Has anyone actually got close to rated capacity on any batteries with C-9000?

[cam94z28]

I recently received the "new improved" 0G0D01 version of the Maha MH-C9000, moving up from a Rayovac PS4, which worked flawlessly for what it was. I got the C-9000 mainly to test capacities, and to hopefully get a more full charge out of my batteries. The PS4 had been tested elsewhere to only charge to 79% on a quick charge.

Anyway, I've tried quite a few different sets of batteries at 1000/500 or 1000/1000 charge/discharge rate, and I cannot seem to achieve a tested discharge capacity thats near the actual capacity, even with very good batteries, my charge capacities are only rarely meeting the rated capacities of the batteries, but the discharge is even lower. Even if I bypass the 1 hour rest, when cycling/etc... I still come in 300mah or more under capacity.

When I started using LSD batteries, I began coming within 50-100 mah of rated capacity. Rayovac Hybrids all tested around 1950mah. Most of the other reports on the same batteries, with the same (probably older versions) of the same charger, or the bc-900 were coming out well over 2000mah. Are most batteries, even Sanyo 2500's, 2700's, or Duracell 2650's really that far off? I'm wondering if the new revision is not as accurate as the previous models.

I have a 80mm computer fan stuck temporarily to the vents(it's not cooling the batteries), and hooked to a old r/c wall-wart tricke charger to cool the charger itself down. Maybe this will make a difference.

 

[koala]

My dear friend welcome to the world of up-rated capacity NiMH batteries. General consumers will buy the highest mAh, baddest, most awesome graphic battery. The manufacturers need only to redesign the cell packaging. I dare say there are not much users with devices such as the MH-C9000 for testing actual capacity. Most intelligent chargers today have a few LEDs, that's all. So consumers doesn't really question what they are getting as NiMH has better performance than Alkaline fresh out of the charger.

You might want to cycle them a couple of times if they are new. Otherwise, accept the fact that we all learn to accept here. :shrug: For premium branded cells, deduct 100-200mAh off the rated capacity, for cheap cells, deduct 200-300mAh for the actual capacity. This not true for all cells, it's purely approx. We need to play along with the manufacturers.

You are right the LSD batteries are very close or sometimes holding even even more than the rated capacity.

 

[barkingmad]

I recently received the "new improved" 0G0B02 version of the Maha MH-C9000, moving up from a Rayovac PS4, which worked flawlessly for what it was. I got the C-9000 mainly to test capacities, and to hopefully get a more full charge out of my batteries. The PS4 had been tested elsewhere to only charge to 79% on a quick charge.

Anyway, I've tried quite a few different sets of batteries at 1000/500 or 1000/1000 charge/discharge rate, and I cannot seem to achieve a tested discharge capacity thats near the actual capacity, even with very good batteries, my charge capacities are only rarely meeting the rated capacities of the batteries, but the discharge is even lower. Even if I bypass the 1 hour rest, when cycling/etc... I still come in 300mah or more under capacity.

When I started using LSD batteries, I began coming within 50-100 mah of rated capacity. Rayovac Hybrids all tested around 1950mah. Most of the other reports on the same batteries, with the same (probably older versions) of the same charger, or the bc-900 were coming out well over 2000mah. Are most batteries, even Sanyo 2500's, 2700's, or Duracell 2650's really that far off? I'm wondering if the new revision is not as accurate as the previous models.

I have a 80mm computer fan stuck temporarily to the vents(it's not cooling the batteries), and hooked to a old r/c wall-wart tricke charger to cool the charger itself down. Maybe this will make a difference.

You cannot look at the 'charge' capacities - that is only the energy put into the battery - not what it actually holds. The discharge capacity is what counts.

Really it's just typical - many batteries do not test at their stated capacities or the manufacturers test them at a very low discharge rate to get (nearer) the quoted figure.

Try discharging them lower than 500ma - perhaps 100-200ma and you might get closer yourself.

Some manufacturers also seem more optimistic than others - some 2500ma 'rated' batteries test at around 2250-2300 - so if you are getting to within 50-100ma of the stated capacity at a 500ma discharge I would not worry about it.

I would also not bother with a fan..

About the most 'accurate' batteries I have seen are Sanyo 2700 or Eneloop - both seem to test very close to their stated capacities.

 

[cam94z28]

That makes me feel a little better that I didn't spend $60 on an inaccurate toy. I just find it odd that the BC-900(which I do not have) seems to come in slightly over capacity on the same batteries that come in a few hundred mah under capacity on the C9000. Hopefully it's the one that's inaccurate.

 

[barkingmad]

That makes me feel a little better that I didn't spend $60 on an inaccurate toy. I just find it odd that the BC-900 seems to come in slightly over capacity on the same batteries that come in a few hundred mah under capacity on the C9000. Hopefully it's the one that's inaccurate.

On charge or discharge? It only counts on discharge and again only if the discharge rate is the same on both...

 

[cam94z28]

On charge or discharge? It only counts on discharge and again only if the discharge rate is the same on both...

My testing was always on discharge. I can't speak for the BC-900 reports on this forum. Assuming that all things are equal, even the reports in this thread show about a 8-10% difference between the two. My ratings appear to be even lower than the average reports with the c-9000 as well.

I have attempted charging my new Kodak Pre-Charged at half the original charge rate once they cool off. I'm going to see if I can squeeze a little more into them this way.

 

[barkingmad]

My testing was always on discharge. I can't speak for the BC-900 reports on this forum. Assuming that all things are equal, even the reports in this thread show about a 8-10% difference between the two. My ratings appear to be even lower than the average reports with the c-9000 as well.

