New electric system on sailboat

[RV8R]

I do have phones and tablets I will eventually charge from this system.

LED lights are running from the lead battery system so I don’t worry about those.
Same with all the boat necessary equipment such as water pumps and gps/autopilot.

This system will run for extra stuffs and/or as a backup for the main system if ever it failed.

Should I go for a smaller inverter if I don’t expand much ? It is true that I most likely won’t have most those things Running at the same time except maybe the fridge + something else.

Nothing comes to mind as to what other appliances I would add in the future. Mostly I wanna be able to power the boat for few days 5-7 without having to go to shore.
Where I live it’s quite rare to have shore power in a marina as a guest.

As for the fan I’ve gotta check but that’s what I briefly read on the Amazon technical spec page. Most likely I won’t be using it much or mostly recharging its 18V battery ( with AV tho)

As far as going 24V, I already have the appliances and some are AC only so that isn’t realistic, either way I would need an inverter.

So far all I have got from Renogy is the MPPT charger.

Good Info;

Phones, tablets, & LED lights are all pretty light loads, but everything should be accounted for or we are just fooling ourselves.

There are many on the forum that for a boat will push you to Victron ,,, I tend to agree. Regardless you have the Renogy MPPT & still need to buy the other components after you complete your design.

I think you missed my point about the inverter;

I assume your fridge “can run on 12vdc”, & if you set it up for that instead of running the inverter 24 hours a day, you could leave it off as the other 120vac appliances ( loads ) were manually operated about 2 or 3 hours per day ( yet to be determined as your numbers are changing - this is why you perform a load calculation / energy audit ). This saves you guessing 400Wh in inverter standby energy.

Further, IF your fridge is 12vdc, then the inefficiency of going 12vdc battery - 120vac inverter - 12vdc compressor & controls makes no sense to me. Every time you transform the voltage you get energy loss & heat gain, which begs the question for what good reason would you do that ?

IMO it all comes down to “How are you gonna charge your batteries”? If you are looking for a DC2DC charger, I think Kisae is worth looking at.

 

[solidseb]

Good Info;

Phones, tablets, & LED lights are all pretty light loads, but everything should be accounted for or we are just fooling ourselves.

There are many on the forum that for a boat will push you to Victron ,,, I tend to agree. Regardless you have the Renogy MPPT & still need to buy the other components after you complete your design.

I think you missed my point about the inverter;

I assume your fridge “can run on 12vdc”, & if you set it up for that instead of running the inverter 24 hours a day, you could leave it off as the other 120vac appliances ( loads ) were manually operated about 2 or 3 hours per day ( yet to be determined as your numbers are changing - this is why you perform a load calculation / energy audit ). This saves you guessing 400Wh in inverter standby energy.

Further, IF your fridge is 12vdc, then the inefficiency of going 12vdc battery - 120vac inverter - 12vdc compressor & controls makes no sense to me. Every time you transform the voltage you get energy loss & heat gain, which begs the question for what good reason would you do that ?

IMO it all comes down to “How are you gonna charge your batteries”? If you are looking for a DC2DC charger, I think Kisae is worth looking at.

So, I will check how I can plug the fridge with the 12V DC. I think it's a simple car cigar lighter plug which I'm not sure how to connect directly to the LifePO4. But what you say does makes sens.
As for Victron or Kisae, I can't find those where I am (Japan) and importing is tricky as I can forget about any warranty.
I will look into it and seems like I can down it to a 2000-3000W inverter indeed.

 

[SparkyGage]

I completely understand your desire for solar, but let me be blunt: The Honda Portable Generator is your friend on multi-day trips. Whatever system you go with, unless you put in a MASSIVE battery bank and tow a barge with panels, you are going to have to make it work for you by making compromises: Minimize every use and figure out what you can do without and do to improve. You've been given the basics of a couple good systems that you can expand or upgrade. More batteries means longer availability. Parallel batteries offers redundancy (think safety net). Solar, will only be a boost while away from the dock (although, over the course of a week or two docked, it might fully charge the batteries while you are elsewhere).

As to connecting the fridge directly, you can:
A) cut the connector at the plug, identify Pos+ and Neg-, put terminal rings on them and bolt them to the battery (good)
B) connect a 12v fuse block to the battery and connect the previously mentioned Pos+ and Neg- to the fuse block (Probably best)
C) get a 12v cigar lighter female, wire it to the battery or fuse block, then plug in the plug. (Not great, but works and affords speedy removal if you need to unhook or swap in something else for a while/emergency)

If you are using the motor's alternator to boost charge the batteries (or a Honda Generator), make sure you are going through an external charge controller and not connected directly like you do with lead batteries.

I envy your dilemma. (AND WE WANT PHOTOS OF THE END PRODUCT - YOU OWE US THAT MUCH)

 

[solidseb]

I completely understand your desire for solar, but let me be blunt: The Honda Portable Generator is your friend on multi-day trips. Whatever system you go with, unless you put in a MASSIVE battery bank and tow a barge with panels, you are going to have to make it work for you by making compromises: Minimize every use and figure out what you can do without and do to improve. You've been given the basics of a couple good systems that you can expand or upgrade. More batteries means longer availability. Parallel batteries offers redundancy (think safety net). Solar, will only be a boost while away from the dock (although, over the course of a week or two docked, it might fully charge the batteries while you are elsewhere).

