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That is one flash controller mate, and possibly a little more cost than most would want to spend on a pure AP system, I can see it's benefit if you are running a complete off grid home system though. Am I correct in the FM80's description of Advanced Continuous Maximum Power Point Tracking Algorithm meaning of "continuous" being it uses MPPT in all charging modes as you say or is that something else again?

I should have been a bit more specific and stated lower end MPPT controllers (which is what this thread was originally about - ebay controllers).

I am pretty sure all the sub $500 ones only utilise MPPT in bulk mode as this is when the battery needs the bulk amps. Happy to be corrected on this, after all I have already learned a few things today. It is amazing how different the technologies, terminolgy and in some cases the information is between different solar uses, ie grid connect, off grid and RV.

Electrical tends to create more arguments than anything else in all RV type forums, how does it go on the energy matters forum Gungalla? I can imagine there being a few arguments between those who are overly concerened with their own opinions. Especially when 12 volt is concerned as there are so many ways to do it and no written standard for most of it.

PWM solar regulators work by connecting the voltage and current produced by the solar panels directly to the battery bank at a high frequency. If I am not mistaken this is a Steca PR PWM in this video vs a Sunsaver MPPT.



You can see the panel voltage drop down to the battery volts in it. While there is a minor increase in amps with the PWM the total power going in is less.

Wellsee and some of the other Chinese copy's are not proper MPPT and may well do what you suggest.

I do have a 100v solar setup with a $400 Tristar MPPT-45A. 90% of the time its in float and I can assure you it is using MPPT during it. The Tri-star has enough brains that I can monitor Panel volts/amps and outgoing battery amps/volts from it.
Unfortunately my panels even re-wired in parallel would blow the Steca at 52v.

Yes, MPPT is available in all charging modes, and Float, which isn't really charging as such, just maintaining full charge and supplying power to any loads. I think it can switch to PWM mode if the demand is lower, such as when the battery is almost charged, but MPPT mode is always there when the load increases or some cloud covers the sun.




There is a bit of MPPT vs PWM debate- actually much of it is people with PWM realising how much better MPPT is , but 12V is really only used for portable camping arrangements or very small systems- it isn't really suitable for a serious off-grid domestic system.

I'll be powering my AP system from my off-grid house Lithium battery(800AH@26V), I'll probably just use a small spare 300W Selectronics 24VDC>230VAC demand start inverter I have to run the 125W pump and air pump, with the DC backup powered by the 26V Li battery. That way I only need to run extra low voltage cables to the AP building, much less involved than 230V mains, new switchboard etc, and certainly safer than running an extension cord across the ground, although I could do that in an emergency.

That video makes no sense to me at all in regard to the PWM vs MPPT debate. I think he has his wiring or description confused as the higher wattage at 19 volts that he says is the MPPT controller can not be fed to a 12 volt battery as 19 volts wll fry it, it is unregulated and has not passed through any regulator MPPT or PWM. 19 volts is about what an unregulated 12 volt panel runs at.

For example, I have an 80 watt 19 volt panel which doing the math of 80/19 should give me 4.2amps. When I stick it into a steca pwm reg it will give me 4.2 amps at 14.4 volts when is boost mode of charge. It regulates the voltage and does not loose any amps. If I plug it into a mppt reg such as a sunsaver it could give me up to 4.6amps if I am lucky as the reg finds the most efficient power point at which it can regulate the voltage down to 14.4 volts.

In regard to the 37 volt modules it is an interesting debate all the same and as stated I would like to get a hold of a 37 volt panel and have a play with it. It seems there are mixed opinions and and results on this with pwm controllers wherever you look. The math does state you will not get the full wattage from the panel using pwm and need mppt to get the full wattage but I would like to test it myself. Maybe I am a pesimist but I have seen reports from people who seem to have gotten the full wattage out of the panel, then again they could have stuffed up their tests as well. I'm off to gumtree to look for a reasonably priced 30 volt plus panel

You'll have to give me the time stamp for when he says that because I certainly could not find it after 2 views.

A 19v panel fed into 12v battery without a regulator would fry it.

