New boat system...looking for advice

Erinscot · April 2013

I have recently purchased a powerboat that formerly lived in a marina, with shore power. I will be keeping the boat on a mooring, with no shore power. I am going to install some PV to keep the batteries charged. My moored demands include a beer fridge (about 5A when in duty), an LED anchor light (miniscule), bilge pump (probably <5A when in use). When we are on board, there will be higher draw including lights, 2A iPod chargers, etc.

Current house bank consists of two exide HP31D's, starter bank is a pair of group 24's. Current charger is a xantrex 40+. I have lots of room to play in the mechanical area, and about 8'x4' for panels.

What recommendations would you esteemed experts suggest for my needs? Is there a setup where I could still use the 40+? Seems like a waste to get rid of it. In the future, I will probably want to add an inverter to the mix. Should I just do this now?

BB. · April 2013

Re: New boat system...looking for advice

Will the boat be free to swing around the anchor? Or will the boat have a fixed orientation during the day so you can point panels at the sun?

Also, solar electric panels do very poorly with any shade/shadows--Will the panels have no shade for most of the day?

-Bill

vtmaps · April 2013

Re: New boat system...looking for advice

Erinscot wrote: »

My moored demands include a beer fridge (about 5A when in duty), an LED anchor light (miniscule), bilge pump (probably <5A when in use). When we are on board, there will be higher draw including lights, 2A iPod chargers, etc.

Welcome to the forum. When you design a system you MUST know your loads. Get a kill-a-watt meter and see what that fridge draws in a day... it doesn't draw 5 amps all day long.

The usual way to design a system is
1) measure your loads
2) choose a battery and inverter that can supply the load
3) buy enough panels & charge controller to keep the batteries happy.

you can go about that backwards... start with a battery and figure out how much load you can power. Is that your plan, to make do with the two HP31D's?

Also, the shade from overhead power line, rope, antenna, etc can be devastating to your production.

--vtMaps

Erinscot · April 2013

Re: New boat system...looking for advice

The boat will be swinging on the mooring. There will be zero shading. I would prefer to stick with the current house bank for now. I know that the batteries will satisfy the draw needs for at least 24 hours (according to the previous owner)

BB. · April 2013

Re: New boat system...looking for advice

If the boat swings on anchor and you have no control... You probably would need to mount your panels either flat (or near flat) or mount them in a triangle (1/2 face left and 1/2 face right tilted to the latitude of your boat's operating area).

If most of your operation is in the summer and near none in winter, then flat may be OK. You can alway use PV Watts and see how seasonal tilt would affect output.

If you do the triangle mount--I would guess the output based on 1/2 of your total array (400 watts left, 400 watt right, just a single 400 watt array pointing south tilted at latitude).

You are getting into an area where it could be difficult to estimate solar output (triangle/tilted to latitude swinging at anchor). Flat would be a lot easier (no tilt to worry about).

For example, lets say Toronto ON with either 800 watts of panels flat or 400 watts tilted to latitude:

Flat:

Month      Solar Radiation (kWh/m2/day)
1      1.47     
2      2.27     
3      3.19     
4      4.36     
5      5.60     
6      6.14     
7      6.02     
8      5.15     
9      4.08     
10      2.55     
11      1.30     
12      1.07     
Year      3.61

Use 4 hours of sun minimum, 800 watts, your AH per day at 12 volts would be:

800 watts * 1/14.5 volts charging * 0.61 DC system efficiency * 4 hours minimum sun per day = 135 AH per day

If I use 400 watts tilted to near 45 degrees:

Month      Solar Radiation (kWh/m2/day)
1      2.69     
2      3.51     
3      3.98     
4      4.68     
5      5.29     
6      5.48     
7      5.51     
8      5.23     
9      4.96     
10      3.61     
11      1.95     
12      1.97     
Year      4.07

You should get more sun in winter. But because you only an use ~1/2 the array, the total power generation will be less (or about the same during a couple of winter months).

If you have issues with snow--That could be another factor--But flat, over all, appears to be a better setup for you, even fairly far north (taking a SWAG--scientific wild a$$ guess). You can play with different combinations of panel tilts and PV Watts and average out NEWS orientations and see what happens.

