Alternator and Solar

[Grime]

Can running solar and a alternator at the same time hurt the alternator?  Had mine tested this morning a O'Rileys. Putting out 11.5 volts.   Alternator number 2 on the way. The first one on the boat was bad when I purchased the boat. 60 watts of solar on a controller.

Would I need a larger controller. Mine now is a 10 amp but the alternator is 35 amps.

[Cyric30]

Grime i really dont know if it would hurt either one or not, but having them isolated from each other couldn't hurt things, that way if something did go wrong there wouldn't be a chance of some sort of feedback. then again someone with more knowledge than me needs to weight in.

[Grime]

Seem no one has an answer so I guess I'll just add another switch. #1 position to #1 battery #2 to #2 battery and Both to my solar controller. When I'm using battery #1 and running off the alternator I'll have the switch set on battery #2 and so on. That way solar is charging to battery that is not being used at the time. 

Thanks Cyric30 for your thoughts

[Captain Smollett]

Yep, keeping them isolated is the better plan.

I can't remember who it was, but some mover/shaker in the boat wiring 'field' a few years back wrote that those "1-2-Both-Off" switches need to go away.  In that dude's opinion, it is far better to use two "On-Off" switches and pretty much never put them both "On" at the same time.

Now, all that said, did I read correctly that you have a 10 A controller and a 35 A alternator?  I would not think you'd have much success running anything over 10 A through electronics designed for 10 A.

I can't imagine the solar panel hurt the alternator directly, though.  When I saw your question, I tried to think of an answer that made sense and really couldn't come up with one...either way.  It would be my guess that the alternator has internal protection against that sort of thing, and if you were pushing both through a controller anyway...?

Good luck.

[ralay]

Sorry to hear about your boat troubles, guys.

It's hard to guess what your problem is without knowing exactly how your boat is set up, but I can tell you that it's definitely possible to set up a solar panel and an alternator to charge the same set of batteries without needing to worry about turning switches.  On Mona, we have a 35A, internally regulated Yanmar alternator and a 75W solar panel with a 25A FlexCharge controller.  The Yanmar alternator is regulated to ~14.5V and I set the FlexCharge controller to ~14.3V.  When the engine is off, the solar panel charges the batteries.  When the engine is started and the voltage goes up to 14.5V the solar panel controller goes into divert mode until the engine is turned off again.  Our 75W panel only puts out 3-4A so it's hard for me to think of how your 60W panel might be ruining your 35A alternator.  You may have a different type of problem. 

For clarity's sake, can you tell us more about your set up?  Do you have an internally regulated alternator or one that needs an external regulator?  Is the 10A charge controller only handling the juice from your solar panel or is it being used to regulate the solar panel and alternator? 

[ralay]

Also, I'm a big fan of checking for the simplest answers to problems first.  Have you had your batteries tested?  A bad battery can overwork and burn out alternators.  You can lug them over to O'Reillys or get a multimeter and a load tester and test them yourself.  (I have a cheap Harbor Freight load tester that works fine).  It may have nothing to do with your problem, but it's free/cheap to test and you'll definitely want to eliminate that possibility before you install (and possibly burn out) alternator #3.  Just my 2 cents.  Good luck.

[CharlieJ]

Hi Raylay- I can answer part of that- he is on his third brand new battery

[ralay]

Well, so much for easy solutions I guess.  If I were back there I'd try to have a look, but it's sure hard to help from afar without being able to stick my head in the engine room.

[Grime]

Ralay,

I installed a new power switch (Guest) so each battery has its own position. I also added a second switch to turn off the solar when the engine is running. So Battery 1 is on the engine and battery 2 is on solar. Then the next day Battery 2 would be on the engine and battery 1 would be on solar. More work but maybe fewer alternators.  I'll get a new controller just to be safe.

Why am I doing all this when the boat is going up for sale after the deck is painted. I guess I don't want the next owner to get stuck with a pile of poop like I did. Very expensive learning experience.

[Grime]

Since CharlieJ has answered for me but only half of an answer. Here's the rest of the story.

I went to AutoZone to purchase a new boat battery. I figured that AutoZone would have better batteries than WalMart. I got their top of the line marine battery. Date on battery 12/13 already 7 months old. After 24 hours on the charger it would only reach 12.11 volts and not the 13.5 that marine batteries should have. Took it back. Battery #2  12/13 again 7 months old.  2 cell weak and one cell dead. Took it back. Battery # 3 I gave up and have to live with it. AutoZone will not refund on batteries.  Went to good old walmart got a group 29 marine battery for less money. Installed it 13.5 volts steady. Runs the RGB fridge/freezer just fine.

This is the reason for the different switches instead of hooking up both batteries together. Autozone would kill good old walmart. O and I forgot the sticker on the walmart elcheapo battery was. 7/14. 

