We have an old Aerogen 6 wind generator
on our boat. It has been working ok, though I have never used it in strong winds till now, as it had rumbling bearings with a flat spot from being parked in the tied off position for the better part of ten years, was quite badly out of balance and I felt the strain from over 15 or so knots apparent wind
would not be a good for it.
So, I got all enthused, hauled it down, stripped it, fitted new bearings (only $18 each
), sanded, painted and balanced the blades, repainted the chassis, and even, in a fit of silly enthusiasm, put neat little black speed stripes on the blades. (They look really good when the blades are moving fast!)
Then, as good luck would have it, there was a forecast
for some seriously strong winds last night and I knew the house bank was down to about 12.6 volts, what a great time to test things.
So I belted down to the boat, untethered the blades (the Aerogen 6 is supposed to be left tied off when not in use, as against the 4 and 2 which can look after themselves.) and waited for the wind
Well it did come, no idea what it was blowing, as I didn't think to turn the instruments on, but it was enough to shake us around in the pen.
Alas, things did not work as I expected. The amps started to climb up to 3, 4, 5, then phhtt... back down to NEGATIVE amps, around -1 or maybe more. It would do this for a few seconds, and you could see the blades slow right down, then suddenly it would go postive half an amp on the ammeter, the blades started spinning up again, 3, 4 amps... then phhtt! Back down to negative amps again.
Now these current
readings were from a new analouge ammeter fitted on a dedicated link to the windgen's regulator
, so they are not influenced by anything else in the boat, which was shut down anyway, except for a few cabin
I also confirmed the current
readings from the house battery monitor
system and it was telling me just about the same thing (minus a bit for the lights that were on) albeit much slower because of the digital readout.
House bank voltage would climb to 12.8, sometimes 12.9 when the 3 or more amps were coming in, but then slowly drop again when the ammeter went negative. Unfortunately, the only volmeters I have on the house bank at the moment are digital, so there is a bit of a delay in the readings.
ANYWAY, I went aft to the regulator
, which is in a compartment behind the engine
with a great big heat sink for the dump resistors, and found that it was buzzing away, apparently alternatly dumping power into the resistors. I tapped in my multimeter at various points to check that it was not seeing incorrect voltages due to cabling problems, but nope, it was seeing excatly the same battery
voltages the rest of the system was seeing, which it should as the cables
are all new and specced for 50 amp loads, not 3 or 4.
So, this FEELS like a regulator problem, but for one thing.
I am bother by the reverse current I observed. I certainly saw negative current flowing back out of the battery bank into the regulator when it was shunting power to the dump resistors. Maybe, just maybe, that is just a relay load to perform the shunt, but I am wondering if it is something more ominous.
If it is normal, then I suppose the reg is out of calibration and simply thinks 12.8volts or so is fully charged, it is supposed to cut over to the dump regulator at 14.2 volts.
But maybe it is something else, something I have missed. Any ideas?
And if the reg is kaput, then what better time to retrofit with a regulator that is better suited to alternative battery chemistries. As it is, 14.2 volts is perilously close to the Lithium maximum, and I would rather there was room for error in the system if I ever fit lithium batteries. If I pursue this path, does anyone have a recommendation of a good windgen regulator that can handle 30 amps and shunt to a dump load resitor, while allowing user calibration of the cutout voltage?
P.S. Forgot to mention... before the rebuild
I had seen it putting out a good 15 amps or more, but that was a year or so ago now.