Your call.

-Bill

Erinscot · April 2013

Re: New boat system...looking for advice

I am looking at a flat panel orientation, and am near Kingston, a wee bit higher in latitude than Toronto. Good guess!

BB. · April 2013

Re: New boat system...looking for advice

I am getting pretty good at guessing at Canadian accents from posts.

-Bill

Erinscot · April 2013

Re: New boat system...looking for advice

Must have been the beer fridge....

BB. · April 2013

Re: New boat system...looking for advice

Us moderators can see your IP Address... Just plug it into a website like this, and we can get close (much of time):

http://www.geobytes.com/ipLocator.htm

It saves a couple posts so we don't give numbers/answers that would be better for Arizona.

I did have one poster convinced for a couple of moments about regional typing accents.

-Bill

Cariboocoot · April 2013

Re: New boat system...looking for advice

You only have a four foot by eight foot space for panels? 32 square feet isn't much room, even for monocrystaline.

Skippy · April 2013

Re: New boat system...looking for advice

Just an F.Y.I - The panels I am looking at are 218 watt - sized 40 inches wide - 5 1/2 feet long.

Panamretiree · April 2013

Re: New boat system...looking for advice

Just surfing the forums and found your posts. Had a 31 foot Uniflite in the 1000 Islands at William's Marina from 2005 to 2007 (then headed to Victoria and lived on a 40 foot Bayliner Bodega for 5 years). When I got the Uniflite, it had two 12 volt starting batteries hooked into two old 20 amp cct breakers. spent the first summer retrofitting the complete electrical system - 120 VAC and 12 VDC.

Had a small bar fridge drawing less than 1 amp on 120 VAC, lights, electronics, stereo, small kitchen appliances. Bought a good BBQ and a small one burner butane cook stove.

Put in 4 Trojan L-16 batteries, 2-100 watt solar panels with charge controller, and a 1500 watt xantrex inverter. Galvanic isolator, new 12 VAC and VDC power panels, and cross-connect switches. Worked extremely well. Could leave the boat for the week in the marina unplugged from the grid, come back the next weekend and the batteries would be fully charged and everything in the fridge cool.

For myself, I would keep the Xantrex 40+. Already wired into the battery system and when alongside, you'll be able to charge your batteries (you will probably visit a marina in your travels). You cannot use it away from the grid unless you have a generator on board hooked into the 120 VAC system.

I know the good people on the threads look at the load analysis, but for myself on small boats, amp-hours are king. This is mainly because when away from the grid most everything is 12 VDC and not that big, or a lot of it when at anchor - the choice of solar panel size also allows you a lot of leeway in this regard. Will say that some of the integrated boat systems that are being operated do consume power - especially radar. Had the pleasure of using such a system when I skippered a 50 foot Maple Leaf from Puerto Vallarta to Victoria last August. Recommend an AIS system if you like to play - a lot of small boats on the west coast not only receive but transmit as well. It's a bit humorous to have an AIS contact and find out it's a small 30 foot sailboat (I digress).

I would change out the house bank (it's 2-12 volt batteries) and install 6-Trojan T-105s (very common - or equivalent) at 225 amp-hrs. You will have battery bank of 675 amp hours and it should be sufficient for all your needs. The solar panels you have should be more than sufficient, but you could consider smaller panels. Install a good charge controller as well.

If you are able to have iPod chargers on board, there must be some sort of inverter on board unless you have us 12 VDC chargers.

For an inverter I would recommend at least a 1500 watt unit without a charger because the Xantrex is installed and will do this job. if you install an inverter, I would also install a galvanic isolator in the 120 VAC ground as it enters the boat and before any 120 VAC power panel. You must now have a remote read out for an installed galvanic isolator IAW regulations as well.

I would then wire in some receptacles and other items. On a boat you do not connect the 120 VAC ground and neutral as you would in a house. This is because the 12 VDC and 120 VAC grounds are connected together on a boat in accordance with Transport Canada regulations (yes ABYC gets mentioned as well).

Just my $0.02 worth of opinion.

