Any way to verify AH on a battery?

unclejemima · Apr 17, 2021

Is there a way to verify AH on a battery purchased from Amazon?

I'm looking at this bad boy...48v 24.5AH!!!! Upgrade from my 48v 11AH unit.
https://www.amazon.ca/gp/product/B08X2F2DC7/ref=ox_sc_act_title_2?smid=A1DQ8CBGDI0TLE&psc=1

I'm not looking to increase speed, rather reliability. So choosing the 48v over the 52v. I'm running an order BBS02 that has had a new controller installed a few years back.

Would love the extra AH the 48v unit provides.

Thanks guys,

fatty · Apr 17, 2021

Require the seller to provide a picture of the Samsung 35E cells built into a pack before you order. If you're skeptical, require another picture of the cells in your pack before it ships out. This won't prove they're new cells, but it's better than nothing.

As an aside, I'd expect any reliability difference between 48V and 52V to be marginal.

markz · Apr 17, 2021

Buy from a reputable seller and not some random seller online.

john61ct · Apr 17, 2021

Yes, if you have or get a load device that pulls a constant very low C-rate, traditionally over 20hrs

If strictly constant amps then just use a timer

otherwise put a coulomb counting wattmeter in between, a bit less accurate

Draw down from 100% Full to 0% empty as defined by the battery data sheet.

If you pull faster or stop earlier you might get say 20% below nameplate.

But lots of makers it's impossible to match because their rating is a fantasy

amberwolf · Apr 17, 2021

unclejemima said:
https://www.amazon.ca/gp/product/B08X2F2DC7/ref=ox_sc_act_title_2?smid=A1DQ8CBGDI0TLE&psc=1

"Sport-lifes
Sport-lifes storefront
Just launched
No feedback yet "
https://www.amazon.ca/sp?_encoding=UTF8&asin=&isAmazonFulfilled=&isCBA=&marketplaceID=A2EUQ1WTGCTBG2&orderID=&protocol=current&seller=A1DQ8CBGDI0TLE&sshmPath=

Wouldn't be my first choice of sellers.

neptronix · Apr 18, 2021

You'd have to buy it, install it, ride it with a watt hour meter attached, and find out the total amp hours after the fact. Not a super precise way to do things, but close enough.

If they lied about the capacity, shipping it back to China would be cost prohibitive and you'd end up ripped off, like many new builders looking to save a buck would.

You'd be much better off spending a bit of extra money with a vendor that actually has a reputation.

john61ct · Apr 18, 2021

Even with the best quality cells and a purely honest vendor

a bank accurately rated at say 40Ah

would only deliver say 30-35Ah in real-life conditions aimed at good lifecycle longevity.

LewTwo · Apr 18, 2021

neptronix said:
You'd have to buy it, install it, ride it with a watt hour meter attached, and find out the total amp hours after the fact. Not a super precise way to do things, but close enough.

If they lied about the capacity, shipping it back to China would be cost prohibitive and you'd end up ripped off, like many new builders looking to save a buck would.

You'd be much better off spending a bit of extra money with a vendor that actually has a reputation.

And you can NOT legally ship it back without find a willing shipper that has a "hazardous cargo agreement" with an international common carrier ...

JackFlorey · Apr 18, 2021

john61ct said:
Even with the best quality cells and a purely honest vendor
A bank accurately rated at say 40Ah
would only deliver say 30-35Ah in real-life conditions aimed at good lifecycle longevity.

I've tested plenty of 3000mah 18650s that all came in at or greater than 3000mah.

The issue is that a seller can sell a "40ah" pack for more $$$ than an accurately rated 35ah pack. So they call it a 40ah pack.

john61ct · Apr 19, 2021

Yes I meant finished packs, normal IRL usage

charged to 4.05-4.10Vpc

LVC set at 3.4-3.6V not 2.8Vpc

discharged at maybe hundreds of amps peak, not CC at the 10-20 hour rate

kmccune3300 · Apr 19, 2021

Figure 2 AH per row and if a battery is really small or light it's not going to very powerful as a rule.

dogman dan · Apr 19, 2021

Same picture, if you select 13 ah, or 24 ah. So that picture is the 13 ah, for certain sure. If you select 24 ah, you will get a square pack wrapped in cardboard and duct tape. It will be a huge box, with cheap ass cells inside.

The kind that burns your house down. Or at least burned my house.

gobi · Apr 19, 2021

I use this
https://www.aliexpress.com/item/32866240382.html

to validate the AH of any battery/cell I have,

Very easy to use, just hookup battery to the input side and set the cut off volts to something lower than BMS setting [so you can double check if BMS is working] and set amps and to keep watts below 180w (ish), and wait...

Lot of cheaters selling sub-standard products.
If they are not willing to divulge the details of the cells, then walk.

Charging/discharging - I read that keeping max charge level 90%, makes em last longer and less heat too.

Also, heed what Dogman Dan said about burning the house down, I always charge attended and turn of chargers off if I will be gone for few hours. Just be prudent.

Any way to verify AH on a battery?

unclejemima

100 W

fatty

10 kW

markz

100 TW

john61ct

1 TW

amberwolf

Administrator

neptronix

Administrator

john61ct

1 TW

LewTwo

1 MW

JackFlorey

100 kW

john61ct

1 TW

kmccune3300

100 µW

dogman dan

1 PW

gobi

10 kW

Similar threads