Stopping confusion with multiple charging sources onto single battery bank?

[DevoDave]

I have a liveaboard sailing catamaran.

It has 500W of solar through my spankin' new Classic 150, and a whopping great 150A Balmar alternator with an MC614 smart charge regulator on one of the two engines.

When sailing, the engine is off and the Classic will happily do it's stuff.  However if I happen to have the engine running, the Balmar has the capability of generating up to 150A, but the smart charge regulator may not operate effectively because it will see the higher charge voltage from the Classic, and so the output power of the alternator may be reduced.

I need a way to automatically stop the Classic from producing power when the engine is running.  I *COULD* whack a relay into the PV input line and interrupt supply, but it would have to be a biggie.

I'm wondering if there are any smarts in the Classic that could do this?

[Halfcrazy]

The classic has a logic input on Aux2 that will stop it from charging. There is a logic high and a logic low mode. I will dig up the specs but basically it was geared around 12v. So in one state you apply 12v and it stops charging in the other you remove 12v and it stops charging. You could run a switched 12v lead from the motor to Aux2 and that way anytime the motor is running the classic would rest.

Ryan

[DevoDave]

That sounds ideal Ryan.  I did read the manual, but I could not find a lot on inputs.

(Would the use of this method mean I could not use a Wizbang?)

[Halfcrazy]

Yes at this time. The Aux2 is the only Logic Input

[boB]

The manual is being revamped now.  There may be nothing about this particular Aux 2 mode in there.

Yes, unfortunately  if the Aux 2 is being used for a WB Jr. then it cannot be used for a disable input.
dang !

However, you might be able to do some kind of communications thing to turn it on and off via
Ethernet ?

boB


Monkey men all in business suits

[DevoDave]

Ethernet is probably adding too much complexity.  I don't think I can convince my 30Hp Yanmar diesel to start spitting out packets.

I think the Wizbang has a lot to offer so I'll try to retain that capability.

What about a high-ampere NC contactor with a 12V drive coil driven by a signal from the engine when it's running.  Engine on = contactor energised = PV array disconnected.  (Resistor-capacitor across the contacts to quench the spark).  GXNC14B would do the trick, but a quick google has not found a supplier here in Oz yet.

That would leave the Classic's AUX2 free for the Wizbang.

(Or... I am an electronics engineer so if there is somewhere on the PCB I could tap into to force the Classic into off mode then happy to go down that path and save the cost of the contactor)

---------------------
boB...   Teachers and critics all dance the poot.

[zoneblue]

Nah, get yourself a 1w computer, with gpio, listens to generator, tells the classic over modbus/tcp to hold up. Side effect... all the system monitoring youll ever want or need.

[DevoDave]

Nah, get yourself a 1w computer, with gpio, listens to generator, tells the classic over modbus/tcp to hold up. Side effect... all the system monitoring youll ever want or need.

Anything that can go wrong, will go wrong at sea.  I want this simple, robust, and bulletproof.

I can source the GXNC14 from the USA for $155 (+$65 freight..  damn it!) straight from Gigavac.  Pricey but quality product.

[zoneblue]

I know what you mean about mobile computers, i have one in a motorhome. For a long while i had trouble with the thing rebooting going over large bumps. Solder a bunch of caps across the dc rails helps. Minimize anything with cards, or on board physical connectors, eg ram, mini pci etc.

>What about a high-ampere NC contactor with a 12V drive coil driven by a signal from
> the engine when it's running.  Engine on = contactor energised = PV array disconnected.

Just where exactly are you planning on putting that relay. I hope not series to the array as implied above. Have you seen the size of the arc those things produce. If you stick it series to the controller, more problems acrue because now you  have pv live to array, and no battery. 'Nobatt' condition. Also not good.

What choices are left...  Actually i woudnt stress about it. Bob said a while back that both aux1 and aux2 will eventually be PWM/input etc. Correct me if im wrong. And theres also WB senior which theyve only hinted at but i get the impression is a external aux hub type a thing. Something like outback hub? Fishing here...

