Cheap Charge Controller - Wind and Solar, Two or Three Outputs ?

[GaryBmth]

Can anyone suggest a cheap basic charge controller for hooking one small solar panel and a small rutland wind turbine (not purchased yet but liked the idea that you can't get hit by the blades) up to two, preferably three batts. I have a motor and a house battery currently but would like to add an extra batt for supplying a 1kw inverter for those things that occasionally need mains, like the wife's straighteners! Thought I'd keep it separate from the house batt so as not to lose the fridge if it went to low. Also assume it's best to connect the controller direct to the batts individually so as not to interfere with engine charging or shore power charging on my Sun Odyssey 32.2 Any advice or thoughts welcome, thanks

[callmecrazy]

define 'small' panel?

I have one of these dual battery controllers, connected directly to each of my house batts, and to a 40 watt panel. I intend to add another 40 watt panel as well.

Not sure how many amps youre rutland + panel will produce... you need to know, but for $40 this one leaves plenty of room in the budget to upgrade in the future. It's identical to the Morningstar controllers (in both appearance and quality, IMO)

But if you're going to have more than 7 or 8 amps going through it, I would get a beefier controller, like a 20amp or better.

[twistedtree]

One controller for both will probably be sub-optimal. In fact, I'm not aware of one that will work with both.

[callmecrazy]

oh, yeah, trees is right. Need a solar controller, then whenever you get the wind turbine, you'll also need a separate wind controller.

In that case, I'd be looking into putting all you're charging sources into the house bank, and charge the start battery with an echo-charge or something similar (instead of charging each battery individually). But you'll still need separate controllers/regulators for each charging source.

[zeehag]

bz makes a 25 amp pwm controller and sells for 80.50 usd plus shipping. does well and lasted me 7 yrs.....

[bangkaboat]

For the solar panel controller, if the panel is 105W, or less, a Sunforce 7A charge controller will do the job. I think that mine was less than $25usd, in Los Angeles. It works, don't know if it's going to fail prematurely.

[noelex 77]

As others have said you are better off with a seperate controler.

The seperate battery for the inverter is a bad idea. The battery capacity of a small battery bank will be very reduced suppling the inverer load. It may not even be able to supply the current you need.
The easist way is to install a battery monitor, use the large house bank, and stop the inverter when the battery capacity is low. This can be automated if you wish, but the complication is generally not worthwhile.

[goboatingnow]

OP, would not reccomend keeping batteries separate, install a battery monitor, but you get significant advantages from maintaining the biggest house bank you can. Most of the time thoses invertor batteries will be doing nothing , better have them available to teh domestics
Dave

[Maine Sail]

Originally Posted by bangkaboat

For the solar panel controller, if the panel is 105W, or less, a Sunforce 7A charge controller will do the job. I think that mine was less than $25usd, in Los Angeles. It works, don't know if it's going to fail prematurely.

Please be careful with "cheap" shunting controllers. These devices begin switching on/off once the bank hits absorption voltage and can really cut your time to FULL by days not minutes..

In the case of some of the Sunforce units they switch OFF at 14.2 volts and they do not switch back on again until 13.0V. This may be fine for off grid where you often have a load that sucks the bank back to 13.0V very quickly, but, with a boat on a mooring, with no loads, it can take a healthy bank a LONG time to drop the surface charge back to 13.0V. I have some customers banks of AGM & deep cycle wet cells that will hang out at over 13.0V for over an hour. That is an hour of lost charging time waiting for a cheap shunting controller to switch back on and provide maybe 60 seconds of charging before raising the bank ti 14.2V and then shutting off again. Sometimes these controllers will never restore the bank to full.

Below is a video of one of the "better quality" shunting controllers, a Flex Charge PV-7. It goes OFF at 14.2v and comes back on at about 13.6v. This is showing the "current" but you can see it turn on and off. I applied a load of 0.1A just so it would go to -0.1A when OFF for the video. When you get close to full your OFF time can be as much as 10-20+ times longer than your on time with some cheap controllers.

In this case the "ON" time is about 5-6 seconds and the OFF time close to a minute to get the bank back down to 13.6v before it can turn back on again. This bank still had 20 Ah's to go and it would take 5-7+ days for this bank to eventually get "full" from an 80-85% state of charge with 5-6 seconds on and 60 seconds off, remove the 0.1A load and it would likely make this even longer..

Cheap Shunting Controller - YouTube

Contrast that Flex Charge controller, or a Sunforce, with a quality PWM or MPPT like the Genasun's and the difference in the last 15% of charge, and the time it takes, can be DRAMATIC.

I just replaced both a Sunforce and a Flex Charge shunting controller in the last month with Genasun MPPT controllers. On one boat "FULL" was cut from averaging 7-8 days to about 2 days and on the other boat "FULL" was cut from roughly 5-6 days to about 1.5 days. Same boat, panels, wiring, batteries just a much better quality controller that does not turn ON/OFF like a cheap shunter will.

If you stick with Morningstar, Blue Sky, Genasun and a couple other REPUTABLE controller manufacturers, you'll be doing well. The eBay stuff is very often a scam.

I have replaced a number of eBay so called MPPT controllers that were NOT MPPT at all but rather simple shunting controllers. MPPT controllers do not shut off for long periods of time....

The Genasun MPPT's are a very good value for smaller for panels. Under 150W, that is pretty much all I am installing these days.

Please be careful with "cheap" controllers as you often get what you pay for.

[bangkaboat]

Originally Posted by Maine Sail

Please be careful with "cheap" shunting controllers. These devices begin switching on/off once the bank hits absorption voltage and can really cut your time to FULL by days not minutes...Please be careful with "cheap" controllers as you often get what you pay for.

Thanks for responding to my post; it's good to have this info & I wouldn't want to lead the OP down the wrong path, either.

[GaryBmth]

Many thanks to you all for your advice and recommendations. Based on that, I've decided to increase the house bank by one rather than add a separate battery - I'm pretty sure the inverter I have allows you to set a threshold for switching off to avoid running things too low; if not I'll set up a voltage alarm and switch it off manually to avoid leaving it too depleted to run essentials.

I've also decided to research mppt controllers more and make sure I don't end up with anything that's too 'cheap and cheerful' that will waste precious charging energy.

I do seem to remember at least two wind controllers that did have the option of running panels in addition to the turbine so I'll revisit those and see what spec/price they were and how they work before I decide what to get - thanks for some makes to look at/avoid.

When I finally get it it up and running I'll let you know what I ended up with and how I wired it in if anyone's up for discussing the pros and cons.