Have a great time boating there, we did.

Cheers

Panamretiree · April 2013

Re: New boat system...looking for advice

My thoughts on kWhs for loads and amp-hours is because of space. kWhs is for array sizing, amp-hours for battery bank size. Boats have limited space for solar panels, but the technology has changed and advanced since I bought my 100 watt panels such that you now get more than double the wattage for the same or smaller surface area, therefore the kWhs for array sizing is no less important, but not as space critical. This is not the same for batteries, unfortunately. Battery space on a boat is generally limited, and the ability to run wiring is a challenge depending on boat and age. The placement of equipment is also an issue, when retrofitting a boat and installing new equipment, you generally loose storage space. Being a contortionist is a plus when working on a boat.

Thought I'd clarify the rationale of my previous post, and trust I'm not too far off the mark.

Cheers and Happy Boating.

Erinscot · April 2013

Re: New boat system...looking for advice

Thanks for the replies.

The inverter is pretty low on my priority list. It is more for my landlubber wife who is used to the convenience of AC. The only AC device currently on the boat is a small microwave, wired into the shorepower panel.

My primary concern (other than keeping the beer cold) is keeping the bilge pump powered. It is a dry boat, but as we all know, thru-hulls can fail. I do not know the actual specs of this pump, but most draw 5A or less when pumping. Worst case scenario is 5A constant.

For the time being, I would like to stick with the HP31D house bank, primarily for cost. Unfortunately, I can not find a 20hr rating for these batteries, as they appear to be starters. The prior owner was very learned, and very carefully analyzed the cost/benefit of all his equipment. I am not in the position to question his choice of storage.

I realize that it is difficult to calculate required panels for this bank without knowing the A/Hrs for the bank, but I guess I am looking for an educated guess here.

Do you think a 150-200W array routed through a PWM would be sufficient to keep this system charged up? Bear in mind that I will be starting up the engine on most (but not all) weekends.

Erinscot · April 2013

Re: New boat system...looking for advice

Looks like I might have found a 36V 280W panel for cheap. Do any of you in-the-know see an issue with running this through a tristar 45 mmpt?

BB. · April 2013

Re: New boat system...looking for advice

What is that 36 volt rating? Is that Vmp (voltage maximum power) or Voc (voltage open circuit)?

For a 12 volt battery bank, that panel even connected in parallel will be fine. For 24 volt, frequently those 36 volt panels are Voc (open circuit) rated and are not high enough to charge a 24 volt battery bank if connected in parallel.

How many panels will you be getting? Depending on how many and your battery bank voltage, you can run from 1-3 panels in series (and more strings in parallel) to get the most effective match to your needs.

-Bill

Erinscot · April 2013

Re: New boat system...looking for advice

I don't have the Vmp or Voc yet. This is a panel from a solar farm that has been rejected by QC, but is still servicable. The engineer is going to get me the info in the next few days. I will be running the single panel through the tristar to the 12V house bank.

Erinscot · June 2013

Re: New boat system...looking for advice

So, I finally have the panel. STC pmax 285, Impp 8.16, Vmpp 35.0, Isc 8.65, Voc 44.4

Obviously, I need an MPPT controller to see the amperage benefits of this panel at the 12V level. What is the most affordable controller that actually works, and will not destroy my boat? I will not be adding any more panels to this system, so the tristar is probably overkill. Any other ideas that will save me some cash?

westbranch · June 2013

Re: New boat system...looking for advice

The currently unavailable, but due very soon, Rogue MPPT is probably your best choice. http://www.roguepowertech.com/products/mpt3024.htm

BB. · June 2013

Re: New boat system...looking for advice

The MorningStar 15 amp 12/24 volt MPPT charge controller would work fine too. It is a tiny bit undersized at 15 amps and 12 volts--But that means you may miss out on 10-40 watts around noon time on cool/clear days (controller will limit output safely and reliably to 15 amps).

Especially with the MorningStar 15 amp MPPT, you want to get the Remote Battery Temperature Sensor. Without it, the controller tends to pull back on charging voltage a bit too much with the on-board temperature sensor.

-Bill

New boat system...looking for advice

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