Brushless controller questions.

[Jakemp]

Hello everyone, new here. Thanks for having me. This isn't really e bike related but it's a diy build nonetheless..

Long story short I am building a electric dolly/hand truck.
I bought a 24v brushless transaxle on ebay (pic below)

I am also looking to get this 24v-60v programmable Controller for it.
To my understanding I set this to 24v volts and that's all the controller can take?

I ask this because my plan was to use 2 power tool batteries. And the combined voltage would be higher than what the controller is "programed" to take. The reasoning behind the power tool battery idea, was for weight and cost.. am I a idiot for wanting to use 2? I am also wanting high ish amp hours..hence the reason for 2 batteries..

am I a idiot for wanting to use power tool batteries? Should I just take it in the chin for the expense battery that has the correct voltage/amp hours i need?

 

[PCeBiker]

I bought a 24v brushless transaxle on ebay (pic below)

I am also looking to get this 24v-60v programmable Controller for it.
To my understanding I set this to 24v volts and that's all the controller can take?

The transaxle runs on 24v and doubling the voltage will most likely damage the motor.

The controller can take a voltage input of anything from 24v-75v and I'm almost positive you can set it to any voltage output to the motor that you want, but 24v may be as far as you can turn it down?
The current output amps can most likely be adjusted for a maximum value as well.

The motor is rated 750 Watts, and at 24 volts, that's just over 30 amps.

Your power tool batteries could be hooked up in parallel to double the amperage instead of doubling the voltage, but I doubt that 2 power tool batteries are capable of delivering 15 amps each.
Hooking up two batteries in parallel needs to be done carefully. Even a series connection needs to be done carefully.

The controller should be able to take the double voltage and convert it to 24 volts with higher amperage, but that probably isn't as efficient as feeding it with lower voltage, and you would still have a lack of total power.

You didn't say what the Voltage or Ah of your power tool batteries are.

They most likely can't deliver the current/power required and the BMS in your batteries will shut down the battery if you try to pull too many amps, assuming they even have a BMS.
If there is no BMS, the batteries are at risk of exploding.

I ask this because my plan was to use 2 power tool batteries. And the combined voltage would be higher than what the controller is "programed" to take. The reasoning behind the power tool battery idea, was for weight and cost.. am I a idiot for wanting to use 2? I am also wanting high ish amp hours..hence the reason for 2 batteries..

am I a idiot for wanting to use power tool batteries? Should I just take it in the chin for the expense battery that has the correct voltage/amp hours i need?
View attachment 173491

I think that your best bet is to buy two 12v Deep Cycle regular lead acid batteries that can reliably deliver high current (like for an electric trolling motor).


They can deliver way more amps, are relatively cheap, and far safer.
They should last longer too.
(maxing out lithium batteries wears them out quickly)

Another more expensive option is lithium iron batteries with way more capacity than a regular car battery, and way safer than regular lithium batteries.
They are heavier than regular lithium batteries, but that doesn't matter much with a hand dolly.

 

[PCeBiker]

My Ryobi power tool batteries are 18v 24wh. A battery only lasts for 5 minutes in my grinder, and my grinder draws nowhere near 750 Watts.

You need high capacity batteries to run a dolly, especially if you're going to be moving heavy loads.

I've used motorized pump trucks, and they used HUGE deep cycle 12V batteries.

 

[Jakemp]

You didn't say what the Voltage or Ah of your power tool batteries are.

Referring to this, I was looking into 40v Ryobi batteries. 12.0 ah each and 432 wh each, was going to run 2.
I got the idea from another dolly manufacturer who runs the same setup with the 2 40v Ryobi batteries. on a 48v system. Now I dont know anything else, the controller setup, axle wattage or amps.

I think that your best bet is to buy two 12v Deep Cycle regular lead acid batteries that can reliably deliver high current (like for an electric trolling motor).

I would love to avoid this if possible.. due to space and weight... Is there any other alternative?

The controller can take a voltage input of anything from 24v-75v and I'm almost positive you can set it to any voltage output to the motor that you want, but 24v may be as far as you can turn it down?
The current output amps can most likely be adjusted for a maximum value as well.

Yes you can adjust the amps. According to the website.

The controller should be able to take the double voltage and convert it to 24 volts with higher amperage, but that probably isn't as efficient as feeding it with lower voltage, and you would still have a lack of total power.

I am not looking to get the full speed/potential out of this motor. it would probably drag me across the yard if I set it up that way.. I'm not sure if that changes anything with the setup I am wanting to run.


Thank you for the reply @PCeBiker, excuses my ignorance, I don't have much experience in this field. Some what all new to me.

 

[PCeBiker]

Well, if it's been before, you should be OK.

I forgot about the big Ryobi batteries.
I know there is a Ryobi lawnmower and snowblower available that use those batteries and those are high power machines.

Those 40v batteries may actually work quite nicely.
I know that Ryobi has a quality BMS in my batteries that also balances the cells.
(I opened up my battery to investigate)
Power tool batteries are generally very safe and reliable.

 

[PCeBiker]

Hooking up the batteries may be a little tricky. It's not just positive and negative that comes out of the battery.
There is a third contact on the battery that "talks" to the machine that it's plugged into and the newer 40 volt batteries aren't compatible with the older 40 volt tools, so you would have to figure out how to connect those batteries to your homemade dolly/cart.

That third contact may just be for the charger though, but the new batteries aren't compatible with the older tools, and I don't know if that's just a size and fitment issue?

