Losing my mind trying to figure this out

[theleagueranter]

I have an ecotric 26 fat tire electric bike. From 2019 i cycled the battery maybe 15 times since I've owned it. The bike is like new, I've maintained the battery very well and I've checked it with a multimeter and it appears to be fine, reading 40v volts at full charge. This is how it all started, The throttle stopped working and I couldn't figure out what the problem was, But i noticed it did work when the handlebars were turned all the way to the right, so that lead me to do more research and i came to the conclusion that it was one of the brake sensors. So I unhooked both of them and now the throttle works fine. And I don't know if this is related or not to the brake sensors being unhooked or shorted out somewhere but now I only get 5 miles on a full charge throttle only, when I used to get like 15 or something throttle only. So after the battery is drained after i get my measly 5 miles it only takes 1 hour to charge, Its the same thing every time and we all know these batteries after being discharged take around 6 hours to fully charge. But for some reason after the battery is discharged I plug it in and an hour later, the green light is on and the meters on the side of the battery say its fully charged. and the LCD display also shows fully charged, but then i only get to ride it for 5 miles, can somebody please help me? I cant figure this out, any help you can give would be greatly appreciated Thank you in advance!

 

[theleagueranter]

I'm asking because this is what happens when you buy an ebike with no brand Chinese batteries.

Is this the bike you're talking about? https://www.ecotric.com/products/26-fat-tire-orange
Looks pretty generic, so if you want to upgrade the controller and battery, it shouldn't be that hard.

yes its that bike, the battery that I have they said they dont make it anymore they have a newer version but im still trying to figure out why this would even happen to this battery or why the brake sensors would go out I believe it is an off brand battery its not brand name

 

[theleagueranter]

What kind of batteries do you have?
Is it no-brand Chinese cells? or is it a brand name is like Panasonic, Samsung, etc?

 

[harryS]

I've had the Ecotric 20" fat tire folder since 4-2019. I don't ride it that much either, but the 36V12AH silverfish battery has always been good for me. Same battery that's in your 26" fat tire bike?



In a perfect world, the battery should read 42.0 volts at full charge. Your 40.0 could just be an inaccurate voltmeter, but if it's real, that's suggesting an unbalanced battery. Next time it runs out after five miles, tell us what the voltage reads. Betcha it's 38-39 volts, plenty of battery voltage to run your bike, but not if it's unbalanced.

This graphic shows an unbalanced battery. At full charge, it will read 41.5V, which is good, but the red cell group is down .5 volts. When the pack is half discharged, at 36.5V, the red cells are really close to shut down. So you only get half the capacity. Then when you recharge it, it stops charging when the other cells get to 4.2 again so you can't get those red cells charged. I suspect that's what you have, only worse.

If you have an unbalanced pack, there's only one thing you can do. Hope that Ecotric put in a battery that can self balance. Leave it on the charger for a few days. See if the 40V comes up.

I have never figured out if my Ecotric battery will self balance, but I talked to another owner in an Ecotric facebook group with a problem similar to yours. He told me that leaving it on the charger for a long time solved his problem, so at least his battery could self balance.

One caution. I dislike leaving any battery on a charger for a long time, so you might want to do this balance charge somewhere safe, as far as fire safety,

 

[ElevenAD]

what do you mean by cycled the battery 15 times?

 

[theleagueranter]

I've had the Ecotric 20" fat tire folder since 4-2019. I don't ride it that much either, but the 36V12AH silverfish battery has always been good for me. Same battery that's in your 26" fat tire bike?

View attachment 92517

In a perfect world, the battery should read 42.0 volts at full charge. Your 40.0 could just be an inaccurate voltmeter, but if it's real, that's suggesting an unbalanced battery. Next time it runs out after five miles, tell us what the voltage reads. Betcha it's 38-39 volts, plenty of battery voltage to run your bike, but not if it's unbalanced.

This graphic shows an unbalanced battery. At full charge, it will read 41.5V, which is good, but the red cell group is down .5 volts. When the pack is half discharged, at 36.5V, the red cells are really close to shut down. So you only get half the capacity. Then when you recharge it, it stops charging when the other cells get to 4.2 again so you can't get those red cells charged. I suspect that's what you have, only worse.
View attachment 92519
If you have an unbalanced pack, there's only one thing you can do. Hope that Ecotric put in a battery that can self balance. Leave it on the charger for a few days. See if the 40V comes up.

I have never figured out if my Ecotric battery will self balance, but I talked to another owner in an Ecotric facebook group with a problem similar to yours. He told me that leaving it on the charger for a long time solved his problem, so at least his battery could self balance.

One caution. I dislike leaving any battery on a charger for a long time, so you might want to do this balance charge somewhere safe, as far as fire safety, that sounds like a really good idea gonna try that right now, I just don't understand why I have to do this when ecotrics website says it lasts for 500 cycles and I only got 20 cycles in. After 5 miles when I tested the battery after I fully discharged it which I heard was not good. So when I take it for another ride I should not let the battery drain all the way? How can I test it when the battery is drained it read 0 last time I tested it. But the battery was fully discharged

 

[theleagueranter]

what do you mean by cycled the battery 15 times?

I only rode the bike 15 times on the trails and that was it, and each time I used 85 to 90% of the battery so i consider that a cycle, im not a battery guru thats the only terms I know to use lol, I put it on the charger every to weeks during the time I was not using it.

 

[theleagueranter]

I've had the Ecotric 20" fat tire folder since 4-2019. I don't ride it that much either, but the 36V12AH silverfish battery has always been good for me. Same battery that's in your 26" fat tire bike?

