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The hemorrhaging of our bank account continues. As our time in the US is drawing to a close, we decided to once again take advantage of our friends’ house as a ship-to location and order an additional solar panel. We have always intended on adding additional solar to ZTC but we decided long ago to wait until getting to the US from Canada to save on installation costs and shipping. Now having the 3 – 50 watt panels on our bimini functioning (in some capacity) has definitely inspired us even more to get this done.

There are multiple websites where discount solar panels can be purchased, with various brands being offered for sale. For all I know they are all made in the same factory and rebranded with different labels. We decided to go with the popular 135 watt Kyocera panel from AltE Store. I shopped through their website selecting both the panel and a charger that I thought would be appropriate but rather than ordering online, I decided to call the company to speak to a rep to make sure that I wasn’t missing anything critical. I’m glad I did. The controller I had initially selected was a MMPT* controller which apparently uses some kind of voodoo to increase the output of the panels (feel free to chime in here Matt Marsh). When I told the sales rep that I intended to run our existing panels and the new Kyocera one through the charger, he told me that MMPT units were not really so good for that. He then suggested that I get a non-MMPT charger which costs approx. 300 dollars less! No, it won’t have that special voodoo power, but it will work for our entire array. Oh, did I mention it costs 300 dollars less?

The panels were ordered at 1:00 PM yesterday and I received a tracking number from them by email around dinner time last night indicating that they were shipping. You can’t beat that! I did pay a bit extra for 3-day shipping so that hopefully we’ll have them in our possession by Monday and then can install them the first of the week. I am not at all sure how we are going to mount the panel, or even where the new charger is going to go. I guess we’ll figure out all those details once they arrive.

Here is how another PDQ 32 has a panel installed on their stern.

Positive amps from the sun… ya gotta love it. Even right now, in the early morning, we are seeing 2-3 amps coming in from our existing panels.

From the AltE website:

“Maximum Power Point Tracking solar charge controllers (MPPT) are different than the traditional PWM solar charge controllers in that they are more efficient and in many cases more feature rich. MPPT solar charge controllers allow your solar panels to operate at their optimum power output voltage, improving their performance by as much as 30%. Traditional solar charge controllers reduce the efficiency of one part of your system in order to make it work with another.”


  1. “When I told the sales rep that I intended to run our existing panels and the new Kyocera one through the charger, he told me that MMPT units were not really so good for that”.

    What did he mean by “that”?
    Was there a problem using two differnt brands of panels?

  2. Looks like it’s time to make your wish list to Santa. . . You do still believe don’t you?

  3. Tracking data…

    LOUISVILLE, KY, US 12/02/2010 9:21 A.M. ARRIVAL SCAN
    MANCHESTER, NH, US 12/02/2010 7:08 A.M. DEPARTURE SCAN
    12/02/2010 4:57 A.M. ARRIVAL SCAN
    CHELMSFORD, MA, US 12/02/2010 4:05 A.M. DEPARTURE SCAN
    CHELMSFORD, MA, US 12/01/2010 10:12 P.M. ARRIVAL SCAN
    NASHUA, NH, US 12/01/2010 9:04 P.M. DEPARTURE SCAN
    12/01/2010 8:15 P.M. ORIGIN SCAN

    I am really surprised to find this much detail as I find tracking numbers seldom work.

  4. While the transom/davit mounts always look good and they’re easy, I have always resisited:

    * We climb in and out of the tender over the transom when it’s rough; it’s easier and safer.
    * It is far easier to pass groceries and “stuff” up than over to the sugar scoops.
    * We keep our bike rack there.

    Where then? I’ve considered in front of the mast, between the hatches, though there is somewhat more chance of impact and the space is smaller. I’ve not measured it.

    Iv’e seen them on the side rails. It would be safe, given how far out the rub rails stick. But you would have to pay attention. Maybe.

    I might also consider an aft rack like you showed, BUT that is easy to fold down against the railing, though that also limits the size a bit, though not much. THIS would be my first choice, I think. It would’nt solve my bike rack conflict, but I bet it would work well for you. You would even be able to vary the angle to greet the sun, when that seemed worthwhile.

    In the end, in 2 days, you will have what you have, in terms of size. Consider the hinged rack; more of a project, no question, but neat. You could always do something simple now and reconsider later, if the davit location sucks.

    • * We climb in and out of the tender over the transom when it’s rough; it’s easier and safer.
      * It is far easier to pass groceries and “stuff” up than over to the sugar scoops.
      * We keep our bike rack there.

      I hadn’t thought of the first two points there. We do those things too.

      The install definitely warrants a fair amount of thought.

