Stealth Bomber from Alibaba

[Stealth Bomber Demon]

Hello everyone,

I just took delivery of a Stealth Bomber from Alibaba. However, I am very suspect that the battery I ordered and paid for is not the battery I received. It was to be a 72 v 70amp battery but looks identical to the 72v 40amp in size. Could they have made a labelling error or not? In addition, I charged the battery today from 47% charge to 100% in under 2 hours with a 10amp charger. It doesn't compute to me. Does anyone have a 40amp or 70amp they are using that they can confirm the measurements or weight for me?

Thanks in advance.
John

 

[ZeroEm]

Think your wanting to use Amp Hours. You size a battery by the Amp Hours or ah. so a 40ah could put out 40amps or 40a or it could be a max 70a. One is discharge rate and the other is capacity.

Want to figure out how big a 40ah battery is. 72V 40Ah Lithium Battery
find out what cells it is using then most battery's had dimensions in the specs.

 

[amberwolf]

Some thoughts on your dilemma:

I just took delivery of a Stealth Bomber from Alibaba.

If it's from Alibaba, it's not a Stealth Bomber. Those would come from
https://stealthelectricbikes.com/
in Australia.

What you got is probably one of the bajillions of clones of clones of clones of clones...each of which may be very different from each other and the original, and most of which are not very good bikes mechanically or electrically.

However, I am very suspect that the battery I ordered and paid for is not the battery I received. It was to be a 72 v 70amp battery but looks identical to the 72v 40amp in size. Could they have made a labelling error or not?

An error is possible, but it is more likely deliberate. The less they give you for your money, the more they get to keep. This kind of scam is not that uncommon; there are battery sellers on all the major sites that do this, wouldn't surprise me if sellers of full bikes are doing this too.

I am assuming by "amp" you actually mean Ah, which is capacity, because A (amp) is a completely different thing (current, or in the case of a battery spec, it's maximum (usually continuous) amps that it can supply before failure/etc, meaning how powerful a system it can supply). .

In addition, I charged the battery today from 47% charge to 100% in under 2 hours with a 10amp charger. It doesn't compute to me.

That doesn't compute here, either--a 70Ah pack at less than half full would need 35Ah+ to fully charge. A 10A charger would need more than three hours to do that (probably four to four and a half).

A 40Ah pack would take more than two hours with a 10A charger to do that. Probably two and a half or more.

My guess is the pack is not even really 40Ah, assuming the 47% SoC is accurate. What is it measured with?

Does anyone have a 40amp or 70amp they are using that they can confirm the measurements or weight for me?

What cells is it made from, and how many S and P are they setup as? Knowing that you can calculate the basic cell weight, and add up to a few pounds for wiring, interconnects, and casing.

The biggest pack I have, for comparison: My EIG NMC 14s2p 52v 40Ah pack weighs between 35-40lbs, no casing, just cells and busbars and cell holders. It's size is something on the order of a handspan by a foot by a foot (I don't have pack dimensions handy, but you can find the specsheet for the EIG C020 cell with dimensions and multiply by 28 cell thicknesses).

At a guess a 70Ah 72v pack could weigh 80-100lbs, depending on what cells it's made from and how their interconnected, secured, and encased.

 

[Stealth Bomber Demon]

Thanks for that. It is EVE cells. I see the battery you linked has smaller dimensions but more importantly is 30 lbs compared with the 52lbs that mine is. Maybe it is 70amps after all. Interesting!

 

[amberwolf]

Amps, or Ah?

As noted before, they are very different things, and the physical size of the battery has much less to do with how many Amps it can supply than how much Ah (amp-hour) capacity it has.

If you use the wrong terms, people can misunderstand what you are asking or talking about, and supply you with incorrect information.

 

[ZeroEm]

you can test to find out the ah.
Battery amps and ah. Difference and testing
Looking for a better thread.
You can setup a controlled discharge to find out the capacity of your battery. No two batteries will be the same so don't expect it to be 70ah, it might be 68ah but close enough. The weight would suggest they sent you what they advertised. Using weight and size are crude ways of doing this.

 

[Adrian_]

As amberwolf said, you probably got a clone of a stealth bomber. I use and deal with these Chinese stealth bombers myself a lot. From my experience, the batteries they come with are typically between 30-40Ah, if they are advertised as 70Ah, it's either false advertising or they are using Chinese cells that are labelled incorrectly that probably do add up to 70Ah on paper but the actual capacity of those cells add up to around 40Ah.

The only real 72v 70Ah battery designed for stealth bomber clones with branded cells that I could find and I use is this https://www.enduroebike.com/index.php?route=product/product&path=137_123&product_id=379

With shipping and fees it's around $2000 just for the battery and that's typically the price of a stealth bomber clone bike.

 

[gobi]

I hope you bought it with a CC.

Capacity test the battery:
I would use cheap 72v inverter or a cheap MPPT which take that volts and that a load that matches the output volts.

I use a $5 desktop heater (300w) > X volts Inverter > capacity meter > battery
to my batteries.

Also, buying batteries on Ali, I find it hard to trust fly by nite sellers.

I have bought prismatic cells from Littokala Official Store (not sure how official they are) but others have had mixed experience.

If they don't tell what CELLs are inside the battery, I don't consider ....

21700 cells are desired.
like this one:
https://www.aliexpress.us/item/3256802629681144.html

Weight: what is the weight of the battery?
What is the weight of a similar battery made with similar cells?
Find the weight of EACH cell and then multiply by XsYp and find the min weight of the battery.

capacity test and weight test should be enough to confirm the validity of the battery.

If they are off, pls ask seller to refund you and if they fail dispute with CC.

 

[gobi]

Thanks for that. It is EVE cells. I see the battery you linked has smaller dimensions but more importantly is 30 lbs compared with the 52lbs that mine is. Maybe it is 70amps after all. Interesting!

https://www.evebatteryusa.com/18650-and-21700-specifications
for Eve cell weight and capacity.

 

[E-HP]

Hello everyone,

I just took delivery of a Stealth Bomber from Alibaba.
It was to be a 72 v 70amp battery but looks identical to the 72v 40amp in size.
Could they have made a labelling error or not?

Definitely an error.
Sounds like they accidentally forgot to mislabel it!