Any advice on solar panels for boats?

[terranova]

You are right about the fires .They have had two biggies .Before my arrival time in Loano end of summer 2019 there was fatality incident on a iirc 20-22 M FB German registered.They got trapped in the mid cabin no second escape route .
Since then the marina authorities do play the “switch the thing off if unattended line “
Maybe they have done a risk assessment and / or it’s driven by there insurers ? Dunno

There was another fire last yr a ferretti jumbo 100 or what ever …..u tube shows it started in the engine room .Thankfully no one was on board it just sank .Later the sunken wreck removed .

@ tera nova just dock walk and see what everyone else does .Some live locally and regularly visit.

When onboard in Loano ( summer season) I tend to burn through about € 4-5 / day .Fortunately we have a Frigomar Aircon 42K BTU ….at bit over specced for the boat .The thing being a AC to D.C. inverter tech with variable speed D.C. motors running the single compressor it’s got a tiny current draw . Blurb says as low a 2 A .I must stress it was specced for it silence not current draw .

If we don‘t go out its on 24/24 and if we do for a swim its back it’s on from 4 pm to 11 am next day .
Electric hob and two fridges .

One more thing not touched upon ……well briefly by hurricane changing a fridge .and reading your post your electrical guy who discovered your charger consumption.
A few yrs ago our OEM charger packed up circa 2002 so nothing unusual.

It was rated at 30 Ah for domestics of 2x180;Ah .lets just park the same size engine batts assume the just sit after a day out ready for tomorrow s trip .Need no charge worth mentioning .

The same guy a boat sparky that fitted the Aircon did his maths 2016 ish and came up with a 80 Ah all singing and dancing multistage charger .
My point is this the new 80 Ah one can stuff up the batt bank (s) quicker get its self down to its trickle / float + lowest mode faster .
If the smaller OEM 30 Ah was still alive apart from the basic fewer functions it would probably be for want of better wording “ revving it nuts off “= net result burning up more shore power to keep the batt charged than the bigger 80 Ah floating ….if you see what I mean ?

Not sure what the maths are for charger size ? I just went with his professional advice.You know the fraction of charger size / Batt capacity-
Was 30. /2x 180 or is it 30 / 4 x 180 if you inc the what should be the full engine bank ?
Now it’s 80 / 2x180 when we park up assuming the engine banks topped up on the run out ?



As far as charging PAYG in this instance for us we prefer it .Last yr ( pre Putin ) I think we went through £3-400 a year max .
Where as in La Napoule our service charge for a 14x 3.8;M berth was almost €4000 payable in advance in two instalments.

There are more folks who spend more time than us and have by todays standards inefficient kit on board .
Dividing it up ( with a size delta ) masks them and punishes the more frugal .Having had both tariffs PAYG works better for us .

A couple of the marina staff told me that, on average, there is a boat fire every fire years in MdL !!!

If that’s true, and it sounds like it probably is, then that’s a valid reason for them setting the rule. I’ve done the dock walk and spoken to a few owners about leaving their boats plugged in - the response was very mixed, but most didn’t know that leaving it connected was actually forbidden by the marina.

 

[MapisM]

We have ten x 140ah Exide Dual AGM 1200 batteries, so by the sound of it the consumption of 10kw a day may well just simply be down to the battery charger, but I will try get more advice on that.

I previously missed this post of yours.
10 kWh over 24 hours means an average absorption of 417 Watts (10000/24).
Now, assuming that the charger is constantly on float, since the batteries are doing bugger all, that sounds way too much to me.

For your reference, the absorption of my 100A charger when on float is just a hair above 100W.
Ok, my battery bank is roughly two third of yours, but I don't think that really matters a lot, assuming of course that both the batts and the charger are in good working order.
Anyway, even assuming that the charger AC absorption increase in linear proportion with the battery bank size, the 100W should raise to 150, which is still much less than half of 417.

In your boots, I would want to check separately not only the absorption of the charger, but also of that ACP thingie.
Of which I know nothing, but I have a funny feeling that whatever it does ain't much different from what old school anodes have always done effectively, and without requiring any current...!

 

[MapisM]

A couple of the marina staff told me that, on average, there is a boat fire every fire years in MdL !!!

Out of how many boats in total (ballpark)?
Just curious!

