Upgrading Prebuilt ebike to 48v or 52v?

My fat tire e-bike is nice and surprisingly fast for its weight, considering it only has a 36v motor. I want to upgrade it to 48v or 52v and about 1500w. I am a little worried since its a prebuilt and the wiring is routed through the frame. Will I be able to replace the battery pack inside the battery shell, since I doubt I'll be able to find a battery that will fit inside the slot for it. Next, I was wondering if there are compact 48/52v controllers that could fit in that little box beneath the battery, If not I guess I could work around it but all the wires are routed to that point beneath the battery. Finally, will there be any compatibility issues with the buttons on the front that allow me to control the speed of the motor, or with the throttle? I would appreciate recommendations for a rear hub, controller, and battery. The rear wheel is a 26x4.0. If there is any other useful information I can provide please let me know.

https://imgur.com/a/2G7ZfVk

whawhawhubsyloot said:

If there is any other useful information I can provide please let me know.

https://imgur.com/a/2G7ZfVk

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Welcome to the forum!

Maybe take a picture of the current controller's label (in the box below the battery) to start with. You may be able to find a 48v version of your battery; not sure if something like this is compatible:

https://www.amazon.com/Joyisi-Ebike-Battery-Li-ion-Electric/dp/B07KCFSN4K/ref=sr_1_56?keywords=ebike%2B20%22%2B48v&qid=1565036940&s=gateway&sr=8-56&th=1&psc=1

You may need to change out your controller and possibly the controls, depending on if they can work with 48v or not.

I agree that you can probably find a 48V silverfish battery. but 52V may not be available.

Some 36V controllers will run on 48V, but the problem is that their low voltage cutoff (LVC) is still locked in for a 36V pack. In fact, my first DIY ebike with a 36V controller will run all day at 52V, but it will try to run the battery down to 30V. Now a 48V or 52V pack will have its own internal LVC cutoff so that won't happen, but you wear out a pack much faster if you run it til it shuts off, and you lose some safety margin, because the controller should always shut off before the battery. Sure, you might over volt your ebike, but I think it's better to upgrade the controller/display to one that accepts multiple voltages. Not too expensive, under $75, if you go with a 20-25A controller.

I recently took out the 17A 36V controller in my 20" (prebuilt) fatbike and put in a 20A 36V/48V controller. Also changed out LED display to an LCD3 display. This gave me 5 level PAS, an improvement over the 3 level PAS. I would have liked to use a 25A controller, but the 20A KT36/48VSVPRM fit inside the controller compartment. None of the connectors matched. Genders were either wrong, or the wire positions were different. The wire colors were the same, so I spliced/spldered the wires as needed. Around 20-24 splices.

My main reason for swapping was to get the LCD plus 5 level PAS. Didn't care about top speed as the bike can do an honest 22 mph on 36V already. I'll try to hook up 48V to see what I gained.

By the way, E=HP, I hadn't noticed your build report before.Nice job on that bike.

Thank you guys for the warm welcome!

My apologies for not providing more information. On the hub motor it states its 36v 300w. On the controls it says 36L, does this mean it only works with 36v? The model of the controls is LCD-S610-C. The controller is 36v 14a. I have provided the pictures below. If I needed to how would I route wires through the frame?

https://imgur.com/a/U1g3NGA

I want to start buying parts, I think ill be able to mount a larger controller at the bottom of the V of the fork since the frame is very thick. It will probably fit nicely in one of those bike frame bags.

Ten years ago, most 36v controllers could do 48v as well. But in your case, it may zorch something in the controller or the display, or simply kick in a protective circuit at about 45v, so it just won't turn on when you put 54v full charged 48v battery on it.

The motor can take 48v, the wires need not be all that big, but you will need to replace both display and controller, and likely the wiring too. ( so the plugs match perhaps) So your bike will look homebuilt.

If you look inside your controller at the caps and if they are 45v or 63v. The later can handle 52v. Maybe not your display thou.

999zip999 said:

If you look inside your controller at the caps and if they are 45v or 63v. The later can handle 52v. Maybe not your display thou.

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I think he will be OK with the display. The 810LED displays come in 24V, 36V, and 48V versions, and they will have a sticker to denote the voltage. I have both the 36V and 48V types. I know that that my 36V model will run on 48V but the battery status will always read full. Similarly, my 48L model will run on 36V, but the battery status will blink showing dead battery. The PAS works right in either case.


To confuse the issue though, there's a digital version of the 810LED that came in my last ebikeling kit, It will work in place of the SW900 display, but is still only 3 level PAS/walk modes. It uses 5 wires like a LCD display uses and needs his later controllers that can work with SW900.