# Lets talk batteries



## Cody01 (Jul 23, 2014)

I keep getting mixed info on how to store ebike batteries and its getting frustrating. I stored my battery back in mid October out of my bike in my house at about 50%. I checked it at Christmas time and it registered no charge at all which amazed me and angered me at the same time. I wouldn't think it should have dropped more than 5% in that period. The tech support where I got the bike says thats ok and I should peak the battery monthly when not in use. I don't see how that is a viable answer. The battery is only like 8 months old. It seems like half of the people say to store at half charge and the rest say store at full charge and check monthly. You should be able to walk away from a batteery that has been removed from a device for longer periods as far as I am concerned. I am thinking my battery might be a bad one and they are just reluctant to go there with it.


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## Fuse6F (Jul 5, 2017)

I store My ice auger lithium batteries in my beer fridge. Its a chemical reaction. So im basically slowing things down in hopes of preserving its life.


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## Cody01 (Jul 23, 2014)

Anyone else have any input?


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## robbnj (Jul 19, 2013)

Cody01 said:


> Anyone else have any input?


LiPo batteries should retain a charge for a long time sitting on the shelf.
My guess is that you have either a bad cell that is pulling the whole pack down, or the circuitry in the pack is draining the cells down by a complex "short circuit" (not a dead short but rather a short through all the transistors, resistors, etc, that bleeds off slowly as heat).
While you can, get it in writing that your battery is not defective, and hold the mfgr. to that if a problem occurs that seems tied to this rapid drain.

That said, storing LiPos with a full charge is not really recommended. Neither is refrigerating it. Run the pack until it's too low for use, but don't kill it completely. Then charge it before using and do the same again. It's kind of like the adage with the old NiCd batteries in cell and cordless phones (thought THAT was due to the "memory effect: run until done, then charge it back up.


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## JackWare (Aug 8, 2016)

From the Bosch battery guide;

Charging - The batteries should be 
charged at room temperature in a 
dry location where a smoke detector 
is installed.
Storage during winter - Store the 
batteries in a dry location at room 
temperature. Fully charging or fully 
discharging results in higher loading 
of the battery. _The ideal charge sta-
tus for lengthy periods of storage is 
approx. 30 to 60 % or two to three 
LEDs on the battery indicator._


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## JackWare (Aug 8, 2016)

From the Yamaha guide;

Storage
Store the system in a place that is:
• Flat and stable
• Well ventilated and free from moisture
• Sheltered from the elements and from direct sunlight
Long storage period (1 month or longer) and using it again after a long 
storage period
• When storing the bicycle for a long period (1 month or longer), remove the battery pack and store it using the following procedure.
• _Decrease the residual battery capacity to where one or two battery capacity indicator lamps are lit, and store it indoors in a cool 15-25 °C, dry place.
• Check the residual battery capacity once a month, and if only one battery capacity indicator lamp is flashing, charge the battery pack for about 10 minutes. Do not let the residual battery capacity become too low._
TIP
• If you leave the battery pack at "full charge" or "empty", it will deteriorate quicker.
• Due to self-discharge, the battery slowly loses its charge during storage.
• The battery's capacity decreases over time but proper storage will maximize its service life.
• When using it again after a long storage period, be sure to charge the battery pack before using it. Also, if you are using it again after storing it for 6 months or longer, have your bicycle inspected and maintained at a dealer.


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## Maxeymum (Mar 2, 2017)

So I bought a Kona Remote 160 a few months ago; it was a demo so was fully charged when I picked it up. I haven't been able to ride it since I bought it due to our wonderful North Dakota winters and have it stored in my living room as I read it's a no-no to keep it out in the cold. So here's the deal: I've turned the power on a few times to check the charge, and it still has all 5 bars showing, which, according to what I'm reading here is also a no-no for storage. So my question is, how should I drain the battery down to the 50-60% range that if I am understanding correctly is how it should be stored? Should I just turn it on and leave it on until, say, 3 bars are showing? And out of curiousity how long would that take approximately? Thanks in advance for any advice anyone can offer.


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## Doug_ID (Feb 22, 2009)

Maxeymum said:


> So I bought a Kona Remote 160 a few months ago; it was a demo so was fully charged when I picked it up. I haven't been able to ride it since I bought it due to our wonderful North Dakota winters and have it stored in my living room as I read it's a no-no to keep it out in the cold. So here's the deal: I've turned the power on a few times to check the charge, and it still has all 5 bars showing, which, according to what I'm reading here is also a no-no for storage. So my question is, how should I drain the battery down to the 50-60% range that if I am understanding correctly is how it should be stored? Should I just turn it on and leave it on until, say, 3 bars are showing? And out of curiousity how long would that take approximately? Thanks in advance for any advice anyone can offer.


You have no where within driving distance you could ride up a hill in turbo mode for 20 mins? Even getting it down to 4 bars would be good.