I have attempted charging my new Kodak Pre-Charged at half the original charge rate once they cool off. I'm going to see if I can squeeze a little more into them this way.

Where do you get the 8-10% difference figure from - I admit I did not read every word and it's 'early' but didn't see a direct / like for like comparison between the two chargers on discharge?

Did you try the C9000 at a lower discharge rate? Try 0.1C-0.2C - i.e. about 200-400ma.

 

[cam94z28]

The results are an average of what was reported in that thread. Some of the results include capacities reported for the BC-900 and the C-9000. I was quoting the average difference in percentage between the two.

The difference is as low as about 7% and as high as 16% (on Energizer 1850's) between them.

I have not tried a lower discharge rate mainly due to time. 2000 / 250mah would be 8 hours.

I managed to squeeze another 75-100mah into my new Kodak's by topping off at 500mah after they had cooled. Lets see what the discharge capacity comes to this time.

I read in this forum (don't recall the thread) that Maha's new charging algorithm in the 0G0D01 revision sacrifices 3% more capacity than before. Maybe a second top off at a high rate is the answer.

 

[FatTony]

I own a MH-C9000 and have quite a few batteries that come up at or over their rated capacity (Sanyo Eneloop's, Titanium high power 1800's for example), and I have a lot of batteries are within the manufacturers spec, for example Sanyo 2700's average between 2550 – 2680 but I have never had one read 2700 or higher.

 

[cam94z28]

I own a MH-C9000 and have quite a few batteries that come up at or over their rated capacity (Sanyo Eneloop's, Titanium high power 1800's for example), and I have a lot of batteries are within the manufacturers spec, for example Sanyo 2700's average between 2550 – 2680 but I have never had one read 2700 or higher.

What revision do you have? It's printed on the bottom. Also, how are you testing? 1000/500 charge/discharge? Even the Sanyo 2500's that came with the charger didn't test higher than around 2240.

 

[digitor]

Yes - I've tested 28 Eneloops to date on my C9000, and the lowest I've got is 99.35% of their rated capacity (1987 mAH) and the highest is 102.9% (2058 mAH). I think the fault lies with your cells, rather than the charger! (Discharge rate I used was C/5)

Cheers

 

[barkingmad]

If you want to test the capacity more accurately the C9000 has a program that does an IEC style capacity test - think it's the 'break in' program.

But generally charge slow and discharge slow for best capacity figures - try a 200ma charge and a 200ma discharge.

 

[barkingmad]

The results are an average of what was reported in that thread. Some of the results include capacities reported for the BC-900 and the C-9000. I was quoting the average difference in percentage between the two.

The difference is as low as about 7% and as high as 16% (on Energizer 1850's) between them.

I have not tried a lower discharge rate mainly due to time. 2000 / 250mah would be 8 hours.

I managed to squeeze another 75-100mah into my new Kodak's by topping off at 500mah after they had cooled. Lets see what the discharge capacity comes to this time.

I read in this forum (don't recall the thread) that Maha's new charging algorithm in the 0G0D01 revision sacrifices 3% more capacity than before. Maybe a second top off at a high rate is the answer.

Is it worth the bother for 3% - most non-LSD NiMH batteries would lose that through self-discharge within a VERY short period and you could potentially be shortening the lifespam of your cells.

I don't know why Maha reduced it by 3% but I suspect (as with Li-ion) it you charge just under 100% it is perhaps safer and you get many more cycles out of the cells.

 

[FatTony]

What revision do you have? It's printed on the bottom. Also, how are you testing? 1000/500 charge/discharge? Even the Sanyo 2500's that came with the charger didn't test higher than around 2240.

I used the break in mode to measure the capacity, but a 500mah discharge gives pretty much the same results (I label the cells based on their capacity so I can see when they fall out of spec). I don't know what revision charger I have (I'm at work at the mo) but I bought it at the start of June, also it's a UK version of that makes any difference.

 

[SilverFox]

Hello Cam,

In order to directly compare the labeled capacity on the battery with its actual capacity, you need to use the Break-In function on the C-9000.

In order to compare the B-900 results in the Test mode with the C-9000, I believe you need to run the C-9000 in cycle mode.

I have found that the BC-900 yields optimistic results, and the C-9000 is pretty close in Break-In mode, but still slightly optimistic. As FatTony has pointed out, discharging at 500 mA often gives very similar results to lower rates. If you look through the NiMh Shoot Out thread you will notice that most cells seem to come in at around 90% of their labeled capacity at a 500 mA discharge.

A critical key to measuring capacity is making sure the battery is fully charged. Also, keep in mind that labeled capacity usually only relates to new cells. Some manufacturers specify that the capacity be determined within 30 days of manufacture.

I generally retire cells that fall below 80% of their capacity.

Tom

 

[wptski]

It is said that a cell is rated using .2C or .2 of capacity. If a manufacturer has a brand new cell to go to market and wants to rate using .2C, how do they know what C is?? How can the unknown be part of the equation to find itself??

 

[Kevin Tan]

C is capacity of the Batt. So a 2000mAh Eneloop charged at 1c is 2A and 0.5c is 1A charge current. .2c is 400mAh for a 2000mAh ( 2Ah ) batt.

1c for a 2,500mAh Sanyo is 2.5A and .2c is 500mAh.

Getit?

 

[coppertrail]

I get between 2700 and 2800mAh with all my Powerex 2700 mAh AA cells . . .

 

[cave dave]

Don't worry wptski I understood what you meant.

 

[Bones]

Don't worry wptski I understood what you meant.

So did I.

Which is why I think he should have to go for the Aspirin...