CA works for a company that gives gifts for various anniversaries. For her 10th anniversary, she asked for the Black and Decker drill. For her 15th anniversary she asked for the Coleman 18W solar panel.
It's 1.5 A at best. Assuming 6 solid hours of great sun (and 4-6 more hours of poor sun) it's good for 10 or so Amp-Hours (Ah) of charging during a day.
It's more-or-less a toy. But it's free.
Red Ranger's batteries impose an upper limit of 225 Ah before they must be recharged. [450 Ah and they're stone dead.]
Our current energy budget estimates 60-70 Ah per day at anchor. This means we can go for three days before the batteries require charging. Our 8MR2018K alternator puts out a peak of 55A (at high RPM's). It would take 4 hours to recharge for 3 days of hanging on the hook.
That's over a gallon of diesel per day. Call it $4 per day for power. A large carbon footprint.
The toy solar panel puts in 10Ah per day, 16-20% of what we use. It's a little bit of a buffer. But it's not a solution to the power problem.
Really, we've got a lot of work to do. In Power Research, I started looking at this issue. Initially, I just wanted to replace the battery isolator diodes. It's never that simple.
We need to get rid of the isolator diodes and use a voltage sensing relay (e.g., BEP 716). This can improve charging efficiency by removing the diode's 0.75V drop. I made a foam-board mockup to see how it would fit in the engine room.
Plus we need to replace the "dumb" (constant voltage) shore-power charger with a MasterVolt ChargeMaster 12/100-3 charger. [I made a foam-board mockup of this, also.]
We really need a proper array of two (or three) 130W panels. Each of these produces up to 7.6A. 10 hours of full-power charging might balance our 24 usage. We need to do more analysis here.
We also want a Duogen water/wind generator. We can use the wind mode at anchor and the towed mode when sailing.
A pure sine wave inverter will keep the computers happy. Something like the Xantrex ProSine 1800. Since we already have plenty of outlets, we need the 806-1802 hardwire model that can be wired into AC circuit #1.
We may also need a separate generator to charge the batteries in case all else fails. A little Honda EU2000i, for example. We could rig a short cord to Red Ranger's shore-power jack and use it to charge the batteries or run AC appliances or even jump-start the engine.
Step 1 is the BEP VSR. We can then connect the toy solar panel (and it's little 7A charge controller) to charge the batteries while we're away from the boat during the week.
That will get us started.