Battery recalibration question

[terryp]

I have an i2 and an i180. Since I don't ride the i180 much anymore, I swapped packs between the two four or five months ago to try to keep them in similar condition. I know that the packs that transferred from the i2 to the i180 were giving great performance at that time, and remember not seeing any difference after the swap.

Last weekend I transferred packs again, and have noticed the following: Bars disappear almost twice as fast and, hills that I could go up at near full speed without a frown now cause severely reduced performance.

I know that having packs on constant charge for months can cause the gauge to read incorrectly, and that a full discharge will recalibrate it. What I'm wondering is whether the lack of use could have also caused this poopy behavior, and whether the recalibration will cure that too.

[Segwaiian]

Terry,

I'm not sure if this applies to your situation, but I cut and pasted the following from Wikipedia:

"Storage temperature and charge

Storing a Li-ion battery at the correct temperature and charge makes all the difference in maintaining its storage capacity. The following table shows the amount of permanent capacity loss that will occur after storage at a given charge level and temperature.

Permanent Capacity Loss versus Storage Conditions
Storage Temperature 40% Charge 100% Charge
0 °C (32 °F) 2% loss after 1 year 6% loss after 1 year
25 °C (77 °F) 4% loss after 1 year 20% loss after 1 year
40 °C (104 °F) 15% loss after 1 year 35% loss after 1 year
60 °C (140 °F) 25% loss after 1 year 40% loss after 3 months
Source: BatteryUniversity.com[14]

It is significantly beneficial to avoid storing a lithium-ion battery at full charge. A Li-ion battery stored at 40% charge will last many times longer than one stored at 100% charge, particularly at higher temperatures.[14]

If a Li-ion battery is stored with too low a charge, there is a risk of allowing the charge to drop below the battery's low-voltage threshold, resulting in an unrecoverable dead battery. Once the charge has dropped to this level, recharging it can be dangerous. Some batteries therefore feature an internal safety circuit which will prevent charging in this state, and the battery will be for all practical purposes dead.[citation needed]

In circumstances where a second Li-ion battery is available for a given device, it is recommended that the unused battery be discharged to 40% and placed in the refrigerator to prolong its shelf life. While the battery can be used or charged immediately, some Li-ion batteries will provide more energy when brought to room temperature."

It sounds like your loss of battery capacity is greater than the table above would predict.

Reconditioning is worth a try, I would think. Hopefully, one of the battery experts like Jason Abel or Dr. Marty will be able to give you better advice. Jason didn't recommend storing our batteries in the fridge in another thread. You could try PMing them.

Aloha,
Roger

[Segwaiian]

Sorry, I tried to reformat the chart into more distinct columns, but the spacing wasn't preserved with my edit.

Aloha,
Roger:o

[bentbiker]

Sorry, I tried to reformat the chart into more distinct columns, but the spacing wasn't preserved with my edit.

Aloha,
Roger:o
Yeah . . . you can use periods - - - or dashes to create spacing.

[shep]

Sorry, I tried to reformat the chart into more distinct columns, but the spacing wasn't preserved with my edit.


Although not as pretty as you might like, you can enclose your formatted message with html markers code and /code. Like this:


Permanent Capacity Loss versus Storage Conditions
Storage Temperature 40% Charge 100% Charge
0 °C (32 °F) 2% loss after 1 year 6% loss after 1 year
25 °C (77 °F) 4% loss after 1 year 20% loss after 1 year
40 °C (104 °F) 15% loss after 1 year 35% loss after 1 year
60 °C (140 °F) 25% loss after 1 year 40% loss after 3 months
Source: BatteryUniversity.com[14]


and it may do a decent job.

[Segwaiian]

Shep, that looks pretty pretty to me.:D

Yikes, now I need to learn computer code to chat. My stepson's graduating this year with a computer science degree. Maybe I can borrow one of his old textbooks.

Thanks for all the posting advice. I hope this helps terryp with his battery problem.

Aloha,
Roger