200W Solar Setup

[Orchidius]

I'm working on my solar setup atm, and I can easily fit a 200W panel. More would require some creative thinking, but isnt impossible at all. What I'm trying to figure out is what I can expect of just 200W of solar on an Atlantic circuit with a season in the caribbean. I have a battery monitor, so I'm monitoring electrical usage now to get an idea. I still have to install a house battery bank, so thats not a given yet either (will probably end up in the 200-300ah range).

The boat is pretty spartan (28ft), with just some LED lights, plotter, vhf, ssb, depth sounder and charging of various devices.

What's your setup and what are you getting from it? What are your thoughts on my setup?


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[monte]

From a 200w panel you can expect about 15 amps in full sun for maybe 6 hrs/day so average it to 80Ah in on a good day. Do an energy budget spreadsheet. The big consumers will be nav gear, fridge,autopilot, each at about 3amps x 24 hrs. Expect around 250Ah on passage, 150 Ah at anchor. Allow for additional charging sources to make the difference. Battery bank needs to be sized accordingly, remembering you can only use a maximum of 50% between charges. Look at ways to reduce power consumption on passage, turn off the fridge, hand steer, turn off unnecessary nav gear, you may reduce the consumption to require less or no other charging.

[Ex-Calif]

You are on the right path in my estimation.

Better the further south you go but

7 effective hours/day * 16.5a * .8 efficiency = ~90 amps

If your energy budget is held to 90 and your bank is 300 you have almost 33% of bank capacity for charging.

But only 1 1/2 days "reserve." - If you can get 400 a/h I would.

Use the engine to top off and for the no-sun days and I think you are in pretty good shape.

[Orchidius]

I dont need the fridge and could use it as an icebox, and (will) have a windvane.


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[Snowpetrel]

Got by ok with 80watts and survived with 40watts. If you are sensible about it you should have juice to spare most of the time.

[atoll]

Originally Posted by Orchidius

I dont need the fridge and could use it as an icebox, and (will) have a windvane.


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sounds like you are good to go,but bear in mind with downwind, east-west passages your panel is in the shade after mid day from your poled out sails which will reduce its efficiency,a wind generator might be useful addition,giving power 24/7.

using led nav lights,and interiour leds will greatly reduce your consuption as well.

[Snowpetrel]

An old budget I knocked up quickly (and roughly) for a single 40 watt panel. To get this amount out you would probably need to chase the sun with it to maximise morning and afternoon amps, and minimise any shading. Your 200w panel should do fine if fixed, specially in the lower lats.

Originally Posted by Snowpetrel

Heres a quick and dirty energy budget, some details might be wrong, happy to discuss usage, but its close enough to get a feel for what wattage panel is a minimum. They Assume portable panels that can be roughly aimed and kept clear of most shadowing.



This is a good sunny day, just enough power to keep up with the basics



Cloudy, starting to have to cut unneeded stuff out. Should be able to keep a battery from getting to badly down in very overcast conditions for a few days or recharge the battery slowly if using this profile on sunny days.

Not alot of slack, and 40 watts is about a minimum for basic battery life support on passage, as I have found works out ok for me over the years. It still takes a rigorous cutting of non essential systems, NO mfd's or other instruments, and no watching videos or autopilots. Needless to say any refrigeration is absolutely impossible to run with this sort of energy budget.

[barnakiel]

We have 150W in two panels, one of which is older than 10 years.

Both panels tilt and swivel (to some extent).

Our regulator is PWM.

Our house batteries are 110 Ah (2x55Ah) plain acid.

Max flow I have seen was some 7A. I think a 30Ah day is easily achieved with this setup, but only some of it can be used for charging the bank - due to battery charge curve limitations.

We normally discharged to some 90% in a daily cycle (this includes navlights/anchor, electronics, plenty of cabin light and free use of netbooks/tablets.

We could not reach full charge only twice in last 8 months on our Atlantic circuit (Canary, West Indies, Azores, Canary).

Our alternative is the alternator (60A) but we never have to run it for power anymore.

This is a small boat too (26 ft or thereabout).

PS Two things we will do better next time: black panels and MPPT regulator (total of possibly 50% gain over our present size/package).

Hope this helps.
b.

[Orchidius]

Thanks for the input guys!

Barnakiel, your setup seems to be roughly half of what I had in mind for both battery bank as well as panel wattage and yet you mention you have been able to fully charge the batts every single day for 8 months!?! Could you give us a rough idea of what electronics are hooked up and how you use them?


As optimistic as it sounds, monte and ex-calif are talking numbers in a while different ballpark...

[barnakiel]

Originally Posted by Orchidius

Thanks for the input guys!

Barnakiel, your setup seems to be roughly half of what I had in mind for both battery bank as well as panel wattage and yet you mention you have been able to fully charge the batts every single day for 8 months!?! Could you give us a rough idea of what electronics are hooked up and how you use them?


