By C45Sanctuary on 8/19/2008 9:24 AM

The two new solar panels arrived yesterday.  Everything needed to design, integrate, and test the new elecrical system is now at the home port laboratory.  The wind generator is mounted approximately twenty feet above the ground, with 10-guage electrical wiring leading to the battery bank.  I've mounted the Heart Interface Link 2000-R control interface flush onto a plywood panel.  Two three-pole switches and an analog amperage meter are also mounted on the same panel.  Most of the wiring will terminate here, simulating the onboard electrical panel.

I'll design a box to contain the equipment that will be located within the battery compartment.  The Freedom 25 inverter will be mounted in a separate physical location than the battery bank.  "Shore power", a.k.a. typical 110 household current, will be connected to the AC input of the Freedom 25.  The AC output (as well as the DC power circuits) will utilize a separate isolated ground, instead of the ground being supplied by the AC input.  Using isolated ground will simulate the difference in ground connections aboard a marine vessel.

For the past few weeks I've been tracking the voltage drop of healthy 6V Trojan T-105 deep cycle batteries.  When they were first purchased, the voltage across the terminals measured 6.30 +/- .005 volts DC.  They decay approximately .01 volt per week.  Two batteries, used as a reference baseline, have never been connected to any recharging mechanism.

Two batteries have been connected to the wind generator for several hours when there was a heavy, sustained wind.  After charging was complete, the batteries measured 6.38 +/- .01 volts.  This dropped to 6.30 +/- .005 after the batteries had rested for 24 hours.  The next test will probably be calculating available amp hours at a C20 discharge rate.

By C45Sanctuary on 8/6/2008 9:35 PM

A few weeks ago I did some research on how much it will cost to make battery cables for the test system.  Wow.  Talk about expensive.  So, to minimize the cost, I ordered marine grade copper wire of the appropriate size, battery lug connectors of the same size, and then waited.  The first order for the battery lugs was cancelled by the vendor since they didn't have any in stock, they weren't planning on getting any more in stock in the forseeable future, and they didn't bother to inform me of that fact until I called them a week after I placed the order.  The second order for battery lugs was also cancelled, this time by a different vendor.  They also didn't have any in stock, but at least they sent me an email within a few minutes of my placing the order so I wasn't left hanging.  The third order for lugs (from yet another vendor) was successful.  But, by the time the lugs arrived yesterday, the marine grade wire had been sitting idle for almost a week.

Making battery cables by hand is pretty straightforward.  Cut the wire to the appropriate length.  Whatever that length is believed to be, add a few extra inches just to be sure.  I used a hacksaw to cut the wire (AWG size 1 is pretty darned thick).  Strip away the insulation from the last inch of cable.  With the insulation removed, force a lug over the exposed wire.  It'll be a pretty tight fit.  Then, with the lug pushed all the way onto the expose wire, use a large vise to crimp the connector in place.  Some people advocate using solder, but I don't since solder doesn't conduct nearly as well as copper, and a good solid crimp will force the wire flush against the inside surface of the lug connector.  After the lug is crimped solidly, use heat shrink tubing to seal the outside of the connection.

By C45Sanctuary on 8/3/2008 3:34 PM

For the past ten days I've been tracking the voltage decay rates on the six new Trojan T-105 batteries.  They all had an initial voltage of 6.31 volts, +/- a hundredth of a volt.  After ten days they have each decayed .02 volts.  The decay rate appears to be the same across all batteries (a good thing) and follows a predictable pattern.

A few days ago I mounted the Air-X wind generator atop the home port dwelling.  Yesterday, I connected it to a pair of T-105s wired in series (to achieve 12v).  There hasn't been much wind to speak of for testing the configuration.  When the solar panels arrive I'll wire them to a different pair of T-105s.  The third pair of T-105s are the reference point in this set of tests.

By C45Sanctuary on 7/28/2008 10:25 AM

I purchased six new batteries a few days ago to replace the six T-105 batteries that have been installed for several years.  I figure I'll bring the six older batteries back to home port and use them for testing and lab purposes.  If I am able to prove the old batteries are still in decent shape, I'll use them for various lab and testing purposes around the house.

After the new batteries had been in the garage for a day, I remembered I would need a baseline for "good" battery discharge decay rates vs "bad" battery discharge decay rates.  All batteries will lose some of their charge over time.  Good batteries decay at a much slower rate than bad ones.  So, with multimeter in one hand an a pad and pen in the other, I began charting all six batteries.  After a few days a decay rate has emerged: they each lose about .01 volts per day, assuming they were fully charged to begin with.

By C45Sanctuary on 7/26/2008 2:13 AM

I couldn't sleep so I thought I'd do some planning on the electrical system upgrades.  So far, I have the Air-X Marine 400w wind generator sitting in the original packaging and two 100w solar panels on order.  I'd like to add a third solar panel to the solar array but there were only two available from my preferred supplier.

The Air-X Marine has a built in voltage regulator that enabled the wind generator to charge the battery bank whenever the voltage drops below 12.75 volts.  The solar panels operate closer to 17 volts at 14 amps max current.  I'll need to use a voltage regulator for the solar array that converts the excessive voltage into higher amperage.  I haven't identified exactly which products can do that, yet.  All of the ones I've researched simply limit the maximum voltage, which ends up wasting a significant amount (more than 30 percent) of the wattage generated by the solar array.  Ideally, the excessive voltage could be stepped down to somewhere near 12.75 volts and the difference be converted back into amps.  I believe this is possible, since watts = Volts * Amps.  If you have a 100w output at 17.4 volts, then the amp output is approvimately 5.75 amps.  If you drop the output voltage to 12.7, the amp output should be close to 7.85.  Such a regulator would require some internal parallel and series circuits to shift those values around a bit, since voltage is a constant when in a parallel circuit and amperage will vary, but in a series circuit the exact opposite is true (voltage drops and amperage stays constant).

So, what does this have to do with the remote control panel (Heart Interface Link 2000) for the Freedom 25 (now Xantrex 25) power inverter?  Well, after digging through some old documentation and doing a bit more research on the products, I learned that the remote control panel was built by Heart Interface Corporation as a battery monitor and charging computer.  It's a lot more than a simple remote control panel.  Yeah, the remote control panel has an RJ-14 plug that connects it to the Freedom 25 inverter/charger.  But, more importantly, it has eight wires comming out of the back of it that I couldn't comprehend until I couldn't sleep Friday night.  Those wires had to be doing something, I reasoned, so I went searching for some engineering documentation that would explain their purpose.

It turns out that the Link-2000 is a pretty decent battery charging and conditioning computer.  The documentation I located identified where, exactly, a solar array should be connected to the charging circuitry.  It also identified where a wind generator should be connected.  So, with that sort of knowledge on hand, I figure I can finally get some sleep.