Voltage regulator

Needing a bit of help please. I have 2 motor drivers that require 24v, I have 18v batteries so there lies the problem , I am going to wire to of them in series to get 36v, and then use a voltage regulator but I can't find one that will handle the current approx 14 amps continuous per motor and driver. If anyone knows of one please let me know.

I have another idear that might be sutible if I wire 3 batteries in series that would give me 56v than wire another 3 in series , then wire both banks of 3 in parallel that would give me 28 v approx. Is that safe and would it work.?

Can we get some link to the drivers and motors?

There is probably a range of voltage that you can operate in. It's not a problem for a voltage regulator.

Two 56v banks in parallel is not 28v ..the voltage isn't halved in parallel. The capacity is doubled voltage would be the same.

A 24V motor will run fine on 18V, just a bit slower, and therefore, last longer.

I doubt that your motor driver “requires” 24V.

Or wire the batteries for 36V and never analogWrite() more than 80% for more than a few seconds.

This assumes the motor controller can handle 36V on its input side. The motor doesn't care what voltage the battery is.

http://www.longs-motor.com/productinfo/detail_12_82_122.aspx

This is the driver I'm using but I believe it can be used on a number of motors that use different voltages. That might not be the case I have been running it with the 18v but it seems a bit slow.

Is it too much trouble to post a link to the motor?

http://www.longs-motor.com/productinfo/detail_12_81_134.aspx

Mine is the 02

Hear you go

The “rated voltage” (24V) is the maximum allowed.

I know, hence the post

So, use less and be happy.

That's not particularly helpful I need my motors to turn at roughly 2800 rpm with 18 v I'm not going to get that. If any one else can help please chip in.

Regards Alex

So I have been doing some research and I have found this http://www.homemade-circuits.com/2015/03/100-amp-variable-voltage-power-supply.html

The issue I'm having is that the guy asks for a circuit that steps down form 240v ac. would this still work to step down from 36v DC to 24v DC?. I have looked at the data sheet for the transistors and they are rated for 100v max but I can't find a minimum voltage. Dose that mean they will work from 0- 100v?

Any one ?

This project is a kludge. You are trying to fit together parts that are not compatible, and any solution will be expensive at those power levels.

Start over, with motors and/or power supplies that are compatible.

The motors I have match the drivers. All I want to do is reduce to voltage down to 18v. I'm only asking a question and you keep hijacking the thread to tell me it can't be done. If everyone took that view we would still be living in caves.

Sorry, it seems my earlier reply didn't make it onto this topic.

The way I read the driver specs, 24V is the minimum for the driver. The motor only has a nominal voltage of 24. Both will run fine together on 36V. What you can't do is connect the motor directly to 36V without the driver. That will kill it. But it wouldn't be possible anyway: it's a brushless motor which always requires a driver.

The only thing that kills motors is temperature. Volts and amps cannot hurt a motor. I can run a 6V motor on 100V but only for a second, before it heats up. You will have to experiment to see what control settings overheat your motor and then avoid using those power levels. "Too hot to touch" is okay. "Fry an egg" is too hot: back off the power level.

The nominal voltage is the motor's ideal voltage for max power. If you use less than that then you won't be able to get that maximum.

I'm only asking a question and you keep hijacking the thread to tell me it can't be done.

No, I told you the solution will be expensive.

Here are two possible solutions: (1) use a high battery voltage, and a high current, very expensive step down converter (2) use a low battery voltage, and an even higher current, very expensive step up converter

High current 24V power supplies, motors and converters are industry standard. Expect to buy from industrial sources and pay industrial prices.

I would just stay at 36v and use a 66 percent duty cycle or less as Morgans suggested so the motor sees an average of 24v. Or just pick a duty cycle that gives you the rpm you need. You will not hurt anything doing this..they are both operating within specs.

The latter suggestion will work well, until a programming error raises its ugly head, or the Arduino fails for some reason, applying 36V to a 24V motor.

Hi thanks for all reply's. I put a taco meter on the motor and its reading 2850 rpm using an 18v battery that gives me plenty to work with.