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ZTC has three 55 watt solar panels mounted on top of the hard bimini and because our new battery monitor doesn’t read any power coming in from them, I have been curious about measuring their input. So, together with a friend, we tried to troubleshoot it. What did my genius friend find? There was NO FUSE in the fuse holder! I am virtually positive I have never opened that fuse holder before and without the fuse, it couldn’t charge.Β This means that it is entirely possible that our solar panels have NEVER been working, or at least, not as long as we have owned the boat.

Simple fix right?

****STOP! All boat owners know that something bad is about to happen. There are no “simple fixes” on boats!!!

We put in a fuse and what happens… we smell something burning. Guess what it was? The solar charge controller. πŸ™Β 

Apparently you can’t mix up the positive and negative wires on those things (there were stickers all over the device which said do not mix up the positive and negative wires), and they were crossed. The controller is now fried.

Here is the good news though:

  1. the panels definitely put out voltage, around 20 volts.
  2. I don’t think that controller could have handled any more panels anyway, and because we want to acquire more, we now have a good excuse to buy a nice MMPT controller.
  3. we found a small, as of yet untested, solar charger at a nautical consignment store yesterday for $1.00 that “might” work until we get the above. πŸ™‚

Just another day in paradise:)

A photo I took back in March of the now-dead charger. Notice that the two outside wires are mixed up! Also notice the multiple “caution” stickers warning about mixing up those wires.


  1. The loss of your charge controller just might have been a good thing…

    Most folk living aboard full time and cruising simply don’t need to control their solar input unless they have really massive arrays, especially if they have a fridge and computer (I don’t know about yours but our MAC’s are hungry critters!) and just by using your electrics onboard is more than enough to keep from over charging your battery bank.

  2. Hey M & R

    Finally all caught up with your blog……Great pictures in your “foggy” post………

  3. Ouch. Well at least you are going to get by for $1.

  4. Re. MPPT controllers: Yes, they are expensive. The improvement, though, is quite dramatic. On the solar cars I used to work on, we’d fit several MPPTs, each controlling a different segment of the array. They’d compensate for fluctuations in bus voltage, variations in cell shading (sunward vs. shaded side of the car), etc. and they worked well enough that I never saw a solar car without them.

    Some of the engineering types over at were trying to figure out how to build their own MPPTs a while ago. There’s plenty of money to be saved… if you like soldering and know what you’re doing with high-power electronics. Otherwise, get the stock ones; they’re simple, reliable and much cheaper than adding additional panels.

    Re. running with no controller: I’d only advise doing this for tiny, trickle-charger panels. If you hook a 50-watt panel directly to the battery, the panel will be operating far away from the ideal point on its voltage/current curve (an MPPT compensates for this). Overcharging is a possibility if little power is being used, true- and this won’t happen on a liveaboard boat. But IMHO, spending a ton of cash on solar panels and omitting the controller that allows you to make full use of their potential output makes no sense.

  5. Sorry to hear about the controller. We like our Outback controller so far. If and when you do add a controller, put a shutoff switch between it and the solar panels so that the circuit can be shut down if desired. FYI, we mounted our controller right next to our battery charger so that we could jump into the battery circuit at the same point.
    Good luck. You are well on your way to becoming a “plumbtrician”. πŸ™‚


    The previous owners probably took the fuse out because they smelled burning and forgot they had done so, thus also forgetting to tell you! Anyway, lesson learned, minimal damage done.

    • I don’t know. It is possible I reversed the wires, not the PO. I may have taken them off to check the controller my last round of troubleshooting. I am pretty sure David was too smart t reverse those wires (unlike me). πŸ™

      • The 3rd-year engineering students I’m currently teaching electronics to have burned through about 30 fuses so far this term. (We also have some boards that won’t blow fuses, but will create strange, intermittent voltage gradients in the ground buses when wired wrong- these are fun.) “Check polarity first” has finally sunk in, now that they’ve learned how long it takes to troubleshoot a board with 1/4 of the power supply offline.

        Glad to hear your $1.00 charge controller is taking up the slack πŸ™‚

  7. The whole world of electronics is a big black hole of mystery to me. I have read a fair bit about it on here, and on a few other blogs and I just don’t get even a small shred of it. This alone is enough to keep me from ever owning my own boat unless a man comes with it.

    Hmmm… I like the sound of that!

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