Adding Solar

[Starscream]

I am planning to add a solar charging system but have a few questions I was hoping the forum experts could help with.

I am on a bit of a budget, so I don't necessarily want to shell out for top of the line equipment. I also don't want cheap crap from a Chinese seller on Amazon. My goal is to add a single 100W flexible panel installed on top of the dodger, and wire it down through a new deck-connector that I will likely install on the side of the cabin, port side, just outside of where the stock electrical panel sits. It's still hard to drop down into the battery compartment from there, but not impossible. My goal is to have a system that could power our GPS and maybe some other small accessories (bluetooth speaker, phones) while sailing. Would be nice if it could keep up with a laptop too.

So, ignoring the $25 "MPPT" solar charge controllers from unknown Amazon sources, here are a few of my questions:

Question 1: PWM or MPPT?
Comparing two good quality controllers, the PWM is about half price or less. Of course MPPT is the latest and greatest and can squeeze every last drop of available juice, but for a 100W system am I going to be upset with PWM?

Question 2: Dual controllers, or dual battery controller? This controller: https://www.solar-electric.com/modubachco251.html is a PWM dual battery controller which can be set at 90/10 or 50/50 House/Starting charging rates. It's epoxy coated, reasonably priced, and does both batteries at once. With dual controllers, I assume I need two solar panels, and I also think that a single-battery controller can't be used to charge two batteries at once?

Question 3: Controllers with AGM batteries: I also assume that it's important to have a setting to switch between sealed and flooded batteries? I have dual Optima blue-top AGM batteries so I guess that I want to avoid the equalization cycle used for flooded batteries.


Right now I am leaning towards purchasing the following components:
https://www.amazon.ca/Morningstar-SSD-2 ... tar+duo%5C
https://www.amazon.ca/dp/B07195WHHX/_en ... DWCB&psc=1
https://www.amazon.ca/dp/B00JTM2U6M/_en ... DWCB&psc=1

Any comments or suggestions would be appreciated. I guess the biggest one is whether I should go MPPT or not, but I can't find a good dual-battery MPPT option.

[kadet]

I'll give you the benefit of my experience after setting up grid tied in solar on the house, a solar powered shed and two different solar installs on my

Question 1.
As you note to get a decent MPPT controller you are going to pay lots more $$. And to get the most out of those MPPT chargers you are going to need to run higher voltage PV cells i.e again more $$. So if $$ are an issue a decent PV with a Vmax of 18v will run just fine on PWM and not waste too much of the available power. About 20% with the Epsolar PWM I have linked below.

Question 2.
No you don't need two panels to charge two batteries but the more panels the more power available so charging times would be less. Space will ultimately be the determiner. You maybe able to squeeze two 60watt panels into the space a single 100watt is going to take so it really depends. Go for the largest amount of unshaded PV panel space you can afford. That dual controller really is just a % splitter I think you would be better off putting all you charging into your main battery with a voltage sensing relay that then diverts the charging to the second battery when the main is full. Or better yet just hook up your dual batteries in parallel and charge as a single large battery and forget about the extra expense and worry of a dual battery system. Install a low voltage cutoff circuit or just carry a Lithium jump starter.

Question 3.
Yes AGMs are sealed lead acid batteries and need a different charging profile to flooded. A specific AGM or custom setting is even better.

Just a final comment 99.9% (made up figure but I bet it's close ) of all solar hardware is made in China these days the good the bad and the ugly. The problem is knowing what is junk and what is not which is not easy for the average punter so I feel your pain. Even the known good stuff is often copied by unscrupulous manufactures with crap components made to look like the genuine ones.

As to what you intend to buy.

PV looks like good quality but remember a 100watt 18V panel is only going to produce a maximum of 5.5A

Forget the dual PWM controller it is over priced and over capacity for the PV.

This would be a far better and parallel your batteries.
https://www.amazon.ca/controller-LS1012 ... psolar+pwm

I would prefer to use good quality tinned marine wire at least 6mm, 8mm would be better if you can get it.

Follow the K.I.S.S principle to keep it inexpensive and reliable.

[Starscream]

Thanks for that Kadet, your comments are very much appreciated.

I don't think it's in my character to put the two batteries in parallel. I already worry about drawing down the house battery so much that something will go wrong with the starting battery and I'll be stuck trying to pull-start the ol' 90-horse. It's this worry that's driving me to add solar: I've never been really close to draining even the house battery, but that's because I'm overly careful. Parallel is a good solution, for sure, but besides my personal concern about draining both batteries at once, the whole thing is already wired up with a selector switch and I doubt I'll have the guts to embark on even that relatively simple re-wire.

