Solar Upgrade verse Running the Generator

[Exile]

Originally Posted by john61ct

A large bank depleted 40-50% can easily take over 8 hours to get truly Full.

A high-amps charger only saves an hour or so of that, and then only with a high CAR chemistry.

Yes some boats motor that long every day, but running a genny just for charging the last 4-5 hours "long tail" when a few panels put out enough current for that would be pretty foolish.

Hence the strategy (for those boats so equipped) of running the genset early in the day to at least get the batts. past the bulk phase before the solar panels kick in.

If I was already out cruising full-time like sailorboy and could afford it, I'd be inclined to add as much solar/wind/hydro (whatever suits best) for no other reason than the freedom & independence it affords. Might have the fridge & watermaker running off 110v for the sake of efficiency and to keep the genset healthy. Then again, the prospect of eliminating the genset altogether is very appealing.

Of course, much of this makes little sense financially, but then neither do sailboats!

[Kenomac]

Originally Posted by Exile

I'm assuming, even with your new solar array, that the electric h/w is too much of a draw for your batts. and/or inverter. If yours is like mine, the h/w heater draws about 10 amps off of 110v, and the start-up draw is at least 2.5x that.

I have a 230v 1500w inverter I can dedicate to the waterheater. So next season, I plan to plug it in full-time to see if the extra solar capacity can keep the water warm all day following an initial warm up using the generator or engine. I first need to install a selector switch on the 230v side for panel vs inverter. The waterheater is 230v., but I'm finding that during the day the solar is producing a steady 20-22amps, but the batteries are only able to accept 2-7amps since the batteries usually begin the day at 86% and end at 95-99%. There seems to be extra unused capacity.

I'm currently at day four without touching the generator and the battery bank is at 82-86% in the morning then coming up to 95-99% by sunset on 450w of solar alone. All I'm using at anchor is interior LED lighting, a fridge, water pump, microwave, two watermakers, on-demand coffee machine, NuWave induction cooktop and electric toilets. No big screen TV or deep freezer.

[Exile]

Originally Posted by Kenomac

I have a 230v 1500w inverter I can dedicate to the waterheater. So next season, I plan to plug it in full-time to see if the extra solar capacity can keep the water warm all day following an initial warm up using the generator or engine. I first need to install a selector switch on the 230v side for panel vs inverter. The waterheater is 230v., but I'm finding that during the day the solar is producing a steady 20-22amps, but the batteries are only able to accept 2-7amps since the batteries usually begin the day at 86% and end at 95-99%. There seems to be extra unused capacity.

Suggests your batteries are quite healthy. Interesting about the h/w heater. They are typically well-insulated so your idea may be viable. Keep us posted.

I'm currently at day four without touching the generator and the battery bank is at 82-86% in the morning then coming up to 95-99% by sunset on 450w of solar alone. All I'm using at anchor is interior LED lighting, a fridge, water pump, microwave, two watermakers, on-demand coffee machine, NuWave induction cooktop and electric toilets. No big screen TV or deep freezer.

That actually sounds like a lot! Along with aircon, a large freezer is often cited as the tipping point for needing a genset.

[ranger58sb]

Originally Posted by sailorboy1

So on my project list is to add more solar panels to my boat.

But since I installed the panel I also bit the dust and added a diesel generator to the boat.

So - talk me into one or the other.

Don't think I'd choose one completely over the other. If I had the real estate and lived at anchor more often, think I'd add to the solar system anyway, and still run the genset to charge as necessary. (Coincident with electric cooking, water heater, aircons.)

But if I already had some solar as you do, I'd probably just get around to adding more whenever spare boat buck$$ presented themselves and no other service/repair/replace issues were looming on the horizon.

-Chris

[sailorboy1]

Originally Posted by ranger42c

But if I already had some solar as you do, I'd probably just get around to adding more whenever spare boat buck$$ presented themselves and no other service/repair/replace issues were looming on the horizon.

-Chris

Now that was funny

[ranger58sb]

Originally Posted by sailorboy1

Now that was funny

Yeah... That situation happens all the time. Not!

I should have mentioned my thought was also based on an assumption I didn't mention. I think solar requires some additional stuff? Charge controllers? Whatever...

So I assume a) you've already got whatever, and b) all that would be usable for additional panels, so wouldn't require additional outlay for ancillary "stuff."

-Chris

[sailorboy1]

So I am still thinking over this extra solar panel. I did a pro/con list and the main con is the cost. I'm a little surprised that since the CF herd says I spend too much money already that only 1 responder said to basically save the cost. The other big cons are the work to install and the area over the Bimini the panel will take that gets in the way of other things.

I WANT the extra panel but don't need it. It still kind of like the water maker that I decided to do without.

[Kenomac]

Originally Posted by Kenomac

I have a 230v 1500w inverter I can dedicate to the waterheater. So next season, I plan to plug it in full-time to see if the extra solar capacity can keep the water warm all day following an initial warm up using the generator or engine. I first need to install a selector switch on the 230v side for panel vs inverter. The waterheater is 230v., but I'm finding that during the day the solar is producing a steady 20-22amps, but the batteries are only able to accept 2-7amps since the batteries usually begin the day at 86% and end at 95-99%. There seems to be extra unused capacity.

