MEGAWATT 60-AMP INTRODUCTION

Where is mexicowander'ers super box? Pictures?

Hi Reed,

The numbers don't seem to work for 1330 watts. 26a X 48v = 1260 watts and 90 X 14 = 1260

Pnichols
We have a Meanwell SD-500L-48 DC-DC converter that converts our 48V battery bank to 12 V (with supposedly high efficiency) at supposedly 508 W capacity. Power comes from the six panels at 90 V nominal to Tristar MPPT-45. Our panels on roof of 5th wheel so there is about a 15 m path from most rear panel (30 V and 235 W) to controller. Panels are in series of 3.

Max power ever seen was 1330 which was 14 amps to controller and then 26 amps or so from controller to battery bank. A 12 V battery bank would have required an MPPT rated at 110 amps.

The controller is about 1 m from the battery bank and the Meanwell converter is about 20 cm from the battery bank (velcroed to one battery)
Reed and Elaine

Thanks for the mention
Just trying to help folks out as we all are

Took me a while to understand but it finally sank in
Some "Get It" Some don't and others NEVER will

Having fun installing several new IP cameras along with the dozen or more analog NTSC/PAL cameras around this place ........ always something to get done

KJINTF wrote:
Put those portable 12 Vdc nominal panels in series
Get a Voc of say 40Vdc or there about - works for me
Reduce that I2R loss aka POWER LOSS
1/2 the current keeping the wire resistance the same obtain a very large reduction in the power loss
Watts aka power is what it's all about - a combination of Volts and Current

Very clearly/correctly stated, right to the point, and kept short on words, too!

Mathematically, the power dissipated (lost) in wiring is represented by the current flowing through it, squared, times the total resistance in ohms of that wire.

That means for portable panels to make full use of their power output, back at the batteries, one wants no more power loss along the wire coming from the panels than is absolutely necessary. This further means that one should minimize the current coming from the panels through the wire.

How do you do the above but still not reduce the power coming from the panels ... by increasing the voltage at the output of the panels ... bearing in mind that when doing this, electro-physics dictates that you get what you want ... current coming from the panels that is reduced proportionately.

To do this means one must put the controller (using one that can take the higher voltage from the panels) back at the batteries so the highest voltage possible back at the panels is what's driving the current from the panels.

So far I can't locate a pre-packaged portable system that is designed, and requires that, you to put it's controller back where the battereis are located.

Niner, I Guess that site did not like an image to be hotlinked from them and changed it out.

Twas just a picture of He-man and his electrified sword.

I'll remove it before they come after me with those funny jackets.

And Yes, for those that did not follow the 22$ cheapowatt thread from last fall, the poor thing burst its guts out after 17 minutes of providing ~538 watts when it was rated for only 350.

Then I bought the MeanWell RSP-500-15, and finally got the charger which does what I , and my battery, want.

And it will max out in the 600 watt range without releasing magic blue smoke or requiring constant twiddling of the Voltage pot to keep it at max safe output

Still have to attach a few extra heatsinks to it that westend mailed me.

I'll likely seek a better 10 turn pot too as it is a bit crusty, but perhaps a bit o Caig DeOxit Gold sprayed inside will smooth things out.

'Till "they" arrive with that neat jacket that laces up the back.

Oops, Captain Charger shouldn't have been so pubically ebulient

landyacht318 wrote:

BillyW wrote:
For us not so technical people, are these Megawatt (or Meanwell) units compatible with some kind of remote voltage control? I have a nice place to mount one close to the batteries but far from accessible. It would be nice to be able to optionally equalize with it without removing the sofa.

Now Mex is mad at me! :B

If you have some soldering skills you can remove the 1k Ohm tiny potentiometer and solder 2 wires in its place, and install a new 10 turn 1 k ohm potentiometer where you can adjust voltage easily, and laugh maniacally at your new found power.

I've done this with my 22$ cheapowatt, may it rest in burnt pieces, and my Meanwell RSP-500-15.

My neighbors are getting a bit tired of me swinging my machete around in my He-man suit screaming :
"I have the Power!!!!"

After dialing my Potentiometer upto 15.3v and plugging my MW into the battery

I am getting funny link for your picture there Landyacht???

The rheostat is the way to go. Landy your lead-foot rested a little too heavily on the gas pedal of that 22 dollar power supply. But I like the 10-turn pot because jiggling the knob a little does not affect voltage. Let's try recommending a service that repairs HAM radios if a person isn't handy with a pencil tip iron. Most hamsters roll their own, but surely somone still offers soldering service up there?

Since locals raided my cheapo stash I'm switching to Megawatt and have to reconfigure my original design to prevent hotel blackouts. So it looks like a pair of 40-amp units will have to suffice. What have the 29-amp units been delivering ridden hard?

Going online manana and getting a pair of those calibrated dial pots. The floater will be a modified 4.17 amp 16-volt power bricks controlled with a 7.5 amp adjustable regulator and it's own pot. I'll leave the second brick as is for equalization duty with it's own 1-hour spring wind up timet. The unit gets an eighth inch stainless steel security cable.

All jammed in a box a little larger than a shoe box. 4 meters, LED indicator lights
Alumimum rack handles, and an ex- Lambda power supply case coated with bedliner. Almost 70 now but I stll get a bang out of Borg cubes...

BillyW wrote:
For us not so technical people, are these Megawatt (or Meanwell) units compatible with some kind of remote voltage control? I have a nice place to mount one close to the batteries but far from accessible. It would be nice to be able to optionally equalize with it without removing the sofa.

Now Mex is mad at me! :B

If you have some soldering skills you can remove the 1k Ohm tiny potentiometer and solder 2 wires in its place, and install a new 10 turn 1 k ohm potentiometer where you can adjust voltage easily, and laugh maniacally at your new found power.

I've done this with my 22$ cheapowatt, may it rest in burnt pieces, and my Meanwell RSP-500-15.

My neighbors are getting a bit tired of me swinging my machete around in my He-man outfit screaming :
"I have the Power!!!!"