Nimh Cells, What Would You Consider A 'full Charge'?

[HomerJHandley]

Another question on these.

I have 2 5000MAH 4 cell packs, recently been Zeroing them (ta biggus!) and getting some false peak charges when doing so.

Anyhow, today managed to get them on the Zero-V, removed not long after the 'lights' went out and then charged them (once they had cooled a bit!)

One went to 4748 and the other 4878, so 252 and 112 mah less in them that the battery should hold.

Is this something to be concerned about?

The cells are not 'named' from what i can see, but provided by a reputable shop.

[Percymon]

I've charged my vapextech 5000 stick packs 3 times so far and they seem to get to 4850ish. Maybe they will improve with more use but I'm not concerned by a supposed 3% undercharge.

[Butler]

My Vapextech 4350 pack only charged to about 4150 ish.

On the same charger my 3000 and 3300 GP packs charge to 3500 and 3800 respectively.

Its probably purely down to how the cells are marketed. Suppliers may think they can push their luck selling cells really only rated to 4800 as 5000.

The temperature is the main indication of how close to a full charge they are.

[HomerJHandley]

My Vapextech 4350 pack only charged to about 4150 ish.

On the same charger my 3000 and 3300 GP packs charge to 3500 and 3800 respectively.

Its probably purely down to how the cells are marketed. Suppliers may think they can push their luck selling cells really only rated to 4800 as 5000.

The temperature is the main indication of how close to a full charge they are.

warm, sometimes hot, so full charge then

ta all

[stu22]

Sounds pretty normal to me. My 4200 Powerizer packs would charge to ~3900, while the 3300 cells would take ~3500 after discharging at 2.7A on a tray. How many amps are you discharging at?

Be careful about discharging to 0v, you run the risk of reversing a cell.

[Blacque Jacque]

I take my packs down to 0.9v & I expect to put about 10% to 15% more than the rated capacity of the pack on the next full charge, eg;

Sanyo 3600s take about 3900 - 4000.

GP 3700s take 4000 - 4100.

Vapex VPR 4300s take about 4700 to 4800.

I'm discharging on a Much More tray, then using Pro Peak Constellation chargers at 4A for the Sanyos & 5A for the GP & VPR cells.

[BiggusDitchus]

For the cells your using chap and the fact that the batteries are warm i would consider them charged.

[HomerJHandley]

yup, jut ordered a charging lead so i can charge directly (see if the extra connections are causing the odd charging issue).

your Zero-V has been well used, each pack had a good 3 or 4 cycles, may pop it on again once more for good luck

may have to forget to bring it on tuesday

[terry.sc]

One went to 4748 and the other 4878, so 252 and 112 mah less in them that the battery should hold.

Is this something to be concerned about?

The cells are not 'named' from what i can see, but provided by a reputable shop.

Not bad for no name cells.

In theory the capacity listed on the cell should be a minimum capacity when new. Over time the capacity will reduce as the cells age as the chemicals inside are cycled.

At the other end of the scale I run GP 3700 cells and when new they were tested and gave almost 4500mah capacity - the number on the label should be the minimum capacity. The performance also matches decent race spec lipo packs as well. The reason is that they are Race Prep worlds spec cells, the cream of the crop with a list price of £75 a pack. The matchers bought thousands of cells and hand picked the best ones for the decent race packs, mid range cells going into high quality basher packs and the lower spec ones going into cheap packs.

There is a noticeable performance difference between cheap cells and the big name brands.

[HomerJHandley]

Just Re-done one of the packs and it re-peaked at 4878, too much of a coincidence for it to not be the same one as last time

Will do the other one tomorrow and can pass back Biggus' gadget