Battery Technology and Best practice battery care

Philip

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Ann Arbor, MI
#41
As far as getting the most life it of these cells, there are a couple of things we can do to increase our charge/discharge cycle life rate. Never discharge the pack below 10% of standard operating charge (SOC). Even though our batteries have a built in BMS that keeps us from over discharge the pack, its not a good practice to ride our machines until BMS LVC shut down. If you don't need maximum watts for maximum distance, don't charge the battery above 90% of SOC. Grincyclery testing has shown that following these 2 guidelines, cycle life of our batteries can will be increased and can even potentially be doubled. Its also recommended to charge to 100% of SOC once every 5-10 cycles will ensure proper cell balancing.
According to Alta, the bikes already have these two safeguards in place in their firmware. You can safely charge to 100% and discharge to 0%, as indicated by the battery charge indicator. Also, at the end of the charging cycle, the bike will often sit, and the charger will run for a little longer. It is balancing the batteries.
 

Rix

Self proclaimed macho man extraordinaire
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423
Location
Fallon NV
#43
According to Alta, the bikes already have these two safeguards in place in their firmware. You can safely charge to 100% and discharge to 0%, as indicated by the battery charge indicator. Also, at the end of the charging cycle, the bike will often sit, and the charger will run for a little longer. It is balancing the batteries.
It's very possible that the software programming Alta is utilizing is doing this automatically for us, in which case, we don't need to worry about it or even have to think. And I know the BMS will protect the pack. I am merely saying that we can manually control this and ensure more battery cycle life and longer life out of our packs in general. If we stop charging at the indicated 90% on the meter, my best guess is this would put the individual cell volt at about 4.10 volts. And not discharging below 10% indicated most likely means we are probably not discharging the individual cell below 3.1 to 3.15 volts or so. This makes any lithium based cell (Except Lifepo4) very happy. I wish I knew what 18650 cells Alta was using along with the series and parallel configuration. If the 350 volt rating is nominal, that means we probably have a pack that is comprised of about 92 cells in series. But if its 350 volts hot off the charger, then our packs could be comprised of about 87 cells in series. Either way, the cell parralel count would probably be different by one. Also, our packs have a 58000wh (5.8kwh) storage capacity rating, is the max storage, or usable? If I knew these numbers, I could figure what the individual cell capacity is, and ultimately determine which 18650 cell was being used and the best way to maximize performance and longevity with out ever splitting the pack's case. I will never attempt to do that. 350 volts and a potential instantaneous ability to discharge 42000 watts, there is no margin for error and this is about 20 times more watts than is required to kill a human being.
 

Fod

Well-known member
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324
Location
CA
#45
It's very possible that the software programming Alta is utilizing is doing this automatically for us, in which case, we don't need to worry about it or even have to think. And I know the BMS will protect the pack. I am merely saying that we can manually control this and ensure more battery cycle life and longer life out of our packs in general. If we stop charging at the indicated 90% on the meter, my best guess is this would put the individual cell volt at about 4.10 volts. And not discharging below 10% indicated most likely means we are probably not discharging the individual cell below 3.1 to 3.15 volts or so. This makes any lithium based cell (Except Lifepo4) very happy. I wish I knew what 18650 cells Alta was using along with the series and parallel configuration. If the 350 volt rating is nominal, that means we probably have a pack that is comprised of about 92 cells in series. But if its 350 volts hot off the charger, then our packs could be comprised of about 87 cells in series. Either way, the cell parralel count would probably be different by one. Also, our packs have a 58000wh (5.8kwh) storage capacity rating, is the max storage, or usable? If I knew these numbers, I could figure what the individual cell capacity is, and ultimately determine which 18650 cell was being used and the best way to maximize performance and longevity with out ever splitting the pack's case. I will never attempt to do that. 350 volts and a potential instantaneous ability to discharge 42000 watts, there is no margin for error and this is about 20 times more watts than is required to kill a human being.
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Speedkills

Well-known member
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163
Location
Nederland, CO
#49
Just browsing this thread, I have seen people often request a way to auto-shutoff the charger at a certain chart percent, say 70% or something like that. It makes me wonder if you could have something like a kill-a-watt to watch the power used at various charge levels, that would shut off the power when the watts pulled dropped to a preset threshold.
 

Trialsman

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409
Location
Pittsburgh
#50
My standard charging proceedure has been fully charge until it shuts off to balance the cells. Then I ride it on a loop that takes it down to about 75-80% charged and that is how I store it. My question is; is it better to do it that way and get the benifit of the balancing at the end of the charge cycle or to just stop it at the 75% level and not let the cells be balanced? I rode it a little tonight and it is at about 55% and wondered if I should do my normal or just leave it as is.
 

snydes

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Pennsylvania
#51
IMO that’s not a bad idea but I wouldn’t feel the need to do it every time. My routine if I know it’s going to sit is to not charge it past 75% and then charge/balance right before I ride it. 3.5v is considered a good storage voltage for 18650’s and our Alta packs only hit that cell voltage at something around 40%, so anything between that and 75% I’m comfortable with. I’ve tracked how much these packs will lose just sitting per month on a few different ones and it’s not much, so you just want to check them periodically if you are planning on a long storage period.
 

Trialsman

Well-known member
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409
Location
Pittsburgh
#52
Thanks for the input. I was probably over thinking it, but was just wondering if the cell balance would be more important during storage or during the ride. It is such a fantastic motorcycle that any little advantage to prolong it's life is worth consideration.
 

snydes

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Pennsylvania
#53
That’s an interesting point. I’m far from an expert but in my mind having the pack well balanced before the ride seems to make sense to me to give it the best chance for an even discharge/max range. I’d like to hear some input from those that are more experienced in battery tech though.
 

Redwolf

My dog thinks I'm cool
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Brinnon, Wa.
#55
Is there anything that should be done in preparation for wet conditions? This thread makes me paranoid about a ride this weekend

2018 mxr Battery apart finally. Interesting pics

The place I want to go requires crossing a small river 4 times each lap, 12-18 inches deep in spots.
I take mine through water crossings like that every winter, the electrics and battery are sealed enough to take it. Your wheel bearings are the most likely to suffer water damage, the rest of the bike will be fine.
 

VINSANITY

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233
Location
Texas
#56
I was having a lot of bearing rust issues in the wheels as I would get them wet trail riding and then the bike would sit for a week or two. I replaced the wheel bearings with ceramic ball type - pretty expensive but no more rust and seizing issues - highly recommend if you get your bike wet a lot
 

snydes

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Location
Pennsylvania
#57
Is there anything that should be done in preparation for wet conditions? This thread makes me paranoid about a ride this weekend

2018 mxr Battery apart finally. Interesting pics

The place I want to go requires crossing a small river 4 times each lap, 12-18 inches deep in spots.
That particular situation we determined was from enthusiastic use of a pressure washer right against the vent screen/port on the bottom of the battery. Under normal circumstances running through deep water shouldn’t be an issue if the battery has never been apart or has been resealed properly. We’ve had guys run their bikes up to the seat deep without problems, so I wouldn’t be worried about 12-18”.
 

C5tor

Chief Comedic Instigator
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960
Location
San Ramon, CA
#59

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