Solar and Wind Generation - Getting the best of both

[Talbot]

My boat is a bit of a power hog with refrigeration and freezer as well as other demands. I have 555 watts of solar panel running through an Outback Flex60 controller which is MTTP and provides the appropriate power in very sunny conditions (def not UK at the moment :distress: )
In order to provide the necessary additional power when it is overcast/raining I have been looking at adding a wind generator. I have decided on the generator I want, but the controller is a different matter. There are no MTTP controllers that can really cope with wind, and the only alternative is a PWM controller with a dump load (basically a heater which is going to be really good on a very hot day (sarcasm mode). Furthermore I cannot see how the PWM controller will work with the MTTP one. To my admittedly shallow understanding these two systems would work against each other. I have tried to ask controller manufacturers, but none have actually answered the question.

Does anyone know the answer?

If not, but you are using both systems - how do you use them?

 

[sailaboutvic]

A good company to throw the question too , is Marlec , I have always found them very help ful .
If it not the wind gem that your buying , maybe best tp keep that quiet
Our Rutland gen runs on one of Marlec reg and the panels are on an MTTP and they seen to work fine to gather

 

[Talbot]

A good company to throw the question too , is Marlec , I have always found them very help ful .
If it not the wind gem that your buying , maybe best tp keep that quiet

Generator that I intend is a Leading Edge LE-450. Their normal controller is a Morningstar and I contacted the company.

I got the following:

Looking at the tech specs for the LE 450
turbine, it seems to give out a nominal voltage. If this is the case, you
can connect the turbine directly to the battery bank. Then, I recommend
attaching a TriStar PWM in Diversion mode to the battery bank. This is what
will send the excess power to a resistive load. I say PWM because
diversion mode is a special mode of operation only available on our TriStar
PWMs.

I responded: Surely if I do what you suggest, this will interfere with the stepped charge from my
solar controller?

They responded

Most controllers, at least Morningstar controllers, communicate with the battery only. So the controller will not even know that a wind turbine has been attached to the system.

Now that doesn't really answer my questions, but leaves me thinking that I have three options:
1. Set the diversion load to operate at battery levels of 14.4vDC (Solar Bulk and Absorb voltages) - and this will provide best charge capability, but risk damage to the battery when it is fully charged and boat is not manned.
2. Set the load to operate at 13.7 vDC - this would attach additional load to the diversion even from the solar charge and significantly interfere with full charge capability.
3. Accept that I will have to monitor the system all the time and use the electric braking on the wind generator. Not a great system if you want to be able to leave the boat, while still allowing the system to charge.

I would have expected better guidance from such a big company! - hence my initial post.

 

[sailaboutvic]

I'm no expect so I don't want to put you wrong , but the way mine work is that both the panels and gen controller pick up there info from the battery's and both work with each other .
There been like that for some years now without any problem .
Marlec does a wind gen FM1830 which they say will put out 60A @ 12v I would imagine there must sell a reg for that . Could be worth talking to them .
If we leave the boat for any length of time , which we very rarely do we always tie of the gen and just let the panel look after the batteries .
Hopefully someone else with more info will come along in a min

 

[Talbot]

.....................Marlec does a wind gen FM1830 which they say will put out 60A @ 12v I would imagine there must sell a reg for that . Could be worth talking to them ..............

Their FM1803 is designed for land use I looked at their site and the HRDI controller does not appear to be man enough for the LE-450.
Letting the solar alone cope when away is great in a sunny climate, but not for UK weather. - today I have only received 52 amp/hours.

 

[crisjones]

As has been stated above in a couple of posts - each controller will only look at the battery voltage, it will have no way of knowing if there is another charging source (or even 2 or 3 other sources).
What this means in practice is that each charge controller works independently to maximise the charge going into the battery UNTIL the battery voltage gets to the absorbtion voltage setting on the controllers. At this point the batteries will be 85 to 90% charged and so charging input will be dropping off regardless of the source, also individual controllers will now try to take the lead role so even if both controllers are set with an absorbtion voltage of 14.6V one will take preference because they may read the voltage as 14.599V and the other controller may read it as 14.601V !!
Obviously very minor differences but that is what today's controllers are measuring.
The Outback is about the best solar controller on the market and if you have set it up correctly it will maximise your battery charging from the solar panels. Whatever conroller you link to the wind gen will be a PWM type (MPPT does not work on wind gen's).
As Vic has said the individual systems will work fine together although at 90% charge levels and above one controller may overide the other but below 85% charge level either OR both will contribute as much as possible depending on atmospheric conditions - ie wind or sun; or occasionally both in the UK???

