Can I use the heating element from a 110VAC 1500W ceramic heater for a dump load on a 460W or 690W off-grid, marine solar system?

[Curious by Nature]

New to the forum. First post. Bought a ton of stuff to experiment in creating a marine solar system and one or two 86lb thrust (48.5 amps ea) trolling motors for a vintage 12 foot, 1960 aluminum row boat (trying to get 20 knotts out of it AND extended run time- fingers crossed).

So one major question I have is if a dump load is required for solar panels (prices for simple dump loads seem too expensive for what they are), or can I just leave the terminals unconnected? My guess is that with a grid system for a house, no dump is required. But for an independent marine system, I think I am going to have to spring for some kind of dump load. My research so far indicates if nothing is connected to panels, they just sit there and no current flows. BUT! it seems the wires in the panels themselves have resistance, and therefore the panels actually heat up higher than they would otherwise, and age faster. In the hot sun, your car hood can reach well over 200 degrees in full sun, and with solar panels the whole thing is glass, which seems like it could be far higher temperatures inside, potentially. The panels get permanently destroyed somewhere around 400 degrees, off the top of my head, - which out on the water, in direct sunlight with glass, seems entirely plausible!!

For a dump load, should I take apart an old 1500W 110Vac electric portable room heater and use just the heating element (for a DC dump-load)? Would it also need a DC muffle fan to prevent heating element from overheating? I don't recall the charge controller's max dump load amperage, or if it has a max, but I could try to find out if necessary (I think it was ten amps in the product info). The panel's voltage to the controller is 30V (parallel) and the batteries are 24V (series), but I'm not sure if the controller says 12V for the dump load. Its a 30 amp controller, but I think it limits the dump load to 10 amps. Does that sound right? Can I just connect it directly to that old, still working, heating element? Or just go with no dump load?

I'm starting with two 30V, 7.6 amp, 230 watt panels, but I have a third I intend to add later to get to 20 to 22.8 amps max. The batteries are two, 122amp-hr deep cycle lead acid (liquid cells) bought at the same time. The 12 foot aluminum row boat gets an added aluminum frame to support the panels and serve as a sun shield for the operator. ((trial with two panels is due to expectations of it being real top heavy (50 pounds each panel, intended to be six feet above the water line, for a boat with only about a 4 foot beam at the water line) puts center of gravity high and overcomes the center of buoyancy very easily)).

 

[Rednecktek]

Solar shouldn't need a dump load, that's just for hydro and wind to prevent over-speeding of the rotors. Your charge controller will just stop drawing power from the panels when the batteries are topped up.

 

[Goboatingnow]

PV panels don’t need or benefit in any way by using dump loads.

 

[32 volt boater]

Watts/Volts/Amps/Ohms Calculator

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I plugged in the 1500w and 120 vac got 9.6 olms

Numbers change alot when voltage is changed.

Maybe if you want to give the solar something to do when the boats not in use invert to 120vac run it to the house.

 

[DPC]

So let’s say for a moment I built a system with more generation potential than I need in n the summer months and I want to ex rss capacity to heat water is there a moot charge controller that is designed with an option like this!

 

[OzSolar]

So let’s say for a moment I built a system with more generation potential than I need in n the summer months and I want to excess capacity to heat water is there a mppt charge controller that is designed with an option like this!

Assuming I'm following your question which I very well may not be..... I can think of at least one that does that.

The Midnite Classic uses programmable relays/dry contacts. See the manual starting around page 39.

 

[DPC]

Assuming I'm following your question which I very well may not be..... I can think of at least one that does that.

The Midnite Classic uses programmable relays/dry contacts. See the manual starting around page 39.

1. I think my fingers are too fat for this key board

2. Yes you seem to understand the question

This phone has auto correct but it’s a bay an issue in English and Latin alphabet

If I wrote something badly spelled in polish or Ukrainian it would go through mistakes… as is

 

[OzSolar]

1. I think my fingers are too fat for this key board

2. Yes you seem to understand the question

This phone has auto correct but it’s a bay an issue in English and Latin alphabet

If I wrote something badly spelled in polish or Ukrainian it would go through mistakes… as is

My comment was not poking at your message in anyway. It was an attempt to point out that I might be confused and really was just trying to help. There’s been a rash or people losing their chit on me lately after reading something in my reply that wasn’t there or even remotely implied.

 

[DPC]

My comment was not poking at your message in anyway. It was an attempt to point out that I might be confused and really was just trying to help. There’s been a rash or people losing their chit on me lately after reading something in my reply that wasn’t there or even remotely implied.

I have struggled with the English language since I was a small boy

Pitty I was never any better at any other ha ha

Smile man!!!!

It’s a pretty steep learning curve, thank you for the link I have reading to do

 

[DPC]

My comment was not poking at your message in anyway. It was an attempt to point out that I might be confused and really was just trying to help. There’s been a rash or people losing their chit on me lately after reading something in my reply that wasn’t there or even remotely implied.

I like you

For what that’s worth