I'm looking for something that will take 12-24v input and vary the output between 0-120v. Like a variable transformer? And if it don't exist, is it possible? It would make my life so much easier.

 

Do you want AC or DC in? AC or DC out?

 

What kind of volts?

 

Where is the 12-24v coming from and where is the 0-120v going to?

 

current levels?

Its unlikely to find something like that though.. Doable.. unlikely to commonly found anywhere..
I wonder what the application/use is?

 

Reverse-connected Variac autotransformer.

ak

 

It's all dc. The 12v in is from a lead acid battey or 2 in the case of the 24v. It' for running a 2000w dc 0-130v motor

 

It's all dc. The 12v in is from a lead acid battey or 2 in the case of the 24v. It' for running a 2000w dc 0-130v motor

That's 167 amps from a 12V battery or 83 amps from 24V.
Your batteries won't last long.

 

It don' have to last long and the speed will be varied. I do plan on using li-ion down the road.

 

Can another method, something else provide motor function?

Is this for loss of AC or normal operation?

Got any more batteries?

 

It is mostly for remote operation. I was looking into a power inverter but I can not find one that is single feed out. Plus it don' make sense to me to go from dc to a.c. and back to dc. The motor controllr I have now uses 110 a.c. input and 0-110vdc output

 

It don' have to last long and the speed will be varied. I do plan on using li-ion down the road.

How long is not long? You would probably not get more than a few minutes from a typical car battery, for instance.

 

In reality I'm not too concerned about battry life. I have seen electric bicycles with equivalent wattage motors that have a 20+ mile range. If I can get 1/4 of that power, i would be happy. I could use their controllr but they are made SO cheaply, there has to be better out there

 

I have seen electric bicycles with equivalent wattage motors

Really? A bicycle with a 2000 W motor? I've seen 1000 W, but not 2000.

ak

 

2 kW seems like a lot to ask of a beefed-up boost converter circuit. I think there is a transformer in your future.

High power / high density DC/DC converters are good for around 500 W per brick. Some have a wide output voltage adjustment range (but I don't recall any that regulate down to 0 V). Some can be paralleled. Some can be stacked up, such as two 48 V output bricks with inputs in parallel and the outputs in series to give 96 V. You need all three features, which will take some digging.

Vicor, SynQor, Astec/Tyco/Artesyn/whatever

You might have to go with a fixed-output boost stage of whatever technology, followed by a synchronous buck regulator for the variable output to the load. The very-wide output voltage range almost certainly means a very wide output current range, and that will make the magnetics a ... challenge.

ak

 

Really? A bicycle with a 2000 W motor? I've seen 1000 W, but not 2000.

ak

I said comparable, and by that I meant close. To be honest I have not seen over 1500w but even then, they still have a fair range. With li-ion batteries, I don' think I'll have much of a problem. I'm very rusty when it comes to all this and I never learned much to begin with. I really want to keep this project cost down by salvaging most of the parts. I got the motors for free from treadmills and I figured it couldn't be that hard to run off of a car battery. I have seen people build gokarts from starters and Ik that would require atleast 4hp. I'm only trying for just under 3

 

I have seen people build gokarts from starters a

Yeah, but there is a big difference between running a 12 V motor on a 12 V battery, and running a 110 V motor on a 12 V battery. Bringing in the whole system for under $1 per watt will be difficult unless there are some super-cheap ebay modules that just happen to fit this application.

ak

 

But I can buy a 3000w inverter for a few hundred and run it off that. I' just trying to save a step and avoid having to convert to a.c. and then back.

 

The best I could find is this 92-97% efficient 1500W converter for $35. It only goes to 90V though. But it is certainly a good deal.
https://www.amazon.com/dp/B076TTBKF...acc2-113e5f87b342&ie=UTF8&qid=1525304480&sr=1

 

Can you also please stop creating so many threads for the same topic? It can be confusing and is borderline spam. Thanks.