solar panel & regulator

[seascape]

i have 1x110ah & 2x75ah batteries no fridge a cd player usual lights instruments etc i like idea of being able to move panel around for efficiency ie sprayhood deck guard wires so lanyard tie attachments would help some flexibility too any suggestions & reputable suppliers please i want to keep batteries topped up when off boat & provide power when at anchor thank you

 

[Channel Ribs]

, .

 

[RufusM]

yes that sounds like it will work.

Not sure of manufacturers though. /forums/images/graemlins/cool.gif

 

[Talbot]

you dont include a locality in your bio. Barden batteries are very good on their solar stuff.

 

[seascape]

i'm based in north west

 

[William_H]

Keeping the batteries good is easy. You can get 3 silicon diodes connect the anodes (the end without the band or the tail of the arrow) of all three diodes together the cathode (band end) of each goes to +ve of each battery. This provides isolation of all 3 batteries while charging all batteries. Note this will not work with a regulator because that provides 14volts regulated and the volt drop of the diodes will limit charging voltage. However the panel without regulator runs at 17 to 20 volts and so a loss of .7 volt is no harm.

However if you havee a really big solar panel more than 20 watts you may need a regulator to stop overcharge of your battery bank. With 20 watts be carefull to charge all batteries, not just one, which could be overcharged after a few weeks of sun.
A slightly better arrangement for the diodes is if you can identify and isolate the built in diode of the sollar panel. (sometimes in a plastic box where the leads come out. If you can make a connection to the panel before the diode you can connect your 3 diodes anodes from there and get an extra .7 volt. Actually you use the existing diode and add 2 more.
Put small in line fuses in each batteries +ve wiring to prevent fire should the battery power short to -ve . It will be live 24/7 even with battery isolator switch open. The solar generated power will not blow a fuse or cause a fire unless it is a large panel. (but the existing battery power will.)

Lastly I found from experience the best place for a panel is attached by bungees to the top of the boom sail cover. Drill 4 holes in the Al frame and fit small shackles. I have 2 power sockets (Single contact banana sockets) just inside the main entrance and the wires go through the gap in the wash boards.

Now for power when at an anchorage. You will need a larger panel IF you are to stay ahead of the nightly drain. eg 4hours of CDs and lights might equate to 15 amp hours. 15 amp hours will take 2 amps or about 30 or more watts of solar to replace each day.
Remember a solar panel is rated at 20 volts not 12 volts so 20 watt panel gives a bit over 1 amp into your battery. The hours per day of full power depends on weather and panel orientation. Hopefully better when you are holidaying on board. If you only stay on board for 2 nights then you don't need to replenish the power used, that can happen over the next few weeks while you are slaving at work so much less solar power is needed. (I use a 3 watt successfully for all power but in Oz summer) good luck olewill

 

[seascape]

thanks for your advice
PBO ran an article on solar panels10/05 magazine best efficiency was Unisolar FLX32
anybody any experience of this type it would seem to fix to mainsail cover as recommended and is flexible
how would i connect a regulator so as to charge all 3 batteries at once can anybody suggest a size of panel for approx needs as detailed above

 

[vyv_cox]

Re: solar panel & regulator

Yes, I think I have the one you mean, it's a Uni Solar USF32. It is incredibly good, giving far more power than it is supposed to, apparently a characteristic of this amorphous type. I also have a semi-rigid panel giving 38 Watts but the Uni Solar outperforms it. Although the panel will strap to the boom we find the best output is to lie it on deck facing the sun as far as possible.

Look at Sunware regulators, http://www.wirefreedirect.com/solar_charge_controllers.asp although there are plenty of alternatives. Other than the simple one panel, one battery arrangement, there are types that will charge two battery banks, giving preference to the one with the lower charge. I have two panels and three batteries, two domestic and one starting. Everything is controlled by the regulator, no additional diodes or other dodgy connectors. Most solar panels nowadays have diodes built in anyway, so separate ones are not needed.

My two panels will produce 4 amps midday Mediterranean and the output is sufficient to run all our electrical demands, including refrigeration, virtually full time.

 

[seascape]

Thanks very much Vyv. Where did you buy the Uni Solar USF32?Did you need to extend the cable run to be able to reach the deck? If so is the extension of the required cable straight forward? Where did you site the regulator, & does the feed from the panel access the boat via a water tight fitting?
Many thanks in anticipation of your help.

 

[jonathankent]

Just being pedantic, but a little punctuation would make this a lot easier to read.

 

[vyv_cox]

The panel plugs into a Dri-plug sited at the foot of the mast. The fixed panel cable also enters the boat around here, via a permanent gland. Inside the boat I ran heavy copper cables aft to the switch panel which is about 1 metre from the batteries. The regulator is located here, the same type of cable being run from it to each battery bank. The cable is multi-strand industrial stuff with a cross-sectional area of about 5 mm2, I guess, to reduce voltage drop.