M.L. Toys
M.L. Toys
HobbyMasters M.L. Toys
Electronic Scooter Controllers have become a popular addition to our vehicles. Ask specific questions about ESCs here!

***WARNING*** this section is for ADVANCED MODDERS. if you try anything in this section you NEED to expect minor issues with the build up to and including complete FAILURE of EVERYTHING in your freshly built BPRO.

Have fun ;-) :-)
By dka56
I'm going to base this kit off the one offered by Wesley which has worked great so far in the gator. I may not need all this extra headroom in the amperage department but I wanted to give it a try.

I opted for a pair of 50A relays and they have arrived today but I had no idea they were this big, good thing the Polaris has a lot of room under the front so mounting won't be a problem.

Here's a size comparison.... :shock:
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We have a lot of hills, and riding two-up with the Banebot 775 motors I figured I would use a larger relay but I didn't realize they were this size...but should work ok.

Hopefully this will be going by the end of the week.

By dka56
They can be purchased with either a 12V or 24V coil. When I opened them up I double checked the receipt and noticed they weren't the ones I wanted to fault not the sellers. I have the 24V coils coming to me, they will be the same size as these.

A 100 ohm resistor can be used to drop the voltage to 12V for the coil. I was going to use a resistor but found the 24V coil relays..but inadvertently ordered the 12V relays I initially looked at.
By Rob222
The coils are rated for AC voltage not DC. Don't you need relays with DC rated coils ?
Just a quick google seems to indicate those will not work.
By dka56
I spoke with the tech guy there and I told him I was running 24V DC. We discussed the 24V issue on a 12V coil and while it will work, long term may not be good.

We also discussed the resistive load vs. motor load and the 50A rating is good for the motors we are running.

This isn't where I'm purchasing from, same price though...but this is the relay.

User avatar
By toycrusher
Personally I prefer to use 12v coils on 24v and 24v coils on 36v. I've experienced where the ride goes under load and the voltage drops to the point that the 24v relay releases or chatters, typically changing direction on the vehicle. The 12v coil doesn't have that problem.

As far as AC vs DC relays, there are some differences i just can't remember what they are. I have a pair of AC relays I ordered by mistake that I wasn't able to use
By Rob222
The relay in the link you posted is part number PBC-RE-GP-DPDT-24VDC.
The relay in your original picture is part number PCB-Powerrelay-12V AC.
I think the 12v ones you have have AC coils.
The contacts are rated for both AC/DC.

Like Toycrusher, I also use 12v coil relays on 24v for my on/off relays and brake relays.
By dka56
Ok.....I have this figured out now.....forgive the confusion and you both are correct, 12V coil on 24V is better than under-volting a 24V coil, and the one I have is an AC coil.

The two coils I ordered were YC-GP-DPDT-6D, which are 12V DC coils, I was shipped 12V AC coils by mistake. The shipper was extremely helpful in resolving the issue and I have the 12V DC coil relays on the way., the 24V coils have been changed to the correct 12V DC coils that I need. I can lower the voltage slightly with a resistor if needed, maybe down to 14-16V but I think even on 24V there shouldn't be a problem.
By dka56
I opted for a left-side thumb throttle as it's a little akward to use the stock reverse selector while turning to the right and backing up with a right-side throttle as you need to reach across the tank with your left arm, this would make backing challenging for the kids.

I also wanted to keep it looking as stock as possible so the handgrip needed to be cut to get the throttle over the grip. I thought about just cutting it at the right side of the grip and removing the large diameter end piece and that would be the solution if this way didn't work.

To reduce the chance of the grip rotating, instead of making a clean cut, I made a square pattern so each piece would at least try to stay together.
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Had to trim the hand guard a little
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The inside of the grip was just too tight of a fit with the aluminum collar on the throttle so I removed a small amount and with the aid of some lube, it went on without a lot of fuss.
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There's a narrow portion of the grip near the end where it's a knurled pattern and is thinner so the throttle fit just perfect.
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Turned out well, maybe a light dap of rubber cement near the two grip joints. I won't put a permanent brake switch in yet, but for the first few days I will secure a monemtary push button switch above the throttle until I can figure out a better alternative for the brake. I like the push button but I want to try to get somethning that activates when the throttle is closed.
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User avatar
By toycrusher
Good choice on throttle location. I used a right hand twist throttle and my kids have a hard time trying to hold the shifter in reverse and twist the throttle. I have a hard time with that too!
By dka56
Looking for a thin piece of plastic, I think I can use a 3-switch wall plate blank for the gauges and a cover piece for the previous foot pedal.