 

[Jakemp]

View attachment 173496View attachment 173497


Hooking up the batteries may be a little tricky. It's not just positive and negative that comes out of the battery.
There is a third contact on the battery that "talks" to the machine that it's plugged into and the newer 40 volt batteries aren't compatible with the older 40 volt tools, so you would have to figure out how to connect those batteries to your homemade dolly/cart.

That third contact may just be for the charger though, but the new batteries aren't compatible with the older tools, and I don't know if that's just a size and fitment issue?

Definitely will look into it. I read somewhere that the newer tools have fitmit issues with the older batteries so your right about that. I will do more research on them before pulling the trigger. I am still a little far out from hooking up batteries. Still need to build the frame, get the controller in, ect

 

[PCeBiker]

I am not looking to get the full speed/potential out of this motor. it would probably drag me across the yard if I set it up that way.. I'm not sure if that changes anything with the setup I am wanting to run.

Going slower will help reduce the power demand, and 750 Watts is the maximum of the motor, but if you were to have a heavy load that needs to go up a ramp or steep grade, that is when the motor needs more power.

But,.. it's been done before so it must be possible.
Maybe try to find some reviews of that Ryobi powered dolly to see what people think of it. It might just be a big Tonka toy.

I wonder about the Ryobi snowblower and how it would handle a foot of snow or heavy wet slushy snow?
You might end up having to use a shovel anyway?

My sister has a plug in electric corded single stage snowblower and it's pretty much useless.
It's faster and easier to just use a shovel.

 

[PCeBiker]

Definitely will look into it. I read somewhere that the newer tools have fitmit issues with the older batteries so your right about that.

If it's just a fitment issue, then that's good news.

I will do more research on them before pulling the trigger. I am still a little far out from hooking up batteries. Still need to build the frame, get the controller in, ect

The tricky part may be fabricating a battery bracket for the dolly. You want the batteries to be removable so you can plug them into the charger.
Designing something might be tricky?
Maybe others have done it, so you can see how they did it?

 

[Jakemp]

If it's just a fitment issue, then that's good news.



The tricky part may be fabricating a battery bracket for the dolly. You want the batteries to be removable so you can plug them into the charger.
Designing something might be tricky?
Maybe others have done it, so you can see how they did it?

From what it looks like this manufacturer used a dual battery charging station to house the batteries, and then just a metal box to keep them dry.

But,.. it's been done before so it must be possible.
Maybe try to find some reviews of that Ryobi powered dolly to see what people think of it. It might just be a big Tonka toy.

From what I read they are very good dollys, now I don't know if it works well because it's 48v? That's going to be the difference with my build vs theirs, my axle is only 24v.. but we will see!

 

[PCeBiker]

From what it looks like this manufacturer used a dual battery charging station to house the batteries, and then just a metal box to keep them dry.

That's a great idea. You will probably still need to install a switch of some sort to switch it from charging to running?

From what I read they are very good dollys, now I don't if it works well because it's 48v? That's going to be the difference with my build vs theirs, my axle is only 24v.. but we will see!

You should be OK as long as the transaxle you bought has enough oomph with 24 volts and 750 Watts?
It may be geared a bit lower for more torque and less speed?

I just checked all my 18v Ryobi tools and they all have only two contacts (positive and negative) it's only the batteries and charger that have three terminals.
The charger checks the condition of the battery and won't charge it if it's too hot, or the battery has failed.

The 40 volt batteries are most likely the same design.

 

[Jakemp]

That's a great idea. You will probably still need to install a switch of some sort to switch it from charging to running?



You should be OK as long as the transaxle you bought has enough oomph with 24 volts and 750 Watts?
It may be geared a bit lower for more torque and less speed?

I just checked all my 18v Ryobi tools and they all have only two contacts (positive and negative) it's only the batteries and charger that have three terminals.
The charger checks the condition of the battery and won't charge it if it's too hot, or the battery has failed.

The 40 volt batteries are most likely the same design.

Thanks for looking! I don't have any ryobi tools, just milwaukee. I was looking at the high output batteries so I can use them with my tools.. but they are expensive as s*it (as you could of guessed ) so ryobi it is!

 

[PCeBiker]

You won't be able to hook the two batteries in series to get 80 volts. That is too much voltage for your controller, but you could put the batteries in parallel.
The 40 volt batteries are actually at a higher voltage when they are fully charged as well.

You could possibly just use one battery at a time and have the other one charging while using the first?

Running both batteries at the same time in parallel creates a problem if you plug in one fully charged battery along with a depleted battery.
The fully charged battery will try to dump its power into the depleted battery. It's like a dead short.

The BMS should cut out the battery but it's still not a good thing.
Keeping the batteries, always paired and always charged and drained together should keep the batteries equally charged or drained all the time, so that there is no voltage difference between them.

You can also use your controller to put a bit more voltage to your transaxle. Not 40v but maybe 28v??

People are feeding 52 volt batteries to their 48 volt ebike motors.
You just can't over do it or you'll cook the motor.

 

[Jakemp]

You won't be able to hook the two batteries in series to get 80 volts. That is too much voltage for your controller, but you could put the batteries in parallel.
The 40 volt batteries are actually at a higher voltage when they are fully charged as well.

Parallel was my original plan for the higher ah, the 40v will be enough.

You could possibly just use one battery at a time and have the other one charging while using the first?

I was also thinking or doing this. It'd be nice to have another battery ready to go, but also, I wouldn't have the ah with one vs with 2 in parallel. Once I get it built and wired I can play with it. Who knows 1 40v may last long enough!