 

[Bouba]

If one battery can’t hold a charge then I assume that the charger will always be on bulk charge ?‍

 

[Bouba]

Out of how many boats in total (ballpark)?
Just curious!

Yes, it actually sounds low...although any fire is a tragedy...MDL is a chain of marina, I think. If you discount fires from onboard activity such as repair work and cooking then the figure might be a lot less

 

[Portofino]

Out of how many boats in total (ballpark)?
Just curious!

Fires seem unconnected . Just coincidence to me .

First (3 fatalities ) appears to have been a electric heater in December , but that’s all we know .
Worth revisiting this thread to see if there is any learning to be had ?

Deadly onboard fire.

Second appears to be a batt so assume charger involved .
VIDEO: Fire on Lady Vanilla - SuperyachtNews

This opens up quite a lot …..in no particular order and not exhaustive.
-Age of the batts ?
- compatibility of the charger ?
- connects ? = corrosion = inc resistance ?
- charger itself it’s health ?
- fire detection and suppression systems ?
- Any batt maintenance/ checking been done ?

I remember Lady Vanilla .Rarely went out and if it did usually late afternoon not very far only for a swim .They mostly just sat at the back round the aft cockpit table .Red Ensign .I never heard the occupants accents or saw a lot of crew for that matter .

Back on topic Halfords do 20w solar for about £30 or £40 .One of theses on each batt should hold them enough or at least ensure they don’t knacker over the winter . A long time deep discharged knackers them , seriously shortens there usefulness.
Quick cheap and simple .

I have been using the smaller 5 w on cars + garden machinery …..obviously smaller batts but it prevents a deep and potentially expensive discharge situation.

 

[Victoriana]

I've just bought a 2003 Rinker Fiesta Vee 250. The microwave only works when attached to shore power so I'm thinking of getting another battery and an inverter and charging it with solar panels.
I've never bought or used solar panels before and when I looked online there are so many with huge price variances.
Does anyone else use a microwave with the aid of battery/inverter/solar panels? If so, I'd really appreciate some advice. Thanks

 

[Hurricane]

I've just bought a 2003 Rinker Fiesta Vee 250. The microwave only works when attached to shore power so I'm thinking of getting another battery and an inverter and charging it with solar panels.
I've never bought or used solar panels before and when I looked online there are so many with huge price variances.
Does anyone else use a microwave with the aid of battery/inverter/solar panels? If so, I'd really appreciate some advice. Thanks

I don't want to disappoint but I don't think you will be be able to install enough solar to run the microwave.

How about looking at the capacity of your engine alternator and existing battery system.
Maybe you could use the microwave whilst running the engine.
You would then need a 2 or 3 Kw inverter (depending on the size of your microwave).
Maybe fit 2 separate sockets next to the microwave - one fed from the inverter and one from the existing shore based system.
If you can get something like this working, it would be much better than solar panels over the boat.[/QUOTE]

 

[Bouba]

I've just bought a 2003 Rinker Fiesta Vee 250. The microwave only works when attached to shore power so I'm thinking of getting another battery and an inverter and charging it with solar panels.
I've never bought or used solar panels before and when I looked online there are so many with huge price variances.
Does anyone else use a microwave with the aid of battery/inverter/solar panels? If so, I'd really appreciate some advice. Thanks

A cheaper alternative would be to install a gas hob/oven…

 

[jakew009]

Say a 2kW microwave for easy maths.

If you get a 105Ah LiFePO4 battery, that will give you about 1kWh of usable power after losses.

Therefore it could run the microwave for about 30 minutes before flattening the battery.

To charge the battery back up again you need to put about 1.2kW back in again.

With a 100W solar panel, in the middle of summer, you will generate around 10kW a month in the summer, and perhaps 3kW in the winter.

So it would kind of work assuming you only used the microwave for a few minutes at a time.
I would just take the battery home with you when you leave the boat and charge it up again.

 

[Victoriana]

A cheaper alternative would be to install a gas hob/oven…

Would that be lpg?

 

[Victoriana]

Would a

Say a 2kW microwave for easy maths.

If you get a 105Ah LiFePO4 battery, that will give you about 1kWh of usable power after losses.

Therefore it could run the microwave for about 30 minutes before flattening the battery.

To charge the battery back up again you need to put about 1.2kW back in again.

