Hillhater
100 TW
broke said:
Looks like you have a measurement problem also. ,
Those numbers dont add up any which way.
Before anyone else jumps to conclusions and solutions, i think we need better measurements/ accuracy and repearability.
Luna ga 14 ah shark pack
- Thread starter broke
- Start date
- Status
Looks like you have a measurement problem also. ,
Those numbers dont add up any which way.
Before anyone else jumps to conclusions and solutions, i think we need better measurements/ accuracy and repearability.
Alan B
100 GW
broke said:
fechter said:
It will take some time to balance that low group, as Richard says, perhaps days. But if you don't have a single cell charger than that's what you have to work with.
The question is, will this pack recover if it is balanced, or is it actually damaged. At this point we don't actually know. What we do know is that it was drained to LVC several times, it is now significantly out of balance, and the apparent pack capacity is reduced (which is consistent with an out of balance pack). We don't know if the pack is bad, or it merely needs a good balancing.
Let's see if I can boil this down.
If you give it a good 12 hour charge/balance and the group that was low goes higher than the other groups, then clearly the capacity of that group is low and the pack needs repair.
If you give it a good charge/balance and the group that was low comes up but stays lower than the rest, then perhaps it is just a balance problem, and it needs a lot of balancing to correct. After fully balancing it, a good charge/balance cycle after each use should maintain the balance, if not the pack needs repair.
If this were my pack, I would use a single cell charger to charge the low group. Single cell chargers are under ten bucks on ebae. But in the case one isn't available, I would put that pack on charge every minute it was possible to do so. Let it charge and balance as much as possible until it gets fully balanced. I'd make a charging log of time, date, and cell group voltage to collect good data to help understand what the status is.
If you are riding the pack every day, and it is not getting toward balance, and charging every minute you can, it may be time to stop using the pack a few days and just let it balance. A single cell charger would be SO much faster.
Here's a 4.2V 1A wall wart charger for under $10: eBay item number:221769572704. Note that I have no affiliation with this seller or experience with his products. A charger like this one may be 10 to 20 times faster than the BMS at balancing.
If this is your daily driver, perhaps use your backup for a few days and let this battery charge/balance (if it is making progress, which your measurements will show). Ebike failures are always possible so some sort of backup is required to have reliable transportation. It doesn't have to be another ebike, just another way to get around.
If you want service from the vendor, you need to talk to them. Perhaps this pack is safe to send back. I can't answer than question. Ideally there would be a local and capable battery repair place that could do the work and the vendor could just send the components.
I'm going to be away from the internet for a few days, so my responses will be delayed.
Hillhater
100 TW
If you can measure individual groups you can charge them alsobroke said:
You are not going to charge one cell, it would be one complete 4p cell group.
..how about you recheck those voltages again...accurately.to 2 decimal places as you have been advised previously, before you do anything else.
Until you can get accurate voltage readings for each cell group and the total pack, you shouldnt do anything
How many times does it need to be said...12 ahr from a 14 Ahr max pack with a 46v LVC, and inder high loads, is not a unusual result.
Ebikes4Real
10 mW
- Joined
- Jun 26, 2016
- Messages
- 25
Hillhater said:
I think you missed where some points were clarified, the OP isn't saying that
To be fair, the OP did state the kit is setup with a 38V, but that is slightly immaterial, as the battery BMS is tripping. If the BMS is tripping, then it can be assumed that the battery is unable to deliver any more juice (at least without balancing it).
The 46V is the unloaded voltage that is measured, maybe 20mins after the BMS has tripped, it is not the LVC (the battery is bouncing back up to 46V, but must be much less when it trips). The OP has stated that the first cell group is low, at about 2.8V (46V unloaded, after bms tripped) and the rest are ~3.2V if I recall correctly.
Yes, it would appear the issue is either a weak cell group or a balance issue. More tests are required (as others have suggested) to determine what exactly the issue is.
Hillhater
100 TW
No, i didnt miss that at all.
What i read is..
..he rides hard...hills pulls wheelies etc
..the 46 v is a "resting" reading, but due to the high current draw, voltage sag takes it down to the Lvc. That is to be expected with GA cells .
What i have missed is the OP responses to suggestions for accurate voltage checks and explanations of the discrepancies in his measurements
What i read is..
..he rides hard...hills pulls wheelies etc
..the 46 v is a "resting" reading, but due to the high current draw, voltage sag takes it down to the Lvc. That is to be expected with GA cells .
