Not worth putting NCR18650B in this powerbank?

14 posts / 0 new
Last post
xelario
xelario's picture
Offline
Last seen: 6 months 5 days ago
Joined: 04/25/2014 - 05:50
Posts: 388
Location: EU
Not worth putting NCR18650B in this powerbank?

I’m looking for a 2-4x (haven’t decided yet) 18650 powerbank and batteries for it. A review of this powerbank and NCR18650B bundle said:
“Overall its a great powerbank, but this bundle is probably not the best choice since you won’t be able to discharge cells to 2.5V and get full capacity out of them.”

Specs say it cuts off at 3V, reviewer measured about 2.8V under load. I looked at the graphs and 3400mAh batteries still give more Ah’s than lower cap ones even if cut-off voltage is 3V.
What do you think?

Edited by: xelario on 07/09/2014 - 03:57
HKJ
HKJ's picture
Offline
Last seen: 1 day 5 hours ago
Joined: 05/24/2011 - 12:23
Posts: 7433
Location: Copenhagen, Denmark

Just about any power bank I have checked has the battery protection very close to 3V

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

xelario
xelario's picture
Offline
Last seen: 6 months 5 days ago
Joined: 04/25/2014 - 05:50
Posts: 388
Location: EU
HKJ wrote:

Just about any power bank I have checked has the battery protection very close to 3V

Yes, but what about the claim it’s not worth putting high capacity batteries in a bank like this? Do you think it’s a waste and would use lower cap batteries instead?

Another question has arisen. This bank uses 3×3400mAh for a total of 10200mAh theoretical capacity. And this one uses 4×2600mAh for a total of 10400mAh theoretical capacity. Which one is better, 3x high cap or 4x lower cap (let’s say everything else is equal)?

CrashOne
Offline
Last seen: 4 hours 26 min ago
Joined: 02/18/2014 - 13:29
Posts: 358
Location: The Netherlands

With lower capacity cells you get exactly that: A lower capacity.

If size isn’t a problem, I would go for the 4x. Just because the 3x would probably put higher load on the cells, making them wear out faster. Next to that, in the future you can consider upgrading the cells to a higher capacity.

HKJ
HKJ's picture
Offline
Last seen: 1 day 5 hours ago
Joined: 05/24/2011 - 12:23
Posts: 7433
Location: Copenhagen, Denmark

xelario wrote:
Yes, but what about the claim it's not worth putting high capacity batteries in a bank like this? Do you think it's a waste and would use lower cap batteries instead? Another question has arisen. This bank uses 3x3400mAh for a total of 10200mAh theoretical capacity. An "this one":http://www.banggood.com/Original-XIAOMI-5V-2A-10400mAh-Power-Bank-For-Sm... uses 4x2600mAh for a total of 10400mAh theoretical capacity. Which one is better, 3x high cap or 4x lower cap (let's say everything else is equal)?

You can always discuss if it word the money to put 3400 cells in the bank. When I test I usual does a test with both a 2600 and a 3400mAh battery.

I would look more at the size and the shape of the bank, than 3 or 4 batteries, except if I need a lot of capacity.

Usual I carry the ENB 2 cell bank with 3100mAh batteries, it is very solid build and has enough capacity for my normal use.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

dangerous
dangerous's picture
Offline
Last seen: 6 years 8 months ago
Joined: 06/17/2014 - 04:54
Posts: 962
Location: Fort Lauderdale, FL

The mah/$ on stand-alone power banks makes it very hard to justify putting the expensive ncr18650b batteries in the 18650 power banks. The 18650 power banks only make sense if you already have spare 18650 batteries IMO.

BLF

xelario
xelario's picture
Offline
Last seen: 6 months 5 days ago
Joined: 04/25/2014 - 05:50
Posts: 388
Location: EU
HKJ wrote:
I would look more at the size and the shape of the bank, than 3 or 4 batteries, except if I need a lot of capacity.

Let’s say size, shape, weight doesn’t matter. 2 power banks with the same total capacity (3×3400=10200 and 4×2600=10400). Which one would you choose?

HKJ wrote:
Usual I carry the ENB 2 cell bank with 3100mAh batteries, it is very solid build and has enough capacity for my normal use.

I’ve looked through some of your reviews, it seems 3100mAh is the sweet spot of price/capacity, would you agree?
I’m also considering an ENB 2x powerbank, but a different one for its 2.1A output (in case I ever need it).

dangerous wrote:
The mah/$ on stand-alone power banks makes it very hard to justify putting the expensive ncr18650b batteries in the 18650 power banks. The 18650 power banks only make sense if you already have spare 18650 batteries IMO.

That’s the thing, I don’t have spare 18650’s. That’s why that XIAOMI for ~$24 looks like a nice deal.

