Another not very old Luna Wof V2 with problems?

[73Eldo]

I have some results of the V1 load test. It went from a full 100% charge of 58.4 to 43.2 in 4.5 hours. I assume it would have gone down to 42 but I didn't see a lot of point in going that far.

So with a steady test load I get more run time on the old V1 battery. I suspect on the bike I get more run time too because with it not cutting till 42 much more headroom to sag. I'm pretty sure the newer V2 would come out to less because of how little sag it takes to trip it plus it comes up on that limit fairly suddenly and when it hits it its done. The V1 I think when I have got that low the controller or display limited things and when it did shut down I was able to restart and get a little more out of it if I went to minimum assist or could at least keep the display running.

I think I will contact Luna tomorrow and see if its supposed to cut out at 47 volts. If its supposed to I guess there isn't anything wrong. Kinda sucky design IMHO but I guess it may be what it is. IF its not correct then I think its a pretty clear defect that I could not have caused that I know of. Could maybe be what happened to the other guy with a V2 that posted recently except his cuts out in the 50's so way more useless than mine.

[73Eldo]

80% charge landed at 56.6. 24 hrs was still at 56.6. Today at about 36 hours its 56.5. Never watched one that close before so don't know if that is good or bad. The V1 got left at 52.1 and is still holding that at about 30 hrs and its raining today so the testing can continue.

Also opened a ticket with Luna today so we will see what they have to say.

[73Eldo]

That is with a cheap meter. I guess just for fun I could go get my work tool kit, pretty sure my Fluke goes to 2 or maybe 3 places. If not I have a Tektronix scope that has a graphing meter mode that I think has a lot of scale adjustments.

I was thinking about getting another meter anyway to see for sure the load my load test is. My cheap meter has an issue with its amp mode which I have never tired to use till now. At least I know why it was on the open box discount shelf now and maybe what the rattle is. Someone likely bought it and put the probes in the wrong socket and poof. Was still worth the $5 since I did get 2 years use out of it before I noticed and it has saved me from forgetting to put my good meter back in my work tool box when I use it around the house.

[73Eldo]

More thinking out loud. If its normal to loose 0.1 volts per day that would be 3 volts per month. I'm pretty sure my others are not dropping that much but I have to admit the few times they have sat that long I have not really paid that close attention. My Dewalt 20v batteries? Maybe. Those suck compared to the life I get out of the 18v nicads.

But if like is likely in my case and my meter is too low res and its more like 0.05 per day thats only 1.5 volts per month so even if you had a long winter season and let it sit for 6 months its only 9 volts so if you started at maybe 75% charge you would still be well above a proper BMS cutoff. Seems like that would be a typical and reasonable ballpark because you really should not be leaving these untouched for that long.

[AZguy]

Again it will depend on the BMS how much it loses over time but I always expect some initial drop in the first day or so before they better stabilize after taking a charge so even if 0.1 on the first day, that seems very normal... like you are thinking if it were to continue to lose 0.1 per day that seems just a little on the high side but not completely out of the question for some BMS's

I've had some batteries that at less than 50% SOC lost less than 2.5V/ over about 4mo but I've had others that lost the same amount in less than a month - I credit it to "leaky" BMS's

[Dshue]

Yeah I'd be looking for more than .1v drop. That could just be your meter trying to round out for its display resolution. Maybe the voltage dropped a couple of hundredths and the meter dropped a tenth to round down.
See what Luna has to say.
Who knows maybe the nice weather just got you going faster but without putting in as much pedal effort as usual.

[73Eldo]

Ya all the usual variables in real riding is why I went to bench testing and where its nice I have another battery to compare to. Bench testing has showed the same result of the BMS kicking it out right around 47v multiple times in a row now which doesn't seem right. On the bike a little throttle up a hill could make it go from 50 to that 47 instantly.

Nothing back from Luna yet but it hasn't even been a full day. I would have been really impressed if I heard back from them same day.

[Dshue]

47v doesn't seem right, my chart lists that as 30%. And I can only assume the pack has good quality cells so the percentage is probably more at 47v. And it's not likely that your punny 1-2 amp test load is causing much voltage sag at all.

[73Eldo]

Yup. I target my rides to end at about 30% so that gives me a 10% margin to add a few extra miles or be extra lazy and still be above the 20% sweet spot and with that last 20% remaining I can deal with some sag that happens because I live at the top of a mile long hill. Worked well till it turned into a hard shutdown at 47 volts.

[paxtana]

73Eldo I see you made a support ticket, just a heads up it is assigned to our lead support technician Seb, he will get back to you shortly.

[73Eldo]

Thanks for letting me know I passed the 'im not a robot' test and got into the cue. You can let em know that if there are more pressing issues like people that can't ride their bikes at all I can wait for a bit. I have other packs I can use while we try and figure if something is actually wrong.

[73Eldo]

We have made contact. They want me to do some specific tests in a specific order on the bike and if those tests confirm its out of spec there is some sort of warranty. So far it all sounds very reasonable and fair and worth paying a little extra to get it from a vendor like them. I can't imagine I would have even made any sort of contact yet with a random ebay or aliexpres seller.

[Tobruk]

My Luna wolf's BMS just bit the dust with only 5 charge cycles. Can't be fixed by Luna and their warranty is only 3 months and then replacements are pro-rated. Seems like they have quality control issues as it is a common problem with the Wolf.

[73Eldo]

When did you buy it? Mid/late 2020 seems to have been when most that have been reported here seem to have been made. What is yours doing?