I think you're right about the 90/10 just being a simple splitter. But if I don't want to go to parallel batteries, I am really leaning towards it because of the simplicity of the parts and wiring. I get what you are saying about a voltage sensing relay but I think that might be too complicated for my very basic K.I.S.S. installation skills. I kind of like that controller because I can add meter to the system later on if I feel like spending more $: https://www.solar-electric.com/mormredime.html, it's "epoxy encapsulated", has a US distributor, its documentation is on the web, andit has a 5 year warranty.

I didn't read anything in your comments that said "don't do this" with regards to the parts I had selected, and that encourages me even if there are better ways. I kinda get what I think I want with my original parts list: a simple system, relatively cheap, and takes care of both batteries. At the end of the day, I need the solar system to be able to prolong the life of the house battery so that I can sail for hours and still have lights (they're all L.E.D.) and a flushing toilet at night, and to be able to revive a dead battery situation (would never happen, right?).

Can I ask two more questions about the controller? It says that for the sealed lead acid setting the absorption voltage is 14.1 and the float is 13.7: Is this OK for the Optima AGM? Also, the manual says that for 8 solar amps, 14 gauge wire is suitable for up to 18' of wiring. I already have a nice roll of Ancor Marine 14-2 yacht tinned cable that I'd like to use up before buying something else, if possible.

[Tomfoolery]

At somewhere around 3.25 ohms/1000 ft with 14 gauge stranded, coated copper, that works out to just shy of 1V dropped over 36 ft (gotta count both out and back) carrying 8A. That sounds like a lot for a LV system.

It's nothing for a 120V system (North America), and half of nothing for a 220-240V system like most other countries use (grid power, of course), and it's actually a quarter of nothing if the power is the same (since the current would be halved, too). But I digress.

[Starscream]

Yay, Tomfoolery is back too!

I think the system I am planning on will never carry much more than 4A on a good day (45.4 degrees North, flat-mount on dodger). The charge-controller manual says 3% voltage drop on a 1-way distance of 18ft using 14ga wire at 8A, or the same 3% drop over 35ft at 4A.

BUT, the wire I plan on using from the PV panel to the charge controller is 10 gauge: https://www.amazon.ca/dp/B00JTM2U6M/_en ... DWCB&psc=1. I plan on cutting this wire in half, plugging in to the two MC4 connections at the panel, and then stripping back the wire at the cuts to plug into the solar charge controller.

From the controller to the batteries, it won't be more than about 4 ft of wire. Would 14ga make sense then?

[Tomfoolery]

Yay, Tomfoolery is back too!

Best forum for Macs, and sailing for that matter, on the web. How could I stay away. Truth be told, I don't even bother with the other ones any more, even when this site was down. I do sniff around the Cruisers Forum, though I'm not a member. Just interesting reading is all.

I think the system I am planning on will never carry much more than 4A on a good day (45.4 degrees North, flat-mount on dodger). The charge-controller manual says 3% voltage drop on a 1-way distance of 18ft using 14ga wire at 8A, or the same 3% drop over 35ft at 4A.

I'm using 3.25 ohms/1000 ft per NEC* Chapt. 9 Table 8 thusly: 3.25 ohm/1000 ft * 18 ft = .0585Ω. Multiply by 8A and you get .468V dropped over 18 ft. At 14V, .468A/14A * 100% = 3.34% voltage drop. That's just one-way. Current has to go the whole loop, so it's twice that.

From the controller to the batteries, it won't be more than about 4 ft of wire. Would 14ga make sense then?

I'd use something heavier myself. The manual shows 10 gauge with a 30A fuse. It's such a short distance that it wouldn't cost much to put some beefier conductors on it. IMO, at least.

*National Electrical Code in the US - I use it constantly for work, so the tables are tabbed and easy to find, including the DC resistance of conductors. Simply a matter of convenience in this case.

[kadet]

What is this gauge you speak of

14 gauge is about 1.7mm so what Tomfoolery said way to small. 6mm min.

This to me is very KISS
https://www.ebay.com.au/itm/ENERDRIVE-4 ... SwsYpaE2Rq

Optima recommends pretty wide ranging charge voltages so just select sealed and should be good to go.

Recommended charging information:

Alternator:
13.65 to 15.0 volts, no amperage limit.
Battery Charger:
13.8 to 15.0 volts, 10 amps maximum, approximately for six to twelve hours.
Cyclic Applications:
14.7 volts, no current limit as long as battery temperature remains below 125°F (51.7°C). When current falls below one amp, finish with two-amp constant current for one hour.
Rapid Recharge:
Maximum voltage 15.6 volts (regulated), no current limit as long as battery temperature remains below 125°F (51.7°C). Charge until current drops below one amp.
Float Charge:
13.2 to 13.8 volts, one amp maximum current, time indefinite (at lower voltage).
Strictly adhere to all limits.