In conclusion you should connect your new wind gen to a decent controller with programmable charge voltages, set those voltages to the same as your Outback solar controller and enjoy maximum charging from both sources for at least 95% of the time - the other 5% only one source will be charging if the sun is shining and if the wind is blowing and if the batteries are above 90% charge!!
Basically it is not really worth worrying about if the controllers are set up correctly.

 

[Talbot]

A good company to throw the question too , is Marlec , I have always found them very help ful .
Our Rutland gen runs on one of Marlec reg and the panels are on an MTTP and they seen to work fine to gather

Had a long series of discussions with Marlec Tech Support, and have just purchased their new WG1200 wind generator, which comes with its own MTTP controller.

Thank to those who contributed.

 

[sailinglegend420]

If two different regulators are feeding the same battery bank one can get confused by the other and may switch off too early. This is a particular problem in the initial “Boost” stage of charging where batteries will take all the charge they can get. Regulators all work in slightly different ways, but in principle they are programmed to reach a maximum voltage for a set time and then drop down to a float voltage. With wind generators there is not a constant source of power to allow the regulator to stabilise itself. Often there is a huge surge in available current from wind gusts, and then their charge may drop. The wind controller will then still see the high voltage coming from the solar panel controller so it will switch to float. When the wind rises there may be a built-in delay of maybe an hour before the wind controller attempts to charge again and so the cycle continues. The wind generator could potentially be providing the highest charging capability, but much of the time it has switched itself off so its energy is being wasted.

The simplest KISS principle, which is recommended by several manufacturers, is not to have a regulator for the wind generator but control it manually with a switch or a safe method of tying back the blades when the batteries are known to be 100% charged. This will rarely be needed when cruising with a large service bank, but a high voltage alarm could be programmed into the battery monitor to warn of overcharging. An unregulated wind generator should not be left running when leaving the boat for an extended period without the risk of overcharging

 

[noelex]

Basically it is not really worth worrying about if the controllers are set up correctly.

+1
Two controllers will not cause any practical problems. It is irrelevant that one is MPPT and one is PWM.

The only slight drawback is under some circumstances you can end up with double the absorption time. If enough wind and solar are both present the regulators will count the absorption time in sequence (the voltage will never exactly match). The batteries will receive the absorption voltage for the absorption time set on one regulator followed by the absorption voltage for the absorption time set on the second regulator. This will potentially slightly overcharge the batteries when this occurs. In practice this is not a big deal especially with flooded batteries.

There is a lot of debate about about the ideal absorption time anyway. The default is anything from 1 to 3+ hours. As the Outback has an adjustable absorption time it is better to set on the short side (1 hour or 1.5 hours) with both wind and solar connected. If the wind controller has an adjustable absorption time also set this for 1 or 1.5 hours.

Even better the Outback can be set up to use battery return amps so it will adjust the absorption time for each cycle. This is the ultimate precise charging method even if just have solar, but it requires the addition of some extra gear (the Outback Mate) and is overkill for most boats.

 

[noelex]

The wind controller will then still see the high voltage coming from the solar panel controller so it will switch to float.

No it will only switch to float when the absorption time has been reached. The absorption time is only counted when the battery voltage is at (or above) the absorption voltage. Switching to float when the absorption time has been reached is what you want the controller to do.

 

[FullCircle]

Thanks for the info in this thread.
I have found a German 40a MPPT controller that does 2 banks of batteries, and has a remote display. £170 from an ebay seller.
Also found Bosch 150w panels on offer for £160 each from Photonic Universe

http://www.votronic.de/index.php/en...-controllers/boat-version-mpp/mpp-430-duo-dig