New electric system on sailboat

[RV8R]

Ok so my bad, I checked again and the "Fridge" cooler box uses 45W in Max and 36W in eco mode.
Also there is a 12V cigarette lighter socket included.. Guess I can plug that directly to the battery ?
If not I can plug it to the inverter with eco mode.

Yes & probably not running 24/7 either ?

I’m guessing it is a 12vdc fridge with a 120vac plug in that converts the 120vac to 12vdc ?

If I am correct, then your daily energy use was grossly overstated & you could run it off the 12vdc system taking the inverter out of 24/7 operation ,,, per my post above.



Before ordering more equipment, it would be best for you to perform a real design ( maybe with help from the forum ). You also need to educate yourself on your current equipment & understand it before being able to perform a design. This is spotlighted by your previous understanding of your fridge ( stated vaguely by you, but indicated 3100Wh daily energy use ).

TLTR; Research & understand your equipment / perform a design / buy stuff ,,, in that order if you can.

 

[SparkyGage]

Hi @sparkgage

This is confusing me ?

View attachment 208653

I should what been clearer that I was talking about where they connect to the SYSTEM: the batteries connect neg to neg and pos to pos, but the neg of the system connects to the neg of one battery and the pos of the other battery so that the energy draw and charge is even across both batteries. Sorry, I was having a bad case of "but *I* know what I meant". I clarified the comment. Thank you.

 

[RV8R]

I should what been clearer that I was talking about where they connect to the SYSTEM: the batteries connect neg to neg and pos to pos, but the neg of the system connects to the neg of one battery and the pos of the other battery so that the energy draw and charge is even across both batteries. Sorry, I was having a bad case of "but *I* know what I meant".

Thanks for clarifying ,,, OP seems newbie(ish) & if he read that the wrong way ,,, well he might need a

Spark Gage

 

[RV8R]

So the boat is 34" and I don't think I can reasonably handle more than 2x200W on the bimini I'm currently ordering. The stern is rather narrow.

I can get another lithium to put in parrallel but I'm starting to wonder if it's not overkill for my need and also rather impossible to charge with only 400W of solar. ( alternator to come soon).
I still have a few weeks to exchange the inverter, would it be better to take a smaller one ? If so what would be good? 2000W ? 3000W ?
A second lithium is possible but it's a good 800$ to add to my already expensive new setup.

This;



Per above ,,, Design 1st then Purchase Stuff.


I don’t know what you need as until a few moments ago I thought your fridge was using 3.1kWh per day.


If you were in doubt, and the return date of your inverter is closing on you, then why don’t you just return it until you do a proper design?

 

[solidseb]

Yes & probably not running 24/7 either ?

I’m guessing it is a 12vdc fridge with a 120vac plug in that converts the 120vac to 12vdc ?

If I am correct, then your daily energy use was grossly overstated & you could run it off the 12vdc system taking the inverter out of 24/7 operation ,,, per my post above.



Before ordering more equipment, it would be best for you to perform a real design ( maybe with help from the forum ). You also need to educate yourself on your current equipment & understand it before being able to perform a design. This is spotlighted by your previous understanding of your fridge ( stated vaguely by you, but indicated 3100Wh daily energy use ).

TLTR; Research & understand your equipment / perform a design / buy stuff ,,, in that order if you can.

Thank you for your answer, most of the équipement I will be using is 100V only so I do need an inverter unfortunately. Although most likely the total power needed is indeed lower than thought.
Except for the fridge I will probably have running most of the time I will only use other appliances for a few minutes, or few hours here and there for the AC.
Where I live it gets very hot and humid in the summer and without it sleeping can get quite tricky.
The highest draw would be from the AC and I checked today, at its max on heating mode it used 700W.

So it’s pretty simple :

400W solar -> 50A renogy Mppt -> 300AH lifepo4 -> inverter (4000W or change to smaller if better ) -> appliances as mentioned earlier.

 

[solidseb]

S

This;

View attachment 208659

Per above ,,, Design 1st then Purchase Stuff.


I don’t know what you need as until a few moments ago I thought your fridge was using 3.1kWh per day.


If you were in doubt, and the return date of your inverter is closing on you, then why don’t you just return it until you do a proper design?

sure I can always return it, I still have a few weeks, I guess if fridge running along with the AC it won’t draw more than 2000W then this one should be better ?

