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View Full Version : Do you think the Battery Manufacturers match the packs before selling


Mike Keely
2012.12.26, 05:28 PM
I just tested a bunch of sells from a few manufacturers. I have some from brand X that all the capacity and voltage and IR are very close from cell to cell in the pack as they came. What I have found is that from pack to pack there can be a big difference. Do you think that this is just from batch to batch or do they match them in each batch to keep the cells close to each other in performance??????

arch2b
2012.12.26, 06:05 PM
just my guess but i think it would be more timing for production batch and packaging. i've bought many whole cases and to date, the orion/peak 900's (same cell really) were the most consistent per case. r1 works 750's were the worst.

Mike Keely
2012.12.26, 06:10 PM
How many come in a case?

twinkie
2012.12.26, 06:23 PM
Peaks come 12packs in a case

arch2b
2012.12.26, 06:32 PM
orion/peak, r1 works = 12 packs per case. i don't recall the other brands as those were 4 year ago or longer. i'm sure nearly all are 12 packs per case.

i find it's cheaper overall to buy in bulk and you can often get a better deal when offering to buy a full case since a shop owner won't have to worry about shelf life of left overs.

TheRinger
2012.12.26, 08:48 PM
Hard to say Mike. Like Ray I've bought first Orion's and now peak racing batteries in a box of twelve sets. And it's kinda of a hit and miss on consistency out of four batteries in one pack. Majority of them are pretty close but sometimes like the latest brick I bought, one cell rebounded while the other three won't. But it was only one pack out of the twelve but I think that had more to do with shelf life and quality of manufacturing. Like cars down an assembly line your ocassionally going to have a lemon. Unfortunetly I never matched by IR in the past, just voltage and amperage. But this time around I'm going to try internal resistance. It's taking a while due to this latest brick I bought, all the batteries registered .01 volts on the DMM straight out the package and I'm trying to revive them before matching. Fortunetly all but that one seem to be coming around. It's just easier to buy in bulk all at once instead of buying a pack here and there. More consistency.
And out of the cells coming around are measuring between 1.41 and 1.45 volts and 450 to 1000 mah. I took the batteries out of the packing and kept them in the order they came out of the packaging. The one pack I'm having trouble with, three cells won't get above 200 mah while the one hit almost 400. And the voltage on the three wouldn't get above 1.39 Volts and the one hit 1.40. The rest were relatively close some pretty close are almost the same. I don't think they match and package them, I think they assembly line test them as they check each cell to see if it meets specs then package them. My opinion.

arch2b
2012.12.26, 09:04 PM
bill has a point, retailers don't know how old the case is before they get it so it could be fresh or a year old already by the time they get it to sell on.

imxlr8ed
2012.12.27, 12:01 AM
Someone told me a while ago that team packs for tenth scales were purchased in bulk, zapped and then cycled for 2 or 3 times to get the final IR numbers. The ones that keep the lower resistance levels are the ones that go into the team packs, the top 1% went to the sponsored racers.

Maybe that's just how one vendor did it... not sure if they all do. It makes sense to me though because once the cells get cycled a few times, their characteristics seem to change. Therefore, matching after a few cycles seems to produce better matches.

I do not live in that world though... I just went and got some Gens Ace cells for dirt cheap from some site and cycled them until they worked. Now I have a few packs that make the pretty blue lights stay on for a long while on my PN dischargers! That's about as technical as I get when it comes to output.

I heard bad things about these cells previously but I didn't run into any issues with mine, one of my racers got some and did have one cell that was DOA. The place he got them are going to ship him four cells to replace that one! Not a bad deal!

Mike Keely
2012.12.28, 08:46 AM
Out of the last batch of cells that I did, I was discharging them at 2 amps to put a good load on them. I matched them with the avg. voltage of the cell under the 2 amp load. I noticed that the IR was always low on the cells with the high voltage under load. I will see how they do at the BTE this weekend????

egonzalez
2013.01.02, 11:26 AM
Out of the last batch of cells that I did, I was discharging them at 2 amps to put a good load on them. I matched them with the avg. voltage of the cell under the 2 amp load. I noticed that the IR was always low on the cells with the high voltage under load. I will see how they do at the BTE this weekend????

There is a direct relationship between cells that have a higher average discharge voltage and a lower internal resistance. I have seen very few cells that have a high internal resistance that also yield high average discharge voltage. I always match my batteries based on the type of racing e.g. For stock, I first, use average discharge voltage and secondly Discharge time. (50 turn and lower) For Mod, I do the reverse and use Discharge time first and then average discharge voltage. (Anything above 50 turn) In Mod the motor is already fast, you don't need the extra voltage. More power may actually make you overshoot your turns.