Quick template and cutout.
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Successful test fit, was able to use the existing top holes and added two for the bottom, now off to be painted.
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By Rob222
I would have moved the fwd/rev switch not the throttle. Every other quad/dirtbike/streetbike that the kids will move on to in their life has the throttle (twist or thumb) on the right hand.
For thin plastic try Walmart cutting boards. Cheap and work great for mounting stuff.
By dka56
Rob222 wrote:I would have moved the fwd/rev switch not the throttle. Every other quad/dirtbike/streetbike that the kids will move on to in their life has the throttle (twist or thumb) on the right hand.
For thin plastic try Walmart cutting boards. Cheap and work great for mounting stuff.
I was thinking about a rocker switch for the fwd/rev, but I wanted to try to maintain the factory switch and make it slightly akward for them but not terribly akward. This way they have to think about what's going on when backing up.

I agree the right side would have been better, had I gone with a twist, then I would have used the right for sure. But at least it's only the thumb so not much dexterity required. I liked the style of this throttle and only could find it in left even though you can use it on both sides. You can use this on the right, but it wouldn't fit as flush.
By dka56
The finished relays before connecting the motor leads, which go to the bottom relay on the top facing terminals. I tinned the flat face of the double terminals to ensure a good contact then soldered them together.
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Fitment was crowded but it went in without any issues.
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100 ohm resistor for the 12V coils.
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I have a 50A circuit breaker in the rear compartment under the seat, I'll get some pics tomorrow but it turned out well. Top speed so far with the Banebot 775's is 11MPH so the gator wins by 1 MPH but the torque in this polaris now is really good.
User avatar
By wesleyb82
In my experience/reading the amperage rating of a relay/contactor/solenoid is the load the contact points can tolerate before they could potentially weld together and the spring rating to break the contact points while current is passing through them. For our purposes here that would mean brake or reverse engaged even when the relay coil was not energized but I have never heard of this happening with 30a relays in these cars.

As an interesting side note for larger applications not only do the contactor contact points need to be large enough and made of good material but the spring needs to be strong enough to break the contacts which want to stick together while current is racing through them. In an emergency if the contactor was not strong enough to break the bond you could be in for a wild ride.
By smoothoperator
I've went through a few relays getting mine right. I started with the 30 amp dpdt relays on ebay and fried them after a few hours. I'm running (2) 1000w controllers, the ones sold at monster scooters and (2 ) 900 watt 24v currie motors.
I then tried the 50 amp ones shown that the op has. They didn't work out, like toycrusher said the coils disengaged at 23+ volts.
The ones that work perfectly I found on ebay, they look exactly like the 50amp ones but are 80 amp and have blue covers instead of green. They are 24 volt coils . For what ever reason the coils engage at 18 volts and work awesome.

The 1000 watt controllers that I have, have been flawless. I have over 200 miles on them.
By dka56
Been awhile since I updated this, but up to today, the 850 has been running great with the Banebot 18V 750 motors. I'm using 10GA wire throughout and I'm trying to figure out how the large yellow and blue wires overloaded.
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I believe it was the controller, I didn't see it happen but witnessed my neighbor holding the wheels off the ground. The motors would stop with the brake button depressed, but when released it was on full power.

I did find the 100 ohm resistor for the coil was broken at the ceramic but that could have been when I was removing the controller.... not 100% sure. I want to say it was intact prior to removing as the brake was working.

The wires to the motors are fine, no shorts, and the motors are still good and were replaced recently.
Based on the wires location, it would seem the high load was at the motors or between the controller and the motors.

Could the controller provide added load to the circuit resulting in these wires to overload to the motors at the connector? Maybe it was the terminals in the connector...?

The inside of the controller did smell pretty bad, I just want to rule out the motors and wiring to the motors.

On the gator I have a separate 50A toggle switch to disconnect the batteries but only a key switch on the 850...I will definitely add a second fai lsafe on this one.

All thoughts and criticism welcome.
User avatar
By toycrusher
A big issue with the chinese controllers is that they are wired with tiny 14 gauge wire that just can't hold up to the load for long periods of time. The alternative is a quality controller like a Kelly but they do run in the $100 range.
If you go back with another cheap controller, I would recommend using heat shrink butt connectors instead of the original plugs. The original plugs do often heat up and melt
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