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## Maxeymum (Mar 2, 2017)

Yeah, I could risk it, but they are bad at plowing the roads here, they don't use salt, and we have had ice on the roads for over a month now. The road out of my condo complex is a skating rink. The low temp last night was -5 degrees Fahrenheit. I'm just not real keen on taking the chance. Hence my question about just leaving the bike on to see if that will drain the battery.


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## mtbbiker (Apr 8, 2004)

Does your bike have walk mode? If it does, put it on a stand and zip tie the switch down until you lose 2 bars. 


Sent from my iPhone using Tapatalk


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## Maxeymum (Mar 2, 2017)

I believe it does, but I'm not sure how to access it through the controller (Shimano Steps e8000 system/motor) --- or did I read somewhere that you can only first activate it through an app?

Sorry, I'm very new to the whole ebike thing, so if anyone can tell me if I can access walk mode on the stock e8000 controller I'd appreciate it. I'm also willing to turn it on and look for it, but a little guidance would be appreciated by anyone who knows.


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## Doug_ID (Feb 22, 2009)

ok yea...........brrrrrrrrr! To cold for me to be on a bike.


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## Maxeymum (Mar 2, 2017)

Last winter it didn't get above zero for nearly 6 weeks, both day and night, so yeah it's pretty brutal. I do ride in this weather, but on a Fat Bike with studded tires, and bundled in many layers and ski gear on the outside, and of course, insulated boots, gloves etc.
I just don't want to risk hitting the pavement on all the ice, which is what initiated swapping over to studded tires...had a pretty good 'smackdown' a few winters ago riding on ice...


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## Doug_ID (Feb 22, 2009)

I am in PNW and 15 is about my cutoff for riding. Walk mode: https://www.manualslib.com/manual/1177600/Shimano-Steps-E8000-Series.html?page=26

Need to figure out a way to keep the button depressed.

GL


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## Maxeymum (Mar 2, 2017)

Hey thanks for that, Doug. I've bookmarked it and will read through it this weekend. If worst comes to worst, I will drive out to the country and ride the bike on some gravel roads to drain it down.


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## RickBullottaPA (Mar 4, 2015)

The only thing you really need to avoid is storing the battery in super cold temperatures and not letting the battery warm back up after a ride in cold weather before you charge it.

Operating it in cold weather should be fine. I've never had an issue.


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## Maxeymum (Mar 2, 2017)

RickBullottaPA said:


> The only thing you really need to avoid is storing the battery in super cold temperatures and not letting the battery warm back up after a ride in cold weather before you charge it.
> 
> Operating it in cold weather should be fine. I've never had an issue.


Thanks for that info., Rick. In any case, I'll only be operating it until I lose a few bars on the display, and then back into my living room it will go. Thanks to all who've chimed in to help educate this noob!


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## matt4x4 (Dec 21, 2013)

Should store the battery a little higher then 50%, like 65-70%, the storage voltage for lithium ion is 3.60V, thats ideal, where the max voltage is 4.20V and a used up level is 3.20V. So imagine 50% of 4.20V is 2.10V which is well below the 3.20V for a no longer useful battery voltage. Used batteries will drop more in voltage, temprature changes will change things up too. Storing at full charge is not good, because it'd be wiser to store at below fully charged. Its about keeping the longevity of the battery intact. Age of a battery is a concern, how old it is. How deeply the battery has been discharged in its life. Storing the battery properly is crucial.



Cody01 said:


> I keep getting mixed info on how to store ebike batteries and its getting frustrating. I stored my battery back in mid October out of my bike in my house at about 50%. I checked it at Christmas time and it registered no charge at all which amazed me and angered me at the same time. I wouldn't think it should have dropped more than 5% in that period. The tech support where I got the bike says thats ok and I should peak the battery monthly when not in use. I don't see how that is a viable answer. The battery is only like 8 months old. It seems like half of the people say to store at half charge and the rest say store at full charge and check monthly. You should be able to walk away from a batteery that has been removed from a device for longer periods as far as I am concerned. I am thinking my battery might be a bad one and they are just reluctant to go there with it.


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## zweeLLAMA (Jan 3, 2020)

The cathode material itself, such as cobalt (CO, NCA, NMC), iron (FePO), sulfur, etc., will mechanically fatigue through expansion and contraction. This is why they degrade.

Voltage changes with temperature fluctuation. A battery charged to 4.2V at room temp should show a lower voltage at 0C/32F. Park an ebike out by the patio at night (lo-temp) for recharging to full (4.2V), and it will show higher than full-charge-voltage in the afternoon (hi-temp). Recharging the battery to high voltage, beyond 4.2V, has been shown to degrade the battery more rapidly.

This is why you're asked to spend a lot of money for quality name brand components--there's a lot of exceptions, mysteries, and you really can't generalize. They're trying to make things simple for the end user, so they don't have to go to great effort to learn all this, and just ride and use the product with faith in the makers.

