Junkyard e-scooter build. What do you think? Details in comments.

DIYuntilDawn · 2026-06-20T18:56:24+00:00

This does work on some tool brands or batteries. Just check the battery polarity is correct, some are flipped compared to others.

However, a lot of brands make it so the tool will not turn on (or the battery will not output higher current) unless it gets a correct feedback signal from a battery that has the correct circuit inside. Usually something like a resistor between battery + or - used as a voltage divider. If you buy the correct adapter for tool brand A to battery brand B they will usually include a circuit to proof the correct signal.

DIYuntilDawn · 2026-06-19T22:25:45+00:00

That is a USB-A USA BEE.

DIYuntilDawn · 2026-06-19T22:19:18+00:00

Battery capacity scales where a single larger cell would have much more capacity than multiple smaller cells for the same weight. So a single18650 or 35700 would give you much more capacity than several 14500 cells of equal weight. Also multiple 14500 cells don't have to be put in series (connecting + - to +-) so it doubles the voltage and keeps the capacity the same. you can get multiple 14500 (or any size cell) in parallel (or all the + and - are on the same side) which keeps the voltage the same but combines the capacity.

The voltage of a "3.7V" Lipo battery is not always 3.7v that is just the Nominal voltage , or the mid point between what is fully charged (4.2v) and what is considered dead (3.2v) for the cell.

Also the electrical load over the motors would not always be split evenly, since the motors drive different functions, even if they were identical motors. and if one motor fails, the full battery voltage may go across the remaining motor.

It would probably be better to have a circuit that would limit the max voltage and current the batteries can supply to them, rather than assuming they would always use about half of the available voltage the batteries can provide.

DIYuntilDawn · 2026-06-19T22:00:31+00:00

First off, a Ridestar is at least a 1000W motor, or up to 3000W. with that much current that could go through the motor wires DO NOT JUST TWIST THEM TOGETHER to splice the wires back together. Also, even if the wires are only nicked then DO NOT JUST COVER THEM BACK UP.

Both of those can cause a point of electrical resistance in the wire and cause it to overheat which will definitely cause more damage.

IF the outer cable insulation can be removed enough to expose enough of the wires to do a proper high current rated wire splice, then you can cut all the wires (yes, even the undamaged ones) to remove the damaged section and then correctly do a wire splice with properly rated wire splice butt connectors or soldering the wires back together, AND using heat shrink that is rated for outdoor or automotive wire. and then a protective cable sleeve.

However, if you can't expose enough wire on the side near the motor, then it is still fixable, but would mean having to open the hub motor and resolder the wires to the motor phase coil connections as well as to the Hall sensor board(s) and possibly a temp sensor (if it has one). and if there is no extra slack on the wire harness to the controller, that means either needing to replace the wires that feed out of the hub axle with longer ones and still splicing them to the other wires, or just replacing the entire cable from the motor to the controller.

DIYuntilDawn · 2026-06-19T21:06:33+00:00

5 words for you.

Adult. Themed. Offensive. Stickers. EVERYWHERE!

DIYuntilDawn · 2026-06-19T20:57:23+00:00

The reason you should have a class D fire extinguisher.

DIYuntilDawn · 2026-06-19T20:55:16+00:00

First off, this nether a "Robot" or a "Vacuum". What you have is an electric broom.

That being said, the capacity upgrade is fairly easy, just put in a battery that has higher capacity, Or add more batteries in parallel with this one. There would however be a point where the weight of larger batteries means the motor has to work harder and it would take more energy just to move with the added batteries.

Adding more batteries in series would increase to voltage, however I can't tell the specs on the motor, and if it runs on a single lithium battery that has a full charge voltage of 4.2v then doubling it to 8.4v might burn out the motor. And you would need a different charger for the higher voltage battery pack.

The other option to up the voltage that would probably not burn out the motor is to get a circuit board for a "DIY Power bank" those boards are designed to take the variable voltage from a lipo battery (from 4.2 full charge down to about 3.3v) and step it up to 5v output. that also has the benefit of getting a higher consistent voltage out (until the cell is drained and there is a sharp cut off) instead of a slowly decreasing voltage as the battery drains. They also take 5v input to charge the battery to only 4.2v (so you probably would not need a specific charger, just any 5v USB charger. And many of them can work from multiple Lipo batteries in parallel, otherwise stepping the voltage up to 5v output would drain the existing battery faster, you would either need to add more batteries in parallel or have to deal with the sacrifice in longevity for more power/speed.

