Tempting fate

[ChrisBarron]

After reading the comments by new member Rog about lithium battery packs from China, I recalled I had an account on a Chinese company business portal and I searched for more batteries , cars and motor's/electric transaxles of which there are quite a few.

Would anyone be interested in sharing a group purchase ? If I can give them enough goodwill to send a sample of each battery to test the quality, and then proved it, would there be any interest from the group ?

I might be able to find funding for such a venture so I may not need anything to be paid upfront, but I'm not sure just yet about that.


Fingers crossed,
Chris

[qdos]

Hi Chris Im pondering the same sort of thoughts myself. I'm not a battery whizz so I'll speak with my battery man as we've got a couple of projects in hand which might have a need for a good regular supply of batteries. It depends how we go about things.

[MalcolmB]

Hi Chris,

I'd be careful about buying lithium ion cells from unknown Chinese manufacturers or resellers. I know of several people in the States who've had their fingers burned buying cells for ebike projects. Many of these cells do not deliver anywhere near the performance promised, quality control can be very poor and you get very little if any warranty cover. There have been some cases of people being supplied with different lithium ion chemistries than they expected. Since some chemistries are much safer than others this can have serious consequences. Two of the safest chemistries available now are lithium iron phosphate and lithium titanate.

Testing single samples from a manufacturer will give you some idea of the chemistry being used (based on voltage at end of charge) and whether the cells can deliver the current promised, but it will give no indication of cycle life or the standard of quality control. Even with a relatively well-known manufacturer such as Thundersky, quality control and customer care seem to be well below average European standards, which is worth keeping in mind when checking out prices.

Cheers
Malcolm

[qdos]

Yep Quality control seems to be a big factor to consider with China. I know of a few imports from China which didn't measure up in delivery.

[ChrisBarron]

Thanks for the warnings and advice. I'll bear it in mind and suggest to any responders that there be some agreement between us for returns and warranty before we went ahead. It will be interesting to see what they say.

Chris

[ChopperMan]

Hi Chris,

Here are my previous comments on this subject.

http://batteryvehiclesociety.org.uk/for ... =4026#4026

When pricing up the economics of importing don't forget to include import duty and VAT. Shipping of small sample qualities is very expensive, I paid £400 for two ebike packs, but £490 for shipping, then they got stuck in Customs for two weeks regarding issues with the transporting lithium batteries, VAT and Duty.

You've obviously got the BMS and Charger issue covered.

I have found a lot of suppliers evasive when asking technical questions but keep asking and request lots of photos and test results for the cells they are sending you. This will help weed out the resellers from the manufacturers.

Good luck.

Ian

[ChrisBarron]

Fair comment Ian, I've been stung with tax issues before, only in a small way though !

On the subject of drives. the first company has responded with the following information and picture of theiur combined 8kW motor/trasaxle for 192V systems. Their price includes the controller.

>>>>>>>>>
Thanks for your attention to our car motor of 8KW.
USD3000/set for 1 set (including motor,transaxle and controller).
USD2900/set for 10 sets order.
Sea freight cost for 1-10 sets is USD100 to London Port.
Lead time is 30 days.
Payment term is TT in adavnce.
Thks & Rgds
Zhongfeng Li
Sales Manager
Shenzhen Unite Industries Co.,
(Unite Motor Co.)
www.shapemaking.com
www.cn-dcmotors.com
>>>>>>>>>>>

....not sure if I can drop a photo in here ? their website should show one of their units though. At curtrrent exchange rates it's about £1550 for a complete trasnaxle and drive system. The downside is that the 192V may be hard to get, although the current is quoted as being below 10A, and the power output is the peak output and not rated by any means, max torque is just 13Nm

They make a larger version too, about twice the size in all respects, which could be more appropriate, this 8kW unit seems to small for anything but NEV's

Chris

[ChrisBarron]

Another couple of quotes have come back if anyone is interestd.

First one was for 100V-140V 120Ah pack (20kW nominal), lithium Ion, which came back at $24,500 including shipping. I nearly fell over.


Second one is below, comes back at about £5000

>>>>>>>>>>>>>>>>>>>>>>>
CITIC GuoAn Mengguli Power Science & Technology Co.,Ltd.

I've discussed about the parameters you sent to me. Accordingly, I'd like to recommend you our EP60Ah battery. I suggest two EP60Ah batteries in parallel connection to reach 120Ah. This model of EP 60Ah can discharge at 1C-2C at normal working condition and 5C at peak current. This way, they can totally meet your request on running current and peak current without any damage to the batteries. Also, according to your proposed voltage of 100-140V, it requires 33 batteries of 120Ah in series connection. Thus, you need totally 66pcs EP60Ah batteries.


And the FOB price for a single EP60 is USD 148.97. The total price for a pack without BMS and charger is USD 9831.73. Additionally, do you need BMS and charger from us? If you do, I will quote for you next time, ok?

>>>>>>>>>>>>>>>>

[EVguru]

To add to the warning of others...

Even if the cells meet specifications (which they often don't), there can be problems with the calendar life. One particular type of cell has been experiencing internal corrosion problems and the company does not seem interested in replacing defective units. It's one thing to go in knowing that you're a beta tester and take the risk as an individual, but if you do a group purchase there is bound to be someone who will want you to give them their money back when things go wrong.

I've just been talking to Denys at Reap Systems about cells for my next motorcycle and it's looking more and more like the sensible thing to do is find enough money to buy the Kokams.

[ChrisBarron]

Kokam are one way to go, that's for sure. I know TS cells have had their problems too.
The thing is someone had to be the first to try out Kokam didn't they, and as time goes on there is less likelihood that only one company can make decent cells, but you are quite right to say what you said