Dump Load Question

RedNeckSolarManRedNeckSolarMan Solar Expert Posts: 34
Hello everyone, I have a question or opinion on what to use for Dump Load for my solar system. I have small solar system to light up my balcony during nighttime. Recently, I was told by the county code enforcement officer that I need a dump load when the batteries are at full charge. I guess its some new policy they are putting into place as a "safety reason". (Reason for county code enforcement officer telling me this because he was checking my complex and seen my solar panels on balcony and checked it out).

Here is what I got on my solar system, just in case:
1. Three solar panels equal to 95 watts.
2. Two small marine batteries.
3. Alot of LED rope light to run from outside of balcony to inside of balcony with switch to turn on or off the lights on inside of balcony.

The panels are wired into Midnight Solar Combiner box and wires go straight to Morningstar PS-30 charge controller.

I seen online dump load controllers with resistors and cage around them. But my fear is the heat load coming off the it. Everything is stored in a cabinet on my balcony. I was thinking using a computer fan as dump load. Reason I am thinking of using computer fan is get rid of extra load and keep it cool in cabinet. So using computer fan will work or is there something else to use.

If anyone has good ideas, let me know and thanks.


  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Dump Load Question

    Solar panels do not require a dump load of any kind under any circumstances. Your code enforcement officer doesn't know what he's talking about. When the batteries are "full" the charge controller will disconnect the panels; no further energy transfer takes place.

    Dump loads are required for turbines (wind/hydro) because they need a constant load to keep them from flying apart (literally).

    If your code officer doesn't believe this, tell him there are a couple dozen engineers here who say otherwise.
  • RedNeckSolarManRedNeckSolarMan Solar Expert Posts: 34
    Re: Dump Load Question

    I knew I would get that statement, LOL :p

    I agree, but something county is doing new and mostly on some of townships with heavy population areas. Rest of townships (country side/rural area) in county don't have follow that policy.
    So I have to have dump load or face fines and solar system out of service. :cry:
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Dump Load Question

    I sure hate it when brain-dead morons who haven't got a clue what they're doing make up regulations.

    Not only is it not necessary, but installing such a thing will actually make it more dangerous for just the reasons you suspect.

    When dump loads are used, btw, they are connected to the battery via a charge controller as on this Morningstar data sheet (bottom right): http://lib.store.yahoo.net/lib/wind-sun/TSdatasheet.pdf

    Tell them to supply you with a wiring diagram if they think it's necessary. The whole solar industry all over the world says it isn't.

    Run-ins with AHJ's? Me? Why yes, now that you mention it. I have yelled at a few until they ran away crying for their mommies. ;)
  • RedNeckSolarManRedNeckSolarMan Solar Expert Posts: 34
    Re: Dump Load Question

    LOL :D

    Honestly, I think why they have this policy because I live in complex in heavy population area. I know couple people live in same county but in rural areas and they don't force it except if you have wind system. I think:
    1. guy is clueless about it (and did act clueless at times)
    2. since I live in complex full of students, grad students and young people. They think I am student and I am not.

    What I may do is get controller similar to that nice Morningstar controller in lower price and wire the computer fan to it. And have it ready in cabinet, so if county code enforcement officer shows back up. I will plug it to battery before guy shows up and unplug it when he leaves. LOL. I have the cabinet locked for several reasons so they just can't open the cabinet.
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