Solar Panels instead of Shore Power

[Simon391088]

Hi,

I have a Sealine SC 35.
It has 4 batteries.
2 are in series and solely for one engine.
The other 2 are in series and are for the domestic supply.

I have been offered a cut price berth for the summer - but there is no power.
Normally I leave the boat in the marina plugged in to top up the batteries.

Could I get solar panels to top up the batteries?

When I use it I would take it to a marina and plug in etc. I just don't want to turn up to the boat and find the batteries flat.
I don't knowingly leave anything draining the batteries at all - in fact I isolate them using the red toggles. But as I understand it if you leave batteries they normally not only drain, they won't take a charge again.

Any thoughts on this welcome - I have done some research and it looks perfectly possible - however I was under the (possibly wrong) impression that Solar Panels are hopeless in reality.

We will probably use the boat for about 5 weeks in one long stretch.

Many Thanks
Simon

 

[BartW]

I have been thinking the same,
in the past I've been struggeling a lot with shore power, either tripping a breaker, or boat unplugged during my absense,
so for this, the SP's would be a good solution,
(not a real problem where I have the boat now)

for me there is second good reason,
in summer we spend quite some time on ancher,
the SP's shorten the time that we have to run the genny considerably,
its not about the fuel consumption, but for the noise and the smoke.

I had a look and a quotation from Solara.de
website is not very good, but when you download the catalog, most info is there.
the Pro-m panels are thin, slightly flexible, and useable for the harsh marine environment,
and you can stand on them.
one 110Wp panel is approx 700 euro, not cheap, but they fit my application; 10 panels on top of the helm station roof.

I'm interested if someone knows other altenatives

 

[prv]

If you're not using the boat while it's moored at this berth, then the batteries will be fine when you come back. You don't plug your car into the wall when you leave it, do you?

Yes, batteries have a self-discharge rate, but it's nothing like enough to be a problem for this purpose.

We don't plug in on our home berth, our only source of power is the engine, and as a sailyboat we run it a lot less than you will

Solar panels would only be necessary if you were living on the boat, without moving (ie running the engines) and without shore power - like Bart is talking about at anchor.

Pete

 

[blueglass]

Often thought about this myself. You can never rely long term on shorepower anyway. Countless times I have arrived at the boat to find it tripped out (probably weeks or even months ago) or somebody has unplugged me to commandeer the outlet.
Where to put them without spoiling the boat's looks is an isssue and of course initial expense. In your case though OP, that expense woul be rapidly repaid with the savings on your much cheaper power-less mooring.

 

[Nick_H]

Yep, perfectly feasible and sensible. I have a small boat on a river mooring and did exactly this to keep the batteries topped up.

If think there's a rule of thumb that if the output of the solar panel (in watts) is more than 10% of the battery capacity (in AH) then you need a regulator, and they are recommended anyway if the panel is >10-20 watts. If not, you can connect it directly.

If your batteries are connected in series then you must have 24V systems, so I'm not sure if you need a 24v solar panel?

 

[blueglass]

If you're not using the boat while it's moored at this berth, then the batteries will be fine when you come back. You don't plug your car into the wall when you leave it, do you?

Yes, batteries have a self-discharge rate, but it's nothing like enough to be a problem for this purpose.

We don't plug in on our home berth, our only source of power is the engine, and as a sailyboat we run it a lot less than you will

Solar panels would only be necessary if you were living on the boat, without moving (ie running the engines) and without shore power - like Bart is talking about at anchor.

Pete

intermittent auto bilge pump might be an issue though

 

[prv]

intermittent auto bilge pump might be an issue though

Fix the leak!

Pete

 

[blueglass]

Fix the leak!

Pete

haven't got one. Just like to know that if I get one, my batteries will have enough power to operate the pump.
you obviously live in an ideal world where such things never happen (they do)

 

[Trundlebug]

intermittent auto bilge pump might be an issue though

Yes it's for this reason that it's always worth keeping the batteries topped up.
Unless you have a Bilgewatch or GSM alarm, how would you know if your bilge pump has been regularly, or even occasionally keeping the bilges under control?
OK that's another question, but the bilge pump does take battery power, and if installed correctly will still work even with the battery isolators switched off.