As optimistic as it sounds, monte and ex-calif are talking numbers in a while different ballpark...

Here we go:

Electronics and electrics hooked up:

- VHF, AIS and GPS (24 hrs continuous on passage, GPS only when at anchor),
- echo and log, (as required)
- nav lights (sunset till sunrise on passage), anchor light (sunset till sunrise when anchored), sure, LEDs,
- cabin lights (plenty, power-LED type, about 4 hours on passage, about 6 hours when anchored),
- a compass light, instrument lights, (as required)
- an SSB receiver (1 hour a day),
- a netbook (4 hours a day+, when anchored),
- a tablet (4 hours a day+ when anchored, 1 hour a day offshore),
- a tablet (unlimited when inshore and piloting).

A typical day (off the battery part only) consumption aboard is some 10Ahs sailing and some 15Ahs anchored. Actual consumption is somewhat higher as we have excess charge capacity that goes into charging off the grid units (like the netbook and the tablet, e.g.).

Typical batt level mornings is about 90% when sailing, about 85% when anchored.

Our batteries are plain vanilla.

It is not an optimistic or pessimistic sound, it is a 6.5k of offshore miles and 6 mnths in the West Indies sound (on this setup, there were other setups before). Anybody welcome to visit the boat and have a look.

The times when we did not charge up to 100% were complete overcast/rain days. You can count on your solar potential to taper down to some 15% of its in the sun capacity on a very gray day.

We both know 100% is actually "100". I believe 99+ is the actual figure. In any case, the charge at the end of the day will drop to well below 1A. Means it is full up.

Mind where and how the boats are used. Day sun hours vary wildly with geography as well as with how your panels are set up. Ours tilt and swivel (much as we tend not to adjust them all that much unless we are anchored).

The important part:

Our 150W panels are 9A nominal, as I have said ours are now capable of up to 7A. With 5 to 6 sun hours, how can we NOT be able to charge our bank in full?

Yes, we can ;-)

Hope this helps further,
b.

[zboss]

A lot of your ability to produce power is how much shading your panels will get. This is a lesson you learn very quickly. In our instance, we have 280 watts mounted on the bimini but we are forced to move our boom to the side so that t does not shade the panels but we still get some shading in the early morning on at least one of the panels.

We also have two panels mounted on wings on the sides. Unless its one or two hours on either side solar maximum, one of these panels is shaded so much it only produces an amp or so.

The max we see produced on a bright sunny day here in Florida in July is about 140ish amp hours. For example, yesterday morning we were down 140 amps because we had two days of pretty much rain rain rain but it was very bright and sunny yesterday for most of the morning and afternoon, so an average of about 11 amps and hour from 554 watts of solar on a great day.

Still, we have only have to run our engine maybe once a month to charge.

The issue we have is that we never really hit the optimum voltage on the Trojans, so even though we are returning all the amp/hours I believe we are still sulfating the batteries a bit.

I'm starting a new thread on using my Balmar to equalize the batteries...

[SV Lift]

Zboss, just to clarify you have 554w total just 280w of that are on the bimini?

You're completely right about the shading. Between the mast, backstay, and radar pole one of my two panels is almost always shaded. Have 320w but only getting 50-70 AH a day. Which would be fine if the fridge took the 30 AH/day I expected but it uses more like 100AH/day.

Half tempted to take a hacksaw to the above mentioned obstructions. I don't really need a backstay if I'm sailing upwind right?

To the original poster- moral of the story is don't have a fridge and you should be fine.

[zboss]

Originally Posted by SV Lift

Zboss, just to clarify you have 554w total just 280w of that are on the bimini?

You're completely right about the shading. Between the mast, backstay, and radar pole one of my two panels is almost always shaded. Have 320w but only getting 50-70 AH a day. Which would be fine if the fridge took the 30 AH/day I expected but it uses more like 100AH/day.

Half tempted to take a hacksaw to the above mentioned obstructions. I don't really need a backstay if I'm sailing upwind right?

To the original poster- moral of the story is don't have a fridge and you should be fine.

We have 2x140 on the bimini and 2x137 on the rails.

I agree... computers and fridges are the amp killers. Also, autopilots vs. windvane.

[leftbrainstuff]

Originally Posted by monte

From a 200w panel you can expect about 15 amps in full sun for maybe 6 hrs/day so average it to 80Ah in on a good day. Do an energy budget spreadsheet. The big consumers will be nav gear, fridge,autopilot, each at about 3amps x 24 hrs. Expect around 250Ah on passage, 150 Ah at anchor. Allow for additional charging sources to make the difference. Battery bank needs to be sized accordingly, remembering you can only use a maximum of 50% between charges. Look at ways to reduce power consumption on passage, turn off the fridge, hand steer, turn off unnecessary nav gear, you may reduce the consumption to require less or no other charging.

I'd also take another 20% off leaving you with 30% of your house battery capacity that's usable.

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