Solar Panel Charge Controller

[lannen]

Hi,

I'm installing a 205 watt panel on my sailboat. I already have a wind generator.

There are two charge controllers I'm looking at,

1. C40 Charge Controller $109.00

C40 Charge Controller [C40] - $109.00 : Solar Panels: Solar Panels Direct under $3 per watt, Powered by Nature!

2. Outback FM-60 Charge Controller MPPT $499.00

Outback FM-60 Charge Controller MPPT [FM-60] - $499.00 : Solar Panels: Solar Panels Direct under $3 per watt, Powered by Nature!


Do I need the MPPT technology? Is the added cost worth it? There is a $400 difference... So, I could use some input on this.

I have 4 - 12 volt led acid house batteries. Does the wind generator need to be tied into this charge controller?

Thanks

[GMac]

Now let me start by saying my knowledge is limited, in many ways inc things like this

I had a bog standard controller which just stopped the panels cooking the batteries but one day it had a slight accident and the casing got smashed leaving the insides hanging out (by a rouge bottle of rum actually.. Opps) so I went to get another. The bloke I spoke too said to get one with XXX, I can't remember exactly what it's called, but it basically fiddled with the output to even out the peaks and troughs. It also did some hocus pocus where it 'boosted' the output later in the day when the the output was starting to fade. The idea is that it feed the batteries a more constant and stable amount of power for longer each day.

As I was a sceptical bugger I did some checking and he was right. I plugged to old one and watch it's output. Then I plugged the new one in and watched that. I'm positive the new one gives me more input per day.

If I read those links properly I think that MPPT is the same or similar to the XXX in my new controller. If it is I like it and think it's a good idea. The price difference is a fair bit though but then it does seem to be a very Gucci bit of kit.

Don't wind generators have controllers built into them? I have power off my motor as well but that doesn't go through the controller.

So there's 2 cents worth from one of the most dangerous things known to man, an enthusiastic amateur

[Fishspearit]

Originally Posted by lannen

Do I need the MPPT technology? Is the added cost worth it? There is a $400 difference... So, I could use some input on this.

Yes, you need the mppt technology. It really does work, I really do get a 20-30% increase in output from mine. But you've got a lot more options than the two you mentioned. The outback is one of the top of the line, and priced accordingly. I have a Blue Sky 2000e that I paid around $200 for.

You'll need to figure out whether or not your wind generator already has a regulator. I think most do.

[bencoder]

Originally Posted by GMac

XXX

Would that be PWM? that's pulse width modulation, it allows you to vary the amount of power that goes through in a simple digital way, by sending pulses of different lengths(longer length pulses allows more power through, shorter pulses allow less power, if you average it out.). That means the charger is able to vary the power that goes into the battery as it gets charged up, allowing it to be charged more fully and safer. I don't know anything technical about MPPT but from the wikipedia page it looks like it's fairly different to me.

[Fishspearit]

My understanding is that all mppt's use Pulse Width Modulation for the charging process also. They just have additional benefits over standard PWM chargers.

[camaraderie]

Fishspearit has it right...the 2000e is definitely worthwhile and you don't need to spend more money for the Outback for a 210w panel.
On a nice sunny day with a cheap regulator, you might expect 50-60ah's from your panel...you should see more in the 65-75ah range with an MPPT controller. Results will be less dramatic on less sunny days.

[phorvati]

for 500$ I would get another solar panel instead of MPPT. Additional solar panel is sure to give you much more juice then the MPPT. I bought BP25 solar charge controller with my two 130W kyoceras. I ended up removing the charge controller alltogether. So I am not even using it. I have a bank of 520AH led acid 12v batteries. I usually take one of the solar pannels out if I am away from the boat more then few days. My Solar Panel boxes have the diodes, and thats pretty much all you need to not leak juice at night and to stay isolated form the alternator.

As far as the wind generator, I have a separate charge controller for it, and I am pretty sure you want to have it isolated from the alternator output as well.

[GMac]

Originally Posted by bencoder

Would that be PWM? that's pulse width modulation, it allows you to vary the amount of power that goes through in a simple digital way, by sending pulses of different lengths(longer length pulses allows more power through, shorter pulses allow less power, if you average it out.). That means the charger is able to vary the power that goes into the battery as it gets charged up, allowing it to be charged more fully and safer. I don't know anything technical about MPPT but from the wikipedia page it looks like it's fairly different to me.

I think you maybe quite correct. It was something like or very similar to that and it's good.

[jcapo]

MTTP does work.

