Challenges with Solar on boats

[newhaul]

Originally Posted by foggysail

You will need to state that a few more times for it to sink in

Look back several pages we have been saying that about over paneling for many days. Doesnt seem to be even getting a toe hold.

[CapnCrunch]

Originally Posted by newhaul

Look back several pages we have been saying that about over paneling for many days. Doesnt seem to be even getting a toe hold.

Thanx for all of your input. IF I've understood y'all correctly, my system will be 3 - 290w (Voc =38.8 VDC/Isc = 9.58 A) thru 3 Victron 100/30 controllers charging a bank of 8 12v wet-cells. Or am I the guy you were referring to? LOL

[newhaul]

Originally Posted by CapnCrunch

Thanx for all of your input. IF I've understood y'all correctly, my system will be 3 - 290w (Voc =38.8 VDC/Isc = 9.58 A) thru 3 Victron 100/30 controllers charging a bank of 8 12v wet-cells. Or am I the guy you were referring to? LOL

The basics are correct your panel volts and amps are slightly off but the 100/30 controller is correct.
We had you taken care of several pages back the other comments on this are not directed at you you are all good to go also if you have any questions feel free to pm myself or mitiempo we would be.glad to help where we can.

[john61ct]

No, those are the precise specs for your panels.

The argument was with me about the possibility of using 75/15 instead at less than half the price.

Since Justin apparently reversed what he wrote me, I concede there would be more wastage of peak power output than most would want.

However the other 240w panels would I think be OK, in my situation well under 5% loss overall.

If anyone has the gear to test the argument I'd be willing to front for the 75/15, as long as there is a corresponding friendly wager on the other side if I'm right, just to make it interesting 8-)

If not, then I'll test myself one day and post the details.

[CapnCrunch]

K thanx Newhaul & John61ct. Next question on this system - with all the batteries & stuff, I'm a bit concerned that my boat may be getting a bit stern-heavy and am thinking of relocating as many as 4 of my batteries. The only problem is that the only safe and practical place I can find is in the forward rope locker which would put them about 30' from the rest of the bank. I would not have to run any additional cable because the control box for my windlass (which is currently connected to the house bank) is there, so it would just be a matter of splitting the existing cables to accommodate the connections to the batteries. Does this idea sound reasonable?

[newhaul]

Originally Posted by john61ct

No, those are the precise specs for your panels.

The argument was with me about the possibility of using 75/15 instead at less than half the price.

Since Justin apparently reversed what he wrote me, I concede there would be more wastage of peak power output than most would want.

However the other 240w panels would I think be OK, in my situation well under 5% loss overall.

If anyone has the gear to test the argument I'd be willing to front for the 75/15, as long as there is a corresponding friendly wager on the other side if I'm right, just to make it interesting 8-)

If not, then I'll test myself one day and post the details.

Already gave you the numbers you resended your challenge. (The mods deleted my response as well. )

[newhaul]

Originally Posted by CapnCrunch

K thanx Newhaul & John61ct. Next question on this system - with all the batteries & stuff, I'm a bit concerned that my boat may be getting a bit stern-heavy and am thinking of relocating as many as 4 of my batteries. The only problem is that the only safe and practical place I can find is in the forward rope locker which would put them about 30' from the rest of the bank. I would not have to run any additional cable because the control box for my windlass (which is currently connected to the house bank) is there, so it would just be a matter of splitting the existing cables to accommodate the connections to the batteries. Does this idea sound reasonable?

Relocate some batteries for the windless and hook up the wires as you have stated easy peasy no problem.

[DefinitelyMe]

Biggest two problems that bother me:

1) Partial shading (really, really difficult to eliminate on a sailboat and so so important for output)

2) I have a huge issue with the lack of control offered by the vast majority of manufacturers of solar charge controllers. Most will only allow you to select 'battery type' and maybe tell it the capacity of your battery bank. It's not nearly enough. You need to be able to control the voltage at each stage of charging, current/time thresholds, temperature compensation etc. Otherwise you're just sacrificing battery life and performance for nothing. Good controllers can be found (rogue power systems...... but what happened to them?) but they're few and far between.

[mitiempo]

Originally Posted by foggysail

You will need to state that a few more times for it to sink in

Probably.

What others stated made no sense. Why would anyone want to put enough panels on a controller to produce twice its rated maximum output?

[john61ct]

If you're talking about me, it was always one panel per controller, and now only 10% over peak rating.

Other way to phrase it, why pay more than $100 more per panel to capture maybe an extra 20w, and that in only peak conditions when you're likely not to need it?

By that logic using lead vs LFP is a lot more wasteful given how often the bank can't accept most PV output. . .

At this point, let's just wait for some real life testing.

[newhaul]

Originally Posted by mitiempo

Probably.

What others stated made no sense. Why would anyone want to put enough panels on a controller to produce twice its rated maximum output?

Hey I resemble that remark

[CapnCrunch]

Originally Posted by newhaul

Relocate some batteries for the windless and hook up the wires as you have stated easy peasy no problem.

The batteries wouldnt be just for the windlass. They'd still be part of the house bank. I was just wondering if the added cable length between the units of the bank would cause any issues with charging or power availability. I'm guessing it wont but it never hurts to ask.

[mitiempo]

Originally Posted by CapnCrunch

The batteries wouldnt be just for the windlass. They'd still be part of the house bank. I was just wondering if the added cable length between the units of the bank would cause any issues with charging or power availability. I'm guessing it wont but it never hurts to ask.

It will cause some issues. It is very likely that the forward batteries will not ever be at the same SOC as the aft bank due to the great distance. Even a 3% voltage drop - which is considered by many to be respectable - takes 14.4 down to 13.97 volts.

[mitiempo]

Originally Posted by DefinitelyMe

2) I have a huge issue with the lack of control offered by the vast majority of manufacturers of solar charge controllers. Most will only allow you to select 'battery type' and maybe tell it the capacity of your battery bank. It's not nearly enough. You need to be able to control the voltage at each stage of charging, current/time thresholds, temperature compensation etc. Otherwise you're just sacrificing battery life and performance for nothing. Good controllers can be found (rogue power systems...... but what happened to them?) but they're few and far between.

The bulk of this thread has been about Victrom MPPT controllers. All of the Victrons, including the smallest are fully adjustable for all voltages as well as absorption time. See below.

[newhaul]

Originally Posted by CapnCrunch

The batteries wouldnt be just for the windlass. They'd still be part of the house bank. I was just wondering if the added cable length between the units of the bank would cause any issues with charging or power availability. I'm guessing it wont but it never hurts to ask.

Ok im going out on a bit of a limb here and assuming your windless was installed with 2/0 or simmilar cables so no there would not be any appreciable or noticeable difference between that and the original install (except likely better performance out of your windlass.)