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Razor ecosmart battery upgrade?

Hi. I have a new razor ecosmart scooter that runs on 36v setup and 3 x 12v 7ah SLA batteries. My question is can I replace these batteries with 3 x 12v 18ah SLA batteries? Would it get more distance/speed per charge? Thank you so much for your time.

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If there is room for 3 18ah yes they will give you range increase. They will also weigh a lot more so you'll be forced to consume some of that extra amperage just  to haul the heavier battery weight. As the motor has a max RPM of 2500RPM (I think) , speed will not increase but you won't loose performance as quickly. For speed increase you could reduce the size of the rear wheel sprocket slightly but that will require more current and reduce your range. Do you have a range & speed goal in mind? I find 20-25 mph is pretty much the safe handling limit on an ecosmart so range and longer good performance to be a better goal than more speed.....just my opinion of course.

I've been riding my ecosmart for 3 years and 2000+ miles now. After 2 sets of SLA batteries I went to a lithium pack (42V @10A and only 4.6 pounds) and while it was a substantial investment I cruise at 16-18mph and get a solid range of 17-19 miles per charge. Performance doesn't degrade much over time either. Other performance considerations is to reduce the scooters weight (aluminum vs steel parts) and rolling resistance. I changed to Kenda 1.5" high pressure tires that also gave me room to add a front brake. I'll admit my mods cost as much as the scooter but it's made the scooter my main transportation during the nice times of the year (I live in cold Wyoming). If you're interested in details I'd be happy too pass along the info. 

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Gene, Thank you so much for the great reply! My main priority is range. The speed and distance your modifications will make are exactly what I hope to achieve on mine. Did you have to upgrade your electronics controller? If you could give me a shopping list to make the 42v @10ah lithium setup work for mine I would be so grateful.

Give me a day or so and I'll put some pics and info together. I've enjoyed tinkering as I've been both a bicycle & electronics hobbyist for decades. You can use the original controller. I changed mine as I disliked the 1/2 width throttle and the stock razor controller won't work with a 'standard' 3-pin full width throttle. Well at least I could never figure out how too make it work? Most part costs aren't bad but get ready for sticker shock, my custom lithium/maganese battery with smart charger currently runs $575 PLUS Fedex hazmat shipping ~ $50 more. It was a big investment but the scooter went from a toy to an actually viable vehicle. I rarely drive my car in town in nice weather. I do give the caveat that all these mods are at your own risk! 

Here's the battery I used -

I avoided Chinese batteries due to many quality issues. If I recall this company is in Texas and builds your battery to order. They can make a custom size etc. They called me when building mine to ensure they were doing the wires and connectors the way I wanted.  Look over their site as it may give you more ideas. So almost 2000 miles and zero battery problems. I just did a complete overhaul and some upgrades and went for a spin in my 40 degree day with a 39mph wind. Still hit 17 mph in the headwind :-) Attached is an ecosmart standard wiring diagram. Also here is a rough wiring diagram of how my ecosmart is wired. The only difference is I'm not using the standard 6 pin throttle/controller but a 3-pin and I'm not using the brake lever motor cutoff function. I also deleted the on/off switch and added a keyed battery cutoff instead. If the price issue is OK with you let me know and I'll put more together for you....Gene

Gene, That would be much appreciated! No worries on the price tag I just want this thing to be a nice functional vehicle. I would be driving it 6 miles to work and back. I really appreciate your time and effort in answering my questions. I really Owe you one.
I also love to tinker and upgrade my stuff. E bikes are my new chocolate!

OK…..this is a lot of stuff lol but it was fun to recount what I’ve done. I also put together a spreadsheet of some of the parts suppliers. I hope to keep mine running as long as I can ride (I just hit 64 years old). I’ll get some pictures in the next day.

Things I did:

First the battery. I’ve heard bad stories about Chinese battery packs so I went domestic. Now the packs are made of multiple cells wired together and yes the individual cells are all made in China to my understanding but it’s the quality of the cell used and quality of building the pack. I believe my pack is made of about 42 cells to get a 10amp pack that at full charge sits around 42 volts. An individual lithium cell is 3.7 volts nominal. For a 36 volt pack they usually go a bit higher than 36 volts to be sure. You need to be sure that the pack includes a BMS or battery management system board. When you charge many cells like in a pack they need to be balanced or you can end up with some cells that are poorly charged and will make the pack die prematurely. I have a smart charger that will show a full charge but a few minutes later it may cycle on & off a bit as the BMS balances the charge between my 40+ cells. This is not something too short change on. A good smart charger is important too. You don’t want to over charge as it can damage cells and worse cause a horrible fire. I charge mine in my apartment but only when I’m home to be safe. After a lot of research I chose and bought a LiM3610-26-01 pack. They built it to order, asked me what connectors to us and cable lengths I wanted. One caveat is Fedex charges a hefty hazardous material fee for shipping. I think I paid $35 haz mat PLUS shipping several years ago and it ca only go ground. I see that they may be going through a reorganization of some sort? I’m sure there are other good places, read reviews!

To make it easier to mount the battery etc I used a 1/4” piece of plastic sheet mounted to the bottom of the original battery box so it was a flat surface. I also used some 1/16” thick textured ABS on the sides of the original battery box to cover old unused holes etc.

I got rid of the plastic chain cover as I felt it made things too difficult to service.

