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Discussion Starter · #1 ·
Hi Gurus

I have recently purchased an 80W solar panel and Blue Sky Solar Boost 2000E Charge Controller.

I also have a Xantrex 3012 (30Amp) controller
2 banks - engine and house.

Solar will be hooked up to the House bank

My question is do I connect the output of the solar AND shore charger right to the battery and not worry about when both are ON at the same time - or do I switch the Solar panel so that I manually turn it on when shore power is disconnected. :confused:

I read through both the manuals and there does not seem to be any indication either way. Both manuals make the assumption that they will be the only device charging the battery.

What have you guys done and what have been your results?

Thanks in advance

Tom
 

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Put a switch on the solar charge controller output. If you're on shore power, you really don't need the solar panels contributing. That's what I did.
 

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Wire both to the battery directly. When my solar is running (mine is a Outback MX60), the voltage basically tells the Xantrex charger not to charge. I did put a switch (and breaker) before the Controller so that I could manually remove the solar charger from the system... but mine is a MUCH larger system than yours.

WIth just a single 80w panel, I don't think you are going to put enough in for it to matter anyways. It will be, at best, some supplement on a bright day. I will tell you that I have 4-Kyocera 130's hooked in series (not parallel) to my Outback. That gives me on a nice day somewhere just over 200ah/day if they are bulking. WIth a single 80w panel, you might be looking at a max 31ah/day which translates to very low amps even at peak bulk.

My opinions and what I did.

- CD
 

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Listen to me and Cam... not CD... ;) His known area of expertise is BBQ grills. If you have a question about searing steaks, ask CD... :)
 

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Turn the solar OFF at the dock. You don't want surface charge fooling the dockside charger.
Hmm, seems like it would be easy to automate this - if the charger were going through a diode (bad idea) all you would have to do is use a bit of charge current to switch a normally connected relay into open position and automatically disconnect your panels as a charge source. Not running the charger through a diode, however, I'm not sure how you'd implement it unless you actually had a controller that would periodically disconnect the panels, read the voltage, and then decide whether to reconnect the panels based on whether another charger is hooked up.

I guess a manual switch is the most simple solution. :D
 

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Maybe some enterprising type will come up with a mother charge controller that minds all the other charge controllers. Run the alternator, wind generator, shore power charger, and solar chargers into a controller that decides how to hook them all up dynamically, another expensive black box to break when you really need it ...
 

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You could probably add something to the AC panel to shut off the solar power when the shore power is live.

Hmm, seems like it would be easy to automate this - if the charger were going through a diode (bad idea) all you would have to do is use a bit of charge current to switch a normally connected relay into open position and automatically disconnect your panels as a charge source. Not running the charger through a diode, however, I'm not sure how you'd implement it unless you actually had a controller that would periodically disconnect the panels, read the voltage, and then decide whether to reconnect the panels based on whether another charger is hooked up.

I guess a manual switch is the most simple solution. :D
 

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I got it ...

Use the actual shore power AC to switch the relay before the charger. Easy, just run the shore power AC to both your charge controller AND a rectifier to convert it to 12vdc, and use that 12vdc rectified current to drive a normally closed relay to its open position thereby automatically disconnecting your solar panels. As soon as you hook your boat up to shore power your solar panels would automatically disconnect.

Implementation - find a high amp Dual Toggle relay and hook that up to some piece of crap wall wart that has the right voltage to toggle it, and plug that into your shore power side should do it ... probably cost you 5$us.
 

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What happens to the "system" when you disconnect from the dock and start the motor?
Alternator jumps it to 14.2 V (assuming no 3 stage) and will take over.

I pesonally do not think he needs to shut it off at the dock either. I do not think he will be putting in enough to make a difference, but it would be a good experiment to find out. Besides, even if he left it on and it fooled the main charger during the day, the panels would go dead that night. THe voltage would drop. The main charger would automatically charge the batts. Come morning, he is not doing anything but floating.

- CD
 

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True... on your boat you probably need control rods to dampen the output of the solar panel collector farm you've got there...
I do not think that is necessary for reasons explained above. Besides, we are talking about an 80w panel.

- CD
 

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True... on your boat you probably need control rods to dampen the output of the solar panel collector farm you've got there...
HEHE.

Well, that is why I would be interested in how his unit would operate staying on and switching off (at shore) as it is a much smaller array.

- CD
 

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Doesn't Houston have rolling brownouts when Chris takes the boat from the dock, because they lose the electricity you generate until she gets back.
HEHE.

Well, that is why I would be interested in how his unit would operate staying on and switching off (at shore) as it is a much smaller array.

- CD
 

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Alternator jumps it to 14.2 V (assuming no 3 stage) and will take over.

I pesonally do not think he needs to shut it off at the dock either. I do not think he will be putting in enough to make a difference, but it would be a good experiment to find out. Besides, even if he left it on and it fooled the main charger during the day, the panels would go dead that night. THe voltage would drop. The main charger would automatically charge the batts. Come morning, he is not doing anything but floating.

- CD
Still, something like this ...



Source: R-adio shack 125vac/10amp DPDT plug-in relay (had to put R-adio to keep sailnet happy)

Relay has a 125vac coil and could be wired directly to AC and it would switch whenever you hooked to shore power, costs 8.49$us, might be worth it if you wanted to make absolutely sure.
 

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Discussion Starter · #19 ·
Thanks for the responses guys - it's a little overkill - but I do like the wall-wart/relay idea.

My concern was more along the lines of the shore charger cooking the solar controller than vice versa

It's more for "experiment on the small boat before you fry the big one"

Tom
 

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My concern was more along the lines of the shore charger cooking the solar controller than vice versa
I don't think you could easily fry the solar controller by applying power to the battery output side unless you started applying the kind of voltages that could reach the reverse breakdown voltage of the diodes in the charger or something ...
 
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