What i have missed is the OP responses to suggestions for accurate voltage checks and explanations of the discrepancies in his measurements
Alan B
100 GW
With a single cell charger running low current, such as 1 or 2 amps, you can charge a parallel cell group (not a single cell) through the balance leads, or with a pair of wires installed specifically for this. It is very important to avoid shorting during measuring and charging the cell group. If you are not comfortable with this kind of work it would be good to find someone local who can work on this pack. Or charging / balancing for several days may be a better alternative. Another advantage of this approach is that it tests the BMS's ability to balance the pack.
Shipping costs to Hawaii are problematic, regardless of vendor. USPS is the lowest cost, but they may not take large lithium batteries. UPS and other shippers are very expensive, and lithium is generally not shippable by air. So slow sea shipping is the preferred route. The time and cost make it even more important to avoid extra shipping.
How many hours of charging have you put into the pack? How is the charging log coming? Can you record cell voltages to 3 digit accuracy (x.xx volts)? What meter are you using for cell voltage measurement? Has the calibration of this meter been checked?
The charging log could also have Satiator voltage, current and amp hour measurements. A measurement of total pack voltage with this meter would also give some cross checking between the meter and the Satiator's meter. Plus the cell group voltages should add up to the Satiator's output voltage.
Another question is what is the Satiator's amp hour reading when the charge is done, and again the next morning after it balances overnight? Does it keep going up, indicating progress, or does it stop rising?
Shipping costs to Hawaii are problematic, regardless of vendor. USPS is the lowest cost, but they may not take large lithium batteries. UPS and other shippers are very expensive, and lithium is generally not shippable by air. So slow sea shipping is the preferred route. The time and cost make it even more important to avoid extra shipping.
How many hours of charging have you put into the pack? How is the charging log coming? Can you record cell voltages to 3 digit accuracy (x.xx volts)? What meter are you using for cell voltage measurement? Has the calibration of this meter been checked?
The charging log could also have Satiator voltage, current and amp hour measurements. A measurement of total pack voltage with this meter would also give some cross checking between the meter and the Satiator's meter. Plus the cell group voltages should add up to the Satiator's output voltage.
Another question is what is the Satiator's amp hour reading when the charge is done, and again the next morning after it balances overnight? Does it keep going up, indicating progress, or does it stop rising?
999zip999
100 TW
Why does richard get credit ? Lol . just charge the one cell group. Make sure pos and neg are right. This could be a one time thing hopefully. It needs balance to start with.
tomjasz
1 GW
broke said:
Given the problems with the return, even though I wouldn't be thrilled, it might be worth getting and trying a new BMS. I opened a pack and tried to help a friend with a similar problem. It appears to be the BMS in that case.
Green Machine
100 kW
Etrike this is none of your business and i ask again what dealer are you affilated with? who are you?
But #1 we are not sure if the pack is defective because we are not sure of the testing methods being used and 12.5ah is reasonable on a pack being run hard as has been gone through in this thread. I really doubt anything is wrong with the battery.
#2 we did not ship to this guy.... we do not ship to hawaii....he had a friend come pick it up in person at our warehouse. So obviously if he wants a refund he needs to get it back to us the same way he picked it up. He did not pay shipping. This was an in person sale.
We have offered him a refund to be done with it.... but really what he should do is have his friend who bought it return it to us so we can test it and see if it tests fine or not. And also examine the pack for abuse.
But #1 we are not sure if the pack is defective because we are not sure of the testing methods being used and 12.5ah is reasonable on a pack being run hard as has been gone through in this thread. I really doubt anything is wrong with the battery.
#2 we did not ship to this guy.... we do not ship to hawaii....he had a friend come pick it up in person at our warehouse. So obviously if he wants a refund he needs to get it back to us the same way he picked it up. He did not pay shipping. This was an in person sale.
We have offered him a refund to be done with it.... but really what he should do is have his friend who bought it return it to us so we can test it and see if it tests fine or not. And also examine the pack for abuse.
eTrike said:
Green Machine
100 kW
We have been taking the time at Luna to video some testing and the results are interesting and we will be publishing soon. we really dont have time for this sort of thing we will do it. I have some great data and will try to find time in the next week to get the video up.
I have more faith in the 14ah GA shark pack and that it puts out 14ah more than ever. We rarely run a test on a pack that says different.
we do have plenty of testing equipment such as 2 batteryconditiontest.com with 2 ports each (can test four batteries at a time) This by the way is the same device that paul at em3ev uses
we also have 2 bicycle dynos which allow us to test our BBSHD, high power controllers, and batteries at the same time.
On top of that we have invested in some very advanced equipment that can not only identify problems such as weak cells, pack construction problems, countereit cells, and can do continual discharge and charge tests and 12 packs at a time. obviously these machines arent cheap.
