Optimizing Battery Usage

[bikerjohn]

The 36v 12Ah battery for my EG Zurich is losing reserve capacity and maybe should be replaced. I have nearly 300 recharge cycles and 5100 miles tallied. The battery seems to be running out of power more quickly than when it was new. Making a call to (Link Removed - No Longer Exists) and speaking with the shop owner, it seems fairly routine getting a replacement for about $500.

During my talk with the shop owner, Paul Morlock, he mentioned that fully discharging the battery before recharging can help prolong the battery's life. I had read different recommendations in the past.

Paul also suggested that waiting about 30 minutes after charging or discharging a battery would help the battery cells "normalize". I suppose I have been doing that some of the time without consciously being aware that was a benefit to prolonging battery usage. Typically, I have been recharging the battery after a commute which is about 1 hour of usage. I've never fully discharged the battery cells because I was under the impression that would shorten the life of the battery. So I have been mistaken? What have other riders experienced relating to battery life?

 

[J.R.]

John, I don't think you're wrong on deep discharging. I've never gone dead either, close a couple times. I do try to allow the battery to rest at room temperature (70°F +/-) for up to 2 hours on the hottest and coldest rides and at least an hour after any ride. I got in the habit over the past 2 years of not charging until I go to bed, which is usually more than enough time to rest. I do pray for no fires though

 

[Ann M.]

@bikerjohn not all lithium batteries have a good lifespan. Some of the LiFePO4 batteries only had 400-500 charge cycles. Newer batteries built with the latest Samsung, Sony or Panasonic cells have 1500-2000 charge cycles. If your battery was built in the last year or two, then you need to get that battery tested for bad cells, otherwise start shopping for a replacement or rebuild of the battery. BTW, you don't fully discharge any lithium battery, only older NiMH batteries which have memory issues. And yes, let the battery reach room temp if it's been in really hot or cold temp before charging to help get a better charge. All of the lithium battery chargers that I've worked with have a temperature sensor as does the internal BMS which would prevent charging if the unit was too hot, but a little extra caution never hurts.

 

[bikerjohn]

I have lithium-Ion cells in the 36V 12Ah battery pack, of which I am unsure of their brand. I believe they are supposed to have a usable life of 1000+/- recharge cycles.

So after speaking with the owner of "ebikes of NE" and some blog info here and on "Bikejournal", I took a ride with a goal to run out the power in the battery,-the idea suggested by the bike shop. That's not easy to do I've found...
After a short ride (12 mi), with climbs and a full load on the battery, the power indicator on the handlebar console begins to flash low power. After a period of time rolling along with the low power indicator flashing the console read-out shuts off power to the motor. Turning on the console again and riding until it auto shuts down again, and again. Repeating this sequence for a couple more miles, I head home to put the bike on a stand.

Back home I put the bike on a stand and ran the drive wheel for 2-1/2 hours under a no-load condition. The power indicator on the console showed 2 bars of energy. The power indicator on the battery pack showed 1 bar. I let the battery rest and normalize for a while, and then took the bike for a low-load ride (3 miles). Another rest period for normalizing, and another short low-load ride. Now the power indicator on the battery pack is in the red. So after letting the battery normalize, even as there is still some reserve power in the battery, It should be time to do a recharge.

Maybe getting all the cells down to a low power state then doing the recharge cycle as suggested by Paul- the shop owner will help the battery maintain a steady rate of discharge during my next commute. We'll see tomorrow...

 

[bikerjohn]

@bikerjohn not all lithium batteries have a good lifespan. Some of the LiFePO4 batteries only had 400-500 charge cycles. Newer batteries built with the latest Samsung, Sony or Panasonic cells have 1500-2000 charge cycles. If your battery was built in the last year or two, then you need to get that battery tested for bad cells, otherwise start shopping for a replacement or rebuild of the battery. BTW, you don't fully discharge any lithium battery, only older NiMH batteries which have memory issues. And yes, let the battery reach room temp if it's been in really hot or cold temp before charging to help get a better charge. All of the lithium battery chargers that I've worked with have a temperature sensor as does the internal BMS which would prevent charging if the unit was too hot, but a little extra caution never hurts.

After speaking with Paul at e-bikes of New England, he contacted Wayne -owner of EG-Bikes. They have a replacement battery available which is comprised of Sony cells. Before I bite the bullet on the $510 purchase, I am trying a deeper discharge cycle on my present battery.

 

[J.R.]

@bikerjohn

If you have to take a bite out of that apple, it should be sweet! Sony is a top manufacturer of lithium ion cells, in the top 5 and has been number 1 at times. I think Panasonic is currently #1, a year ago it was LG, but Sony is always in the mix.