2000W 12V Pure Sine Wave Inverter

Renogy 2000W Inverter transforms the DC electricity stored in batteries into standard household AC power. Limited time sale, 10% off code: Renogy10off

www.renogy.com

Would work fine with the 300aH battery right ?

 

[RV8R]

Thank you for your answer, most of the équipement I will be using is 100V only so I do need an inverter unfortunately. Although most likely the total power needed is indeed lower than thought.
Except for the fridge I will probably have running most of the time I will only use other appliances for a few minutes, or few hours here and there for the AC.
Where I live it gets very hot and humid in the summer and without it sleeping can get quite tricky.
The highest draw would be from the AC and I checked today, at its max on heating mode it used 700W.

So it’s pretty simple :

400W solar -> 50A renogy Mppt -> 300AH lifepo4 -> inverter (4000W or change to smaller if better ) -> appliances as mentioned earlier.

Have you performed a “Load Calculation” spreadsheet ( sometimes referred to on forums as an energy audit ).

That IMO is required before you can design your system. If you have performed it post it & you can receive Forum Help on review if it makes sense or if any glaring errors. That is the real magic of this forum ,,, you get free help to hopefully get you going in the right path ,,, hopefully safely.

 

[RV8R]

S

sure I can always return it, I still have a few weeks, I guess if fridge running along with the AC it won’t draw more than 2000W then this one should be better ?

2000W 12V Pure Sine Wave Inverter

Renogy 2000W Inverter transforms the DC electricity stored in batteries into standard household AC power. Limited time sale, 10% off code: Renogy10off

www.renogy.com

Would work fine with the 300aH battery right ?

I can’t say it would work fine ,,, maybe.

A System works as a System. No Load Calculation ,,, No Math ,,, I have No Clue

 

[littleharbor2]

I don’t know what you need as until a few moments ago I thought your fridge was using 3.1kWh per day.

I was the one that stated 3.1 kwh per day. The op stated the fridge ran at 130 watts, constantly. 130 x 24 = 3,120 watts.

 

[solidseb]

Have you performed a “Load Calculation” spreadsheet ( sometimes referred to on forums as an energy audit ).

That IMO is required before you can design your system. If you have performed it post it & you can receive Forum Help on review if it makes sense or if any glaring errors. That is the real magic of this forum ,,, you get free help to hopefully get you going in the right path ,,, hopefully safely.

Here it is :

Energy Load Calculation

Feuille 1 Equipment,power (W),hours used,amp hours AC,700,3,2100 Cooler Box,45,24,1080 Microwave,700,0,1,70 stove,500,0,1,50 Monitor/TV,30,2,60 Laptop,80,2,160 Kettle,1250,0,1,125 Fan,700,2,1400 Total,5045

docs.google.com

 

[Supervstech]

Ok…
This is on a boat, right.

Don’t buy renogy.

On a boat, I would ONLY use top tier equipment.

Victron.
It has the lowest standby draw, and will last.

Do some searches for renogy problems… yeah. Not on my boat.

That said, you showed pulling nearly 3000W on the inverter you have now. I wouldn’t reduce the inverter size.

Taking the fridge off the load, by switching to 12v input there will only reduce your load 50 watts or so… best to keep a higher wattage capable inverter.

 

[SparkyGage]

So the boat is 34" and I don't think I can reasonably handle more than 2x200W on the bimini I'm currently ordering. The stern is rather narrow.

I can get another lithium to put in parrallel but I'm starting to wonder if it's not overkill for my need and also rather impossible to charge with only 400W of solar. ( alternator to come soon).
I still have a few weeks to exchange the inverter, would it be better to take a smaller one ? If so what would be good? 2000W ? 3000W ?
A second lithium is possible but it's a good 800$ to add to my already expensive new setup.

If you only run the appliances one at a time, and run the fridge straight to the battery bank, *I* would think you can go down to a good 2000W inverter. Heat your water, then run the microwave, then run the AC before bed. Do all this and don't plan any week long trips off shore to begin with, and you can start with the one battery.

Also with the fridge: If you fill the extra space with ice packs (frozen 2 Liter bottles of water) it will lower the draw and act as a buffer when you need to kill the power or loose it. I keep about 6-8 in my upright freezer and about 5-6 in my chest freezer at home as I live in an area subject to 4-5 power outages a year. We also did this on the family house boat back in the 90s that had a full size refrigerator/freezer. We would run the generator about 3 hours a day and it would keep things cool and safe. What I am saying is Experiment with your devices early on and figure out what they are really using and are capable of.

