Solar power 12v & 32v battery charging

[q240z]

Since the transient season has begun we're out on the hook. The upsides are that the view is excellent and it's pretty quiet. The downside is having to run the genset to charge the 12 and 32v house batts. I've been looking at my options and solar is what my blowboat buddies are recommending. 180w PV panels run about $800. PV controllers that can output from 12-60vdc and 60A (with equalization and multistage charging capacity) run a touch over $400. For that kinda money, I can buy enough diesel to run the genny for quite a while. On the other hand, once paid for the solar setup provides clean, "free" energy, and the system could be split to tend the 12v system one day and the 32v side the next. The controllers can also handle several additional panels.

Any thoughts on solar? This question is particularly aimed at those who spend substantial amounts of time on the hook.

[JLR]

Is that a 57 Chris Craft Constellation?

[q240z]

Close. It's a 52.

[Passages]

Cool, looks like a late 60's model. First time I saw one was in 1968 and admired them since.

Anyway back to your question. I'm a fan of solar, just wish the panel price would go down. When calculating genny costs, don't forget maintenance and the noise factor. Solar is silent. BUT $1200 is a bunch of change. You could run you genny for about 300 hours. What is that? - one or two seasons on the hook? After that you'll be cost free.

Your call, but to me, a 2 year payback is a good deal.

[MikeP]

I agree it's a great way to go if you don't need to run the high power items - stove, A/C, water heater, etc.

Last year I did a bit of checking and was looking at a GE 200W panel and an Outback controller. The panel was nearly 5 feet long and over 3 feet wide. I thought it might go on the deck just forward of the windshield but the Admiral nixed that idea as making Brigadoon look like an "Okie-Boat"

Then I thought about somehow incorporating the panel into the bimini top. But after checking it all out it didn't really matter, a 200W panel didn't put out near enough power to keep the batts adequately charged to sustain us in the lifestyle to which we've become accustomed!

We almost never stayed in Marina's with Brigadoon - mostly anchored. And we don't run the genny when we don't need it - the 3500W Outback inverter does a nice job. But we run the A/C quite a bit and the thought of no A/C and no hot water is too much like camping. So for us the genny would be running at least several hours a day, just as it does now, regardless of how much solar we had avialable.

I suppose with a big enough batt bank, a big enough invertor, and enough solar panels, you could run the serious stuff but it would take a lot of panels and serious batteries and general system re-engineering I think...

I'll wait for them to sort out that cold-fusion!

[MarioG]

Wouldn't solar be a good choice for our boats that are unattended on a mooring? could current "off the shelve" solar panel technology keep up the demand of our 32 and 12v systems? lets say fridge, pumps, and starting batteries? On top of the bimini top is a good place I would think.

[Pascal]

from what i see, a 200W panel will give you 60amp/hrs a day...

on average we use about 350amp/hrs a day when on the hook (fridge, lights, TVs, etc...) so i'd need at least 5 of these panels to keep the batteries charged. at $1000 a piece... $5000 buys a lot of fuel !

or i'd need to live like a ragboter ! :-) ok so maby using a more efficient fridge/freezer, etc... woudl be a good start but still not cost effective.

[q240z]

MarioG, that's what I was thinking. I don't watch much TV, none when I'm on the hook, and we don't need AC here until about August. I'm installing a propane stove soon, so the biggest concern is keeping the batteries topped up.

[egaito]

MarioG, that's what I was thinking. I don't watch much TV, none when I'm on the hook, and we don't need AC here until about August. I'm installing a propane stove soon, so the biggest concern is keeping the batteries topped up.

Same here...when we're out on the hook with Misty, we tend to live pretty simply. We run the genny in the AM for coffee and showers, again in the evening to cook and cool off the cabin. Rarely is it running all day. I think a couple of PV's on her hard-top would reduce the need to run the genny to top off the batteries.

When considering all of the expenses of operating the genset, fuel, oil changes, filters, impellers, other maintenance/repairs, and probably somewhere about $1/hour of basic wear and tear ($10000 installed / 10000hrs), it starts to make some sense.

[Pascal]

the problem is that you're looking at $1200 (incl regulator, wiring, etc...) to get 60amp hrs a day...

the inverter built in charger produces that in 30 minutes.... or about $2 (1/2 gallon and $0.5 wear).

which means that you'll need 600 days on the hook to re coup the cost of the panel... in my case, we average probably 50 days a year, considering 2 day weekends but at the end of the second day we recharge at the dock... that's 12 years.

do my numbers add up ? maybe i'm wrong...

dont' get me wrong, I'd love to put a few panels up on a hardtop and reduce genset time but it doens't quite add up just yet.