HKJ
HKJ's picture
Offline
Last seen: 1 day 5 hours ago
Joined: 05/24/2011 - 12:23
Posts: 7433
Location: Copenhagen, Denmark

xelario wrote:
Let's say size, shape, weight doesn't matter. 2 power banks with the same total capacity (3x3400=10200 and 4x2600=10400). Which one would you choose?

I would say that size, shape and weight does always matter, I will be carrying it.

I do not really care if I get the capacity from 3 or 4 batteries, but four 2600mAh might have slightly more capacity, especially under heavy load.

xelario wrote:
I've looked through some of your reviews, it seems 3100mAh is the sweet spot of price/capacity, would you agree?

I have not really done the calculations on that. Generally I do prefer to get batteries with as much capacity as possible. At the current time I am using 3100mAh batteries in much of my equipment, but that is because is is batteries that I have retired from my charger test.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Dru_dragon
Dru_dragon's picture
Offline
Last seen: 2 months 3 weeks ago
Joined: 09/10/2013 - 08:00
Posts: 131
Location: South Australia

I asked this very same question myself when I looked at powerbanks, then I realized between 2.5 and 3 volts you would be lucky to get 150mah, so you dont miss out on that much of the extra capacity. I ended up getting the Qidian 4×18650 but only because I had some spares from a laptop pull.

The genuine Xiaomi for $24 is very hard to beat. If it’s genuine it comes with LG 2600mah, so you end up paying $9 for the bank itself. I’d probably choose that over the ENB triple simply from a price perspective. Most important with power banks is the charge rate, nothing worse then waiting 10+ hours when its only 0.4a charge per cell Sad

Andrew

flydiver
Offline
Last seen: 5 hours 44 min ago
Joined: 06/19/2013 - 19:16
Posts: 1295
Location: Seattle, WA
Dru_dragon wrote:
I asked this very same question myself when I looked at powerbanks, then I realized between 2.5 and 3 volts you would be lucky to get 150mah, so you dont miss out on that much of the extra capacity. (

Agree completely! Big Smile

Look at some discharge curves, there is almost NO CAPACITY left in a cell after 3.0v. In addition at that point you are stressing the cell and promoting an earlier death. In RC we recharge when there is still 20% capacity remaining. This improves longevity.

To Air is Human, to Respire….Divine.

xelario
xelario's picture
Offline
Last seen: 6 months 5 days ago
Joined: 04/25/2014 - 05:50
Posts: 388
Location: EU
HKJ wrote:
I would say that size, shape and weight does always matter, I will be carrying it.

I wasn’t talking about you specifically, just wanted to know which setup would be better if everything else was equal/irrelevant (that’s the “let’s say” part) Wink

HKJ wrote:
four 2600mAh might have slightly more capacity, especially under heavy load.

That answers my question, thanks.

Dru_dragon wrote:
I asked this very same question myself when I looked at powerbanks, then I realized between 2.5 and 3 volts you would be lucky to get 150mah, so you dont miss out on that much of the extra capacity.

I wasn’t asking about the capacity between 3-2.5V, but between 4.2-3V. That’s the range I’m interested in. Sorry if it’s confusing, English is not my “mother tongue”. The reviewer says it’s not worth putting NCR18650B’s because you lose the 3-2.5V range and don’t get the full capacity. To me it sounded like he meant you could get a cheaper lower mAh battery and get the same capacity as the NCR18650B in the operating range of the power bank (4.2-3V). But I looked at the discharge graphs and argued it’s still better than any lower cap battery in the 4.2-3V range and wanted to clear this up with you guys Smile In other words, even if cut at 3V NCR18650B pumps out more mAh than lower capacity batteries, so the claim that “it’s not worth” using them sounded strange to me. If it’s just about the money… Well, it’s probably not worth having as many flashlights as we have, but… Wink

xelario
xelario's picture
Offline
Last seen: 6 months 5 days ago
Joined: 04/25/2014 - 05:50
Posts: 388
Location: EU
gauss163 wrote:
6x new Samsung 2600mAh for $12

I wish, “Shipping:$45.00 USPS Priority Mail International”. All the good battery deals I’ve seen are US only Sad

hank
hank's picture
Online
Last seen: 3 min 21 sec ago
Joined: 09/04/2011 - 21:52
Posts: 9596
Location: Berkeley, California

Boy oh boy, something that lights up and superficially looks like it works, stuffed with bags of powdery stuff.
This could make the owner very popular at an airline security screening.
Talk about “buyer beware” — scary.

aoeu
aoeu's picture
Offline
Last seen: 8 months 1 week ago
Joined: 02/16/2014 - 04:44
Posts: 793
Location: Sydney, Australia

The problem with buying crap chargers is they don’t used the cell’s power efficiently and waste a lot of it through noise. That’s why HKJ puts up those graphs that look like someone’s cardiac arrest printout. Definitely would buy one that’s gotten the tick from HKJ rather than just the cheapest you can find.