Boat life is about managed compromises for the overall "life".

And if it was me based on all your descriptions I would:
- go 24v with a second IDENTICAL battery in series, or better still (2)24v batteries in parallel because if one fails, I still have one to work with.
- get a Victron 24v 3000VA inverter/charger: this is an inverter on the water and a charger at the dock.
- get a get a 24v to 12v Victron converter for the fridge ($50 for just the fridge or $150 for the 70A version if you want to run more stuff on 12v or use as an emergency backup charger for your motor batteries. - This is a whole different discussion)
- get a 24v kettle for water. ($50)

Victron are marine grade devices. Salt-water, humidity, heat, etc. You can do this 12v with Victron, but the 24v advantages would be worth it *TO ME*

But I would absolutely return that 4K inverter while you can. Too much for your loads and too much draw for your battery.

 

[Dave in AZ]

Eventually I wanna make sure to have enough energy to power the air conditioner if necessary ( it's a residential one the previous owner installed in the boat), a fridge (camping one) a microwave and a water boiler.

I would return that monstrosity inverter, and get a 2000W one, absolutely.


Air conditioner is a complete non starter, it is an order of magnitude different from all else. There are 100 threads here on powering an airco, you will need a huge battery and panels. You need numbers on that model, no guessing... But a 2000W inverter will run it at night if not using other stuff.

Don't buy Renogy, certainly not on a boat. Get Victron. I wouldn't put a Renogy in my truck, camping 2 miles from a Walmart with replacements...

I would go 24V system myself. There are some 24v airco for truck cabs I'm looking at videos of, almost all LED lighting can be bought 12 or 14v able, fridges are 12/24v. Only Maxxair or Fantastic fans are 12v or a diesel heater.

However, the other items:
Your fridge is a dc fridge, good. By the way, almost all dc fridges I have looked at can use either 12 or 24v! Certainly most Dometic, ARB, Bouge, Iceco.

A small 700W microwave actually uses 1100W to run, no matter the power setting. Buy an INVERTER microwave instead, they actually use less power when run at 70% instead of just cycling 100% power on and off.
You can run both on a 1500W Pure sine wave inverter, but get the inverter microwave and it can use less power.
Get this $119 Emerson
Emerson MWI1212SS Countertop Microwave Oven with Inverter and Button Control, LED Display 1000W 10 Power Levels, 8 Auto Menus, Glass Turntable and Child Safe Lock, 1.2 Cu. Ft, Stainless Steel https://www.amazon.com/dp/B0C15FXWP1/
Or this top rated panasonic

Panasonic NN-SN65KW Microwave Oven with Inverter Technology, 1200W, 1.2 cu.ft. Small Genius Sensor One-Touch Cooking, Popcorn Button, Turbo Defrost-NN-SN65KW-(White) https://a.co/d/iditsZs

Water boiler, get a 120v electric kettle, they are 99.9% efficient converting power to heat. Decent ones are 1400W, again a 1500W inverter will run them. Yes, you waste the 15% of Watts converting dc to ac as inverters are only 85% efficient. However, a 24v electric kettle is so slow and painful with such few and poor choices, I wouldn't wish it on an enemy. I researched the heck out of these. I bought both of these because good reviews, stainless, no rust, no leaks, and double walled insulated. This one is awesome.
COSORI Electric Kettle Stainless... https://www.amazon.com/dp/B09BQD3YDY?ref=ppx_pop_mob_ap_share

This one also good, smaller but stable base:
BOMICHING Electric Water Kettle,... https://www.amazon.com/dp/B09YLT13QW?ref=ppx_pop_mob_ap_share

 

[RV8R]

I was the one that stated 3.1 kwh per day. The op stated the fridge ran at 130 watts, constantly. 130 x 24 = 3,120 watts.

Thanks ,,, But I did know that.

The OP started “In Spirit” 3.1 kWh with the info he provided ,,, I did the math in my head & said to myself, that probably ain’t right.