I'm currently at day four without touching the generator and the battery bank is at 82-86% in the morning then coming up to 95-99% by sunset on 450w of solar alone. All I'm using at anchor is interior LED lighting, a fridge, water pump, microwave, two watermakers, on-demand coffee machine, NuWave induction cooktop and electric toilets. No big screen TV or deep freezer.

Originally Posted by Exile

That actually sounds like a lot! Along with aircon, a large freezer is often cited as the tipping point for needing a genset.

I tried hooking up the hot water heater to the extra 230w inverter two days ago and it was an epic failure. When I plugged it in, it was like that scene in the National Lampoon movie "Christmas Vacation" when his wife plugged in the Christmas lights and set off the alarms at the nuclear power plant. The Smartgauge went from 92% down to 78% in 10 minutes, something about the voltage drain. I quickly disconnected and put things back as they were.

[Exile]

Originally Posted by Kenomac

I tried hooking up the hot water heater to the extra 230w inverter two days ago and it was an epic failure. When I plugged it in, it was like that scene in the National Lampoon movie "Christmas Vacation" when his wife plugged in the Christmas lights and set off the alarms at the nuclear power plant. The Smartgauge went from 92% down to 78% in 10 minutes, something about the voltage drain. I quickly disconnected and put things back as they were.

When I turn on my 12 gal. (110v) water heater the start-up surge is literally "off the meter." Amps while running are more like 10-11 @110v and it usually takes 20-25 mins. to heat the water & shut off. So say yours consumes 10 amps @110v (5 amps @230v) -- this would equal about 101 amps @12v and 50 amps @24v, plus maybe a 10% efficiency loss. That's approx. 55 amps for you. Smartgauge may not be all that reliable with this type of load. What did your amp counter show, and what's the total ah capacity of your house bank?

I'm very interested since my fridge & freezer run off 110v and I've been told it's too much for an inverter, even with a large battery bank. Not exactly sure why . . . .

[a64pilot]

There should be no start up load on a purely resistive load, it's not like there is a motor at zero RPM that has to spool up. It's like a big light bulb.
Many water heaters are 1500W, that is like 150 amps or so on a 12V bank and of course half that on a 24V.
Making heat with electricity to heat water or cook food is a monstrous load on a bank, there is a tremendous amount of energy in heat.

[Kenomac]

Following the 750w water heater surge and putting things back to the way they were, the Smartgauge remained at 78% for the next 12 hours. So clearly the amp hours weren't drained, but the surge seemed to create havoc with the 230v 1500w inverter, Smartgauge, Magnetronic counter and 400ah battery bank. No breakers were tripped, but the Magnetronic stopped working for one hour, and all this when the waterheater was already quite warm when I first plugged it into the bank.

[sailorboy1]

You guys would probably get a better discussion if you started a thread with a title that matches your thread drift than slipping it into this one

[Kenomac]

Will do tomorrow. Will you be getting a watermaker this year?

[Panacea2183]

Originally Posted by Exile

Hate to be the only naysayer thus far, and it would no doubt be very nice for a lot of reasons (already discussed) to be more self-contained. Except for economic reasons that is. Especially if your boat already has a genset. If so, then nothing comes close to the energy/cost packed into a gal. of diesel, even when factoring in the add'l. costs (and hassle) of maintaining another engine. My 8kw genset is noisy down below, but almost inaudible in the cockpit (silent for other boats in an anchorage), and I can quickly charge batts. & also run every appliance on the boat while burning 0.5 gal/hour or less.

I think if/when I manage to leave the dock for good I'd take a look at a Watt & Sea instead, and maybe one 100-watt solar panel to keep up with battery self-discharge for when I'm at anchor and away from the boat. Decent quality solar panels & controllers are expensive, esp. if you also have to install arches, etc. to mount them (easier on cats). And I am doubtful that the added cost of potentially shortened battery life (from not topping up as much) improves the equation.

For Sailorboy, he already has a healthy amount of solar and has already made the investment in the genset. So adding more solar at this point would be more about reducing the inconvenience & hassle of running the genset (as Kenomac has done), and not saving boat bucks. There are good reasons for doing so, but the cost of doubling solar capacity would buy him a LOT of diesel & genset run-time.

Only problem with genset only is you'll never get your bank charged to 100%
Unless you run it 5-7 hours (talking flooded batts here) there is no substitute for time when charging flooded batts from 80% to 100% no matter the size of the charger.
I use a lot of power, have 780 watts of solar, 1000 ah bank.
Run genset in am to make water, heat water bulk charge batts, then solar fisnishes the job by early afternoon as well as runnning fridge and ice maker all day.
Also running the genset during absorption stage doesn't put much of a load on it, which is not good for the motor.
Works for me and on sunny days I can go 48 hours with no genset.

[john61ct]

It is IMO just silly to incorporate high-consuming systems designed for incredibly cheap shore power, into designs for mobile applications relying on very expensive low-voltage DC power.

Some very wealthy boaters pay out the wazoo for dishwashers, walk-in freezers, electric hair dryers, ovens and induction cookers, even air conditioning! while living off battery power.

But that doesn't make it any less silly in my book.

Unless you are very power conserving, or running the genset for hours every day anyway, IMO it is always a good investment to maximize solar panels, available space and aesthetic issues are the limiting gactors, never cash cost.