My reason for buying those machines was not only for our own quality control but also to finally get some real data on how long these ebike battery packs are meant to last and how much does high amp usage affect that life ....i think that is data that nobody really knows and its time someone tests that. i know es guys love to speculate...but real testing is rare and is what is needed to move forward.
I have decided to post less on ES and focus on stuff like creating written content, video content, bettering our products, and dong my best to better Luna and lead our team.
I love ES, and i think everyone who knows me knows i am sincere. I dont need to argue with the bad apples who obviously have an axe to grind for obvious reasons.
I think that Lunas results speak for themselves.... and our products are strong. i hope our many happy customers will defend us.
I have more faith in the 14ah GA shark pack and that it puts out 14ah more than ever. We rarely run a test on a pack that says different.
we do have plenty of testing equipment such as 2 batteryconditiontest.com with 2 ports each (can test four batteries at a time) This by the way is the same device that paul at em3ev uses
we also have 2 bicycle dynos which allow us to test our BBSHD, high power controllers, and batteries at the same time.
On top of that we have invested in some very advanced equipment that can not only identify problems such as weak cells, pack construction problems, countereit cells, and can do continual discharge and charge tests and 12 packs at a time. obviously these machines arent cheap.
My reason for buying those machines was not only for our own quality control but also to finally get some real data on how long these ebike battery packs are meant to last and how much does high amp usage affect that life ....i think that is data that nobody really knows and its time someone tests that. i know es guys love to speculate...but real testing is rare and is what is needed to move forward.
I have decided to post less on ES and focus on stuff like creating written content, video content, bettering our products, and dong my best to better Luna and lead our team.
I love ES, and i think everyone who knows me knows i am sincere. I dont need to argue with the bad apples who obviously have an axe to grind for obvious reasons.
I think that Lunas results speak for themselves.... and our products are strong. i hope our many happy customers will defend us.
liveforphysics
100 TW
You've had an incredible history in ebikes and LEVs Greenmachines, and I'm super thankful your efforts get large volumes of ebikes under butts world-wide.
Im thankful to every vendor of EV parts that gets working ebikes under butts! However, very few have been better at getting a larger volume of ebikes on the road than Greenmachines.
Im thankful to every vendor of EV parts that gets working ebikes under butts! However, very few have been better at getting a larger volume of ebikes on the road than Greenmachines.
Ykick
1 GW
Green Machine said:
I missed this so maybe it should be repeated. If I buy a defective product ANY seller only needs to reimburse the same form return shipping. What apparently went down here isn't Luna's responsibility.
Luna's position is fair. Get the battery pack back to Luna and go from there. At this point I'm sure they'd be happy to refund even if proven to be within 100% spec.
Green Machine
100 kW
Thanks buddy i really appreciate your support. I have nothing but good intentions.
liveforphysics said:
Ebikes4Real
10 mW
- Joined
- Jun 26, 2016
- Messages
- 25
Hillhater said:
The OP did state the 1st cell group was at 2.8V resting voltage and the rest were higher, when he checked the pack voltage, some time after the pack tripped. This clearly shows that the BMS tripped for a valid reason and it also indicates, that the 1st cell group (at least) is fully discharged. A cell group at 2.8V, does not show that the pack tripped prematurely and has a significant capacity remaining.
The pack is out of balance for some unknown reason, or there is a weak cell group. This is still a relatively new battery, it is not a year or 2 old.
To be fair, the OP did purchase a built battery, not some lipo packs, so expecting him to be a battery expert is a little unfair. This particular battery is offered as being a great match for the BBSHD kit, that he used it with. It wasn't like he was using it at current levels, way beyond the recommended levels. Expecting the OP to second guess and know better than what the supplier states and recommends, is also a little unreasonable.
These are some of the (unsuitable, IMPO) battery options offered on the Luna site, as being a suitable match for a 30A BBSHD kit:
(http://lunacycle.com/bafang-bbshd-1000w-middrive-kit/)
Mighty Mini 52v GA (14S2P)
Mighty Mini 52v 30Q (14S2P)
Performance and Range Pack 48v Panasonic GA 10ah (14S3P)
Ykick
1 GW
Hello? Luna already offered a refund.
Trouble here is, OP/buyer took a circuitous method/route to get it to their homeland and due to things out of Luna’s control it’s gonna cost OP a considerable sum to return it.
It sucks, I feel bad for the OP but to expect any merchant to reimburse for a different return shipping method when they (Luna) never shipped it in the 1st place is ridiculous.
It sounds like the OP found a way to return it for $180 which would hurt but that’s their cost to bear. Not the merchant.
