Replace SLA Battery with Water Bottle Li-Ion in EV Global E-

I need to replace the dead SLA battery in my 36V, 500watt EV Global bike and want to keep the battery within the existing down tube compartment. I found a water bottle case, 10 AH, 15A max discharge, 92mm X 360mm, 18650 cell battery pack from Bat-Bike on Ebay that should fit into the down tube compartment. My concerns are: Will the battery in the aluminum case overheat in the down tube compartment? Compartment has vents in the front and back. Is the battery 15A max discharge rate sufficient for the 500 watt motor (500w/36v=13.88A Right?) for casual, less than 10 mile rides? Has anyone done business with Bat-Bike out of Jacksonville FL? There E-bay ad does not contain much info as to the BMS or the provided charger. It looks like bikes are there main business and batteries are a sideline.
Does anyone have a better idea? I desire to keep the battery in the existing down tube battery compartment and get as much capacity per $$$ as I can. Most of the battery packs I’ve found on the web are too large to fit in the existing 4”x4”x14.5” compartment. I have the existing battery case, but it is a little warped, and I do not have the skills fix it and install 18650 cells.

Motor size means nothing. You need to match your battery pack output to the max draw of the controller. If the max output of the battery is 15A, then that should be the max draw of the controller. If the controller max is more than 15A, then you want to go easy on the throttle and not be going wot from a start.

That battery won't be powerful enough. 500w systems at 36v normally have contollers above 20 amps. If you're lucky, the max current will be written on the controller.

If you over volt, or over amp your controller it can break. Replacing a controller is sometimes hard to do because many older models have been discontinued.

I could be wrong, but the EVG had an 18 amps controller is what I seem to remember.

You should be able to get a pack custom made, from the very best cells, that will fit the space you have in the original battery box. Ask Paul about it, at EM3ev. Then the small size pack will easily handle your bikes controller. You need about 30 amps continuous specification, so you never get close to that in reality.

The easy thing, is to just get a larger battery that can carry on a rear rack. But the EVG battery box is so nice, it's real tempting to use it. No worries about a good battery overheating in there, at the rate of discharge you will be doing. A cheap one might get too hot though.

Thanks for the help folks. The controller does not have the max amp rating on it, only EVG P/N 3B1-49100-00-00. I checked the web and the service manual and could not find any specs on the controller. Your advise saved me from buying an inadequate battery.
In the mean time I bought a original EVG SLA battery from Electric Wheels of Florida who bought out all the EVG bike spares when the company went out of business. The battery cost around $150 delivered and should get here next week. I bought both the bikes at a yard sale, and this will give me a chance to make sure they work before I spend the extra $$$. The bikes appear to be in excellent condition, but have not been ridden in several years. Also, my wife and I are both in our 60s, and this will us give a cheap way to see if we can safely handle the bikes.
I will continue researching a LI-Ion replacement and post on how the short term SLA fix works. Thanks again for all the help. Great forum!!

You'd better hope that the SLA batteries you got are not original EVG parts. SLAs have a lousy shelf life unless they are trickle charged or topped up frequently.

Received the SLA battery in from Electric Wheels of Florida. Not made by EVG as I was lead to believe. Instead 6 6volts batteries wired in series and shrink wrapped, which covered battery specifications. Very small output tabs considering the bike’s positive output cable appears to be 8 gauge. Had to modify the bike cables to mate with the battery tabs. The ganged 6 volts fit snuggly into original EVG battery case.

Good news – both bikes work perfectly!!! I live in a very hilly neighborhood and I only got 8 miles, use pedal assist, before the low battery light came on. Ran the bike mostly in the Economy mode, but did use the Performance on some hills. Also, my wife did a short ride and loved the bike.

My next step is to contact EM3ev and others to see is I can get an 18650 cell battery pack that will fit into the original battery case. If not, the old option of two 12 volt SLA batteries in the case and one on the rear rack is looking like a possible alternative as the goal is to use the bikes for occasional casual rides. We live near the Glenwood Canyon trail, and I would like to get enough range to ride its mostly flat, 18 mile length. Any other suggestions would be greatly appreciated.