I am in the process of installing 6 65W Kyocera panels on the bimini.
Two were installed for testing in December and I'm just getting
around to installing the other 4 panels.

I'm running the two panels in series to a Morningstar Sunsaver MPPT
controller, less than $250 at mavericksolar.com and other online
sellers. The controller is rated at 200 watts of solar and/or 15
amps output which is just right for 3 65W panels. I will use two
controllers with 3 panels on each controller. If one fails I'll
still have power.

The Kyocera 65W panels are rated at 3.75A max at STC, standard test
conditions. Rated output is only seen due to cloud edge effect and
that's for short periods of time. 80% of max is rule of thumb with
high sun and no shadows.

My Link 20 routinely shows 8.5 amps into the batteries at peak sun
from these two 65W panels and as much as 10 amps at times. That's
MPPT at work. I'm seeing 50 to 60AH into the batteries on a good
day.

The Morningstar MPPT controller is the only small MPPT controller
on the market and its highly recommended for small installations
by a controller designer that hangs out on the wind-sun.com discussion
board. Look for posts by 'solar guppy'. Lots of good solar info
on that discussion board.

[camaraderie]

Originally Posted by phorvati

f I ended up removing the charge controller alltogether. So I am not even using it. I have a bank of 520AH led acid 12v batteries. I usually take one of the solar pannels out if I am away from the boat more then few days. My Solar Panel boxes have the diodes, and thats pretty much all you need to not leak juice at night and to stay isolated form the alternator.

Sounds like you have two 8D's in the bank. Am I to understand you have NO regulation on your two panels and are pumping in 15 amps at 17.6 Volts during peak sun?? You may be fine at night with the diodes but you are frying your batteries during the day. Max voltage to wet cells should be around 14.5V.

[phorvati]

I actually have 4 trojan 130AH 12 V group 27 batteries. I am pumping lots of amps from the solar panels, but the voltage never rises beyond 14.5 amps. I have a fridge and other electrical loads.
The panels put a lot of amps though. They blew 25 amp fuse on several occations. It usually happens in june (summer solstice). Around 1PM, I usually get readings of over 20 amps. But nowhere near enough to drive the battery voltage to 17V. These are deep cycle batteries with thick plates and it takes a lot of amps to drive the voltage to that level.

I even tried equalizing one battery at a time using both pannels unregulated. And the voltage got up to 15.5V at the most. I was not happy with the equalization cycle as the voltage never got as high I really wanted to burn off the sulfation. I got better results when using alternator/regulator.

[Strygaldwir]

Do you need MPPT? No, you don't need it.

Is MPPT worth it? My experience is a resonding yes. I am continually amazed at the amount of current I can put back into my batteries, or make available to run systems, even in light conditions that are not ideal. When your batteries are getting close to full, their voltage rises, with just panels, you get the same current as you would at the lower voltages. This results in your getting less power, so to speak. With MPPT the voltage is adjusted and you maximize the power available. This is especially beneficial in lower light or conditions where part of the panel is shaded.

With MPPT, you can get higher voltage panels and connect them to 12 or 24 volt systems. You could take 2 24 volt panels, connect them in series to get 48 volts. The MPPT could then drop voltage to 12 (okay 13 point something) and charge your batteries.

Do You tie the wind generator into the controller?

The wind generator needs its own controller. Wind generator profiles are a LOT different from solar panels. How the output is optimized is very different. Currently there are no controllers that do both well that I am aware of.

Oh, yes. I LOVE my Outback MPPT. But it is the only MPPT I have ever used, so I am VERY biased toward it.

[captain58sailin]

I have a question about charge controllers, it is a little off the subject. I have 2, 4D batteries isolated into two separate banks. I have a small solar panel with a charge controller that has two sets of terminals for output, one is for the battery, and one set of terminals looks like it is for a load. The charge controller is currently connected to just one battery. Could I run another set of wires from that load terminal to my other battery? If not. If I were to run two sets of wires from the battery side of the controller to both batteries would I lose my isolation? This is a very small panel only intended to keep the batteries up while the vessel is in the yard.

[GMac]

I was told today by someone who should know, that if you have a 10W panel or less a controller isn't really required. I had a 5W uncontrolled for years and never saw anything bad. Actually I still am using the very battery it was hooked too.

That's about all I can offer captain58.

[Thermal]

I bought one of the MPPT controllers and cost wise it was a wash - I got about as much extra power out of it as if I had bought another panel with the extra money that it cost. Of course, I have no room for another panel so the MPPT was definitely the way to go for me.