I'm interested in how this all pans out for you. Especially the deep discharge and recharge.

 

[MLB]

I'm seeing many bikes now using 500 charge cycles as the warranted battery lifespan. Im sure how hard we use them and how far down we draw them has huge variables. And that's aside from temperature differences and other local environmental factors.

 

[Ravi Kempaiah]

The 36v 12Ah battery for my EG Zurich is losing reserve capacity and maybe should be replaced. I have nearly 300 recharge cycles and 5100 miles tallied. The battery seems to be running out of power more quickly than when it was new. Making a call to (Link Removed - No Longer Exists) and speaking with the shop owner, it seems fairly routine getting a replacement for about $500.

During my talk with the shop owner, Paul Morlock, he mentioned that fully discharging the battery before recharging can help prolong the battery's life. I had read different recommendations in the past.

Paul also suggested that waiting about 30 minutes after charging or discharging a battery would help the battery cells "normalize". I suppose I have been doing that some of the time without consciously being aware that was a benefit to prolonging battery usage. Typically, I have been recharging the battery after a commute which is about 1 hour of usage. I've never fully discharged the battery cells because I was under the impression that would shorten the life of the battery. So I have been mistaken? What have other riders experienced relating to battery life?

You can get your pack rebuilt by RPE.
They are based out of Las Vegas. http://rechargeablepowerenergy.com/
When I was riding through San Diego, I stopped by an E-bike store and the owner showed me a rebuilt pack which was lighter and better.
Your pack has Samsung 22p and it can be rebuilt with Samsung 29E or 32E (19Ah) cells for higher capacity.

 

[bikerjohn]

@bikerjohn

If you have to take a bite out of that apple, it should be sweet! Sony is a top manufacturer of lithium ion cells, in the top 5 and has been number 1 at times. I think Panasonic is currently #1, a year ago it was LG, but Sony is always in the mix.

I'm interested in how this all pans out for you. Especially the deep discharge and recharge.

After trying a more complete discharge of the battery and then recharging the battery -there may be a slight performance improvement.

When the battery was new there was no appreciable loss of power on typical climbs during the first 30 minutes of use. Today, on a typical commute I continue to note early fade when there is a higher output demand -such as when on a climb.

I've thought replacing the battery could correct the situation but at $510 that may be throwing good money on an entry level bike. So now I am considering a different alternative.

The front hub motor does have some handling characteristics that would be eliminated by changing over to a crank drive set-up. Another option would be to modify the bike with a crank drive kit instead of keeping the current Front hub motor. Decisions...

 

[bikerjohn]

You can get your pack rebuilt by RPE.
They are based out of Las Vegas. http://rechargeablepowerenergy.com/
When I was riding through San Diego, I stopped by an E-bike store and the owner showed me a rebuilt pack which was lighter and better.
Your pack has Samsung 22p and it can be rebuilt with Samsung 29E or 32E (19Ah) cells for higher capacity.

Thanks for the link, Ravi! I've inquired about upgrade options and am awaiting a reply from RPE.

 

[vincent]

Thanks for keeping us up to date on all this

I too want to see how this plays out for you

 

[PhilD]

Deep discharge of lithium batteries seriously reduces its life ... this is bad advice from your dealer!!
Best to charge just before a ride so the battery spends the least time at full charge, then only use up to half of it.... this way you get many many cycles - way more than if you fully discharge it regularly. that's why it is best to get a bigger battery than you might think you need so you only use a portion of its charge. Of course this costs, but the pack will last WAY WAY longer.

 

[bikerjohn]

Deep discharge of lithium batteries seriously reduces its life ... this is bad advice from your dealer!!
Best to charge just before a ride so the battery spends the least time at full charge, then only use up to half of it.... this way you get many many cycles - way more than if you fully discharge it regularly. that's why it is best to get a bigger battery than you might think you need so you only use a portion of its charge. Of course this costs, but the pack will last WAY WAY longer.

What gets confusing here Phil, is so much conflicting info. And there is no lack of specific conflicting ideas for maintaining and or revitalizing a battery.

Paying close attention to the battery use this week I have become more aware that lith-ion batteries benefit from a rest period during use. As in 30 minutes on, then a short rest period. This seems to rebalance the cells within the battery allowing for a more even discharge between recharging. Perhaps more ideal would be a partial recharge after a short 30 minute ride?

Another question begs clearer explanation: Why is it best to have a lithium battery at full charge for only the shortest length of time?

 

[bikerjohn]

Anecdotal experience has led me to these conclusions for prolonging Lithium-Ion Battery power:
Never fully discharge the battery. Fully discharging the battery does not even seem possible with the type of controller on the EG Zurich.
Allow the battery a period of time to "normalize" before and after recharging.
Recharge the battery after every ride.

