Solar Panel Help Needed

[ciclon1942]

Hi,

I am in the Med (Turkey) at the moment and have always had problems with flat batteries, I am no electrician but would like to know what we are doing wrong and how best to put it right.

We have two 95Ah cranking batteries and two 100Ah deep cycle batteries and although we do not have a lot of electrical items we do have a fridge that is a thief on battery power but is a necessary evil as a man needs a cold beer at some point. I am thinking about putting in another bank of batteries just for the fridge due to the fridge working overtime in the summer when it gets close to 50 but am unsure of the best way to go about this.

We have a petrol generator which I plug into the shore power socket and charge the batteries through the battery charger whilst we are at anchor and we do use the engine a fair bit in the Med so that keeps things charged up as well. I am unsure of the benifits of solar panel and due to not having much room I have decided to test the water by buying a 50 watt panel and 10 Amp controller, I thought about putting this direct to the fridge bank of batteries but am not sure if this is the best way to go, if this helps I plan to buy another 50 watt panel next time I go out.

I am also not sure about the best place to mount the panels, we have a classic hull shape and so this does not allow for a lot of beam or good places to mount a panel. I have thought about putting a tube between two stantions and mounting it that way but any suggestions regarding any of the above would be very much appreciated.

[forsailbyowner]

We have panels mounted on our dodger and bimini. Your problem is probably universal with people who run fridge. I have 8 solar panels with around 320 watts and its still can be a problem. Our windgen usually makes the difference but its been down getting serviced so we've resorted to backpacking ice to the boat to take some load off the system.

[ciclon1942]

Originally Posted by forsailbyowner

We have panels mounted on our dodger and bimini. Your problem is probably universal with people who run fridge. I have 8 solar panels with around 320 watts and its still can be a problem. Our windgen usually makes the difference but its been down getting serviced so we've resorted to backpacking ice to the boat to take some load off the system.

Thanks for the reply, We put in a couple of large blocks of ice to help things out but would like a better solution so that we dont have to go back to civilisation quite so often.

Thanks again

[Artful Dodger]

Just wondering as to what kind of fridge system you have, some newer ones will operate great if they are a smart type meaning they also monitor battery availability, and can step down their demand. We use three 50 watts panels with two battery bankings and the fridge is on 24/7, with little to no problem. We also use no other source for energy, we have also swtiched everything on the boat over to LED's which also has help greatly.

[Strygaldwir]

I'd imagine a 50 watt panel would give a slight help to your energy issue, but I'd be surprised if it resolved the issue. I have a frigoboat variable speed compressor for my refrigerator that is very energy efficient. But, it uses something on the order of 4 amp hours per hour. I imagine during peak production, your 50 watt panel will generate a little bit more than 3.5 amps hours per hour. I'd expect only to get that peak production for about 3 or so hours per day. At that rate, you'd still run a signifcant deficit. But, having the one panel might cut off 1/2 an hour of generator run time a day. I think you might be better off with something closer to 200 watts of solar panels.

I have seen folks mount them on the safety stantions. They swivel up out of the way when they are underway and the bring them up when they are at anchor. It might be possible to mount four 50 watt panels in this or a similar configuration.

By the way. I am a BIG fan of solar panel. They are one of the most pain free things on my boat! But, they are not cheap

[olepedersen]

we had your problem in 2007-2008, we run refrigeration 12 volt, and an Engel freezer. at xmas 2008 I instaled 2 120 watt panels, and a 15 amp controler no more problem at noon in the bahamas I read 13.75 volts . I am pleased, but thinking of a MPPT controler, like outback 60. just waiting for the money ha,ha Ole

[Maggie-K]

Look at better insulation . I put in Vacuum panels from here
Vacuum Insulation Panels (VIPs)
and cut my power consumption nearly in half on the freezer. My solar is 165 watts and can keep up all electrical need without running the engine to charge. Battery Bank 550AH.

[bobfnbw]

50 watts of solar should supply you with around 15 amps per day. That will not nearly be enough.
I suggest at least 2 100 amp panels mounted to stainless rails between the stachions with adjustable mounts that lets you lay them down or adjust them up depending on your needs. 200 watts will give you about 60 amps per day and that should cover the fridge.
Depending on your total needs that still might not do it enough but will be a good start.
If you have dingy davits you can put them above it, and or mount them above a bimini.
I have 2 100 watt panels now, but plan on adding at least 200 watts and would like a total of 600, which would supply all my needs. Then the main engine would never be used for charging, and my occasional topping up the bank would be done with honda ac generator. That would be my goal. And a wind generator for those days the sun don't shine, and to supply power at night as well.
Add the biggest MPPT controller you can, cause if you go small now and decide to add panels later you will need to upgrade it.