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  Topic Review (Newest First)
08-24-2013 07:33 PM
Re: Stupid solar question

Lots of material out there. Learn to look for it. I sound like my dad now.

Here are just a couple of links I googled.

Fusing a Solar Panel

Fuses for Solar panels - Cruisers & Sailing Forums
08-24-2013 07:16 PM
Re: Stupid solar question

Erm. How would you fuse it? I'm all ears. It appears to be working fine for a few weeks now. No smoke. But I'd be happy to fuse it. What fuses would I be putting in it?
08-18-2013 09:14 PM
Re: Stupid solar question

I hope you fused everything.

When I first installed my array I was in a rush and didn't patch in the fuses. My friend then commented, "hope your boat doesn't burn down".

As he's in the boat business I knew he wasn't joking.

I didn't have any problems but I sure sleep better now that the fuses are installed.
08-18-2013 08:59 PM
Re: Stupid solar question

Originally Posted by sully75 View Post
I guess my question is am I likely to damage the panels controller or battery this summer until I get a better controller?
I just wouldn't want to leave my boat with that controller hooked up. Looks scary to me. (I have seen much better looking ones overheat & melt) Maybe set it on something non-flammable. (I'm only partially kidding)
08-18-2013 01:49 PM
Stu Jackson
Re: Stupid solar question

mango, no you don't need a cut off switch. There is nothing wrong with multiple charging sources at the same time. Only caveat: turn off the shorepower when you start your engine, if you bank is full the alternator's tach won't work until you apply a load.

There are a LOT of solar websites out there with good information.


Maine Sail is a great resource. Go to his website.
08-18-2013 01:19 PM
last mango
Re: Stupid solar question

So if you add panels, do you use a cut off switch while sitting at a docks and the boat is hooked to shore power and battery chargers? Looking to add some to mine and just in the planning and learning stages of what I need and how to tie it all together
08-02-2013 03:47 PM
Re: Stupid solar question

The cheap charge controller is just a regulator. What it will do is lop off any extra voltage coming from the panels, which might put out 22 volts unregulated at their max. So the charge controller is making sure the panels don't cook the battery, but it is set to 14.2 volts, and that might still cook a battery in extended use. If the battery is never getting fully charged, no problem, 14.2 should be fine for bulk charging wet lead cells.

the charger also apparently has a cut-off, so that it will prevent the battery from pushing back into the solar panel in low light conditions, which saves you from needing a diode to do that.

Instead of lopping off excess voltage, an MPPT controller convertes it to lower voltage at higher amerage, so you may see 10-20% more charging power from the panel but you've got to balance that against the higher cost for an MPPT controller.

On the amp ratings, you're OK where you are. Odds are that if the battery is never getting fully charged, you're just not getting enough power from that one panel and lop-off controller.

If you have conventional lighting on board, replacing it with LED lighting can sometimes do more for your charging needs than spending the same amount of money on anything else.
08-02-2013 02:17 PM
Re: Stupid solar question

If you're under charging your batteries they will be damaged I'm just not sure of the timeline. I couldn't find any specs on the maximum input voltage to your charge controller but assuming the 18.9V of the solar array isn't to high you shouldn't damage anything else.

Any chance you can dock the boat and use an ac powered charger to top off your batteries as often as possible?
08-02-2013 09:01 AM
Re: Stupid solar question

7 amps is fine.
When you get the money buy a MPPT controller, the output will amaze you.
You really do get what you pay for, provided you shop for quality.
08-02-2013 07:14 AM
Re: Stupid solar question

Originally Posted by macwester26 View Post
I have a large 85 watt solar panel I was told that i should use a 15 or 20 amp controller.

The cheapest i found was £15.00 GB Pounds from eBay...

Fitted into a lift up hatch It does keep both 120 amp batteries fully charged...With no Problems.

See Here PAGE 12

By the way there is Nothing stupid about asking questions.
After all how would we know the answers..
As a simple concept, watts = amps x volts. So at 13 volts x 20 amps, the 20 amp controller is capable of managing a 260 watt array. Even at 15 amps it adds up to 195 watts. You have 85 watts. Mmmmmm.

I have two 140 watt panels that are managed by a 20 amp controller and the reason the setup continues to work is that the panels never deliver 100%. YMMV
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