I've just installed a 150w solar panel, semi flexible from http://www.titan-energy.co.uk/
Really good prices.
Ultimately the best way to install is to measure the space you have available and obtain panel(s) the nearest size to it you can get.

 

[jac]

with regards to looks - modern flexible or semi flexible panels are only a few mil thick and will flex to your deck shape so just find a spare bit of deck you don't use and put panels there. A regulator is a really good idea and are cheap - a dual output PWM controller will prioritise your engine start battery and then switch to the domestic bank when engine start is full - loads around for £20- £30. MPPT controller is better - about 30% more claimed output for about 6 times the price and not seen any that can charge both banks.

Loads of us sailing boats have panels and no shore power - you have the advantage of no huge great mast casting shadows all over it.

 

[Hardmy]

We are most of the time anchoring in a quiet place, avoiding generator use as much as we can. We have 4x220 ah batteries (2x only for hotel purposes), with fridges running etc. they can got quickly drained. So I just ordered 3x100W Solarpanel Monocristallin to be mounted this month (together with a 30A controller) on the hardtop covering our cockpit. I found them on JWS-Store and paid EUR 227 for the 3 panels. Boat goes back to water mid-april, and we will see how this stuff works.

 

[BartW]

I've just installed a 150w solar panel, semi flexible from http://www.titan-energy.co.uk/
Really good prices.
Ultimately the best way to install is to measure the space you have available and obtain panel(s) the nearest size to it you can get.

all interesting stuff on here,
on my wheelhouse roof fit 6 x 150W of these panels,
nice solution at a very good price,

for those who care about esthetics,
if these thin panels are nicely arranged on the roof top, they almost look like roof windows.....

for those interested,
I just came across a range of intelligent controllers from Victron,
MPPT (Maximum Power Point Tracking) range
to get the best efficiency out of the SP's

 

[BartW]

We are most of the time anchoring in a quiet place, avoiding generator use as much as we can. We have 4x220 ah batteries (2x only for hotel purposes), with fridges running etc. they can got quickly drained. So I just ordered 3x100W Solarpanel Monocristallin to be mounted this month (together with a 30A controller) on the hardtop covering our cockpit. I found them on JWS-Store and paid EUR 227 for the 3 panels. Boat goes back to water mid-april, and we will see how this stuff works.

interesting info V,

will you be at messe this year ?
I'm planning to go on thursday and Friday,
if you're around we might meet and have a drink together ?

 

[adey]

If you have a 24v system it's probably easier to put 2 12v panels in series.
I have a 40W panel on my arch which gives about 3a/hr (12v) on a good day.
I also have a dual battery bank regulator like this http://www.futurlec.com.au/Solar_Charger_Dual.jsp
I can unplug the shore power when I leave the boat or leave it plugged in, makes no difference, except if the shore power goes off the batteries stay topped up and will drive a pump for longer (hopefully until someone notices!)

 

[Hardmy]

interesting info V,

will you be at messe this year ?
I'm planning to go on thursday and Friday,
if you're around we might meet and have a drink together ?

Hi Bart!

You mean in Frankfurt April 15-18? I will be in town until 16th in the evening ('cos I make an extended week-end on the boat). Actually my flat is in 10 min. walking distance from your event. Would be really super if we could arrange a drink before I leave!

Best,

 

[Simon391088]

You don't plug your car into the wall when you leave it, do you?

Actually - that's exactly my concern... I have a car which I don't use much and got through a couple of batteries before I conceded that I needed a battery conditioner. (Ok - the alarm probably drains the battery or some earthing fault or something - but no doubt the boat probably will find its own way of draining the battery over months).

Having said that - I have had power trip out a number of times whilst not there - probably for months and had no idea - so maybe it's not such a problem. I just don't want to turn up for my holiday and have to go home again! (Or buy 4 batteries)

Thanks
Simon