Author Topic: Capacity test of 4.0 High power 18V BP 18 Li 4,0 HPC-ASI  (Read 3338 times)

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Offline ach_78

  • Posts: 65
Hi all,

So I've got 2 of these 4.0Ah high power 18V batteries as well as 2 of the "normal" 5.2Ah 18V batteries.
All Airstream, bluetooth latest versions.
All were tested when new.

All tests are performed following the same sequence :
start from a low state of charge, onto the SC8 charger, until full and until the fan stops (about 30 min IIRC). Batteries are generally around 25°C when that happens.
Then, onto the discharger set at 4.8 Amps discharge (highest I can do) and 14V cutoff (2.8V/cell).

First of all, the discharge curves of units of each model virtually line up perfectly. First that gives me confidence in the fact that both samples of each type of batteries are solid performers and I did not get a lemon. Second it gives me confidence I'm getting repeatable results that can then be compared.

The onto the comparison :


Facts :
- Available capacity : 4,88Ah for the 5.2Ah battery (94% of stated capacity) vs 3,68Ah for the 4.0Ah battery (92% of stated capacity)
- Weight : 715g for the 5.2Ah vs 615g for the 4.0Ah

So for 86% the weight of the 5.2Ah version, you're getting 75% of Ah capacity (actually even less if counted in Wh).

That is 146g per Ah for the 5.2Ah vs. 167g per Ah for the 4.0Ah.
A 14% difference at the 5.2Ah version advantage.

I don't have the mean to test the available capacity under heavier load but I'm unimpressed by these results.
Even under a modest 4.8 amps load, I don't see any less sag on these high power batts than that of the 5.2Ah non-HPC version.

The volume is definitely a point going towards the 4.0Ah version which wins hands down in that regard.
But at this point I wonder if that is not all there is to them.

Any experience anyone making you think they actually pack higher OMPF ?

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Offline squall_line

  • Posts: 1735
Re: Capacity test of 4.0 High power 18V BP 18 Li 4,0 HPC-ASI
« Reply #1 on: May 11, 2021, 02:18 PM »
My understanding from the marketing was that it was intended to be as close to the 5.2 Ah battery in power delivery as possible.  Your testing seems to bear that out, so I'm confused as to the concern.

My understanding was also that the "Hi-Power" moniker on the 4.0 Ah battery was in comparison to the similarly-sized (in height, but not in weight or girth) 3.1 Ah batteries, which it is supposed to out-perform.

Or is there supposedly a different 5.2 Ah battery that has even more power delivery?

Offline ach_78

  • Posts: 65
Re: Capacity test of 4.0 High power 18V BP 18 Li 4,0 HPC-ASI
« Reply #2 on: May 11, 2021, 02:48 PM »
My testing doesn't show power capabilities, unfortunately, because that's exactly where the value of the 4.0 battery may supposedly be. 1C discharge like I did isn't enough.

The curve of the 4.0 isn't as flat as I expected it to be though.

Need more data on high power discharge but I can't find any data of tests anywhere.

Offline usernumber1

  • Posts: 257
Re: Capacity test of 4.0 High power 18V BP 18 Li 4,0 HPC-ASI
« Reply #3 on: May 11, 2021, 02:54 PM »
i thought it was just a case of newer 21700 cells

Offline Coen

  • Posts: 1987
Re: Capacity test of 4.0 High power 18V BP 18 Li 4,0 HPC-ASI
« Reply #4 on: June 18, 2021, 01:11 PM »
Well, compare again vs the 3 Ah batteries and you will find a very very slight increase in size, a tiny increase in weight, a big increase in capacity and an even bigger increase in *OOMPF* in the sense that it doesn't sag as much under load.

4,8A discharge also is way less than some tools would draw under load.

The 5 Ah batteries all have 2 rows of cells, the 4 Ah HPC batteries have a single row of slightly bigger cells; the 21700 instead of the previous standard 18650. This means higher capacity per cell.

Capacity and maximum current draw are somewhat interchangeable. If you want cells that can deliver higher currents, the total capacity will decrease.

I have the 4 Ah batteries with 21700 cells from the blue competitor and compared to the 5 Ah batteries of the same brand at work... I prefer the 4 Ah ones. Lighter, more power and a lot compacter,