As to connecting the fridge directly, you can:
A) cut the connector at the plug, identify Pos+ and Neg-, put terminal rings on them and bolt them to the battery (good)
B) connect a 12v fuse block to the battery and connect the previously mentioned Pos+ and Neg- to the fuse block (Probably best)
C) get a 12v cigar lighter female, wire it to the battery or fuse block, then plug in the plug. (Not great, but works and affords speedy removal if you need to unhook or swap in something else for a while/emergency)

If you are using the motor's alternator to boost charge the batteries (or a Honda Generator), make sure you are going through an external charge controller and not connected directly like you do with lead batteries.

I envy your dilemma. (AND WE WANT PHOTOS OF THE END PRODUCT - YOU OWE US THAT MUCH)

Haha thanks, I'll try to go with B for the fridge.
I do understand the necessity to have more input to properly charge the battery.
I think as far as the current setup I will keep the recently bought 300aH LifePo4 cause I don't see any issue with it.
I returned the inverter and am looking at what to get instead.
So far found the Victron Phoenix inverter smart 12/3000 (https://www.tradeinn.com/waveinn/ja/victron-energy-%E3%83%90%E3%83%83%E3%83%86%E3%83%AA%E3%83%BC%E3%82%A4%E3%83%B3%E3%83%90%E3%83%BC%E3%82%BF%E3%83%BC-12-3000-smart/140468888/p?utm_source=google_products&utm_medium=merchant&id_producte=141625168&country=jp&srsltid=AfmBOoqM0GuRle-xOXL6l_updbZXJ6ZjiSdokIKwSiQLhuLLQAIf1RKlN-k)

I am thinking about getting it.
So while on the water I would mostly rely on the solar panel only I could limit myself to only use the fridge, which at 35watt/h won't kill the batteries (24*35= 840W or 23% of the total battery capacity). Solar should cover it as I can expect around 1600W produced during the day right ? If I have to use some more I can always charge using an AC to DC charger (20A) connected to the Lead battery system which can be powered with the engine alternator. That is if I really need it.
Otherwise I gotta hope I will be able to find shore power at night. And if I don't no AC for me ! So I can still keep the battery fairly charged and hope to charge it the next day.
What I would use are monitor or PC for a couple of hours and again, it wouldn't be a big issue for the battery (30W monitor, 60W PC = 180W/2h)

My understanding is that LIFEPO4 batteries can be used safely up to 80% of their capacity. Which If my calculations are accurate :
drain of electricity at night :
-12h of fridge ( 420W )
- PC and monitor (180W)
- maybe microwave for 5 min (at 700W = 58W)
- maybe AC if really too hot for 1h (700W)
So I would be at dawn with a battery 3600W - 1358W = 2242W

Day time solar panels works, let's say not such a good scenario, only 1600W a day.
For 12h the fridge still runs (420W)
and let's say I don't use anything else as I'm sailing anyway. so 1180W produced, I'm back to 90% charged at dusk.

Well I know it's quite approximative but in theory it's about it right ?
Really depends on how I use it but even if let's say I use more electricity and end up using 2000W / day, knowing i can produce 1600W a day if the conditions are good ( and I wouldn't go sail under bad weather), wouldn't it take 3-4 days for my battery to go around 70-80% discharged ?
Or am I missing something ?

PS : Yes of course, I will put pictures once everything is set !!

 

[SparkyGage]

...
- PC and monitor (180W)
- maybe microwave for 5 min (at 700W = 58W)
- maybe AC if really too hot for 1h (700W)
So I would be at dawn with a battery 3600W - 1358W = 2242W

Something else I would mention is a for your PC (laptop I am assuming) is a DC-DC converter. I have one for my laptop so I can plug it into the cigar lighter on the road. Again, more efficient than using the inverter for DC to AC back to DC as the inverter has a loss and the power brick has a loss, where as the DC-DC converter has a minimal loss. You will also find many monitors use external brick power supplies (the super slim models) that do the same thing: They take 120v AC and turn it into XXv DC via a power brick. Find one of these monitors and get a DC to DC converter that does 12v DC to XXv DC and you have another efficiency improvement. They all add up.

 

[RV8R]

So, I will check how I can plug the fridge with the 12V DC. I think it's a simple car cigar lighter plug which I'm not sure how to connect directly to the LifePO4. But what you say does makes sens.
As for Victron or Kisae, I can't find those where I am (Japan) and importing is tricky as I can forget about any warranty.
I will look into it and seems like I can down it to a 2000-3000W inverter indeed.

I understand & have no experience with Japan & Importing there;

The Kisae has been the best customer service I have received in decades ;

Kisae Technology Inc – Fresh Ideas In Power

Email Ricardo about your warranty concerns & Japan ,,, ya never know ,,, I will PM his email to you ,,, Done

Coincidentally ,,, Kisae & Ricardo are in Vancouver BC ,,, Just a Short BC Ferry ride for me as I live on Vancouver Island ,,, You know where Japan free floats products after a Tsunami .

Yes a cigarette plug is just a 12vdc connection. You can buy the called “power plugs” on Amazon or wherever, but you can also direct wire as it is just a positive & negative.

Typically the 12vdc efficient compressors are DB35s “Dan Foss” now called Sepco IIRC & even if they have a 120vac it just is a cord that goes to a converter to 12vdc ,,, hope your fridge is like that.

If you can design your system to have the inverter turned off unless needed you will be more efficient probably to the tune of 500Wh per day.

Conservation & simplicity is the key ,,, & a backup Honda 2200 generator as a backup.