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.

[stts]

Yea, you don't understand how this stuff works. If you want to observe more voodu, put a meter on the battery and read the voltage right after the charge is done. Then take another reading of the battery a few hours later. Hocus Pocus, it's changed all by itself. Hah. If there's no smoke, the charge don't take forever, and the battery runs for many many miles, then everything is likely fine. For a more detailed analysis, you have to learn the details and the process of detailed analysis. Otherwise you have no informed basis for suspicions. Literature could even have typos in it.

[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)

[stts]

Links links, take your pick. There's countless of them that say the max charge on Liion is 4.2 volts. While the working voltage is 3.7 volts. You don't build battery on the charge voltage, but on the working voltage. So when charge complete, its 4.2 volts. But when the battery cools down or even starts being discharged, it immediately starts heading for 3.7 volts. That's the voltage where most of the power is sucked out at. The working voltage. So voltage is all over the place despite its current charge level. Pull huge amps for a short time and you read well bellow even 3.7v. But it bounces back up after you stop. You have the mistaken idea that the the voltage you read is the current charge of the battery. That is totally wrong. It is only an indication of weather the battery is probably full or probably empty. Or probably somewhere in between. The more precise measure is a reading of how many Watt hours have been fed into the battery or sucked out of the battery. Then you know where the battery is. But that reading is only available on battery testor machines. And gizmos don't put anything but a volt meter on gizmos. So you only see a rough idea of the battery charge in most cases.

The other battery chemistries have different charge and working voltages. All published on equally endless numbers of links. Only lead acid batteries discharge in a linear way where battery voltage is pretty much the state of the charge when at rest.

As an example, a 52v battery is 14s and 48v is 13s biuild. So for a 52v battery, the max charge is 14 times 4.2 which is 58.8v charge voltage. When the charge process reaches this voltage, the whole pack is considered fully charged and is shut off. Then you will see the pack drift down to 52v eventually as it cools down. Or go use the pack immediately. And it don't matter what literature you read from anybody or any link. This is the chemistry of a 14s Liion battery. Period. Back calculate all that for a 13s 48v Liion battery or a 10s 36 volt Liion battery. Or any battery pack build in between.

So chargers not plugged into a battery may meter out to even higher voltages. But the charger CPU will stop charging when the pack reaches that max charge voltage for the pack. That's why the factory says to only use the charger for that pack. Its programmed to stop charging when that pack is at the max voltage.

And all this is for fresh working cells and charger. If the charger is malfunctioned, it could charge on the batteries until they explode. Or if its just a cheap charger left plugged in that doesn't shut off. Like those trickle chargers. A trickle charger is bad news for Lithium chemistries.

Malfuntioned cells also mess up the plan. Old cells run out of capacity so they hit max voltage level without taking in many watts of power. Those cells are useless and block the proper charging of the rest of the pack. Hence poor capacity with seeming full charge voltage on volt meters. And each cell has atomic differences from each other so no 2 cells are truly identical. Hence the need for balance circuits. You don't have to really have those circuits to get lots of pack usage. But to really get the maximum life out of each cell in a pack, a balance circuit is required to compensate for the slight differences in the charge of each cell in packs.

There you go. All the facts that matter. Hopefully that helps when you look at the info in the links that you find.

[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]

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.

[stts]

Well clearly we have a difference of opinion. So I'm going to take my arrogance and charge my battery. And you can take your facts and demand a refund. May you have as good a success as I. :)

[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.

[stts]

A "typo" ? I think I read that in a post somewhere...

[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.