I found the wood/bamboo foot board was difficult to remove for servicing and mods so I got rid of the original screws and mounted screws coming up from below. I over-sized the holes in the foot board so it would easily slide over the upright screws and then fastened the foot board with wing nuts. Now the foot board can be remover in a minute with no tools. Yes the scooter could be hot wired this way so I ALWAYS use a cable lock even in my low crime city. I also covered the foot board with a pair of rubber Safety Steps.

I replaced the stock charge connector on the side of the scooter with a 3-prong connector with dust cover that mates with my smart charger for the lithium battery. I broke 2 stock ones before that.

I deleted the on/off switch entirely. Instead I used a common battery cutoff switch to kill all battery power. These are available all over. It did take a lot of trial and error and many trips to Ace hardware lol.

I didn’t like how everything was connected together so I made a modular approach. I put a connector on the side where the motor wire comes out and a mate on the motor. Now for service I can just remove the 3 motor mount screws, unplug the motor from the outside and it’s removed.

I deleted unused wires. You do need to be comfortable with wiring/electronics for some of this as mistakes can burn up things or even cause fires. I didn’t like the brake lever motor kill function. So I opened the controller (you’ll need too pry it open after removing the screws) and removed the 4 wires that would go to brake levers. They can be left out as they only function if switched closed. When they do close the scooter stays on only the motor is kept from going. Next, as I used a battery cutoff key switch to turn off the battery so I wired the on/off wire on inside the controller permanently on. Finally as the lithium battery pack has it’s own internal battery maintenance board and charge connector, I removed the charge wires from the controller. This isn’t all necessary but it simplified the rats nest of wiring. On my scooter I have the following wires coming out. 2 wires to the motor, 2 wires to power from the battery ( after the key switch) and the wires to connect to the throttle. Much simpler. Again it depends on your comfort level, I’m a retired electronics designer lol. Don’t forget to add a fuse!!!

Currently the controller, motor, battery etc can all be removed easily without cutting wires etc.

The rear rack and basket. I didn’t like the seat post mount rack so I found an adjustable aluminum one and modified it so it sits low over the rear wheel. It is very sturdy and I’ve mounted a larger basket.

I pretty quickly got rid of the stock tires. Being an avid bicyclists I knew that they used a lot of energy to push around. I changed to a pair of Kenda K193 Kwest 16 Inch Tires. The current model says they run at 65psi but mine say 100psi. I run 90-100psi all the time. Yes they ride hard but handle great on roads and the extra performance is noticeable. If you use these the tubes are hard to find locally but Jensen USA carries a 16’ x 1.5 tube for $4. The 16” tubes most places sell are for kids bikes and are too wide, you’d have to cram them in and hope for no blowout. I also fill my tubes with the green slime sold all over. 2000 miles hauling all kinds of crap and no flats (yet!).

I disliked the bolt on wheels as it’s hard to service. I found vintage Huret (French) wing nuts for the axles so no tools needed. You can find them on ebay but watch prices they’re all over the map. I believe the axle threading is 10 x 1 (10 millimeters by 1 millimeter pitch)

I did replace the front steel wheel with an aluminum one. They are lighter and stronger and rim brakes work better on aluminum. I did need to use the original wheels axle as the spacing on the fork is unique. I have no clue where I got the wheel??

I modified the rear brake so I can remove the wheel without tools other than loosening the brake cable. I drilled out the bolt hole and used a holed pin and hairpin (Ace hardware) to secure it. Just loosen the axle wing-nuts, remove the clip, loosen the cable and off it comes.

I didn’t like the ‘lowness’ of the seat and it took a bit of doing but I finally found an 18” aluminum seat tube and used a lightweight bike seat. It took a few adapters to fit the frame tube diameter.

All in all its a blast to ride and very practical. I have no qualms about the money & time I spent. My only upgrade is to change my current 25 amp controller for a 30 amp one. I’ll cut my range a little but have 20% more power. I can live with that.

Standard Twist Throttle (THR-35) ElectricScooterParts.come $20
36V 500W Speed Controller SPD-36500A ElectricScooterParts.come $40
Battery Cutoff Switch Harbor freight or similar $8
3 Pin House Charger Port CNX-605 ElectricScooterParts.come $5
3 Pin House Charger Port Cover CNX-600 ElectricScooterParts.come $2
Sigma Bicycle Computer BC5.12 or similar ebay/walmart/Amazon $18
Greenfield Rubber Bicycle Kickstand Boots  ebay/walmart/Amazon $8
Digital LCD Voltmeter Backlight ebay $5
Schwinn-SW76120-3-Folding-Rear-Rack Amazon $20
Tektro R539  Niagara Cycle $31
Bell Basil Class Rear Bicycle Basket  Amazon $55
Kenda K193 Kwest 16 Inch Tire $18
36v 10 amp lithium battery w/BMS & Charger Code: LiM3610-26-01 $580

Here's some pics and a drawing. I have lots of general pics if interested....good luck!

Gene, Thank you so much! I have much to do! I am really looking forward to this project. I will let you know how it turns out. Your help is more appreciated than you know.

No was fun to pass along. Just be safe.....lots of power running through there!

Here's a few random pics. I'm pretty much 'done' other than maybe upgrading to a slightly higher current controller at some point for a bit more zoom.....but at 64 not sure how much zoom I should have ;-)  Now if it would just not snow this weekend I could sneak out in the cold for a ride!

If you ever have any questions or Ideas, feel free too message me.


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