Is it the battery or the controller?

Likeitis

New Member
Hey All, so I have about a 5yr old ebike with a 36V10AH Lithium battery..not sure how close to the estimated 500 charge lifespan of the battery I'm at as I bought it used.

I've had it for around 6 months and started to notice in the past month that when I go to all throttle power, the battery drains quicker than before and if I'm not watching the display when it starts blinking at the 1 level, it'll shut off.

I can get around 10 miles of charge with the way I ride and can definitively say that I now get around 7.5 miles for the exact same ride.

This is both unsafe and annoying as I need to pull over and turn key on/off and then pay attention to avoid it happening again. This usually involves following a series of pulling down/easing off the throttle to make sure there's juice until I use pedal assist again.

I checked the battery with a voltmeter and it consistently shows around 36V..which seems normal for this battery.

Assuming that the Voltage is normal why would the battery be discharging quicker?

TIA
 

Likeitis

New Member
Yikes...just charged her up again and got 37.2

Might be time to invest in a new battery.

I did a search on Ebay for 36V10AH Lithium battery and came across a few that were around $180 or so..

Any advice on what to assure before purchasing..aside from the obvious "is it new and if not, how old is it"?

I guess asking what the Voltmeter reading is after it's fully charged wouldn't hurt.

Thanks for your help
 

harryS

Well-Known Member
I've bought most of my batteries from unit pack power. This first one was also 36V10AH in 2015 and it runs a lot better than yours. I'd estimate it can still put out 7AH.


They have an ebay outlet.
 

Likeitis

New Member
Appreciate the link. So, my receptacle is the rectangular one and not the water bottle type. I came across one of their other offerings that from the picture, looks like it's made for my bike

UPP 36V 10Ah Silver Fish Lithium Li-ion Battery for 350W 500W Electronic Bicycle

However, I noticed that the bottom of my battery where it snaps into the receptacle base doesn't have 2 wires coming out of it like this one. I'm guessing that I can unscrew that part and take it off?


Thanks for the help..
 

harryS

Well-Known Member
You then need a silverfish battery with top discharge. That's an older design, probably a better one because I don't like the way the new ones sit on the contacts. You can "contact the seller" and ask if he has a top discharge 36V silverfish (and price). They carry so many types that they may not list on ebay. Other sellers have them,
 

Likeitis

New Member
Awesome..thanks.

I was also wondering that as long as I'm ordering a new battery, why not upgrade and get a more powerful one 36 or 48V & 14Ah for example..possible?
 

harryS

Well-Known Member
Depends on how your 36V controller can handle 48V. Some 36Volt models have a max voltage limit and will not turn on. Other's will appear to work, while some components will degrade/fail from the excess voltage. Others will work and not burn out , but the user has to be vigilant and manually make sure the battery voltage doesn't go below 40V, because the bike will try to run it down to 30V. Usually the battery will shut itself off before it goes that low, but it hard on the battery. There are dual voltage controllers that can run on 36 or 48. Usually not used in connercial ebikes.

However, you can buy your 36V pack in a higher AH size if you wish, as long as it fits.
 

Thomas Jaszewski

Well-Known Member
Be safe, stay with 36v. Not many OEM Ebike controller, especially 5 years old will run on multiple voltages. Some serious research before EVER doing that. Especially given you seem cost conscious and not wanting higher levels of performance, speed. I’ve gone back to 36v. Cheaper and I get all the speed I need. UPP is OK for lower powered systems. With eBay you have paypal protection. They can be slow at warranty coverage. I always add a backup duplicate BMS. Cheap and the most common problem. Worth the $12-15 to not have to wait. You can always flip it on eBay.