Review of our $270.00 Marsrock 12volt 400W Wind Turbine
I put this review together for Amazon but they've not posted it yet so I though I'd share it here.
OUR POWER SITUATION: We bought this for our boat while passing through Marathon
Florida and didn't get a chance to install and test it until we arrived in the
Bahamas.
Our boat has 400 watts of solar, 470Ah batteries in 4 Trojan T105 flooded lead acid batteries and a separate 12v starting battery powering the usual boat
LED lights and
equipment, a 9 Cubic Foot fridge cooled with a Danfoss 12v
compressor with air cooled condenser, a recently added large 12v Engel type portable fridge which we use as our deep
freezer. The Engal also has a 12v Danfoss type
compressor and air-cooled condenser. When running the fridge and
freezer they each draw about 4 to 5 amps and cycle on and off about twice per hour and when running they are on for about 10 to 15 minutes. The
refrigeration is our largest consumer of amp-hours on our boat. If we had a R.O. water-maker that would be the big one. Without the turbine we were generally fine on solar power if we had good direct sunlight and adjusted the
panels toward the moving sun and only needed to run the main
engine (has one 70-amp
Balmar alternator) about every 5 days for about three hours. Our plan with the wind turbine was to avoid running the
engine at all and since we are back in the tradewind belt. So far, with the turbine we have been able to avoid running the engine to charge the batteries.
Overall the unit looks to be well made and the fit and finish appear good. The blades seem well balanced and fit snugly into the mounting hub and the tips are measured to be equal distant. When first looking at the turbine right away I wondered how a 12-volt turbine that is rated at 400 watts can ship with such a small gauge wire coming out of its base. It appears to be 16 gauge at best. At the turbine’s rated voltage and power, it would need to handle a peak of 30 Amps of current. Okay fine, over a short 12" run that could
work since the unit won't be operating 100% of the time at the rated 400 watts. To avoid voltage drops in the three-phase line from the turbine to the supplied MMPT060 controller I used a 35-foot length of 3 conductor 12-gauge wire. When pushing and pulling the rotor shaft in and out (axially) there seems to be no thrust bearing which gives me the impression the shaft is allowed to float on the magnetic force between the rotor’s magnets and the
steel in the stator’s
core. After looking into this further it seems several other
reviews of these Chinese turbines said the fit between the bearings’ inner races and the shaft is too loose allowing it to easily slide; more on this later.
We had a fabricator in
Nassau make us a really nice 8-foot mast from type 316
stainless steel 2” tube and stayed it with two short pieces of 1” stainless tube using common stainless yacht awning
hardware instead of welding.
Since we are not on a farm and on a
small boat living close to this thing, we definitely needed a way to stop it instantly, so we added a STOP/FREEWHEEL/RUN switch. We bought a 5-dollar two pole three position toggle switch at Home Depot and wired it using the pictured diagram. Basically, the thing just shorts the three turbine leads together creating a magnetic break for STOP and opens the leads up for FREEWHEEL and conducts them straight through when in RUN position. No need to waste your $90.00 on one of those “black box” stop switches
sold by “wind companies” that do the same thing without showing you the
wiring.
For about two weeks now we have been using the turbine in about 12 to 15 knots of wind and have found we get 4 to 7 amps of charge current in those conditions. With it running 24/7 we have had no problems keeping our batteries topped off. Today we are having a cold front pass through and are seeing 20 to 25 knots of wind with higher guests. In those conditions we are seeing about to 20 amps of charge current. In reviewing Wind versus Power output for 400-watt turbines I’d say that ours is living up to expectations for far less
money than the expensive Made in
Germany turbines that sell for $1200.00 vs $260.00
ISSUES:
The turbine produces two kinds of
noise, aero
noise and mechanical structural born noise. The aero noise seems worse (like whistling and whirling sounds) at wind speeds of 9 to 12 knots. Sometimes I find myself thinking the noise is not worth the 2 to 3 amps of charge and consider switching it off during the day when solar is doing the heavy lifting. At 13 to 20 knots the turbine kind of purrs and the annoying high
pitch whistling sounds go away. The mechanical structural born noise is likely from the loose shaft to bearing fit and at low speeds it make a kind of random, wobbling, loose bearing sound but it too gets better with steady 15 knots of wind.
The MMPT060 controller that came with it is a piece of junk, but I thought I would try it out before upgrading to something better. I say its junk because the leads are also a bit small (gauge wise) for the 600 watts the controller is alleged to be rated. Also, what really *sucks* about is apparently no thermal dissipation was considered when they designed its package. Its’s heat sink is just too small to adequately dissipate the heat it generates passively. In fact, it gets so hot I nearly burned myself when I touched it when the turbine was operating in 20 knots of wind. I don’t have a laser thermometer on board to prove it, but my experience says it felt like at least 170 deg F. Too hot to be healthy for the MOSFETS doing the switching inside. I also don’t want it burning our boat up. Since I can’t easily get an upgrade in the
Bahamas, I had to quickly find a solution which ended up being mounting it at about a ½ in from the wall it was screwed to and turned it around so the black heat sink fins are not against the wall. For added measure I attached a spare 12v “computer” fan to it. These measures seem to have worked and I may not burn the controller up before I can get an upgrade.
As far as the bearing issue goes, I plan to take the unit down and disassemble to see if the included bearings are capable of taking axial loads. If that is the case, I will figure out a way to fix the shaft to the inner bearing hubs using blue Loctite or something similar. This should stop 90% of the annoying structural noise.
Bottom line is I like messing about with stuff like this, so the
price makes the cost to play reasonable and, in the end, I get what I want for our boat’s energy system. If you don’t like
DIY projects and just want a turbine that works, go for the $1200 model and hire an installer.
For those you live on land and don’t have steady winds that are non-turbulent forget any kind of wind turbine and buy all the solar you need for less than $1.00 a watt – you’ll be much happier and won’t get caught in the dark. I can’t believe the number of people who think they can mount this turbine to their second story
deck railing and it or ANY turbine to
work. Those reviewing that have inadequate wind are wasting everybody’s time.
HEY SELLER: SHIP WITH A BETTER CONTROLLER even if it costs a bit more and EXPLAIN why and you’ll have happier customers. Also address the thrust bearing issue – you fix this you’ll have a real winner! And if you send me a free revised turbine I’ll test and review it also for FREE!
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