Purchasing from ShenZhen Victpower Technology

[cwah]

Same for a group buy in uk. Anyone interested?

[ohzee]

The price was 18.40 a cell plus about 127$ US for shipping 20 cells total.

[flexy]

I am trying to complete a second purchase from Victpower.

The first I did through paypal for 104 cells, it went Ok and the cells arrived quickly apart from one cell being punctured.

I requested 27 more and a replacement for the punctured cell. Xin was fine about this but insisted on direct money transfer.

I made the payment on 30 May to KING TRONICS INTL ELECTRONICS LTD, which was the account name she had specified, it all went through according to my bank.

She has since contacted me twice to claim the money has not come through.

Has anyone had a similar experience?

Edit- I have since found a mistake was made with the account name, not enough room on the web form to fit it all in. It's best to do this in person with your bank if you are in UK.

[cwah]

Sometimes international transfer takes time to arrive. Maybe you have to wait a little

[Spacey]

Same for a group buy in uk. Anyone interested?

I'm up for 22 Cells in Uk

[cwah]

I was thinking about buying a pack but I can maybe also buy 22 cells and make my own pack if it's easy.

What charger do I need and how do I balance them?

[Spacey]

Any Lifepo4 charger that charges to 3.65v per cell and any decent BMs that balances to 3.65v will do.

[cwah]

Does a 20s lifepo4 charger directly balance the cells? I thought it would be a bulk charge. I could directly ask Victpower for a charger then.

[flexy]

This is a 20s BMS,http://www.evassemble.com/index.php?main_page=product_info&cPath=6&products_id=45&zenid=8lgo528s0oo1b7a1noucoju0u2 I don't know of any 22s options apart from distributed BMS and Peter Perkins design.
I can't vouch for reliability but they have been helpful with stuff I bought (and replaced under things under warranty). Don't forget you can move the charger and BMS to a new pack when the cells do lose capacity.

If you don't have much electronics knowhow then don't go down his route, just get a package from Ping or similar.

[cwah]

Thanks Flexy. Ping is still a bit expensive with low density. So not a good combination.

I am planning on a 20s with 2 spare cells. So should be classical a 20s bms.

Anyway keep us in touch with the seller, if you can solve the problem

[cwah]

Probably a stupid question, but why their 20s battery is rated at 60V?

Each A123 20AH cell has a nominal voltage of 3.3V. So a 20s battery should be at 66V isn't it?

[deVries]

Did anyone incur customs fees in the USA for these A123 cells???

Thanks.

[999zip999]

Cwah buy a plug and play battery. You will learn a lot for starters.

[cassschr1]

I bought 100 cells, no customs. They come 14 in a box. If you order just a couple more they fit them in. Twenty twenty two , they probably send 2 boxes.
The cells seem a little soft,compared to some others Ive handled. They might stiffen up with use.
With DHL they came quick.

[cwah]

I think you're right zip999. I'll most probably get a complete pack for starters. That way I'll already have a pack to follow later on

Casschr1, how were the cells? Are they all good? All at 19ah as expected? no dud cell?

[cassschr1]

All were good . Only messing with 30 right now. There not all the same voltage out of the crate.
I'm getting 12a out before (or at) 3.2 on a full charge at 20 amps discharge so there s not much sag.
This is stopping at 3.2

[999zip999]

Cwah it just a lot of work getting it all togethere witgh all the parts and bms charger ect.

[voicecoils]

Just received my order of 48 20Ah cells. New full tab cells which cost almost exactly AU$25/cell with all charges included.

7 days from T/T payment sent to acknowledgement of payment received.
3 days organising/packing
5 days in transit with DHL

Could have been handled a bit more efficiently and had the cells in hand in 10 days or less, but overall I was happy with the service and particularly Xin's prompt and polite communication, even after my money was received.

photo (9).JPG (145.14 KiB) Viewed 315 times

I've only opened 1 box so far, top cells a bit bent, the others look fine. I'll unpack and begin checking electrical health tomorrow.

[cwah]

They proposed me a 60V20AH pack with 20A-40A bms.

I told them that I'll probably only use 15A continuous and they said they can modify the bms.

I understand that the bms could have a peak (40A), but why is there also the working current? I mean if I want to run the bike at low amp (ex: 2-3 amp), it should still be possible isn't it?

Not sure about the value of the working current?

[voicecoils]

The only point of current limits on the BMS is to protect the cells.

These A123 20Ah cells can deliver up to 400-600A each.

If the rest of your system needs current limits (to protect the motor or controller for example) then set the limits in your controller or with a Cycle Analyst.

A 20-40A BMS sounds fine in your situation, but if you decide you want a more powerful bike later on, that BMS could annoy you and might need to be bypassed.

They often rate the BMS with a few current limits, one is the continuous current it can pass and the other is peak/spike or pulse which is a higher current that if only present for a short time, won't cause the BMS to cut out.

If the BMS cuts power to your bike and your battery isn't actually fully discharged, this can be frustrating, especially if you are stuck out in the middle of nowhere!

[cwah]

I completely agree with you. I just don't understand why they need 15 days to customize the bms from 20A to 15A when nothing would happen to the cells

[999zip999]

Cwah get the 40 amp or 60 amp bms. How much. plus shipping

[voicecoils]

I completely agree with you. I just don't understand why they need 15 days to customize the bms from 20A to 15A when nothing would happen to the cells

My feeling is that they would send the cells elsewhere to get built into packs, BMS modified etc.

Their core business may be repackaging boxes of cells and shipping them out and any other requests could take a lot longer.

You can always modify the BMS yourself my adding/removing shunt material to trick the BMS into different current limits.

[dnmun]

.

[cwah]

It would still be a 40A peak bms but it would accept lower power continuous usage at 15A. Not sure about the reason of that