52v 40Amp Battery From ebay

[mybike]

Hi all.. it’s been awhile. I wanted to get my ebike on the road again for summer and I need a battery. I come a cross one on ebay uk as I’m not good in battery cell and specs stuff I thought I get your views and thoughts about this first.

https://www.ebay.co.uk/itm/234276277639 ... SwY-NhiOB5

I’m looking to get the 52v 20AH dos the battery spec look right?

My controller is an Infineon 40Amps

[amberwolf]

Hi all.. it’s been awhile. I wanted to get my ebike on the road again for summer and I need a battery. I come a cross one on ebay uk as I’m not good in battery cell and specs stuff I thought I get your views and thoughts about this first.

https://www.ebay.co.uk/itm/234276277639 ... SwY-NhiOB5

I’m looking to get the 52v 20AH dos the battery spec look right?

My controller is an Infineon 40Amps

The specs, if accurate, would match your controller's current limit. Can't tell if any of it would match the rest of your system (no info on that in your post).

Whoever wrote the page doesn't use English as a first language, most likely, so there are various things on there that are open to interpretation, and/or have insufficient detail.

Regarding the specs themselves, this part:

Cells: Built in Chinese Top A Grade 2500mah

means you really have no idea what is in there; it's almost certainly just "marketing speak". Without knowing exactly what cells are in there, and having a cell-manufacturer spec sheet for those cells, you can't know if they really match the specs provided for the whole battery.

This part

Each cell has its own fuse for ultimate in safety.

might (probably) means they're using cells with built in PTCs in their endcaps. (I doubt they would spend the time building it with actual individual fuses wired to each cell, or using busbars with fuse wire to each cell, etc). PTCs increase resistance as temperature goes up, so the warmer the cells are the higher the resistance of each cell, and the more heat is generated by the PTCs due to their higher resistance, and so on.

There's other things like CIDs, which have their own disadvantages.

They could use tabs with narrow spots in them that melt open under high enough current; this will disconnect any cell permanently that is connected to one of these that opens.

Other methods also exist.

Without them stating which method is used, you'd just ahve to use the pack normally and wait till problems occur (they will eventually even with the best pack) and disassemble then to find out. (presuming you wouldn't want to void their "1-year warranty")

This part

- Fully potted pack for the ultimate in battery protection.

contradicts this part in the warranty:

1. The battery goes over water.

which probably actually means "the battery gets wet". No way to know; it's too vague a bad translation.
But anyway, if it is fully potted, then water "won't" hurt it (probably submersion might, but simply getting rained on or splashed wouldn't). If water can hurt it, it's not fully potted. They don't give an IP rating (like IP67, etc) so how water resistant or waterproof it might be is impossible to know without opening it (and probably testing it to destruction. ). So a warranty that won't cover water problems isn't very good, if it's supposed to be resistant to or proof against water.

This part, in reference to the part above, might be about right:

Configuration: 14S 8P (14*8=112 cells)
Battery Net Weight: 6.6Kg
Battery Dimensions: 260*160*70mm

6600g / 112 is about 59g per cell. This, in comparison to the average weight of a typical 18650 cell of around 45g, is probably enough to leave mass for potting as well as all the cell interconnects, bms, pack wiring, external covering, etc. 45*112 = about 5kg, leaving a little more than a kg and a half for the rest.


For future readers if the linked page goes away: Specs from that page show:

- Fully potted pack for the ultimate in battery protection.
- Each cell has its own fuse for ultimate in safety.
- Built in BMS with short circuit , over-current , over-heat , over-charge , over-discharge protection.
- High quality electronic core , heat shrinkable casing, battery shrink wrap with waterproof glue, lighter weight.
- Short Circuit Safety Test √ Overcharge Safety Test √ Crush Safety Test √ Needing Safety Test √ Extrusion Safety Test √


52V 20Ah 40A BMS Specifications:

Fit Motor Power: 52V or 48V 500W-1500W (Max Matching 1600W)
Nominal Voltage: 52V
Rated Capacity: 20Ah
Watt Hours: 1040Wh（52*20)
Cells: Built in Chinese Top A Grade 2500mah
Configuration: 14S 8P (14*8=112 cells)
Cycle life: ≥80% Capacity After 800 Cycles
Battery Net Weight: 6.6Kg
Battery Dimensions: 260*160*70mm
Standard Charge Current: 3A
Max Continuous Charge Current: 5A
Max Continuous Discharge Current: 40A
Peak Discharge Current: 120A
Charge Cut-off Voltage: 58.8V
Discharge Cut-off Voltage: 39.2V

Warranty：
We provide 1 year warranty for all electric bike batteries.
Any battery with quality problem in one month we can return the money after you provid the proof.
After one month we can send BMS or cells to you for repair,or you can send it back to repair as well.
All our electric bicycle batteries with high quality cells and BMS, and they will be 100% tested before shipping.

We don't supply warranty service for the following situation :
1. The battery goes over water.
2. The battery is broken man- made.
3. Return the battery without reason.
4. Open a case without contacting us.

[mybike]

Thanks amberwolf for your prompt detailed reply.
I did contact the seller and they said the cells used are G25 Chinese 2500mah 3.7V Cells.

Not fully sure about getting it, the price is tempting and the battery is in the UK. If I brought a battery from over sea I will have to pay over all way more for the battery to get to me and will be a one way ticket. So this may be better to try?

I have:
Infineon controller 40A
1000w rear hub motor
Front & Rear 19 inch motorcycle rims

[99t4]

So this may be better to try?

That is an interesting concept (try).

What is their return policy?

Constant repeated experience has shown us that battery vendors reliably over-exxagerate their battery performance specs.

So if the battery does not perform up to its promises, can you easily return it for a satisfactory refund?

[mybike]

Hi 99t4…
There listing for the battery dos say if there is quality issue then return battery for a full refund.
Also payment is via PayPal so I have some protection there.

[LewTwo]

Hi 99t4…
There listing for the battery dos say if there is quality issue then return battery for a full refund.
Also payment is via PayPal so I have some protection there.

You might want to check the shipping regulations. Most consumers do not have access to any method to legally meet the shipping requirements for a lithium Ion battery of more than 300 watt hours.

UN Identification Numbers Applicable to Lithium Battery Shipments
UN3480: Loose lithium ion batteries
UN3481: Lithium-ion batteries “packed with” or “contained in” equipment

[mybike]

Iv have already brought the 52v Battery and I have received it. I did have a issue with the charger they sent, I contacted the seller and the seller is sending a new one from china 10-15 days wait.

Mean while I have brought a charger of ebay and I changed the Voltage by adjusting the pots inside to 58.8v and the battery is taking charge.

[99t4]

Mean while I have brought a charger of ebay and I changed the Voltage by adjusting the pots inside to 58.8v and the battery is taking charge.

Okay but be aware that the charger's output voltage may vary depending on whether the battery is connected and not.

(Assuming you measured the charger output voltage when it was powered up, with no battery plugged into it.)

[mybike]

Hi 99t4
The charger has Voltage pot and Amp pot. I powered the charger up and no battery was connected to it then I set the voltage to 58.8v by slowly turning the voltage pot.