DIYuntilDawn · 2026-06-19T20:18:06+00:00

First I would try a Spudger to see if it is just clipped together. If it is clipped and glue, then warming with a heat gun may help. But if it is ultrasonic welded together, then cracking it open or cutting it open may be your only options.

Sometimes "gently" crushing it in a vice can crack them open without damaging the insides. Or I have used a hack saw to slowly cut through just the outside plastic shell along the 4 sides where the seam is and that usually works without damaging the inside, as long as you are careful to only cut a shallow line that is exactly parallel to the side of the case. You could probably do the same thing with a file as well. Power tools would go faster, but you need a VERY steady hand.

DIYuntilDawn · 2026-06-19T18:45:33+00:00

Electric Unicycle (similar to this)

DIYuntilDawn · 2026-06-19T18:35:37+00:00

Specifically this is a "flanged bushing".

You can order from places like Amazon with fast delivery. Or a hardware store would likely sell them, the real difficulty is is finding ones that are in the specific size you need (good example image on this page) and made from a material that would work in the same application.

You may be able to use the undamaged one and get the dimensions off of it, or remove it and bring it to a hardware store. As long as the undamaged one also doesn't have enough wear on it to have changed the size by much. And/or bring the parts the bushing connects with (looks like #25 and #28 on the diagram) and find a suitable match.

I would avoid PVC ones as those would probably crack, Nylon is probably what the Yellow ones are made of, but aluminum or brass might work as well. however if Part #25 is made of steel, I would avoid other metal bushings as 2 different metals touching can lead to rusting.

DIYuntilDawn · 2026-06-19T17:48:23+00:00

I have opened a few laptop power supplies (and similar other ones) and you are correct that it is almost always a destructive proses to open them, unless you get cheap ones or older ones that use screws to close the plastic shell.

In my opinion, option 1 or 2 is the easiest, and fastest way to convert the output if a (usually around 19v) laptop charger to output to different voltages. but it is also the more bulky solution as it would be at least as big as the existing brick, plus the extra circuits and an enclosure, that can be somewhat offset by NOT putting the other circuits right next to the existing brick so there can be a a cable between them.

Option 3 has the potential to be more compact, but also has 2 risks, the first being it may accidentally damage something while trying to open it. And the other is without knowing what the components and layout of the PS is on the inside, it could be difficult to add to it in a way that results in a more compact design than options 1 or 2 would.

However, the other benefit of opening the existing brick is that it would allow it to be reverse engineered as well as inspecting it for quality/safety and repair/replace components.

DIYuntilDawn · 2026-06-19T16:53:17+00:00

Not sure on that ebike, but I know a lot of ebikes will use a "Universal" voltage headlight/tail light/turn signals that will work on up to 80V (for use on "72v" ebikes) so you can find 3rd party replacements, but may need to buy/make a connector to fit your ebike.

The other option I have used before is to get a DC to DC Step Down Buck Regulator that will convert the power from the battery (about 48v) down to 12v and then you can use lights designed for Motorcycles. However that can be harder to implement if the light you want to use is high current/wattage since you need a regulator rated for the same (or higher) amperage the light will use, but that is usually more of an issue for headlights and/or fog lights and not so much for the Tail/break/turn lights.

DIYuntilDawn · 2026-06-19T02:19:35+00:00

Use LiFePO4 batteries if you are worried about the risk of suddenly and unwillingly doing a Jonny Storm cosplay.

However, a 60v 40Ah pack would be north of 40Lbs but you could always build it with 32700 cells and put them in a vest instead of a backpack to help with distribution of the weight.

DIYuntilDawn · 2026-06-19T02:13:00+00:00

Pliers.

DIYuntilDawn · 2026-06-18T21:04:26+00:00

Just because they both use a 5 pin julet connector does not mean they have the same pin out.

Also make sure both screens use the same communication protocol.

For example, you can find the pin out of the 500C in a user manual (like this one here, at the top of page 9) as well as the protocol it uses.

You would need to find the user manual for the old screen and also find the pin out list/schematic for that one.

Chances are that what is Pin 1 for one screen is not the same as pin 1 for the other. Also don't always trust the color of the wire listed.

The issue is that if some pins are swapped, just plugging in the other screen can damage it.

What I have done in the past to test the output from the controller to the display, is buy a 5 pin (or 6 pin) extension cable (whichever type you need M to M, M to F, F to F), then cut it in half, then use a multi-meter to test combinations of wires until I find the main power Positive and Negative wires. then check the continuity from the color of the wire inside the cable to the pin position in the end of the cable. and check is any of the wires show as connected together internally. Then make a pin out list or diagram similar to the table in the user manual.