No there is nothing that won't work in your setup but I think you can get better bang for your buck. That controller is way overpriced for a PWM it is rated at 25Amp so running 4-5A through it is overkill and controllers tend to me more efficient the closer you run then to their rated power. The extra $$ could be better used in my view like on a larger PV or Low Voltage Cut Off. And if you are worried about hand starting the 90 get a lithium jump pack.

[Starscream]

Thanks guys.

10 gauge it will be.

I think I'm gonna be the guineau pig for the dual-battery charger. It's the only one I can find that does two batteries at once, and even though it is oversized and therefore underefficient, the simplicity of the installation really appeals to me. According to the literature, as battery #1 reaches full charge, it transfers the amps to battery #2, so that's nice too. Plus I can add the meter accessory in the future, if I feel the need.

The questions that occur to me now are:

Any ideas on the best way to mount the PV panel to the top of the dodger? I was thinking about buying some sunbrella and sewing in four folded-over strips in loop form near each corner, then using a small amount of 1/8" line to attach the four corner-grommets of the PV panel to each loop.

Any recommendations on how to best bring the wire from the PV panel into the boat? I hate seeing wires running everywhere, so I was thinking about bringing the wires down the side of the dodger to...where? I'd like to have a flush-mount deck connector, like the one used at the mast for the steaming light. But where to put it to have easy access to the bilge?

[kadet]

Me again

My current setup is 2 x 200w 33v flexible panels. One is permanently mounted on a light alloy frame off the mast crunch carrier on the back. The second gets temporarily mounted on the bimini top on longer trips when the freezer is on board .

I use 2 to 1 Mc4 plugs to hook the panels in Parallel I then run the cables back down the mast crunch to the outboard control entry then through the bilge to the battery.

I used rubber auto panel edging to smooth the edge of the PV for the bimini so it does not cut the sunbrella as sunbrella i not very chafe resistant I then just use bungee cord with stainless hooks to hold it on to the bimini frame.

https://www.ebay.com.au/itm/Rubber-Edge ... 0005.m1851

I will try and take some pics and post a link later.

For a dodger mount could you run it through the hatch into the head liner then down behind the galley to the battery?

[kadet]

Some quick phone pics, might give you some ideas

https://photos.app.goo.gl/VM55vn7b54RGBYhM2

[Bilgemaster]

The questions that occur to me now are:

Any ideas on the best way to mount the PV panel to the top of the dodger? I was thinking about buying some sunbrella and sewing in four folded-over strips in loop form near each corner, then using a small amount of 1/8" line to attach the four corner-grommets of the PV panel to each loop.

Any recommendations on how to best bring the wire from the PV panel into the boat? I hate seeing wires running everywhere, so I was thinking about bringing the wires down the side of the dodger to...where? I'd like to have a flush-mount deck connector, like the one used at the mast for the steaming light. But where to put it to have easy access to the bilge?

I lash down my own little 50 Watt flexible panel with its corner grommets right on top of the sliding hatch from the hatch corners with those little bitty black bungees (say that 3 times fast), four of which come in that Harbor Freight 12 Piece Assortment. It all fits perfectly, and it's going nowhere. Handy little buggers those wee bungees. They might work for your imagined rig as well. Get 'em on December 31st or New Years Day, and get 25% off along with a freebie 27 LED portable worklight/flashlight that just happens to have both a magnetic mount AND a handy little flip-out hanger doodad that makes it a great little occasional cockpit lamp. I keep one hanging from one of those mainsail cover closure latch doodads right over the companionway when she's on her trailer. It's like it was designed for it. A little squirt of ArmorAll rubbed into the case now and then keeps her nice and blue and happy and watertight month after month after month.

As for a good location for some sort of flush-mount port to plug your panel's cable into, my later-model 2001 X has a handy access port in the roof of the rear berth area just aft of that little kitchenette seat, under which I stow my two batteries. Just above and forward of that access panel, on the aft cabin wall--port side, is where my separate AC (shore power) and DC switch panels are found side-by-side. My 30 Amp AC shore power plug inlet is mounted nearby outside, on the port side, just aft of the black stripe. If your X's layout is similar to mine (that is, you also have that access hatch already there in the rear berth roof for easier wire routing), then somewhere thereabouts abovedeck might be a fine spot for a good sturdy water-resistant inlet for your solar juice.

My little 50 watt solar setup's arguably more "ghetto" than most folks', with the whole shebang costing me a lot less, what with sales and coupons and all, than the $170.94 that anyone could get the whole bundle for right now (Essence of Unicorn Burp not included). Still, it pumps out an honest 50 watts, gets the job done for my modest power needs, and is easily expandable, should those needs change, and I ever wanted to toss another 50 watter panel onto the bimini. The whole rig's also very portable. I even used it once to give a much-needed jump charge to the worn out and undersized little geriatric battery I'd originally gotten with my faithful Durango V8 "tow beast" when she was overtaxed pumping out my little Foundling Com-Pac 16's flooded cabin with a jury-rigged electric bilge pump when I first rescued her.

