Charging Issues

[Highland Fling]

Charging issues.

Now we have got the first phases of our solar installed two 100W panels (phase two is an additional two Kyocera 135W panels) and the Rutland 913 wind generator installed too with the HRDi controller. We are having what I see as issues. With the batteries at 13.3 V the HRDi controller puts the WG into a regulated charge mode (runs slower and produces less amps) and I am assuming the Morningstar MPPT Solar Controller goes into a float mode as well but it does this at a much higher voltage as with the WG in regulated mode the VEM still says I am charging the batteries at a much higher level than what the WG is putting out.. NOW when the fridge/freezer compressor starts up (6/8 times at day) and we switch on the inverter (2/3 times a day) both the solar and the WG don’t see the loads on the batteries and come onto a full power mode right away. They will sit and wait till the batteries get discharged (battery voltage drops to around 12.5 +V) before moving back into full power mode. This seems rather silly and very inefficient as to me it would be more sensible to have the solar and WG handle the loads and take any top up from the batteries at a much lower rate or pass any excess into the batteries should the generation exceed the loads.

Now am I asking for something that does not exist? A system / sensor that will do as above – or is this something I will have to invent and construct - a load sensing bypass relay - that bypasses the solar and wind controllers when the batteries are ‘almost’ fully charged when I want to run one or two loads while/where there is potential (measured) available energy that I can harvest and use without discharging the batteries.

FYI the low power Rutland 913 is nice and quiet - we mounted it on a Charlotte Pipe Schedule 40 white PVC water pipe but I need to decouple one of the triangulation S/S support struts as it (this one strut alone) is transmitting a vibration into the boat and in particular the Stb Aft Cabin. Amazingly the Rutland 913 Wind Generator produced 95 A/H in one 24 hour period. We were storm bound with F7/F8 winds in Anse du Colombier in Saint Barthelemy so it was a ‘little’ windy. Then with Anse du Colombier being at the end of Saint Barthelemy in the wind acceleration zone that only made things even windier. .

[rebel heart]

Sounds kind of weird. I have a blue sky solar controller, and it responds much the same way one would expect. It puts out more wattage as the voltage drops, barring battery temperature issues.

So when the batteries are just in float/trickle mode (~14.2 volts), I'll see maybe 2-3 amps passing through the solar charge controller. When the fridge goes on the amperage will immediately jump to 4-5. Response is under a split second.

Can you disconnect one of the charging sources and see how they behave independent of each other?

[hellosailor]

David, I suspect that what you want is "one ring to rule them all" and that, sadly, does not exist.

Each of your power sources (alternator, solar MPPT controller, dump-regulator on the wind generator) has a separate voltage sensor and when any one of them provides power, the other two see that "source" voltage instead of the battery voltage. So the three of them will constantly squable about what the real battery state is, and what each one of them wants to do about that.

As best I can tell, right now the only way to manage this is with human intelligence and rather bluntly disconnecting or overriding the controllers. When you run the engine, disconnect the other two, let the alternator do the brute work. Other times, you may have to make the decision which one (one) to allow, or which ones (plural) to override and just tell them to charge away at full blast.

Integrating different charging sources would require all of them to be run into one common regulator, and then some type of combined controlled output. Probably not a simple or cheap task, making it difficult to market one at a profit.

[cwyckham]

You shouldn't be seeing any serious negative interaction between the controllers. When the battery voltage is less than about 14.4V, they should be pumping out full amps, and even with full batteries, they should be pumping out as much as the batteries and loads (combined) can take.

Two ideas: Can you provide a wiring diagram? Maybe something weird is going on with how you've set it up. especially with where the voltage sense leads are. And as somebody else mentioned, what happens when you run each controller independently?

[Highland Fling]

the WG controller is NOT a dump controller it regulates the WG slowing it down

wiring diagram GULP this is about as simple as it could be from memory both WG and Solar Neg outputs go to the load side of the Victron Energy Battery Monitor shunt as does the engine alternator output......with the Pos leads going to the house batteries.

I have not tried testing them one at a time.

Looks like i need a double pole relay that i can use to bypass the wind generator and the solar controllers - i could easily trip that from the fridge compressor and include an on off switch in circuit as well. Clever electronics (voltage and load sensing) to control this/these relays will need to wait a while but should be possible without too much effort.

[hellosailor]

The WG controller slows down the wg by applying a brake? Doesn't really matter I suppose. I think you're on to the right track by testing each solo and using the fridge and some relays to control what's running.

I suspect a really smart integrated controller would have to so some high speed power switching, i.e. disconnect each supply for a split second, look at the output from it, compare to the other supplies and the battery state, then decide which one(s) to reconnect. Wait another xx shakes and then do it all again, constantly. Since the engine alternator (or a genset) would be the only fuel hog in the picture, that would be the easiest one to cut back first. I can't see any kind of "at least three inputs and deals with high power levels" integrated controller happening at less than "damn that hurts" prices though. Cheaper and more entertaining to retrain an organ-grinder's monkey to throw switches, eh? :-)

[Highland Fling]

AH BUT my SiL is an electronics engineer and these sort of issues/problems and design(ing) are right up his street so this wont be a big bucks fix

Juts hate re-inventing the wheel and wondered if there was an OOTB sulution

[s/v Jedi]

Originally Posted by cwyckham

You shouldn't be seeing any serious negative interaction between the controllers. When the battery voltage is less than about 14.4V, they should be pumping out full amps, and even with full batteries, they should be pumping out as much as the batteries and loads (combined) can take.

Two ideas: Can you provide a wiring diagram? Maybe something weird is going on with how you've set it up. especially with where the voltage sense leads are. And as somebody else mentioned, what happens when you run each controller independently?

I concur with this except the voltage would be say 13.8 or 13.2 if in float mode. If your loads pull the voltage below that, the charge controllers must immediately recognize that and start pumping out more juice to try and bring the voltage back up to the float voltage. If they don't do that they are either broken or flawed.

ciao!
Nick.

[djmarchand]

Well, it isn't that silly or inefficient for the various controllers to wait until the voltage on the batteries drop to about 12.5 before kicking into bulk charging mode.

It sounds like you have a holding plate refrig/freezer if it only cycles on 6-8 times a day and maybe a larger compressor than the typical Danfoss. But even so, it won't take that long (unless you have a really big battery bank) for that load to bring the batteries down to 12.5 volts. Until then, yes you are losing 10-20% charging efficiency (Peukert's equation factor) but so what. If your batteries were already up above 13 V then you have plenty of charging capacity and can afford that efficiency loss.

Is there a device to solve this non problem? Yes a voltage controlled switch set at 13 volts that bypasses all of the controllers below that voltage and lets the charging devices dump their full output to the batteries.

[hellosailor]

dj, I don't see how the switch would do it. Battery voltage will always be below 13V, but the various controllers aren't just "on/off" devices, they generally vary their output based on the voltage level they see. And a PWM alternator puts out the same 14.3-14.4 volts ALL the time, it only varies the pulse frequency/width. I expect there's all sorts of similar little problems, i.e. regulators that want to perform time-based cycles, not just output voltage responses.

David, if you SiL can figure it out and he's not interested in pursuing it, at least ask him if he can share some schematics with the rest of us!

[s/v Jedi]

Originally Posted by djmarchand

Well, it isn't that silly or inefficient for the various controllers to wait until the voltage on the batteries drop to about 12.5 before kicking into bulk charging mode.

Huh? Bulk charging mode? His batteries are full, how can you start bulk charging full batteries!? No, controllers should stay in float mode and try, with all their power capacity, to keep the voltage at float level. If they don't then they are broken or flawed.

cheers,
Nick.