What voltages to expect in each cell from new?

**Made2Fade** · 13-05-2012, 11:21 AM

Recieved a new OptiPower 6S 2700mah pack yesterday... what voltages should i expect to see in each cell from new? Reason i ask is the pack i recieved the week before was half charged, around the 48% fuel mark on the 10S. The new one showed 20% fuel and around 3.82v per cell which is a bit too close for me. Should i send it back or will this be acceptable? Its now fully charged and ready to fly in the 500EFL today. I will be keeping an eye on it but just wondering what you guys think? Im concerned because there is such a diffrence between the way both new packs arrived. They also came from 2 diffrent shops.

**busterboy** · 13-05-2012, 11:35 AM

They always come storage charged Lee.

Around 50%

I take it there was no connector on the Lipo, As you know they don't come with any fitted from new.

**Made2Fade** · 13-05-2012, 11:36 AM

Originally Posted by busterboy

They always come storage charged Lee.

Around 50%

I take it there was no connector on the Lipo, As you know they don't come with any fitted from new.

Correct mate, this is why im a little concerned.

**busterboy** · 13-05-2012, 11:39 AM

A phone call to Andy I reckon and ask him, I have endless Opti packs and they all come with 50% storage charge.

Good thing is he will swap out if you have any issues mate.

**Paulice** · 13-05-2012, 11:39 AM

I got some Optipower 2s 3650's RX packs and they also came with 20%, I charged them up and they are fine.

**waveydavey** · 13-05-2012, 11:39 AM

I would let them know what state of charge that it is in and then charge it. You've got the waranty Lee and at least you will have let them know previous. I had a Gens Ace reach me with the same voltage and it's fine

**ChrisB** · 13-05-2012, 11:41 AM

I have had them come with around 3.8v per cell also,doesn't concern me as I have a habit of running them down to around 3v per cell to 3.5v per cell after most flights with no issues to date.

3.8v is about a minutes worth of 3d for me still

**Made2Fade** · 13-05-2012, 11:46 AM

Well its charged now so i cant do that, obviously i started the charge to find it was at 20%. Im kinda looking for that 'it'll be alright' comment so i can just go fly it today. But from the horses mouth i suppose. If everyone thinks it'll be fine then ill just go fly it today and get some slow cycles on it then go from there. Paul if it were a rx pack i dont think i would be too bothered as they pull little but the fact its a flight pack and it will pull some C then im a little more concerned.

**Mark_T** · 13-05-2012, 11:48 AM

Unless you've taken the time to generate a fuel table for that pack type and size then the percentage figures don't really mean a lot, just go by the voltage and if all cells are close to each other and around 3.8V then all is fine.

**Made2Fade** · 13-05-2012, 11:50 AM

well it was certainly balanced just the 20% mark is a little low for my liking. I usually leave a little more in than that myself.

**Mark_T** · 13-05-2012, 11:55 AM

You are assuming that the 20% actually means something though.

All it is doing is checking the voltage and guessing the remaining capacity.

You can help it make a better guess by generating a specific fuel table for the pack but if you didn't do that then the '20%' figure is pretty meaningless.

Storage charge is usually around 3.86V but I really wouldn't be getting concerned about it being 0.04V lower than that. What matters more is were all the cells close together, or were one or two significantly lower than the others?

If not then just charge and enjoy.

**Made2Fade** · 13-05-2012, 12:00 PM

That'll do for me then... just being overly cautious probably

**Mark_T** · 13-05-2012, 12:24 PM

The amount you put into the pack on the first charge is a much better guide to the real state of the pack on arrival.

As an example, I've just done the first charge on a new 2700 rx pack.

The charger saw it as 3.80V per cell and 38% on start, it then put in 1421 to bring it to full charge so if the pack capacity is accurate that means it really started out at 47%.

**cjcj1949** · 13-05-2012, 05:15 PM

The volts don't matter that much within reason. The storage value has no real meaning it's just a compromise. The higher a cell is stored and the higher the temperature it's stored in the quicker it will degrade. If you use your cells a lot this may not matter. The lower the volts the longer the cell will last so long as it stays above 3.0V. Storing it at half charge just means it will keep it's charge for longer, so can be stored longer. Also it is quicker to charge to full the higher the storage volts. The important thing is the variation of volts. If one cell is more than 50mv different from another then there may be a problem with that cell or the charger that charged it. It may have been charged to storage volts at a higher current than normal which would also leave it lower open circuit.

**avroboy** · 13-05-2012, 05:22 PM

The packs from new are typically at 3.83V which is 38% capacity or thereabouts (thats not always accurate) but 3.83V is in fact storage charge. We do test the packs but not every one these days as there just too many in process but 3.8V is fine. As for the capcity being viewed as 20% that could also be possible.

I would charge it, use it five or six times each time bringing it down a bit so 50%, 45% 40% and so on. When you get to 20% it should be 'formed' and they work as you would expect. Any issues discharge to 3v and recharge at 0.5C to reset it.

And as someone said in the thread earlier any issues at all return it and we will investigate and/or replace FOC. We do get the odd duff cell go through the system sadly but returns of any type are running at less than 0.02% which we are very pleased with.

If anyone has questions best mail us at sales@optipower.co.uk and direct the mail to Andy. I trust this helps.