Best of luck on your own quest for juice!

[Gazmn]

Hey SScream.

Good to be back eh brother? I still don't know how to post pics minus photo bucket

I ended up buying 3 of those Amazon Solar P's & made my own frame to hang off the back with an MPPT charger & meter + 2 AGM 6V golf batteries run in series & my starter bat, split by an isolator. My advice: Do it right - once. Take your time if you have to, but do it once. I got a PWM controller if ur hungry. But invest in the MPPT with a monitor & rig something from 1-300Ws that you can keep on permanently. For your future possible expansion, consider 8 ga & the 30Amp MPPT w/ monitor
I'll try to list my project, but I'm 300W's of your chosen solar; Hooked in series & suspended on the back of my in the same way I once held only 1 @ 80Watts I also used another 30A MPPT on my camper with my old 150W & 100W slaved to the top of my 30 YO Camper With 2 new 6V Golf bats in series

So, my advice, is to think "long rum". Invest in your components as you can; With MPPT [ with monitor] & 1 panel your first bet. Don't start until you can successfully do step 1. Get some Home Depot 1" x 36-48" 90* aluminum angle iron + 3/4-1" square aluminum x 36 or 48" & make your own damn Solar array panel. 3x 100W flexible panels & hang it off the back of your MotherShip

[Gazmn]

Continued:

https://www.amazon.com/gp/product/B06WV ... UTF8&psc=1

https://www.amazon.com/gp/product/B01L6 ... UTF8&psc=1

https://www.amazon.com/gp/product/B00FW ... UTF8&psc=1

https://www.amazon.com/gp/product/B075W ... UTF8&psc=1

Good Hunting - U can find All ur parts on Amazon

[Starscream]

Wow, I sure am glad this board is back up.

Excellent advice, thanks to everyone! Good thing I have all winter to figure it out. Motor Cable Entry! Why didn't I think of that?

Gaz: I think I've said it before, but Holy Moly how does your boat even float? That's gotta be a Mod record. Even zooming into the photo of the back of your boat I can't really figure out what's going on back there. Do you leave the solar on while towing?

One of the design parameters that is important for me is to make it relatively easy to trailer, since we often "road trip". I can't put the panel on the sliding hatch because the dodger covers it, so that's out. (In my original post I think I said that I want to put the PV panel on the dodger, but I meant on the Bimini part of the enclosure.) I like the idea of some sort of lightweight structure like the Gazm one, but that makes it a major project and I'm not sure how easy it would be to tow with. The problem is complicated by our full cockpit enclosure: there's no good place to put another arch, let alone 300W of panels. That's why I was thinking about one 100W flexible panel on the bimini top, mounted just to port of where the backstay passes through it. The enclosure really encapsulates the entire rear half of the boat, so I don't really see where else to put solar without embarking on a major project.

[Seapup]

One of the design parameters that is important for me is to make it relatively easy to trailer, since we often "road trip".

This was one of my challenges with my also.

The solution I liked was folding panels that are stored when not needed on trips. You can easily move them anywhere to avoid shading. A tiny amount of shadow the size of your hand, (the mast or boom) basically turns a panel off. Even the backstay shadow. If part of a folding panel is shaded the other sections still work since its several panels in parallel. You can lay them out just about anywhere in a minute or two then put them away at night.

My first one was same as this - different vendor though. It has performed very well. I have several other panels now, and some have been very disappointing.



https://www.amazon.com/ACOPOWER-Foldabl ... f=ast_p_ep

Adding a cheap power meter inline with the panel is almost too easy not to do. It really helps show the importance of angling the panels and shading. It will also let you know the AH put in each day.


https://www.amazon.com/dp/B01LVTST80/re ... rd_w=tY7KF

BUT, the wire I plan on using from the PV panel to the charge controller is 10 gauge: https://www.amazon.ca/dp/B00JTM2U6M/_en ... DWCB&psc=1. I plan on cutting this wire in half, plugging in to the two MC4 connections at the panel, and then stripping back the wire at the cuts to plug into the solar charge controller.

From the controller to the batteries, it won't be more than about 4 ft of wire. Would 14ga make sense then?

Sounds opposite. Solar Panels put out a steady voltage and the amperage varies. If you are using a PWM controller they cut the steady 18V output of the panel to 13.4V or the controller setting. Loosing voltage between the panel and PWM controller does not really matter since that is exactly what the controller does. You don't want voltage to drop between the controller and battery though.


I am not a fan of MC4 if you ever plan on disconnecting the panel. For quick disconnects and through deck fittings standard SAE plugs are hard to beat. Quick, cheap, easy to replace. Make sure you get ones that specify the wire gauge.



Here is ten 10 guage plugs for under $15 https://www.ebay.com/itm/5-10-Gauge-2-P ... SwhMpT0HR2