solar regulator question
Hi guys
ive picked up a second hand 80w solar panel , and intend to use it just to keep the boat batteries topped up.
firstly , for a 80w panel would a 10A or 20A regulator be required? on the 20A units ive seen there are 6 terminals - 2 for panel , 2 for the battery and the last 2 for load. why is the load required ? all i want to do is float charge the battery. can i leave them disconnected or shall i connect a dummy load here?
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The load isn't required.
It's usually so power to the load device can be switched from the panel or the battery.
A 10 amp or 20 amp regulator would be fine for an 80w panel.
Just make sure the regulator you use can take the open voltage of the panel.
Tiny (13-09-15),VroomVroom (13-09-15)
thanks for that much appreciated
Get a 20amp mppt charge controller from ebay, not a pwm, then you will get the best out of your panel. The load section on the charger also controls the input to the battery, it doesn't matter what your battery is used for, just connect what you use to the load section of the charge controller and that's it. The charge controller will take care of the battery, most controllers require a load connection which helps gauge voltage parameters and charge regimes. Make sure you connect the battery to the controller before the panels, or you could destroy it.
Last edited by spook; 15-09-15 at 07:39 AM.
VroomVroom (15-09-15)
The cheap Ebay $50 controllers listed as MPPT aren't.Originally Posted by spook
The load connections are, as implied, for your loads that are sensitive to over voltage as the charge voltage can be over 14VDC while the load can be set to 12VDC. And you don't require anything on the load terminals, for the charge output to function properly.
Unless you intend to put up more solar at a later date, the 10A controller is all you need. You'll be lucky to see 5A from an 80W panel on even the best of days, more likely about 4A to 4.5A max.
Never said you need a load connected, but as it is a battery and used for something. It's a simple process to connect whatever you use to the load connections, then it takes care of it's self.
Mentioned a 20amp controller, because they are cheap and less than $30. In my experience, having a controller which has a much higher capacity than the input, means it doesn't have to work hard so lasts longer and is available for upgrade to higher inputs down the track. There may not be much room to fix another panel on the boat, but you can always carry a folding panel for more energy when cruising.
I ran a 60amp charge controller for 240w of solar to begin with on my bus, which allowed me to add more panels as I could afford them. Now they are so cheap, have put 1kw of solar on the bus and had built 2 x 40amp dedicated lifepo4 charge controllers which are very different to what's used for lead acid crap.
Last edited by spook; 15-09-15 at 11:45 AM.
do you have some pics of your bus solar setup?
Keen to become a grey nomad myself and drive a bus around in the next few years, would be great to be self sufficient
+1 for pics & some pricing or links to where you purchased.
By my guesstimate your bus power system is worth nearly as much as the bus would be without it.
Originally Posted by spook
.......have put 1kw of solar on the bus and had built 2 x 40amp dedicated lifepo4 charge controllers which are very different to what's used for lead acid crap.
Cheers, Tiny
"You can lead a person to knowledge, but you can't make them think? If you're not part of the solution, you're part of the problem.
The information is out there; you just have to let it in."
Hi, are you the one using other peoples rooftops to collect sun energy as in the TV ads.lol. I like it.
weirdo (15-09-15)
lol
my missus reckons that's me
haven't seen the whole clip on tv yet so here it is
Tiny (16-09-15)
While you are waiting for spook to upload some pics.
I have been using the Plasmatronics PL40 Solar Regulator for around 2 or 3 years now weirdo.
I haven't bought any fancy fold away camping solar panels (yet), instead i bought a 200Watt solid panel from Low Energy Developments in Melbourne.
As bob says, not all MPPT controls are the same. Mine is an older PWM system, but it comes with the flexibility i wanted for building a custom and ever changing system as new parts are added.
My idea with the solid panel was to permanently mount it under the roof rack (haven't done that yet).
So currently i just lug it in the vehicle for times i will Free Camp for more than a 2 days without driving.
Anyway, not to highjack the thread, but the Plasmatronics was suggested to me when i was doing a job that needed a remote power supply.
EDIT: I see for the same price now, you could buy a 30A MPPT Charge Controller from Victron Bluesolar.
Last edited by ol' boy; 15-09-15 at 09:21 PM.
If u want to go on an expedition get a Land Rover, if u want to come home from an expedition get a Landcruiser!
Got no pictures, in the process of changing the panel frames from steel to aluminum to reduce weight and to give it a paint job. The old panels had steel frames, but going from a couple of hundred watts to 1kw is a big jump so the need for reduced weight on the roof.
Except for the panels, which are from ebay and cost $250 for 250w delivered. All my equipment is custom made, to the best of my knowledge there are no dedicated charge controllers or active BMS which work properly for lifepo4. So I designed and had what I needed made up, the charge controllers can't be used with lead acid as the charge parameters are vastly different. The final improvement is to have a 60 amp dc to dc charger with lifepo4 parameters so can charge the house pack when the engine is running, got one on the bus but it's for lead acid and may stuff my panel controllers and pack.
The cost of my bus energy set up would be close to $3000 and the bus only cost $4000, but the results are excellent. When traveling we never have to stay at van parks or run out of energy. Will put up a photo of the bus before I started to put on the new panels and re-paint it, you can just see the panels on the top, but will post some when it is finished. Plus a photo of my lifepo4 pack when building it.
I've used both pwm and mppt charge controllers when I had lead acid in the bus, in my opinion mppt are way ahead in providing energy and even cheap ones will provide energy in shade, when a pwm won't. Pwm are good for lead acid, as they pulse charge which helps stop calcification but in low light conditions, they are way behind MPPT. Have seen combined chargers, which have a pwm and mppt section, got no idea how or if they work well.
Sorry, I should have been more specific.. The cheap controllers, $50 and under, controllers that are listed as MPPT controllers, are NOT MPPT controllers...
Matching controller size to the solar array size is more efficient than using one that is 5 times what you need.
Where you said this: "The load section on the charger also controls the input to the battery" that is not correct, and implies that you need to connect your battery loads to the "Load" terminals. The battery connection output works independent of the load connection. Of course, as I stated, if you are powering something like 12V specific LED replacement globes, you may damage them from over voltage. I did that to some of mine, but this is only a problem if you leave the lights on during the day.
Just to add to my post about those MPPT controllers..
Tiny (16-09-15)
I agree most cheap controllers are not really mppt, but better than a pwm so I've been told. As to whether you use a panel amperage equivalent charge controller, or a larger one is a personal preference and in my experience, when using cheap controllers, they operated much better, safer and for longer when they were only working at 50%, rather than flat out. It also allows for the input spikes you can get under certain weather conditions. Not sure of the official name, but it's when it is cloudy but really bright and you get much more input from your panels. A bit like putting mirrors round your panels to increase solar input, but then you have the problem of heat lose from the panels.
The 40amp controllers I have and the 60amp I'm having built, are not cheap and extremely robust, they cost me $400 each because they had to be specifically made and not off the shelf. They have to be connected to the battery and load before the panels, so it can regulate itself. They do a wonderful job and now don't even use the BMS, the controller takes care of it all. Wanted to get them made in Aus, but was quoted 3 times what they cost overseas and not as robust. Have designed a lifepo4 controller that has built in individual cell controls and already building a test one out of bits I've hunted on the net. Once I get it working satisfactory, will see who will make it for me in one unit.
Last edited by spook; 16-09-15 at 11:00 AM.
ol' boy (16-09-15)
1) a 10A PWM will suit your needs fine, something like one of these
2) you do not need to connect anything to the load terminals. The Load terminals are for what I already described previously.
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