PL8 Cell #1 IR

[GimpyGolden]

I believe I have an issue with my PL8.
When measuring Internal Resistance my cell number one is always higher, as much as double the rest which are all about spot on the same.
I've read about this from others and it has always been chalked up to a glitch. Upon purchasing new packs I saw that cell 1 was same as the rest of the group, weird.

Now after ~20 cycles in with said new packs I am seeing the same issue I did with all my other packs.
Do you have any idea what is going on here, I am worried the charger is somehow 'mistreating' my new packs.

Thanks for any help

[nightflyr]

Do you have the latest firmware?
Do you have the correct wire mode selected?

[GimpyGolden]

Yes on both counts.

[HFMan]

I have always had the same issue. When charging small 2S batteries (like my 130X batteries), it is an exaggerated difference. When charging 6S 3300 or 5000 packs, not so much- but if I parallel charge six 6S 3300 packs, then it again is obvious. Latest firmware, MPA board, clean connectors.

[GimpyGolden]

Ya I've always had it to but with these new packs I had same IR across the board, which I'd expect but then cell one started rising and is now double any other cell.

If I can't get a reply from FMA I think I'll grab an iCharger before my brand new Revolectrix 60C packs are ruined.

[Gregor99]

Originally Posted by GimpyGolden

I am worried the charger is somehow 'mistreating' my new packs.

This is a measurement issue only, and does not affect the chargers ability to correctly charge your packs. Here's a little more info, some will apply, the rest is just FYI. There are a number of things that can impact IR measurement.

When parallel charging, the IR values are only guidelines. If there are any very high or very low numbers it could be there is a SoC imbalance between cells in parallel. Or there is one more balance leads broken or corroded. If this happens check each pack separately after the charge is complete. If all cells checked on all packs are fine, continue to monitor that set of packs by checking the cells after the charge.

Last cell has high IR - This is caused by using older firmware or the wrong wiring mode. Verify the Powerlab8 is using at least 3.31 (latest as of today) and the wiring mode is correct for the balance adapter in use.

First Cell has high IR - This is caused by minor differences in resistance (less than an ohm) between the two main leads (not the balance leads). This is commonly seen when there is a fuse on lead but not the other. There are fused parallel boards on the market that include a fuse on only one of the two main leads. The fused 130x board is an example of this. Additionally, a small about corrosion or carbon build up can give this same result. Many hobby connectors cannot be properly cleaned. Use if a product like Deoxit can help.

First inspect the main lead connections between the charger and the pack. If there is only a single fuse (like the 130x parallel board), that configuration will always be off on cell #1. Next, if possible clean contacts between the pack and the charger. If you still have issues, I'd make or purchase a single pack cable with fresh connectors for IR readings only.

[HFMan]

Done all that you mentioned. It's not a fused 130x board or anything like that. Every single battery, from 2S to 6S does this. The higher the IR (like for small capacity packs), the worse it is. MPA board, quality balance cables (TP, XH, Hyperion), doesn't matter. Completely cleaned everything and put deoxit on all, no difference.

[GimpyGolden]

All checked here too.
FW 3.31.
No para board here, Dual pack para cables w/o and fuses.
This happens with single packs as well as para charging. Packs plugged direct into SPA adapters on XH mode.

Any explanation why these packs read oK ~10 cycles ago but do not now?

[Gregor99]

Hard say. Perhaps carbon build on one side of the connector due to the spark that occurs when charging the ESC's capacitors.