Solar upgrade May 08, 2021, 10:10:44 am I'm in the process of doing a new solar PV install in our boat. AM solar spec'ed out the system and parts, were very helpful, and shipping was inexpensive and prompt. Since it is a new install, the process of running wiring through the headliners and trim is a little more involved. I did a new PV install on our camper and the resulting system worked well.The Lazy Daze is next. I presently have 2 X 100W panels and a Blue Sky 3000i controller with two seven year old 6v AGM's. I would like to upgrade to four new 6V batteries for a combined 440 Ahr rating and 200more watts on the roof. I'll stick with FLA or AGM.Can anyone tell me the wire gauge pre-wired into the LD and has anyone up-sized their wiring?Harold 1 Likes
Re: Solar upgrade Reply #1 – May 08, 2021, 10:38:30 am HaroldWhile you were away, Mike Coachman gave an update on his battery and solar upgrade project in this thread. Also note Larry’s advice to upgrade wire gauge from roof to solar controller later in the same thread. 2021 Rear Bath "Villa Verde" What's new & improvementsWarren 1 Likes
Re: Solar upgrade Reply #3 – May 08, 2021, 10:49:05 am At the recommendation of AM solar, I am running 6 gauge wire from the panels to the controller and then to the batteries. The run in the boat is longer than in the Lazy Daze, but if I have to rewire the coach, bigger is better top accommodate for voltage drop and line loss.HD
Re: Solar upgrade Reply #4 – May 09, 2021, 08:53:45 am [Can anyone tell me the wire gauge pre-wired into the LD and has anyoneup-sized their wiring?]Harold, Before adding the 200-watt additional solar panel I checked with Todd @ LD who said the wire size from the roof to the 3000i controller and then on to the converter's DC fuse board is 10-gauge. That size wire is rated to safely carry 30-amps and is also the size the shore power cord is. I was wondering if I should rewire from the roof to the DC fuse board but that wiring in our rear bath is well hidden in the walls and under the flooring making that conversion extremely difficult. I checked with an electrician friend and there should be no problem with amperage load or voltage drop for the short distances from the roof and ultimately to the batteries so the rewiring was not necessary. The 400 watt (combined) panels will almost never provide 30 amps to the charging system. Also when checking with Blue Sky they said that their 3000i controller can easily handle the 400 watt panels. That is the maximum the controller is designed for. Since you are adding two more 6-volt AGM batteries to what you now have, the battery set should meet some parameters to make the group balanced. All four batteries need to be equal age (preferably new). The 12 volt cables parallel connecting the two sets of series wired 6 volt batteries need to be equal length. The cable size should be 1/0 gauge. Connect the load (positive) wiring at one 6 volt battery set and the ground (negative) at the other 6 volt battery set. (see schematic image). This will allow the energy to be pulled through the full battery set. 3 Likes
Re: Solar upgrade Reply #5 – May 09, 2021, 10:10:39 am It is important to note the differences between low voltage and high voltage wiring. Ohm's law is the same: V = A X R for voltage drop, e.g. a 0.05 Ohm conductor resistance at 30A drops 1.5V. Here's the difference:at 14.5V a 1.5V drop represents a 10% Voltage drop, and charging the batteries at 13V won't work.at 120V a 1.5V drop is a 1.25% drop in voltage, which is insignificant.Not saying the 10 gauge is inadequate, but upgrading is usually worthwhile, particularly from the charge controller to the converter or batteries.Steve 3 Likes
Re: Solar upgrade Reply #6 – May 09, 2021, 12:08:03 pm Quote from: Steve - May 09, 2021, 10:10:39 amIt is important to note the differences between low voltage and high voltage wiring. Ohm's law is the same: V = A X R for voltage drop, e.g. a 0.05 Ohm conductor resistance at 30A drops 1.5V. Here's the difference:at 14.5V a 1.5V drop represents a 10% Voltage drop, and charging the batteries at 13V won't work.at 120V a 1.5V drop is a 1.25% drop in voltage, which is insignificant.Not saying the 10 gauge is inadequate, but upgrading is usually worthwhile, particularly from the charge controller to the converter or batteries.SteveSteve is absolutely right, every 0.1v count in this case for the 12v dc system. No one wants to have those hard "earned" solar electricity turns into heat by wire resistance. It is better to invest thicker wire gauge in the initial installation and capture the better performance over the years. 1 Likes
Re: Solar upgrade Reply #7 – May 09, 2021, 12:43:48 pm As Steve pointed out, voltage drop is a serious issue in charging circuits.To calculate voltage drop, the lenght of wire, to and from the panels to the controller must be known, as well as the expected current levels.I have used West Marine’s wiring chart for decades, it lets you see what size wire is need to obtain either a 3% or 10% voltage drop.Marine Wire Size and Ampacity | West MarineUsing the chart, let’s say your wire run to and from the solar panels to the controller is 40’, with 10-amps flowing through the circuit, similar to the conditions found in a LD with two 100-watt panels. The 3% chart shows that a 8 gauge wire is needed, the 10% chart show a 14-gauge wire to be adequate.With two, 100-watts panels, the 10-gauge Factory wiring may be too small, depending on the wire run distance, for best performance. If adding anymore panels, changing to heavier wire shouldbe part of the game plan.When sizing solar wiring, I use West Marine's 3% chart and then upsize the wire one size, in an attempt to reduce the loss to close to 1%.If possible, the wiring from the solar controller to the battery or Power Center should also be upgraded at the same time.Most people are surprised to learn about wire sizes and the large effects of different size wire. Charging circuits is an area where upgrading can pay definite dividends. Don’t cheap out on the wiring. If you do, you will not receive the power output expected.One way of over coming the voltage loss with too small wire is to wire the panels in series, to raise the voltage high enough not to need heavier wires. This will work but the shading of an individual panel will shut the entire charging down.Larry 4 Likes