Maybe next time Charlie let me talk for myself. I've been doing it for near 70 years.

[ralay]

I think I might understand.  Have you got one good Walmart battery and one bad Autozone battery that you want to isolate because you can't get the Autozone battery up to charging voltage?  If that's the case, you may want to consider the bad battery a sunk cost and get rid of it.  A battery that won't accept a charge can definitely ruin your new alternator.  I saw your engine model on your other post.  If you purchased the Yanmar/Hitachi replacement, you have the same 35A, internally regulated alternator we have on our 3QM30.  It's regulated to around 14.5V.  If the battery doesn't come up to 14.5V, the alternator will keep trying with all its might to bring it up to 14.5V and can burn itself out in the process.  Since a bad battery can destroy a good alternator (and visa versa), you want to make sure that both are good before replacing one or the other.  Please correct me if I'm still not understanding your current arrangement. 

[Grime]

You have it right. Know how hard it is to throw away $126.00. But then that is cheaper than buying alternators.

From you description with the Autozone battery that's what cost me my alternator.  Since we aren't using the boat I'll kill the autozone battery before the warranty runs out 12/14. Maybe by then they will have a good battery.

Thanks for the help.

[ralay]

Yes, I feel your pocketbook pain.   :'(  Anyways, that's my best guess.  That may or may not be your only problem.  Let me know how it goes.

Also, in answer to your second question, no it doesn't matter if your charge controller is only 10A if you're only using it to regulate the juice from the 60W solar panel, which probably only puts out 3-4A.  If you were running the alternator juice through it, it would be a problem.  But I suspect you might have a regular old alternator with a built-in regulator in which case I don't know why it would be hooked up to a controller.  Is your new alternator one like this? http://www.ebay.com/itm/NEW-ALTERNATOR-YANMAR-MARINE-KBW-10-YSE12-YSE8-YSM12-YSM8-1CYL-0-331L-0-510L-/110850090846 

[Grime]

Alternator is new right out of the box. Its not hooked up to the controller. Same alternator Got it from the same guy on Ebay. 

Will let you know how it goes.

[ralay]

It's the same alternator we have from the same guys.  It has a built in regulator, it just needs the third wire (besides output and ground) hooked up correctly in order to regulate itself.  My only gripe was that our new alternator didn't include a wiring diagram.  It took me a few calls and looking at the service manual to figure out what was what.  If you have any doubts/problems when it comes time to hook it up, I made diagrams on which terminal is which and how the alternator is wired up to the key switch, indicator lamp, etc.  I can email them to you if needed, though the folks at rareelectrical also seemed happy to answer questions over the phone.  Or maybe y'all are sick of messing with all this and just want to sell the boat as-is.  I wouldn't blame you either way, but if we can help, let us know.  I have neurotic .pdf diagrams of EVERYTHING if you need examples of working set ups.

[Grime]

Mine came with a wire already connected to the back of the alternator. I hooked that up to the key switch ( which is also new) If you look at the back of the alternator the one that had the wire already runs sideways to the alternator the other spade connector runs up and down. Hope this makes since.

I would be nice if you did send me your pdf file.  We are at home now for a few days.  I think James has my email.

[Kettlewell]

Essentially, it is unlikely that solar power will damage the alternator in any way. In fact, alternator life should be prolonged by having less charging to do. I would suggest wiring the solar direct to the batteries with a fuse very close to the battery. Just leave it hooked up 24/7. I like the system that all charging sources go direct to the larger house bank of batteries and a single start battery does nothing but start the engine. That way you know you can always start without the danger of leaving a switch in the wrong position. The start battery gets the little bit of charging it needs by something like a Trik L Start which bleeds off up to 5 amps to the start battery whenever the house bank gets above a certain voltage. Has worked like a charm on my boat for years.

[Kettlewell]

By the way, for a truly simple system for smaller boats just tie all the batteries together into one battery bank, whether it is two or more, and lead all charging sources to the bank (properly fused). Keep an eye on voltage so you have enough to start the engine, or even add an alarm so you don't let it get too low. A master cutoff switch is nice to have. I used that system for living aboard a 32-foot cat for more than 12 years. The solar will not interfere with the alternator, except to reduce the charging time.

[Grime]

Thanks for replying but I have my system in place. Can't afford to throw away 2 new batteries and start all over.

[Kettlewell]

Ha! I have completely reworked my electrical system on my current boat probably five or six times since I bought her in 2005, based on new information, better equipment, and trial and error. There is no single, perfect system, and you may find that what now sounds perfect on paper needs to change once you are on the water for awhile. But in answer to your first question in the thread is that, no, the solar does not hurt the alternator. Leave the solar hooked up and reduce your charging time.