I've noted too, that the battery seems to have more usable energy over a 20-mile round trip commute when it gets a stabilizing rest period part way through the trip. (As when biking 10 miles then parking the bike for a period of time before completing the round trip).

 

[PhilD]

I'm just going off the clever guys from endless-sphere - there is a huge amount of really detailed info here - some of it is distilled into a wiki

https://endless-sphere.com/w/index.php/Battery_Deterioration

These guys are reporting on empirical findings too.
They call it "sag" when the voltage drops off under a sustained load, then you leave it a minute and it comes back. I believe lesser quality cells are more prone to this effect, but all cells suffer from it to some extent.

Also see

(Link Removed - No Longer Exists)

and Battery university is a cool place for info too:

Similar to a mechanical device that wears out faster with heavy use, the depth of discharge (DoD) determines the cycle count of the battery. The smaller the discharge (low DoD), the longer the battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine. There is no memory and the battery does not need periodic full discharge cycles to prolong life. ​

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

 

[bikerjohn]

You can get your pack rebuilt by RPE.
They are based out of Las Vegas. http://rechargeablepowerenergy.com/
When I was riding through San Diego, I stopped by an E-bike store and the owner showed me a rebuilt pack which was lighter and better.
Your pack has Samsung 22p and it can be rebuilt with Samsung 29E or 32E (19Ah) cells for higher capacity.

Well, after speaking with Rebekah at RPE today, I finally packed-up the battery and controller and sent it off to them for a rebuild. I'm expecting they will rebuild the battery to a 15Ah capacity with a cost under $500. I will keep everyone informed on the outcome.

 

[JohnT]

I tell customers that the only bad thing you can do with a lithium ion battery is drain it way down and let it sit. Charge those right away.

Draining it all the way down is hard on a battery, but if you don't do it often, it's not too bad. If you commute, and do it every day, it'll definitely shorten your battery's lifespan.

They're most happy at about 40% to 80% charged, if I remember correctly, so keeping your battery fully charged isn't ideal, but it's not that bad. It's better than not charging it enough and draining it way down. We keep the batteries in our rental fleet fully charged so they're all ready to go all the time.

We usually try to let them cool a bit before charging, but if we need to get them topped off before the next renter comes in, we'll charge them warm.

I'd recommend thoroughly researching anyone you want to refurbish a battery, but I'd bet that Ravi would only recommend someone trustworthy. FYI, you're supposed to have special certification to ship lithium ion batteries.

 

[supermasj]

I agree .

The advice the topic starter got is more or less ok on NiMh cells, but will only harm a Li-Ion battery pack. You typically keep 80% capacity out of Li-Ion batteries after 500 cycles of full drain. If you limit yourself tou draining the cells only to 50%, you get 1500-2000 cycles before dropping to the same 80% capacity

 

[bikerjohn]

I tell customers that the only bad thing you can do with a lithium ion battery is drain it way down and let it sit. Charge those right away.

Draining it all the way down is hard on a battery, but if you don't do it often, it's not too bad. If you commute, and do it every day, it'll definitely shorten your battery's lifespan.

They're most happy at about 40% to 80% charged, if I remember correctly, so keeping your battery fully charged isn't ideal, but it's not that bad. It's better than not charging it enough and draining it way down. We keep the batteries in our rental fleet fully charged so they're all ready to go all the time.

We usually try to let them cool a bit before charging, but if we need to get them topped off before the next renter comes in, we'll charge them warm.

I'd recommend thoroughly researching anyone you want to refurbish a battery, but I'd bet that Ravi would only recommend someone trustworthy. FYI, you're supposed to have special certification to ship lithium ion batteries.

Liking your advice on Li-ion! I had no issues during the first 300 recharge cycles and amassed more than 300 hours of usage.

I sent my battery to RPE with all the correct "special certification" for ground shipping, and the battery has arrived at RPE. In my initial phone conversation with the RPE customer service rep., I was given the impression that follow-up would be prompt. However, follow-up has been non-existant. Further badgering for an updated status with no definitive reply from RPE has only left me bewildered and wondering.

 

[bikerjohn]

Here is the latest:
Today I spoke with Rebekah and Shawn at RPE. They tell me there are some space challenges with my battery pack for upgrading it with 18650 cells. They think it may be possible to fit enough cells to upgrade the battery to 13Ah, but there is a bit of lag-time in procuring the 3-volt cells from China due to the Chinese New Year holiday. In order for them to determine what will be doable with regard to refurbishing, Shawn's guess is that another 2 weeks or so to best configure the rebuild.