Strange battery behavior on new kit from Luna

[Quovadis]

This is my second BBS02 kit that I've ordered from Luna. The first kit, I got a Direwolf 52v battery. That one works fine and I love it.

In the new kit, I got the Wolf V2 52v battery with the minicharger. First off, I found it strange that the charger documentation has a voltage chart much different that the Direwolf battery. The chart for the Direwolf lists 100% as 58.8v whereas the Wolf V2 and minicharger says the max is 53.0v. I wasn't aware of any 52v battery that maxes out at only 53.0v.

When I used the minicharger (labeled as 52v minicharger), the Wolf V2 charges up to 55.8v when set to 100% charge. I've used the bike a few times, and on the 3rd charge, I set the charger to only charge to 80%. Strangely, the max voltage is still 55.8v. Turning the knob to 100% resulted in the green light still being on and no more charging.

This is all very strange. What I think is happening is that I was given a 48V battery and not a 52V battery. This would explain the charging behavior and max voltage. But Luna doesn't sell 48v Wolf batteries, and the charger and invoice clearly say 52v. But why does the chart in the booklet say the max is 53.0v? I'm concerned that I'm attempting to charge a 48v battery with a 52v charger, which would be bad. But nothing really adds up.

Luna has not responded to any help tickets in 2 days on this subject, so I'm reaching out to the community.

Thanks.

[Mike_V]

Please read the directions for the charger and battery in the knowledge base because, for example, the Wolf pack directions are to initially fully charge the power pack.
Ex: Voltage is not the controlling parameter during charger operation.

[Maxxim]

Very confusing replies here..? My experience with e-bike batteries is zero, but I have been playing with other lithium batteries, Li-Po and LiFePO4. Always the charger, BMS etc. is controlled by the voltage range. When the packs are up to the max voltage(and amps drop to zero) the charging would stop, and in this case it should stop at 58.8V. What am I missing here? I don't understand why 55.8V would be ok? A 52V pack isn't fully charged at that point.

Even Luna says about the 52V Mini charger, "This Charger is a very small electric bike charger for 52-volt battery (14s 18650 lithium ion) which charges to a maximum of 58.8 volts."


If I'm totally wrong, please link me a direction where I can get proper info about this, thanks.

[Quovadis]

Please point me to something specific. I've done a lot of research before posting and read the knowledge base. I also have another battery with 6 months of experience and no issues at all (58.8V on first charge). A few tenths of a volt difference is no big deal, but nowhere have I read where a 52v battery maxing out at 55.8V is normal. I've charged it to 100% 4 times now, and verified with a multimeter that the final voltage is only 55.8V. The 80/90/100% settings on the charger all charge to the same terminal voltage. So what am I missing?

Confusing still is the documentation sent with the battery and 52v charger that has a chart where it says 100% SOC is at 53.0V. That has to be a misprint.

[AZguy]

Please point me to something specific. I've done a lot of research before posting and read the knowledge base. I also have another battery with 6 months of experience and no issues at all (58.8V on first charge). A few tenths of a volt difference is no big deal, but nowhere have I read where a 52v battery maxing out at 55.8V is normal. I've charged it to 100% 4 times now, and verified with a multimeter that the final voltage is only 55.8V. The 80/90/100% settings on the charger all charge to the same terminal voltage. So what am I missing?

Confusing still is the documentation sent with the battery and 52v charger that has a chart where it says 100% SOC is at 53.0V. That has to be a misprint.

Unfortunately chinese documentation is terrible and often not to be trusted... a quote from a manual I have:

Display devices are easy to pollution easily broken, the installation
process and avoid touching the collision force, use screws to secure the
controller firmly, avoid installation in order to avoid irreparable damage
to the internal circuitry in severe vibration device.

What gobbledygook

Regardless, see if you can measure the open (no-load) voltage on the charger and if you can that will tell you what the charger is meant for - if 54.6V it's a "48V" charger and if 58.8V it's a "52V" charger which is highly likely although measuring doesn't hurt - if you can make that measurement throw the manual away or burn it or whatever makes you feel better

Battery is almost certainly "52V" (max 58.8V)

In the end, if you aren't sure, contact luna (best by email)

[Quovadis]

Well, thanks for trying, but none of that info is new to me or really relevant to the issue. It's a new battery and only gets to 55.8V right off the charger. If I let it sit for 12 hours, it's at 55.7V. You don't think it's a problem that seconds after the charger shuts off that it's only at 55.8V? I have not read this to be normal behavior anywhere. Could one cell be bad in the battery?

I did test the charger output voltage, and it's 58.8V, so the charger is fine.

[Maxxim]

Ok, so we don't need to fully charge a old battery as the capacity isn't same as new? Well, if you wan't the battery full then you have to charge it to max charge voltage regardless what the capacity is. Maximazing the lifespan and charging cycles with a lower SOC range is a totally different thing.

[Maxxim]

I fully understand what you mean, you are talking about rest voltage as we are talking about charging voltage. I don't know if Quovadis has measured it the right way, but he was saying he measured directly after the charging stopped. Usually batteries don't drop to rest so quickly.

I think you are missleading here and behave quite arrogant.

[Maxxim]

Why would I need a refund? Clearly you have something wrong with your ability to read and understand. :D

[Circuitsmith]

The 80/90/100% settings on the charger all charge to the same terminal voltage. So what am I missing?

55.8V is a 14s (52V) string charged to approx. 80%.
My rule-of-thumb for SOC vs per cell rest voltage is 3.15V empty and 4.15V full.
So I think the problem is the charger is stuck on 80% charging mode.

But why does the chart in the booklet say the max is 53.0v?

I also think 53.0V is a typo in the documentation.

[73Eldo]

I'm not clear on what you have to work with. Do you have 2 chargers or just one that you bought with the the original dire wolf?

Either way you have 2 batteries to play with so does the Dire charge to 58v and then if you take that charger with the same settings to the Wolf it only charges to 53?

Also where are you reading these voltages? You said the mini charger so that one doesn't have a display on it or charge rate options, only a % selector.

I have an advanced and a couple minis. I have noticed things don't seem consistent and the voltage reading on the bikes display usually doesn't match the advanced charger or an external voltmeter however I have not seen them to be off by as much as I think is being implied here.

An advanced charger or some other method to monitor the charge current could be handy here. If there is a bad cell group I would expect to see the current suddenly drop because the BMS would cut off the other groups when they maxed out their charge. Normally the charger would cut out before any group reached its max.