With a 100W solar panel, in the middle of summer, you will generate around 10kW a month in the summer, and perhaps 3kW in the winter.

So it would kind of work assuming you only used the microwave for a few minutes at a time.
I would just take the battery home with you when you leave the boat and charge it up again.

Would a starter battery be better?

 

[Victoriana]

I don't want to disappoint but I don't think you will be be able to install enough solar to run the microwave.

How about looking at the capacity of your engine alternator and existing battery system.
Maybe you could use the microwave whilst running the engine.
You would then need a 2 or 3 Kw inverter (depending on the size of your microwave).
Maybe fit 2 separate sockets next to the microwave - one fed from the inverter and one from the existing shore based system.
If you can get something like this working, it would be much better than solar panels over the boat.

[/QUOTE]
OK so if I get a 3kw inverter with a 230ah AGM battery, would that work if I keep the engine running whilst using the microwave?

 

[Bouba]

Would that be lpg?

Yes, bottled gas....a proper installation will be expensive and require a gas locker..but you will have unlimited cooking ability. Or a cheap option is a portable camping gas hob and gas bbq. A microwave really needs a generator ...it could have a start up load of upto three times it’s running consumption

 

[Portofino]

Gas would a retro grade step.
keep the boat all electric.

 

[Croftie]

OK so if I get a 3kw inverter with a 230ah AGM battery, would that work if I keep the engine running whilst using the microwave?

A 3Kw inverter at full chat will draw around 300 amps, from a 12v battery, thats quite a load on the battery and needs serious cables

 

[Victoriana]

A 3Kw inverter at full chat will draw around 300 amps, from a 12v battery, thats quite a load on the battery and needs serious cables

Hmmm ok, it would seem I'm at a loss whichever way I go.
What does everyone else do? Do you use your microwave whilst not hooked up to the electric?

 

[Bouba]

Hmmm ok, it would seem I'm at a loss whichever way I go.
What does everyone else do? Do you use your microwave whilst not hooked up to the electric?

I agree with Porto that an electric boat is ideal....but you need a generator

 

[Hurricane]

I've just bought a 2003 Rinker Fiesta Vee 250. The microwave only works when attached to shore power so I'm thinking of getting another battery and an inverter and charging it with solar panels.
I've never bought or used solar panels before and when I looked online there are so many with huge price variances.
Does anyone else use a microwave with the aid of battery/inverter/solar panels? If so, I'd really appreciate some advice. Thanks

Hmmm ok, it would seem I'm at a loss whichever way I go.
What does everyone else do? Do you use your microwave whilst not hooked up to the electric?

I'm afraid the answer from me is that I use the generator.
You might like to check what your engine alternator can provide and if you would do any damage to it if yo connect an inverter to your DC system.
A friend with a sailboat changed his engine alternator to provide more power - maybe thats an option (alternative to a generator).
But taking Croftis's point, you need to size your DC cables carefully and keep their length down.

 

[vas]

happy new year all!
first post of the year, got some time to spare so thought I'd post an el. overview of my setup.
so following is a victron screen output for the production/consumption/soc of my setup in Greece.
600W solar on the hardtop almost flat, no shading whatsoever.
24V system on a twin engine 43ft mobo
4XT105RE Trojans up to spring (April) and then custom LiFePO4 8x304Ah cells, diyBMS, Victron MPPT controller, VenusOS etc.
Consumptions are one or two 80lt compressor 24V fridges (one with a duty cycle of 80-90% due to placement will be converted to seawater cooling for next season) during the season and after the end of Sept one and now no fridge. Lots of domotics and a v.elaborate NMEA2000 bus plus the raspberry pi and a teltonika router running 24/7 means an average consumption of 1.4-1.5A [off season with no fridge running!]
During the season a 3000VA Victron MultiplusII inverter is on 24/7 and used for laptops and all other necessary bits plus an almost daily use of the 2kw watermaker...
no aircon use at all (no need for us), gas cooking, and a v.rare use of a 8kva generator.

I'd focus on the solar production (which again is indicative as if bats are on float or LiFePO4 charged, output drops to zero...)
Note that with LA consumption was relatively high, later on with the LiFePO4, drops significantly as there are not all these endless float charges.

anyway, can give you a overview of what can be achieved with 600W in the med, do your calcs and decide what will work (give or take) in your case: