Electronics bods please...
 

whats the best way to get 240 AC mains to 24V DC - I need about 650 watts at 24V DC. I will chuck it all in a box and wire it up etc. Is there anything I can Mcguyvor, ie and old Hifi amp or something.

Had a look in RS, bur supplies of the rating I need are about a grand!

cheers,

Mike.

anyone?

I just need to source a tranny & rectifier, got the box, got the new toy, I need to power it up at home without wasting the batteries.

Its rated at 635 watts, and the batteries are Nicad 2.4AH, the output on the DC side is about 26A.

Would a 20A 24V battery charger do it?

:)

A BIG battery charger is your best bet...I cant think of anything else that can pull that much current from the mains...you need one that can put out 26amps continually.

One thing you must note. Is that although the power will be rectified and is DC it won't be very "clean". The voltage will ripple, so whatever your powering may suffer from interferance.

To sort that out with that kind of current load you'll need capacitors the size of beer cans!

You are going to be calling for 27Amps!! :eek: Thats a MASSIVE request!

Battery charger? doubt that will be any good, could that supply 27Amps? Also, as said - its a very dirty DC ...... not much smoothing going on out of a charger!

Pete

ALi-B, now I've got you I'll bombard you.......


26A at 24VDC is a tall order from what I've seen on the net without batteries. Does a battery charger pump the juice in, or is it load driven? I am trying to power a DC motor on a saw.

could you get 2 smaller DC supplies connected to the same AC input, and would the DC output sync without blowing fuses/shagging new toy?

ETS .......and the elusive PS Lewis, so it would seem :D

is this correct? : 2 AH = 4A over 1/2H?

What kind of load are you driving?

yep..2AH = 2A for 1 hour..so 4A for 1/2hour.

:idea: One possable solution may be (not knowing what you are trying to do) is having a good battery and clipping the charger to it and then the load to it aswell.. i have done this with a 85ah leasure battery and a 10A charger to charger cells for my R/C cars, had 7 chargers all drawing about 5A (yes 35A)each on at the same time and it worked fine, but i was only doing this for 1/2hour bursts..might work might not

the load is a 24v mitre saw, the motor is rated at 635W. I thought a power supply would be a good idea to save the batteries when I was near a socket. Seems like the size of the power supply would be more trouble than its worth though.

Get a couple of good 12v car batteries and connect them in series. This will give you 24v (+/- 2v), with more than enough capacity for the current required.

If you are going to be using the saw for a few hours, then connecting the batteries up to a couple of battery chargers at the same time should give you enough reserves.

Just remember that the cables need to be a decent thickness to handle the current, without overheating.

John