View attachment 92517

In a perfect world, the battery should read 42.0 volts at full charge. Your 40.0 could just be an inaccurate voltmeter, but if it's real, that's suggesting an unbalanced battery. Next time it runs out after five miles, tell us what the voltage reads. Betcha it's 38-39 volts, plenty of battery voltage to run your bike, but not if it's unbalanced.

This graphic shows an unbalanced battery. At full charge, it will read 41.5V, which is good, but the red cell group is down .5 volts. When the pack is half discharged, at 36.5V, the red cells are really close to shut down. So you only get half the capacity. Then when you recharge it, it stops charging when the other cells get to 4.2 again so you can't get those red cells charged. I suspect that's what you have, only worse.
View attachment 92519
If you have an unbalanced pack, there's only one thing you can do. Hope that Ecotric put in a battery that can self balance. Leave it on the charger for a few days. See if the 40V comes up.

I have never figured out if my Ecotric battery will self balance, but I talked to another owner in an Ecotric facebook group with a problem similar to yours. He told me that leaving it on the charger for a long time solved his problem, so at least his battery could self balance.

One caution. I dislike leaving any battery on a charger for a long time, so you might want to do this balance charge somewhere safe, as far as fire safety,

I used to have a rc helicopter and i used to use a balance charger for the lipo batteries, and i would have to put it on balance when i charged it. I was wondering if there was a way i can get a balance charger for the battery that i have for this bike maybe something with an adapter for the plug to balance the battery, what do you think?

 

[harryS]

To balance the battery, you need access to all the cells, but they're all wrapped up and encased. I've got this problem, right now with a two year old battery. Stops working just under 40 volts. I need to get inside, find the unbalanced cells, charge them back up, and then see if they stay balanced.

I can't even slide the cells out of the case. I think they glued them in, so I'm not making it a priority as I don't ride the Ecotric that much.

 

[Robspace1]

I'm on my 2nd Ecotric Seagull battery in 1.5 years. These things are not to be trusted. My next battery will be from this company in S.Cal. They rebuild as well as sell new bike batteries that are made by Samsung. Many people say this is the best place to buy the replacement batteries. https://www.fthpower.com/

 

[harryS]

I've had the Ecotric 20" fat tire folder since 4-2019. I don't ride it that much either, but the 36V12AH silverfish battery has always been good for me.

I must have cursed my battery when I wrote this. In July, my Ecotric Silverfish starting shutting down 5 miles into a fresh charge. It turned out one cell group got unbalanced. The Ecotric BMS is unable to handle that, I bought a replacement from Unit Pack Power, 36V18aH for $260 on ebay. Came in 5 days.

I'll store the old one in a fire safe place. Maybe fix it or recycle it.

 

[Robspace1]

Good price. My girlfriend wants a backup 36v for her Peace Dove but Ecotric no has. Back in stock in a few weeks.

 

[Robspace1]

I did some reading on these Chinese battery packs like the one you bought. It's not good. Hopefully you got a good one. I'm sticking with American made batteries from FTH power-Samsung insides and 2 year warranty.

 

[harryS]

I understand your position. My main concern on batteries is one catching on fire. Based on what I've seen in my batteries in 7 years, they have gone from using glue/tape to nylon forms, better insulators, and machine spot welding, quite an improvement in construction. The cells in my Silverfish were located in a plastic form, which is encased in a stiff fiberboard and shrinkwrapped. Then as you know, the whole center case of a SIlverfish is extruded aluminum, so those cells are well protected.



What was lacking in my battery was a balance BMS. Once a cell gets low, it can't be fully charged, and further usage causes it to drift lower and lower. I swapped the circuit board in the above photo for a balance BMS, and it was able to bring the unbalanced cell close to full charge. The pack was good for about 80% of original capacity, not bad for a 2 year old battery.

I had a safety concern though. The weak cells had discharged down to 2V, below the safe operating range for lithium. That now poses a risk of a fire, so I'm no longer using it unless I can replace the cells.

 

[Robspace1]

If you have more problems with it FTH Power can repair it for you using Samsung or LG parts. About 1/2 the cost of new! I like that option.

 

[harryS]

I think LG and Samsung are among the standards for lithium cells, but then you read this.

Cells in GM, Hyundai EV battery fires linked to several LG plants

Shares of Korean battery maker LG Chem (051910.KS) slid to a nine-month low on Friday as investors digested reports linking fires in General Motors Co and Hyundai Motor Co (005380.KS) vehicles to LG batteries from at least two Asia plants.

www.reuters.com

 

[Robspace1]

Sounds like LG had other companies in other countries like China putting their batteries together for them. That's real common. US auto makers do the same thing having other, cheaper companies put parts of the cars together. Places like China and Mexico will work for cheap. Best to have an American company assemble the battery using LG and Samsung parts.FTH Power does from LA.

 

[rainystateguy]

I know that this is a long shot, but are the batteries in the following video the one's that you have? If so, they are available through the guy who made the video...

 

[harryS]

No, we're talking about run-of-the-mill silverfish case, which has been around for years. Ecotric sells a 36V12aH for around $359 for our bikes but rarely has them in stock. Nonetheless, equivalent packs available on ebay for $100 less.


The guy in the video is always selling off surplus/used batteries, and some of them are good DIY deals. He is out of those packs, by the way.

 

[Robspace1]

No not at all. Nothing like it. The shape is all wrong and that's a 500 watt. Mine is 1000 watt. And, I would never, ever trust any lithium bike battery that cost just $49.00. lol-That's some Chinese junk battery probably found on Ebay. Dangerous!