Battery charging from multiple sources

[DaveEv]

I know this subject has been touched on before, however the threads seem to drift a bit before any definitive conclusions are reached.

On my Seafarer 37, I run a 675AH house bank along with a separate dedicated starting battery. These are separated (connected) via a combiner and presently charged via either alternator or AC charger (shore power). This year I am adding a small wind generator (internally regulated Air Breeze) and am not clear how the three sources will interact if each is directly wired to the house bank.

My assumption would be that any one source seeing any charging level voltage from another source, even at a very small current value (ie wind generator), would self-regulate itself down (or off). As intuitive as this would seem to me, the issue is not even mentioned in the Air Breeze user manual, so I'm starting to wonder if I'm missing something??

Should I be adding some sort of charge controller to the system, or alternatively be wiring a switch capable of removing the Air Breeze from the bank when running the engine or shore power?

Thanks for any advice,

Dave

[btrayfors]

Dave,

Since the manufacturer offers Systems Design and Consulting services, suggest you put the question to them. They'll no doubt be able to help you.
System Design & Consulting

My guess is that if the internal microprocessor-controlled regulator works as a multi-stage smart regulator -- as it should -- it shouldn't be a problem working with other charging sources.

Remember, although the charging source might be capable of high voltages, when you connect it to a sizable battery bank such as yours the battery voltage will be considerably lower if the battery is discharged, and until it's fully charged (after which, both the wind generator and other charging sources should shut down).

Bill

[DaveEv]

Bill,

Good point on the consulting call - they should be the pros on their own stuff. I realize that the battery would slightly hold down the charging voltage, but I would have guessed that it would still be high enough to "confuse" the other sources. I have a feeling you are right, though, otherwise they would have definitely tried to peddle an additional (expensive, I'm sure) controller!

Thanks again,

Dave

[Cruisingdad]

Good question.

I will tell you what I was told, then I will tell you my experience.

I have a Prosine 2.0 100 amp inv/chg. I also have a Outback MX60 MPPT with 520 watts of panels. These feed 840ah house bank.

Now, what I was told is to leave both of them on. THey should not interfere with one another, per the reasons that Bill said. This is true when the batts are bulking/abs.

What I have seen is that often, when floating, the Outback shuts down saying that the batts are full while the Prosine continues floating. As such, I rarely leave them both on (almost always turn off the Prosine as my solar is suffucient for my needs).

What would be an interesting experiment is to take a true reading off of the batts when that happens to see what is going on and the true battery state. However, I have not done that.

I hope that helps answer your question or gives you some food for thought.

- CD

[chucklesR]

I think what CD is experiencing is the fact that some systems/ devices /manufactures have sensors that are more sensitive than others; or they may in fact be set to different voltage settings.
Normally I would intuit that CD has his stuff set up with a systemic view (i.e. takes into account ALL the sources), but lately I've seen pictures of him outside IHop so I've come to doubt his judgment.

[negrini]

individually they will shutdown based on its pre-set (current and/or voltage sensing), and just leave everthing on. The regulator purpose is not to fry your batteries, as in DC sources, everything in parallel will sum-up. Another good use for the regulator, is to avoid any source draining current in the reverse sense (like old solar pannels connected directly). Well, what you'll see is the most powerful source will superimpose above others, so when your engine fires, the solar pannel regulator will sense batery full, and shutdown, so will your small wind generator. Once engine is off, the second larges source of amps will take over the function, and surely your off engine will not drink any amps from the source, making sure everything goes to the batt.