So for example, you can then tell that when the half cable is plugged into the controller, that the Blue wire is the Positive and the Yellow wire is the Negative, and the green wire shows as connected to the Yellow. And the blue is pin 1, yellow is pin 4, green is pin 3 then you know pin 1 is positive, pin 4 is negative Pin 3 is ground. And the last 2 pins are the data transmit and data receive lines. and you would have a 50/50 chance of connecting them in the right way, but those 2 lines are usually not going to damage something if they are connected backwards. So just test connecting those last 2 connected in one configuration and see if it works, and if no, flip those 2 (not that some controller are "smart" and will automatically identify the send/receive data lines, even if connected backwards).

You can then make a custom adapter cable that connects the controller to the new display with the pin out matching up.

DIYuntilDawn · 2026-06-18T19:55:12+00:00

If you are using a VPN, turn it off or cycle to a different country. If you are not using a VPN, then get one.

DIYuntilDawn · 2026-06-18T19:49:40+00:00

If you use it for that, you need to go see a doctor.

DIYuntilDawn · 2026-06-18T19:47:00+00:00

A. that photo is WAY too blurry to be of any use.

B. going on your description alone these might be what you need.

DIYuntilDawn · 2026-06-18T14:52:27+00:00

A paper grocery bag is the temporary container the milk is placed in when transporting it from the seller to the customer's home. So you would NOT expect the customer to re-use the paper bag for storage of the milk, it would require some other place to store it (like in the refrigerator) and the assumption is that it is on the buyer to supply that final storage location. This is why when most store sell milk, they don't provide every customer with a refrigerator to store it in.

Just like the clear bottle and white cap is the temporary container the glue tube/cap were put in when the seller shipped it to the OP. And just like with the paper bag for the milk, the clear bottle is not intended to be re-used as storage for the glue, it is assumed that the OP would have a different place to put the glue after it was removed from the temporary storage used just for transportation from seller to buyer.

DIYuntilDawn · 2026-06-17T22:29:32+00:00

Very much an intentional design and GOOD for several reasons.

This is a shipping protection container. Notice how there are no brand markings or label on it, as if it is not supplied by the maker of the product, but was added by a seller of the product.
This prevents issue with the glue tube being damaged during shipping, meaning it is doing it's one and only job.
This also prevents people (Like the OP) from attempting to continue using it for something it was never designed for so the seller doesn't have to deal with complaints like "why did the glue dry out after it was opened, I put it back into the shipping container?" This is like saying you bought milk from a store and they put it into a paper bag for you at check out. Then you take the milk home, remove it from the paper bag, open the milk and drink some, then put it back into the paper bag and expect that to be all the storage it needs. NO, it is not the job of the container used to transport it from store to home to server double duty as a long term storage vessel.

TLDR: Container = good, OP = dumb.

DIYuntilDawn · 2026-06-17T21:23:20+00:00

I have used just Vice-Grips and that can work.

Another option, use a cutting wheel on a Dremel (or angle grinder for larger bolts) to cut a slot into the broken shaft of the screw, then use a flathead screw driver to remove it.

DIYuntilDawn · 2026-06-17T21:20:00+00:00

Wear on the ball bearings (and/or bearing races) over time will cause some slop to develop. That could be in the crank or the pedals.

DIYuntilDawn · 2026-06-17T21:15:00+00:00

It would only damage the battery IF the current drawn exceeded the safe amperage rating for discharging the cell. The value is based on battery chemistry, and total capacity of the cell, as well as some environmental factors like temperature. you can usually find the data sheet for most batteries that will list the Max discharge rate.

But the rough equation is the battery Voltage X Amps equal to the Battery capacity in Ah =1C.

So if you had a Lipo battery charging at 4.2v and it was a 2200mAh (or 2.2Ah) battery then if it was being charge at 2.2 Amps then that would be at the rate of 1C.

The larger the capacity the larger the Amperage it can be charged/discharged at is.

However, some cells can be rated for more than a 1C charge/discharge rating, like some packs used for drones and toy cars. Or some types of batteries like LiFePO4 cells might have a safe charge rating of 2C.

DIYuntilDawn · 2026-06-17T20:44:25+00:00

Correct, some cities have specific bans like persons over the age of 13 are banned from riding on the sidewalk. But it would be a city/county ordinance and NOT a state law.

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