Solar battery charger

LaRea

Anybody have recommendations for a solar charger to keep my house battery charged during winter storage?

I'll be in a spot where they won't let me leave shore power connected to the boat.  I don't want to disconnect the house battery, because then I'd have to manually close and open the engine hatch every time.  And I can't leave the battery connected because parasitic loads would drain it within a week. 

My plan is to disconnect the starter batteries, and use a solar charger for the house bank.  I'm going to measure the parasitic load (current used by GPS receivers and other devices when everything else is turned off).  That will tell me what size panel to get, and whether I need a regulator.  

Liberty44140

Hi @LaRea, testing your parasitic load is a good idea. From your other posts I know that you have newer technology than I do, and more of it, but I can tell you that with my panel switched completely off (main battery switches on) I've left my boat not plugged in but batteries connected for 2 weeks without draining the batteries. I disconnect my batteries in October and then reconnect them in the early spring in storage to work on the boat so this two week period is in the spring in storage. 

Dream_Inn

I guess the only issue would be if or when we'd get snow.  You'd have to have the panels reachable to clean off, but yet not hidden by shade of your boat or anyone else's (might be tough).  I know someone that had a 75W one they set out on the bow of their 400 and it just plugged into their cig lighter (right at their dash).  Seemed to keep things working pretty well and no regulator.  For parasitic loads, I'd think something small like that without a regulator is all you'd need.

How are you covering your boat?  I'm asking because I'd think you could leave your engine room open with a cover or shrinkwrap on it?  I know my hatch will open with my cover on it (I do it all the time in the winter).  Then, you could leave all batteries disconnected (reconnect house in winter when you tinker around on boat).

LaRea

Mine drains the battery in less than two weeks, so I have to do something.  I don't have a cover, and I'm not planning to shrink-wrap it, so I can't leave the engine hatch open.  (Well, I guess I could if I rig up some way to secure the canvas.)

For that rare snow cover that lasts longer than a couple days, I'll go check the boat anyway, so I can clear off the solar panel.  

I'll measure the parasitic load tomorrow while I am (heavy sigh) hauling and blocking the boat for winter.  

Dream_Inn

You could also figure out what the drains are coming from and just pull those breakers.  I think I'd be curious enough to disconnect the ground off the battery, and put a meter (on amps) to see figure out the load (sounds like that's what you're going to do).  Then, with meter on, start pulling breakers to figure out what is pulling the current.  Then just leave those breakers out/off.  Should be simple enough to do and then you don't have to mess with solar stuff (although that would be fun too   & give you another toy in the summer)

Handymans342

What is drawing the batteries down? Everything should be off

Dream_Inn

Handymans342 said:

What is drawing the batteries down? Everything should be off

CO detectors, memory items like radio and GPS, also Genny electronics can pull some, but that switch should be off.  Other things like little green light in the fridges (not sure how to get them off, breaker and 12VDC and knob inside all off)... 

I guess when you test the parasitic load, turn the battery switch off as well and see what changes.

Willhound

Handymans342 said:

What is drawing the batteries down? Everything should be off

Most of your electronic devices these days are drawing some current even when turned "off". Preserves pre-sets and menu's etc.  Known as "ghost current".
And if you have the Mercathode system on-board it is wired direct also, not switched so draws all the time that batteries are hooked up.

Handymans342

Just unhook the battery

Dream_Inn

Handymans342 said:

Just unhook the battery

Did you read his post?   It says he would then have to manually put down his engine room hatch. 

Handymans342

Still you could unhook and use a jump box to open hatch. I saw a nice little solar charger at west marine. 

Cableguy Greg

On my 280, the bilge pumps, stereo memory, and Mercathode are on "24 hour circuits" which are connected to the switch on the side that it can't be shut off via the switch. On my battery panel diagram, the battery breaker disconnects everything.

Liberty44140

One other comment - on my 342 I can open and close the engine room hatch using the button on the dash with the batteries completely disconnected. As long as I plug the shore power in and have the battery charger switch on, on the AC panel, the engine room door switch works just fine. I assume the isolator makes this magic happen? So LR can you just disconnect batteries and plug in when working on the boat?

LaRea

Handymans342 said:

Still you could unhook and use a jump box to open hatch. I saw a nice little solar charger at west marine. 

That works on some boats, but not mine.  The jump terminals on mine can only open the hatch, not close it.  

@Liberty44140 - I will definitely try that tomorrow!  

Ian

Odd, why not the other way when reversed? 

Handymans342

LaRea said:

Handymans342 said:

Still you could unhook and use a jump box to open hatch. I saw a nice little solar charger at west marine. 

That works on some boats, but not mine.  The jump terminals on mine can only open the hatch, not close it.  

@Liberty44140 - I will definitely try that tomorrow!  

Well that's all you need to do to rehook up the batteries

LaRea

Yes, but when I leave, I need to disconnect the battery and close the hatch, and the jump terminals won't do that.  @icoultha - I never figured out why they did it that way on some boats.  Makes no sense.

kordo

Had the same problem.  There is a connector just before the hatch motor that I pulled apart.  I attached two blade connectors to two wires about 8' long and then inserted them into the connector going to the hatch motor.  Use the same gauge as the existing wires.  I then touched the other end of the wires to a jump battery to close or open the hatch.  Reverse the polarity to change direction.  I put a two foot 2x4 in the floor channel so that the hatch will not close completely to avoid crimping or cutting the 8' wires when the hatch is closed.  Also, tied the wires around an empty anti freeze plastic bottle so that the wires don't slide back into the closed engine room.  Good luck.
 

Ian

LaRea said:

 @icoultha - I never figured out why they did it that way on some boats.  Makes no sense.

Isn't it just reverse polarity? You mean they've put diodes in to stop reversal? Makes no sense.

LaRea

@Liberty44140 was right -- even when the batteries are disconnected, the charger can operate the engine hatch!  This is such a good tip that I made a separate post for it.

For my 2007 370, the "Easter egg" is: 
* shore power connected
* battery charger on
* stbd battery switch on
* helm power switch on

So, I do not need a solar panel for winter storage.  @Liberty44140 - if you ever come to the DC area, I'm buying you a beer (or two).

Liberty44140

Hey @LaRea glad it all worked out! Saw your other post, that is great. Funny, the admiral and I planned to come to DC this past fall as I’ve never been to the monuments and we could not get a reservation to see the White House so we put the trip off until spring or fall so we can plan in advance for tours. I may just cash in 

LaRea

If you come during good weather, I'll show you the monuments from the water!

Liberty44140

Sounds great!