Battery/Solar questions

[chowdan]

Hey guys,

I have been thinking a lot about the placement of my new battery bank. I am currently thinking I will be installing the new bank under my port settee as it currently is empty(unused storage space).

My current house bank is 4 Lifeline gpl-4c(NOT the CT variant) which are located under the cockpit sole and incredibly difficult to get to, hence one of the reasons for moving them.

I see that AGM batteries can be "placed on their side", but yet they state they can't be placed upside. I believe I could get Trojan Reliant t105-agm batteries under my settee but I may need to lay them down on their side. That being said, as a monohull sailboat, I wonder about certain points of tacks, where they may not be upside down entirely, but definitely would be significantly flipped in a way that I would consider "upside down".

I am not a fan of wet cell batteries after experiencing a completely(visually) sound 8D battery bust open. A nightmare of a chore to clean up and fix I might add. Removing any battery that can leak incredibly corrosive liquid is my goal for sticking with AGM over something like a regular golf cart battery.

The next thing is - wonder is how much solar would you need to properly maintain the battery? I have an Atlantic Tower and I have the solar mounting kit(yet to be installed), and am looking at installing 2 LG NeON R panels. They are 360W each, giving me a total of 720w of power. Surely it would be enough for a bank of 440amps(4x6v @ 220amps), but would that be enough power for a bank with 660amps(6x6v @ 220amps each)?

I am currently located in Seattle WA and will be cruising around here for a bit before setting off to head south to sunnier locations.

TL;DR:

• Can AGM batteries be placed on their side on a cruising mono, even though certain points of sail will have them in unfavorable angles?
• Will 2x360w solar panels support a 440amp house bank, or more likely 660 amp bank?

[Uncle Bob]

Originally Posted by chowdan

Hey guys,

I have been thinking a lot about the placement of my new battery bank. I am currently thinking I will be installing the new bank under my port settee as it currently is empty(unused storage space).

My current house bank is 4 Lifeline gpl-4c(NOT the CT variant) which are located under the cockpit sole and incredibly difficult to get to, hence one of the reasons for moving them.

I see that AGM batteries can be "placed on their side", but yet they state they can't be placed upside. I believe I could get Trojan Reliant t105-agm batteries under my settee but I may need to lay them down on their side. That being said, as a monohull sailboat, I wonder about certain points of tacks, where they may not be upside down entirely, but definitely would be significantly flipped in a way that I would consider "upside down".

I am not a fan of wet cell batteries after experiencing a completely(visually) sound 8D battery bust open. A nightmare of a chore to clean up and fix I might add. Removing any battery that can leak incredibly corrosive liquid is my goal for sticking with AGM over something like a regular golf cart battery.

The next thing is - wonder is how much solar would you need to properly maintain the battery? I have an Atlantic Tower and I have the solar mounting kit(yet to be installed), and am looking at installing 2 LG NeON R panels. They are 360W each, giving me a total of 720w of power. Surely it would be enough for a bank of 440amps(4x6v @ 220amps), but would that be enough power for a bank with 660amps(6x6v @ 220amps each)?

I am currently located in Seattle WA and will be cruising around here for a bit before setting off to head south to sunnier locations.

TL;DR:

• Can AGM batteries be placed on their side on a cruising mono, even though certain points of sail will have them in unfavorable angles?
• Will 2x360w solar panels support a 440amp house bank, or more likely 660 amp bank?

The solar will be more than adequate to maintain a larger battery bank.
I have 190 watts maintaining a bank of six six volt golf cart wet cell batteries. Runs the fridge, led lights stereo etc as well.

[chowdan]

Originally Posted by Uncle Bob

The solar will be more than adequate to maintain a larger battery bank.
I have 190 watts maintaining a bank of six six volt golf cart wet cell batteries. Runs the fridge, led lights stereo etc as well.

Well that's great news. Is there a way to determine panel wattage to bank size?

[zboss]

If a battery is placed on its side it should be done so the top faces forward or backward... not toward the side. Otherwise, the battery will be partially upside down when the boat heels over. If you have room to mount a battery on its side, you might also have room to put a battery with a taller and thinner form factor that would allow you to place the top up.

https://www.trojanbattery.com/pdf/SA...375_AGM_DS.pdf

[Uncle Bob]

Originally Posted by chowdan

Well that's great news. Is there a way to determine panel wattage to bank size?

Beyond my pay grade I'm afraid but I just know someone will be along shortly.
My panels are 12 volt nominal connected in parallel through a PWM controller and has worked well for me to date, (touch wood) but if I was doing it again I would go for a higher voltage panel through a good MPPT controller for the higher power harvest.
As it is I have been pleasantly surprised at how well it all works.
Cheers

[Suijin]

*In general* your total watts of your panels should at a minimum equal your total amp hours. Of course, performance of the system will depend on where you cruise, when you cruise, and the types of loads you experience on average.

I think a better approach is to create an energy budget (ideally from real world testing), design a battery bank to meet those needs, then design your charging sources.

[chowdan]

Originally Posted by Suijin

*In general* your total watts of your panels should at a minimum equal your total amp hours. Of course, performance of the system will depend on where you cruise, when you cruise, and the types of loads you experience on average.

I think a better approach is to create an energy budget (ideally from real world testing), design a battery bank to meet those needs, then design your charging sources.

Thanks for this. I know all of our usages will be different, so thats great to know. I am in the process of getting my amp meter installed so I'll be able to determine what my consumption is, then go from there. I appreciate the help!

[noelex 77]

Originally Posted by chowdan

Will 2x360w solar panels support a 440amp house bank, or more likely 660 amp bank?

For boats that receive most of their battery charging from solar, the wattage of the solar panels together with the insolation of the location and installation details (fixed, tilted etc) will primarily determine the available usable electrical power. Thus the solar panels “support” the required power consumption rather than the battery capacity.

The battery capacity will primarily determine the ability to even out the usable power in variable conditions.

For example, a boat spending the sailing season in the Mediterranean would be fine with a relatively small battery bank. In this location, during the sailing season the days are very consistent with very few days of poor solar output where the battery capacity will be utilised to even out production. Daylight hours are reasonably long, so the solar output will be directly providing power much of the time. The battery bank will have an easy time.

Consider the same boat with the same amount of power production in Australian waters during the sailing season. The solar isolation may be similar to the Mediterranean (depending on location, Australia is a big place). The average output from the same solar panels will also be similar. So the boat will have a similar amount of usable power. However, the conditions in Australia are far more variable. There can be many days of poor solar output followed by excellent conditions. The average may be the same, but the variability is much greater. The battery bank will be called upon to do far more work to maintain the same average output and consequently it is sensible to make the battery bank much larger.

These examples show the concept of just matching the size of the battery bank to solar wattage is fundamentally flawed.

Hopefully someone who is familiar with insolation and importantly the variability in insolation in the area around Seattle WA, will be able to give you an answer.

[a64pilot]

There are websites that can tell you Solar insolation.
However just speculating that part of the US is I believe the only rainforest in North America makes me suspect that it’s not a great place for Solar, much different than say Arizona.
If so that increases the need of both Solar and bank size.
Then of course the season has a lot to do with to top of course, Summer is often much better than Winter.

There are many, this is just the first one Google popped up.
https://www.nrel.gov/gis/solar.html