If it were me, I’d probably dig down enough to figure it out for certain but not everybody has that skill set…
Maybe all it needs is a new BMS and the cell strings brought back into balance? IME, BMS tend to suffer shorted balance transistors which drain cell strings. If so, did that damage the cells? Possibly but that’s for another day to sort out.
Self-appointed “consumer advocates” or not, bashing a good merchant (IME) over something (shipping) that’s clearly not their responsibility is not helping anybody or anything.
Trouble here is, OP/buyer took a circuitous method/route to get it to their homeland and due to things out of Luna’s control it’s gonna cost OP a considerable sum to return it.
It sucks, I feel bad for the OP but to expect any merchant to reimburse for a different return shipping method when they (Luna) never shipped it in the 1st place is ridiculous.
It sounds like the OP found a way to return it for $180 which would hurt but that’s their cost to bear. Not the merchant.
If it were me, I’d probably dig down enough to figure it out for certain but not everybody has that skill set…
Maybe all it needs is a new BMS and the cell strings brought back into balance? IME, BMS tend to suffer shorted balance transistors which drain cell strings. If so, did that damage the cells? Possibly but that’s for another day to sort out.
Self-appointed “consumer advocates” or not, bashing a good merchant (IME) over something (shipping) that’s clearly not their responsibility is not helping anybody or anything.
tomjasz
1 GW
Get a BMS. They're inexpensive and cheap to ship. It's the most common problem with the value priced China made packs. I ordered a backup BMS with my shrink wrap pack and it was all of $12.
2 cents a couple of long charges with a new BMS and the cells straighten up and fly right.
2 cents a couple of long charges with a new BMS and the cells straighten up and fly right.
999zip999
100 TW
The battery is only as strong as its weakest cell or group of parallel cells. One group of cells easy to charge that group up to voltage. Or just a little higher. Seat and watch very closely and never go above 4.2v on any cell. Make sure you get the polarity right. Check polarity. After this has been done and the pack is balance we should find what is going on after a cycle or two. State of charge
tomjasz
1 GW
I friend noted that when he used a 5A charger the cells got out of balance and when he used a cheap 2A charger the battery performed differently. It actually started delivering the previous mileage. I'm not throwing that in as the problem, just an interesting observation on a Luna pack and BMS.broke said:
Ykick
1 GW
Something's seriously wrong with this PM. They're now on iggy list and any further PM's deleted by rule.
eTrike said:
999zip999
100 TW
At this point it's a balance problem . After balance is done. Then after it is balance we can see if there is a problem. So first step is to balance the pack. Best to start with step one. So let's not get to far ahead of ourselves. 180.00 is a lot for shipping.
It does seem like a pretty blatant personal attack. Not allowed by forum rules. 
I just don't understand why eTrike is trying to make it look like Luna is some kind of crooked dealer when everything I've read indicates they are doing a pretty good job of standing behind their product given the circumstances. I consider the comments of the OP much more than somebody who has no direct interest in the issue.
Readers can make their own judgments.
If it was my battery, I would try to figure out exactly what's wrong with it for educational purposes. A common fail mode is one shunt transistor shorts and the shunt stays on, bleeding that cell down. If this happens, the cell voltage will steadily drop when the pack is idle. At 100mA, you can calculate how long it would take to fully drain a cell. I guess it would be totally dead by now if this was the failure. Anyway, it wouldn't hurt to measure the cell voltage over time and see if it is dropping and how fast.
Checking the voltage immediately after charge termination might be interesting also. If that cell goes higher on charge than the rest, it would indicate a possible bad cell or broken connection.
If it's always just lower than the rest, it seems like charging to balance would fix that.
I just don't understand why eTrike is trying to make it look like Luna is some kind of crooked dealer when everything I've read indicates they are doing a pretty good job of standing behind their product given the circumstances. I consider the comments of the OP much more than somebody who has no direct interest in the issue.
Readers can make their own judgments.
If it was my battery, I would try to figure out exactly what's wrong with it for educational purposes. A common fail mode is one shunt transistor shorts and the shunt stays on, bleeding that cell down. If this happens, the cell voltage will steadily drop when the pack is idle. At 100mA, you can calculate how long it would take to fully drain a cell. I guess it would be totally dead by now if this was the failure. Anyway, it wouldn't hurt to measure the cell voltage over time and see if it is dropping and how fast.
Checking the voltage immediately after charge termination might be interesting also. If that cell goes higher on charge than the rest, it would indicate a possible bad cell or broken connection.
If it's always just lower than the rest, it seems like charging to balance would fix that.
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