Use dimmer switch to limit current to converter work?

[Guda]

Why don't you want 30 amps?

Mainly don't need that much & don't want to wire for that much amperage. My original post has a link to another post that has a video that has a gizmo that has this ability. Also you can see other reasons why someone would want variable amperage charging in that post.

If you increase the resistance in the charger output, the charger will see a higher voltage and begin tapering current on its own. In order to do this, you need to push the converter to see its absorption voltage. This relationship would change as current, voltage and temperature changes, and RV converters frequently only operate at absorption for a very short period of time.

The behavior of the converter also influences the outcome. Some only provide a fixed output voltage.

Your converter is likely only 360W. 30A * 12V = 360W.

Will a variable resistor of suitable rating work? Yes. Will it be a little tricky and finicky? Yes.

I really like @snoobler ! You are my favorite mod!

This is good news. Now, its science time! 2000w dimmers are not cheap, like $200. Found 5 on eBay for $80 each. I will buy one & test it. If it works, sweet. If not, oh well $80 for science is cheap!

Much thanks again guys!

 

[FilterGuy]

Makes me think its possible

I can't say it would not work..... but my guess is that it won't.

As the video shows, the dimmer is a Pulse-Width-Modulation device.

The AC-DC converter is almost certainly a switching power supply. As such it will probably only switch on the AC-in at the top of the sine wave. So, right off the bat, if the dimmer is not letting at least half of the sign wave through so the AC-DC converter sees the peek, nothing will get through the front-end circuit of the AC-DC converter. As you turn the dimmer further up and present more of the sign wave, it will quickly get to the point where the sign rest of the sign wave voltage is lower than the AC-DC converter needs. That means there is a very narrow range out of the dimmer where it can effect the AC-DC converter.

Furthermore, I have no idea how the AC-DC converter would react to the chopped signal in the active part of the sine wave. I can imagine all sorts of problems.

 

[FilterGuy]

Mainly don't need that much & don't want to wire for that much amperage. My original post has a link to another post that has a video that has a gizmo that has this ability. Also you can see other reasons why someone would want variable amperage charging in that post.

I really like @snoobler ! You are my favorite mod!

This is good news. Now, its science time! 2000w dimmers are not cheap, like $200. Found 5 on eBay for $80 each. I will buy one & test it. If it works, sweet. If not, oh well $80 for science is cheap!

Much thanks again guys!

Keep us all posted on what you learn!!!

 

[snoobler]

The voltage delta between the charger and pack is what... 3V max? 3V * 30A = 90W. No need for a 2000W resistor.

A $35 10A charger from harbor freight might be the better choice?

Thinner wire gauge is also a great way to add voltage drop. Warm wire means you have power loss. I have a 100A converter in my motorhome, but the 6awg wiring creates such a big drop, the charger instantly hits absorption and starts tapering current.

 

[Guda]

I turned my truck into a generator

This was one heckofa build. Some information I got from this very forum helped me build this BMF. Its a work in progress. Will be adding more wiring & new batteries under the hood to up the capabilities. I am also adding about 1000w of solar & a MC 250 SCC. I might build a rack for my trailer to...

diysolarforum.com

 

[grizzzman]

The voltage delta between the charger and pack is what... 3V max? 3V * 30A = 90W. No need for a 2000W resistor.

A $35 10A charger from harbor freight might be the better choice?

Thinner wire gauge is also a great way to add voltage drop. Warm wire means you have power loss. I have a 100A converter in my motorhome, but the 6awg wiring creates such a big drop, the charger instantly hits absorption and starts tapering current.

As an example I had motor home. The batteries were 3 feet from the converter. The positive lead from the battery to the selunoid disconnect back to the battery compartment ,through a 30 amp breaker then to the converter (60 amp unit) over 20 feet in total. There use of a 30 amp breaker tells all about what they were up to. Heat kills

 

[Guda]

It's pretty much just a trickle charger that I use on days I'm not driving. I'm kinda funny about wanting to use up stuff I have laying around. I might even been able to not put in the dimmer as it might never draw much. Should have tested that. I think thats what Snoobler is saying