Depends on what size you want but I found this supplier OK.
http://www.solarenergyproducts.com.au/e ... l-190w.php

27 seconds "and that is coming in through the mppt controller"

I can't find anywhere where he actually shows the power analyser readings with it going through the mppt controller only through the pwm. But as I said I have no doubt the mppt could be putting out up to 10% more amps if it is in boost mode on that 19 volt panel as opposed to the pwm output.

My experience with basic 12 volt mppt regs is they only scavenge the addional power over a pwm during boost mode. This is all with 12 volt modules though so I would like to have a play with some higher voltage ones and see what happens.

There are a few on gumtree for reasonable prices so I may grab one. Currently awaiting a response from my counterpart in QLD to see if he has played around with any on the stecas and what his experiences were.

The power analyser is on the solar side of the controller's reading what is coming in from the 2 panels.

When its at 19v, ie at 27 seconds, the solar is going via the MPPT controller to the battery and there is 58w going to the battery.
He changes the switch which puts the solar via the PWM and the volts at the panel drop to ~12.9v and the battery is only getting 40w. With a 37v panel there will be a even bigger difference.

I think you are listening to this with preconceived notion rather than actually what is said.
You quoted the very point in your first line that he says the current readings are going via the MPPT.

Anyway rather than further de-rail BullwinkleII's thread I am going to leave it there and let you do your own research. Feel free to start a new thread or post on energymatters forum which is a bit more specific for this discussion.

For sale - Solar stuff

OK, so my battery can be discharged to 10.5v or something.

My electric outboard still runs at voltages as low as that. I know, because I've run it that low before.

My solar panel has three strips of connected solar goodness, that each put out whatever voltage I said they put out... somewhere near 12 volts - whatever - more than 10.5v.

If I disconnect the three strips of solar goodness into 3 solar lumps in series, I'll never be able to fully charge a battery, but will I be able to run away on my epic solar adventure for as long as the sun shines?

Will that just keep my battery at 11.5v or something ... or could I just forget the battery, forget the charge controller, and just connect the solar panel to the motor and go?

I NEED A HOLIDAY!

Sure, you can discharge to 10.5V, but your battery wont last very long...

If you want to operate with that panel and that motor and not use a battery- I wouldn't go messing with the PV connections, you either need to get yourself a maximiser, as I mentioned previously, its like an MPPT regulator, but designed for running motors directly, or else a DCtoDC voltage converter to step your panel voltage down.

Just for completion, I have asked steca and you guys are right in that the higher voltage panels should not be connected to their pwm regulators unless you are running a 24 volt sytem and you will likely loose the extra power in the conversion without mppt.

My statements regarding the benefit of MPPT on 12 volt systems using 12 volt panels (19 volts) stands though, really we had two arguments running simultaneously here which probably confused those who are looking into solar and not that confident with it (sorry Bullwinklell).

In regard to that power analyser Privateer, I sell the wattmeters which I understand to be the same thing (all based on the turnigy power analysers). They are an inline meter that run between a source and load and don't have the capability to read the wattage from one thing (MPPT controller) and voltage from something else (solar panels) as I think you are suggesting. You see when he switches the switch all the readings change as he has redirected through a regulator so you get regulated amps, watts and voltage being read. As such I am still unsure of what the guy is trying to or is showing.

Anyways, I have learnt something about regulating 24 volt and higher panels that I did not know/understand so thanks. And also sorry for the off topic sidetrack Bullwinklell.

Off topic in one of my threads! It couldn't happen

I'm looking at some plans for a maximiser, ...

http://www.voltscommissar.net/minimax/minimax.htm

and there doesn't seem to be a lot to them. As I understand it, the solar panel charges capacitors, that are then dumped to the motor.

What is the solar panel doing when the motor is pulling power from the capacitors? It seems like the power would be wasted for half the time.

With the variable output from a solar panel, wouldn't the maximiser or DCtoDC voltage converter be delivering unstable voltages to the motor?

DC to DC converters can deliver a stable regulated voltage, I'm not sure about a basic maximiser, although the more expensive units probably can.

Given how reliant you are going to be on your power system, I really don't think its worth sacrificing reliability with dodgy mismatched components... it might be a very long paddle to the next exit point for a lift back home!