  5. Hi Folks, Due to us having our camper van for some years we have had loads to do with the 12v. System & our friend on “sv Hirieth” completely burnt out 6 batteries on their boat. This was due to the batteries not being checked for “Acid/water” they had not inspected the levels & this cost them almost $1000.To replace them. For best results have all your batteries the same amp out put i.e. 85amph or 110amph etc then all the panels have to be the same rating going in to the regulator then on to your batteries, the regulator must be strong enough to take the full charge from the solar panels. Our friends have their panels mounted on the rear tube frame that way they are able to angle them as the sun moves. Thus putting them at an angle facing sun rise and then almost flat at mid day etc etc . But the main thing is make sure you have distilled water to top the batteries up every 2 weeks if required. I look at mine every 2 weeks when we have sun every day. Hope this helps & I can even talk you through fitting it all via Skype if you need some advise or help, but it sounds as if you have it all sorted 🙂 Regards Andy

    • Hi Andy

      Thanks for the post. I am pretty careful about checking and topping up the water in our batteries.

      Being able to tilt the panel would be a “nice” feature. I have read that many people give up on that practice after a short while, determining that it just isn’t worth the extra effort. I am curious what % increase tilting the panels offers.

      • Hi Mike what we found when we were with them if there was no sun after say 3 pm by having them tilted early as the sun cam up the charge was say 3amps instead of 2 that is a good charge over say 5 or 6 hours. It was a ver easy system as well, just 2 adjustable butter fly screws mounted on a swivel. I will be looking at doing it that way once we have our Cat. As I found it did make a diff. especially if you only have 2 or 3 panels with low rates. They had /have 5 pannels but run lots of them so need a charge every day to keep them full

  6. Isn’t it great when a salesperson is honest and actually saves you money?! Glad to hear that you got a break. I’m getting nervous adding up this stuff in my head. I hate to think about it! It all works out, though. Drew has some good advice, I love the thought of the transom/davit installation, until it comes to practicality. Not sure what the best answer is for us yet.

  7. Mike, I agree with your salesman: mixing panel types upstream of an MPPT controller is asking for trouble. To use MPPTs, you would need two controllers: one for the three 50W and one for the 135.

    In bright sun, you’d get about 22 A at 13 V from this array with MPPTs. With standard regulators it’ll likely be about 15 A.

    The MPPT voodoo magic is really just an old equation from elementary school (power = voltage times current) combined with the current-voltage response curve of a solar panel (example: ). At some point on the curve for a given light intensity, Power (= V * I ) will be maximized. If the voltage goes up a bit, the current drops a lot and so does the power. The MPPT is just a clever voltage changer that lets power flow from the panel’s preferred voltage on one side, to the battery’s preferred voltage on the other side. So as the battery charges- and its voltage goes up- the panel’s current and power output aren’t reduced.

    The trouble with mixing panels on these things is that if your panels aren’t identical, their maximum power points are different. The MPPT will try to find an average for the whole array, but this will be far enough from the ideal points for each panel that there’s not much benefit over a (simpler, cheaper) conventional controller (generally a voltage regulator- it actually forces the panel to work at a non-ideal point on the curve so that the panel and battery voltages are compatible).

    • Thanks Matt. I knew you would chime in on this.

      The improvement with a MMPT controller sounds impressive but it seems a bit silly for me to install two separate controllers.

    • We are using an MPPT with 3 panels, two Sharp 80W and one Kyocera 85W. I *think* the MPPT still helps substantially because our panels are very close in wattage…but I have no idea because it isn’t like I’ve tested them with another controller.

      Curious what the experts think.

      • My “guess” is that it certainly can’t hurt to have such a controller. It probably just doesn’t work quite as well as if the all the panels were the same. Again, I am just guessing.

  8. Matt has it right. MPPT will not help if the panels are different. The cheap grid-tie inverter that I installed with the old panels from Eolian on my shop works very well tho – it is fun watching the volt and ammeters to see the controller hunting for the best current draw to use as conditions change (clouds passing by).


    • Interesting point about grid-tie inverters, Bob.

      It’s worth noting that since a grid-tie inverter, by definition, must already include voltage conversion and frequency/voltage matching circuitry, giving it MPPT capability is trivial. I don’t think I’ve seen one, at least in the last five years, that didn’t do MPPT.

      Mike, if you think two controllers would be silly, take a peek under the canopy of a solar car. The Queen’s U. two-seaters had, IIRC, six or eight independent MPPTs- with the array subdivided this finely, we could compensate for the illumination fluctuations due to the shape of the car in early morning and late afternoon. But I agree with you that unless you really need the extra 6-7 amps or so, it would be hard to justify the cost of twin MPPT controllers on your rig.

  9. Glad you got competant advice from the retailer. Now all you have to do is figure out where to put them! Good luck!

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