Re: Solar upgrade Reply #8 – May 09, 2021, 12:47:24 pm I'm with Steve, CLI288, and Larry. "Rated to safely carry 30 amps" is not at all the same as "rated to carry 30 amps with minimal voltage drop." (And as Steve pointed out, the comparison to a 120 V shore power cord is irrelevant.)I'd upgrade the wiring, to avoid throwing away power that new 200 W solar panel is generating for you. In solar panel wiring, I aim for as close to 1% voltage drop as I can get. 1 Likes
Re: Solar upgrade Reply #9 – May 09, 2021, 11:19:23 pm Thanks to all of you who have offered your experience and advice. I appreciate your insights.The run on my boat is 27 feet from the panels to the controller and Garret at AM Solar recommended 6 gauge to reduce the line loss. I'm using two 200W panels in parallel since there is always a shady piece cast from the radar array. Another friend followed Garret's advice and his system charges about 25% faster than a second friend's who has the same system but with smaller gauge wire. I start the install on the boat on Wednesday. When I'm finished, I'll get serious about the Lazy Daze.I do like the Blue Sky 3000i controller and appreciate Mike's comment that it will still be sufficient for the upgrade. My next question will be directed at seeing how much PITA rewiring the existing wires from the panels to the controller in the Lazy Daze will be. I'll check the existing Solar thread to see if this is addressed there.We are heading for three weeks in the northwest at the end of June. I hope I can get it all installed by then.Harold 1 Likes
Re: Solar upgrade Reply #10 – May 10, 2021, 01:35:35 pm Quote from: Blueox25 - May 09, 2021, 11:19:23 pmThe run on my boat is 27 feet from the panels to the controller and Garret at AM Solar recommended 6 gauge to reduce the line loss..I do like the Blue Sky 3000i controller and appreciate Mike's comment that it will still be sufficient for the upgrade. Is 27’ the round trip distance or one way?Interesting that LD thinks that 230-watt of panels only needs 10-gauge wire and for your boat’s 200-watts of solar, AM Solar recommends 6-gauge is recommended. IMO, LD is doing their customers a diservice by not increasing the size of the solar wiring to utilize the entire solar output. 10-gauge was adequate years ago when one 85-watts panel (maybe two) was standard. Today, a pair of 115-watt panels is common, still equipped with the same 10-gauge wiring. Wiring has never been one of LD’s strong suits.Our LD’s 3000i now controls 505-watts of solar panels and it has never reach the maximum input amperage of 24-amps, the highest seen has been 23-amps. In case the input was to exceed 24-amps, the controller dumps the power, without damage.405-watts of solar was adequate in the summer but sometimes not enough for winter, long-term dry camping. The extra 100-watts made the difference in the winter. Winter charge rates are much lower, an extra 100-watt panel could be used in the winter and unplugged for summer use.Larry
Re: Solar upgrade Reply #11 – May 10, 2021, 02:30:07 pm Larry,The 27 foot run is one way, so the round trip is 54 feet. The 6 gauge wire recommendation from AM Solar is consistent with the West Marine recommendation.I agree that the existing Lazy Daze wiring is too small. Did you upgrade the wiring between your panels and the controller when you added panels? I'm not eager to do another major rewire job.Harold
Re: Solar upgrade Reply #12 – May 10, 2021, 04:55:29 pm Quote from: Blueox25 - May 09, 2021, 11:19:23 pmWe are heading for three weeks in the northwest at the end of June. I hope I can get it all installed by then.Harold, we are heading that way at the same time so perhaps will cross paths! 2 Likes
Re: Solar upgrade Reply #13 – May 10, 2021, 06:53:32 pm Quote from: Blueox25 - May 10, 2021, 02:30:07 pmThe 27 foot run is one way, so the round trip is 54 feet. The 6 gauge wire recommendation from AM Solar is consistent with the West Marine recommendation.I agree that the existing Lazy Daze wiring is too small. Did you upgrade the wiring between your panels and the controller when you added panels? I'm not eager to do another major rewire job.The lead in cable was changed to 6-gauge. In our 23.5’ FL, the change was realtively easy, all the wiring from the roof junction box to the solar controller was accessible. Adding larger wires, from the solar controler to the battery, was a bit more complicated, they now run along the side of a window valance for a ways, hidden in white wire tubing . There is not practical way to access the original wiring, it was sealed in the wall, instead of removing it, it was supplimented with two new cables, wired in parallel with the original wires.Instead of an inline fuse in the Power Center, it was replaced with a panel mounted marine circuit breaker that doubles as a switch.Sky Blue 3000i solar controller | FlickrLarry . 2 Likes
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