 

[RV8R]

Here it is :

Energy Load Calculation

Feuille 1 Equipment,power (W),hours used,amp hours AC,700,3,2100 Cooler Box,45,24,1080 Microwave,700,0,1,70 stove,500,0,1,50 Monitor/TV,30,2,60 Laptop,80,2,160 Kettle,1250,0,1,125 Fan,700,2,1400 Total,5045

docs.google.com

This is a good starting point ;



Things I question;

Cooler Box ,,, running 24/7 ? ,,, ya sure ?

Fan 700W ? ,,, same power as your microwave & AC

“E” is not amp hour ,,, i would be watt hours ( divide by about 12.8 v to get amp hours )



*********



Future Loads ,,, You have any desire to expand. This can sometimes be a hard question to answer, but usually people expand their system ,,, rarely reduce it. It is worth pondering & listing it to see what a theoretical difference might be.


*********


Glaring Inconsistencies ,,, I once helped a van DIYer with a load chart. He wanted to “be out for 5 days” & figured 1.0 hours per day for the water pump. Glaring Error ,,, RV water pumps rate a 3 USG per minute ,,, 5 hours is 900 USG ,,, unlikely,,,


Ya got phones, tablets, or LED lights ?

 

[solidseb]

This is a good starting point ;

View attachment 208841

Things I question;

Cooler Box ,,, running 24/7 ? ,,, ya sure ?

Fan 700W ? ,,, same power as your microwave & AC

“E” is not amp hour ,,, i would be watt hours ( divide by about 12.8 v to get amp hours )



*********



Future Loads ,,, You have any desire to expand. This can sometimes be a hard question to answer, but usually people expand their system ,,, rarely reduce it. It is worth pondering & listing it to see what a theoretical difference might be.


*********


Glaring Inconsistencies ,,, I once helped a van DIYer with a load chart. He wanted to “be out for 5 days” & figured 1.0 hours per day for the water pump. Glaring Error ,,, RV water pumps rate a 3 USG per minute ,,, 5 hours is 900 USG ,,, unlikely,,,


Ya got phones, tablets, or LED lights ?

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.

 

[littleharbor2]

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.

This thread is getting fairly long but the elephant in the room hasn't been covred at all. How are you going to power all this on 400 watts of solar?
Once you do a detailed energy audit you will be able to figure out battery size, then how much PV you need to run it. 400 watts won't do it.

 

[solidseb]

Ok so let’s put it that way, I can only have 400W of solar panels, and the engine alternator which I use a few hours a day in general if I wanna make it ok time, put aside the consumption from my appliances that I can adjust, let’s just keep the fridge for example, how big of a battery and inverter would be more fitting ?

 

[littleharbor2]

Ok so let’s put it that way, I can only have 400W of solar panels, and the engine alternator which I use a few hours a day in general if I wanna make it ok time, put aside the consumption from my appliances that I can adjust, let’s just keep the fridge for example, how big of a battery and inverter would be more fitting ?

Lead acid, for example, you want no less than 3x daily usage capacity. Let's just say 9 kw. @ 12 volts that's 750 amp hours. That 750 amp hours would want 10% of that in charging current, =75 amps. A 12 volt PV array of 900 watts is your target. But keep in mind, that's with optimum exposure to the sun, which on a sailboat isn't possible being there's always shadows from cables and always being in motion (never aimed optimally). That's for the refer only. You really need a more efficient refer

 

[tpenfield]

Greetings @solidseb . . .

I just finished a system for my boat (power boat), and like you I did not know much about LiFePO stuff going into it. I have a thread here on the Marine section if you want to look through it. https://diysolarforum.com/threads/design-of-agm-lifepo4-solar-system-for-my-boat.78139/

Just a few comments, much of which has been touched upon.

400 watts of solar will net you about 30 amps to the battery. So, figure 10 hours to replenish the battery . . . which is essentially much of the sunlight day. The 300 Ah battery seems a bit light for 4000 Watts of inverter (320 +/- amps). So, the 'math' does not work out too well . . . and sort of depends on how much power needs (stuff) you will actually connect to it. But you need to provide according to what the inverter is capable of out-putting. . . . then there are the cloudy days . . .

The engine/alternator can provide some power, depending on how much you will want to use it. . . Of course there is the 'buffering' (as I call it) in sourcing power from an alternator or Lead-Acid battery, so you'd want a DC-DC charger in the mix, if that be the case.

Maybe post up a drawing or 2 for further comment. . . plenty of examples here and elsewhere on the web to review.