[dgd]

What about a high-ampere NC contactor with a 12V drive coil driven by a signal from the engine when it's running.  Engine on = contactor energised = PV array disconnected.  (Resistor-capacitor across the contacts to quench the spark).  GXNC14B would do the trick, but a quick google has not found a supplier here in Oz yet.

I see you have four 135watt PVs, you haven't said how they are wired to the Classic, all four in parallel or two strings of two in series?
I would not go the large contactor way to switch out the panels, instead I would use a separate SSR, 10amp, 100v type to switch out each panel or each series string. These are NO but your application would need NC. For that a simple transistor/2 resistor NOT gate with input from the engine (12v) would make SSRs go Open and hence disconnect PVs from Classic. When engine stops they reconnect.
Low cost too, cheap SSRs on Ebay, see wiki for NOT gate design, I seem to remember a SAINSMART ready made pcb with SSRs for a few $
Just my thoughts...

dgd

[DevoDave]

Panels will be one series string.  Voc is 22V per panel giving me 88V total, Isc is 8A.  Given the panels are on a mobile platform (yacht) with varying orientation to the sun, and the additional complexity of shade from the sails I should think series is my only choice.

I considered SSR's, but again in the interest of robustness I discounted them.  It's very difficult for a mechanical NC contactor to fail with the contacts left in an open-circuit state.  I was going to put the the contactor in series with the array, and had given thought to the arcing issue by selecting a contactor that might mitigate the issue.  The switching chamber is a vacuum so there is no air to turn to plasma, and it's rated to 300,000 operations with the expected load.

However, in saying all that if boB is able to suggest that AUX1 may become an input in the near future, I'll happily hold off for a bit.

Whaddayasay boB?

[boB]

Panels will be one series string.  Voc is 22V per panel giving me 88V total, Isc is 8A.  Given the panels are on a mobile platform (yacht) with varying orientation to the sun, and the additional complexity of shade from the sails I should think series is my only choice.

I considered SSR's, but again in the interest of robustness I discounted them.  It's very difficult for a mechanical NC contactor to fail with the contacts left in an open-circuit state.  I was going to put the the contactor in series with the array, and had given thought to the arcing issue by selecting a contactor that might mitigate the issue.  The switching chamber is a vacuum so there is no air to turn to plasma, and it's rated to 300,000 operations with the expected load.

However, in saying all that if boB is able to suggest that AUX1 may become an input in the near future, I'll happily hold off for a bit.

Whaddayasay boB?

Unfortunately, making AUX1 able to be an input would require a hardware change as well as software so I don't see that happening
anytime soon on the Classic.  Yes, I ~shoulda~  ~coulda~  ~woulda~ done that originally but it's kind of late if compatibility with older Classics is going to be maintained.  Also, since it would require a PCB change and some change to the circuitry, there is just no room left on the PCB for much of anything.

Sorry I can't give you more positive "input" on this.

boB

[dgd]

I need a way to automatically stop the Classic from producing power when the engine is running.  I *COULD* whack a relay into the PV input line and interrupt supply, but it would have to be a biggie.

DD
Ok, after re-reading this thread I don't quite understand where there would be confusion with multiple charging sources to one battery bank?
Multiple charging sources is, at least from my experience, quite common. Can I ask where you may see this as a problem in your setup?
When your engine is charging the bank then the Classic will still go through its bulk, absorb, float cycle and eventually stop sending PV power to the bank when its full.
Maybe I'm missing something here but contactor or ssr switching out the PV array doesn't seem to be necessary.
Again just IMHO
dgd

[TomW]

Dave;

I have to agree with dgd here.

It sure seems you are concerned over a non issue. Perhaps I misunderstand your concern?

I know of many many systems with multiple charge sources, including my own, and all seem to work fine with no special modifications.

To be blunt and to the point you seem to be over thinking the plumbing here?

Good luck with it.

Tom

[dbcollen]

I would welcome ANY input from the pv. The diesel alternator reducing its output is a good thing, every watt you take from that alternator costs you more diesel, and last i checked, diesel here is $4.29/gallon and the photons are still free.