you pay the bill before they even bother to turn up

John: The order is from door to door, no additional fees.

I will confirm when they are delivered.

James

[Vitolds]

When buying in China, you must have friends in China. otherwise it may be so

[Scooterman]

The order is from door to door, no additional fees.

What so the price you paid includes UK VAT and import duties?

[Irving]

The order is from door to door, no additional fees.

What so the price you paid includes UK VAT and import duties?

That's the theory.

AliExpress now seem to offer their equivalent of eBay's 'Global Shipping Programme' where you pay in your local currency and all import/VAT duty is pre-calculated and included in the price. UPS, DPD and others appear to have signed up to it. I've had a couple of things off eBay from the US recently like this. On the one hand it avoids those random 'end shipper' charges you have to pay to get goods released, on the other you get stuffed for charges you might just have been lucky previously to have avoided, but with the added value of guaranteed inclusion in a consolidated shipment so, in theory, cheaper & faster delivery. The RNet PM120 I bought from the US recently came that route, at checkout they added $15 for import/VAT but it arrived door to door in 5 days - 2 from supplier to global shipment hub, 2 from US hub to UK hub and 1 from there to me.

[ex-Gooserider]

Yes, that was fine until Alibaba.com realised that I was an individual and not a company, then shut me out!

It can sometimes be helpful to create a company name for use in dealing w/ business to business types - just don't use any of the suffixes that go with specific legal entities like ".inc" etc... (doing so can get you in legal trouble) "<Some-Fancy-name> Consulting" is often a good one, along w/ appropriate title like 'Engineering Manager" ....

I don't know about other countries, but in the US it isn't that hard / expensive to even get legal recognition for small entities like a 'Limited Partnership' or a 'Limited Liability Corp.'

ex-Gooserider

[Burgerman]

Dynopower Dynamometer Systems, was my real company. It built automotive dynamometers.

And letterheads, or bills, and order forms, fax numbers, web address etc all help if buying trade. A letterhead and my logo, all help if buying trade etc.

[shirley_hkg]

This is the weaker half of the lot ; all are under 100Ah.

[Burgerman]

Can you return them?

[Irving]

This is the weaker half of the lot ; all are under 100Ah.

How many did you buy in total?

What was your test protocol?

Do the batteries have a serial # or something to ID them or did you just label them? That square looks like it might be a QR code?

[Burgerman]

He measured capacity from full, to 3.00V with PL8 at 10A presumably or at 1C with a PL8 plus load.

[Irving]

He measured capacity from full, to 3.00V with PL8 at 10A presumably or at 1C with a PL8 plus load.

Which supplier were those from? If it's the one originally linked to I think they were spec'd to 2.5v (low I know) so they may be marginal on 100Ah at 3v.

[shirley_hkg]

Can you return them?

No. They weakest is still 99.256 , at my conservative criteria @3.605---2.99V,
CC only at 0.25C.

[foghornleghorn]

Do the batteries have a serial # or something to ID them or did you just label them? That square looks like it might be a QR code?

It is a QR code, but just says the same number that is written beside it in a format easy for a machine to scan.

Mine had such different serial numbers spread through the 16 I couldn't work out how they were issued or any relation to batches.

[Irving]

Can you return them?

No. They weakest is still 99.256 , at my conservative criteria @3.605---2.99V,
CC only at 0.25C.

Might be worth taking it lower to see what 105Ah discharge actually gets to volts wise. It might not be so far off. Even @ 3v they're within 5%, and if you're not planning on caning them is it really an issue?

[Burgerman]

At the 2.7, 2.9. 3.0 volt level (and the absolute limit that you should not do really 2.5V) theres around 1% dfference in capacity. The line just goes almost straight down.

The difference in capacity from these 4 end points in negligible.
You DO get a little extra capacity if they are slightly warmer. But I think that he tested all cells in the same contitions, so if all the rest were 100+ up to 105Ah, then these are just the "rest". They claim 105 is the highest. And that there may be a few percent that are not quite that good. But still withinn the +/- allowed tolerance.

Remember that this is the end of a 24 hour discharge. So this drop off on the empty cell we see here, happens about 3 times steeper if you look at the full graph. It falls in volts in a rapid time frame as you watch. So 3, 2.9 (as set for cut of below) 2.7, 2.5 are all practically the same thing. Look at 3V on the graph, and remember that you cant go lower than 2.5 (and you shouldnt or the cells develop high self discharge rates).

GRAPH: download/file.php?id=12060&mode=view

[shirley_hkg]

It's really compact. 100Ah in a original G24 battery box.

[Burgerman]

Can you give the overall dimentions of the pack as seen W x L x H?

Actually that should read 200Ah, 12V as its a single lead brick box right?

[Scooterman]

I'm currently saving up for 8 x 105Ah or 8 x 90Ah for my powerchair.

Been having a clear out and bashing stuff out on ebay

[Burgerman]

It will work but these are low rate cells, so much better to fit all 16. Plus if you only fit 8 they will all be hiding in the corner cuddled up trying to keep warm.

[Scooterman]

It will work but these are low rate cells, so much better to fit all 16. Plus if you only fit 8 they will all be hiding in the corner cuddled up trying to keep warm.

You haven't seen how thick my insulation is!

I totally get why you say that, and others will agree with you. But me and my chair is such a lightweight combination, especially with on 16kg of cells on-board and a rearward seat. We will be half the weight of the average user & chair.

And less cells mean less connections, a quicker build, and not such a tight fit in the battery box. Plus two people will be able to easily lift the chair into the back of a vehicle if ever needed. I'm confident it'll be okay because I know how I use my chair and how it's never under load or struggles. And the AGM leads in it are 3-4 years old.

BUT! I will do what you've done before. In that I've got a clamp ammeter and will clamp it round the battery cable with the leads and see what the amps are under max load conditions.

Are the lifepo4s about 3C? So that would be 270-315A max output, is that correct?

My controller is only 90A per channel and I'm not sure what boost amps it's delivers, is it 110A? I did know at one time. It's the rnet el90 controller.