Bottom Line - the guidelines to store at 50% charge at a cool moderate temperature, not exposed to sunlight, are very simple and wise. Might be inconvenient, but it's the best for the health of the battery, if you care about retaining full capacity (you should if you ever run low, starting from a full charge).

Trivia: there have been numerous cases of first gen Nissan Leaf batteries degrading exceptionally fast in especially cold winters, with owners reporting that they lost their "first bar" on their battery life indicator, and never regained it in summer. The battery that Nissan ultimately chose (it was proprietary for that car) was susceptible to very cold winters. Owners in more temperate climates were not affected. I did not hear of competing cars suffering a similar fate.


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## matt4x4 (Dec 21, 2013)

Cold batteries lose capacity, I notice it all the time when I ride my diy tool pack battery pack (Makita) in the cold weather, -10C and colder. 

From what I can tell, watching Rich Rrebuilds Teslas, EV's have battery warmers. I do plan to have a battery warmer on my pack, simple math equation using a separate tool pack, and vape coil wire, NiChrome. 

Moving over to LiFePO4 may have benefits for cold weather, but its really not relevant because you need more battery for same battery compared to Lithium Ion, 18650.

With the specialization of the store bought ebikes, insurance coverage is a big part for those companies, and having a safe battery that is fool proof for the end consumer is their goal. But consumers arent used to the respect batteries need to be given. Can't just throw the bike in the shed for 8 months while the temperature cycles through the seasons, consumers are not used to that. They do it though. Thats why I put zero value on used batteries being sold whether separatly or as part of the ebike. The bike and battery could have been under water, frozen then charged, over charging the battery, killing the battery, yet you throw a digital multi-meter on the battery pack and sure it looks good, but the crystalization within the battery has damaged the battery. 

If the battery pack is 36V (10S), that means the maximum voltage coming off the charger is 42V (4.20V/cell), a battery cut off by the controller at the low voltage point would read 31V (3.10V/cell) maybe 32V (3.20V/cell), so storing at room temprature and 37V would be good. If you are going away for a longer period of time, there is no harm in a settled voltage of 38V. The balancing aspect of the battery pack would be superb with the store bought ebikes, so there is no risk in the balanced state of fully charged all the cells would not reach past the critical max point of 4.20V. But its not healthy to leave the battery that fully charged, that is why 37/38V is just fine. Then just keep an eye on it every few weeks or every month. And by all means never leave the battery installed in the ebike, always take it out, always. Dont want more possible failure points with the battery hooked up to the controller.

The battery is healthiest with lots of shallow discharges, rather then lots of fully charged to voltage cutoff cycles. We are talking 1.5X or more the life of the battery.


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## zweeLLAMA (Jan 3, 2020)

Lithium batteries would degrade far less if they were charged to 3.92 V instead of 4.2 V on a daily basis. That's about 80%, if 4.2 V was 100%.

After a few hundred cycles the battery would degrade to the point that 100% would be 3.92V anyways, and people would have developed habits that made them used to more. I suppose some might only use a battery for 2-3 years before they want something fresh, where basically 1 bar isn't missing from the get-go, but they don't get tossed in the trash if there's some life still left in them.

Trivia: Tesla has revealed that they follow this guideline to maximize battery lifetime, such as when they unlocked maximum range for Florida evacuation. It wasn't told to consumers, but no doubt ignorant people would feel robbed of having extra capacity locked away, just in case, not knowing the damage consequences (which they'd likely complain about when it comes time to pay for it).


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## fos'l (May 27, 2009)

Good advice above. Supposedly, Tesla is able to offer an eight or whatever year warranty on their batteries by only allowing them to charge to 80% SOC and not go lower than 20%. Most important is to not charge the batteries at a temp lower than 50 degrees F, and don't let them get lower than 20% SOC (if possible). My Luna 52V, 10 ah battery is in its fifth year powering a 1000w direct drive rear hub errand bike or a BBS02-equipped hardtail MTB. Usually I use it to 30 - 50% SOC, then charge to 100% just prior to riding. It still charges to 58.5V vs 58.8 when new. Probably it has at least 350 - 400 charge cycles. Residing in CA, I don't need to worry about the cold although I've taken the bike to high altitudes where the temp probably was 30 degrees F or so. FME, storing a battery at 30 - 70% is fine. Also, FME with my wife's system, good batteries (Yamaha eMTB) hardly change their SOC when stored for months (she rides her eMTB infrequently).


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## matt4x4 (Dec 21, 2013)

The shallower the discharge the better, thats fore sure. Like if your controller cuts you off at 30V for a 36V system which maxes out at 42V after the charge is completed, then its way healthier to drain to 35V then charge it back up to 42V. Now a days, it doesnt matter if you charge to 41V or 40V as there is little concern of a cell being stray and going over 4.20V. Maybe the LiPo guys are doing that more. The BMS' are top notch these days if you buy a quality BMS, but if you buy a generic BMS then that can be sketchy.


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