Low cost MPPT solar controllers.

"the 12v gods haven't hit me with lightening "

That's Jenny Craig's job. The 12v gods use lightning.
Sorry, couldn't resist. :-)

hahaha
i looked at the spelling three times and still thought there was something wrong ;)
there was :)

"i'm more than happy with paralleling deep cycle lead acid with vrla batteries..."

So am I. Is there any reason anyone shouldn't be (whilst charging)?
They are both lead acid and hence the same "type".
(That ignores manufacturers that claim their AGMs can or should be charged above 14.4V (2.4V/cell) or use constant-current charging etc.)

greybeard,
what's the *maximum* Amps you have recorded from your 130 Watt panel using the mppt12-1 Solar Charger ?

Maîneÿ . . .

Greybeard,
do you actually get 30% extra power from your solar panel ??

" mppt12-1 Product Info: Increase your panel output by up to 30% "

Maîneÿ . . .

Mainey - do you have a reason for asking?
Doubting this unit perhaps?

20% increase seems a minumum typical gain. 30% and better have been achieved.

Thanks....

ChipPunk,
Yes, I do have a genuine reason for asking, I ask because Greybeard says he has one.
He also has a similar panel to what I'm about to install for someone else, so if he says it gives the claimed output numbers in real life conditions over a period of 8 hours, a day, then I will look further into them for this particular installation.

Based on your 20% minimal gain statement then if they maintain that 20% gain in low light conditions then they must be worthwhile.

If I install one and it does not do as claimed, then I will let you know.

Maîneÿ . . .

I don't know about low light conditions.
The 20-30% gains are more at "reasonable" light levels.

The problem with low-light is that the voltage output drops hence limiting the gain of the MPPT.
Their beauty is when panel voltage far exceeds charging voltages, you don't lose the voltage-dropping power as you do with linear regulators.

For low light you'd get more benefit with a mirror (cost-analysis wise....).


Now if we had photmultipliers instead of photovoltaics, low light wouldn't be a problem... Hmmm - I have a couple of tubes..... (LOL)

ChipPunk,
That’s pretty well what I was told by someone using a mppt unit, he suggested in the full day he did not get any measurable increase because in low light conditions in the morning and late afternoon it was not working as good as his Morning Star Regulator did, making it not worthwhile to him to keep it and hence he was offering it to me.

I'm now looking for some definitive testing evidence over a full day in realistic conditions to clarify the information posted.

Maîneÿ . . .

Google and you should find....
It's almost intuitive anyhow....

What is a (typical?) high voltage from a panel? (most specs quote around 20V)...
What is a typical charging voltage? (eg 14.4V)

The difference is what can be harvested noting however that the panel's output curve is like a toe and the MPPT point is the maximum power (VxI) point [ie - area under the curve... which is not a straight-line as in OpenCircuit voltage and ShortCircuit current lines on Voltage versus I-current power graphs for linear loads; but a slightly downwards curve out from the (vertical) V axis until it curves hard & dives to the I axis (V=0)... but see the MPPT explanations etc ].
But realistically, it's like saying a 3-4V gain over 14.4V - ie, using the panel at 17-18V instead of "dropping" it to 14.4V. 3V in 14V = ~20% etc.


Then there is the inefficiency.
But like sun-trackers, the gains far outweigh the energy used.
Or should.... I'd assume MPPTs switch to idle and have a simple over-voltage sensor to re-initiate. (But I have a tendency to overestimate commercial devices...)

As I recall, more is gained by trackers. But that is cumbersome etc whereas MPPTs are small, light and simple to add-on. (Besides, I've seen some tracker designs that use microprocessors - full-time!)
Not that Ive seen "real" tracker data for a while, but 30% MPPT gains were achievable under "ideal" conditions - which is no doubt what advertisements will quote. (Get UP TO 100% extra with.... 10% is still "up to" 100%.)

Phil.
I have a perfectly good PWM controller now.
I was more curious about the reliability and performance of the low cost MPPT jobies. They're getting cheap enough to be a go on small solar installations if they perform.

Saw the Oatley one. Appears to be a rebranded Wellsee MPPT15

Any references to these people that are happy with Wellsee & Jutas please.

The Oatley website states:
"This 12v 15A MPPT switched mode controller will increase the charging rate by 10-30%! For example it will deliver 100 watt into a 10v battery (Flat) from a panel that has a maximum output of 100 watt at 17v"

How can a battery will get down to 10v ???

Remember; ALL quality solar regulators have *load disconnect* switching capability
The battery just can't go flat, therefore their analogy is very misleading, but probably makes for good entertainment if you don't actually understand what it's saying.

If a battery is 10v (flat) then any 100 watt panel, when in sun, will put 100 watts into the battery initially, using their own terminology :-)

Maîneÿ . . .

"How can a battery (will) get down to 10v ???"

By being discharged to 10V.
It's not good for the battery, but it has been done.

Hmmmm. starting to regret I asked this question.....

Yeah - I'm sorry Lex.
I'm very aware of your request to stay on topic...

Whilst I did throw in the Oatley - that's one of those "since you are after cheap and in case you didn't know". Also my experience elsewhere is that people didn't really mean "answer only the question" after they learn of the better alternatives (only after their unreliable or expensive implementation of course!)
(Thanks for pointing out the Oatley-Wellsee possibility!)

The only strict answers I can give is
(1) my web & other readings seem to indicate reliability and gains/benefits as claimed (when higher panel voltages or output); &
(2) IMO, the products should be reliable (well proven components using old principles that has finally been commercialised).


As to my last reply, oops!
I promised I would not get drawn into digressions or questions unless condoned by the OP. In this case I thought a simple reply would get Maîneÿ back on track. (Diversions, questions etc can be linked and continued to new threads.)


IMO - the MPPTs are expensive, but can be well worth it given the cost of panels (now about $5/Watt). Even a smaller gain of 10% on a 100W panel is equivalent to $50....
IMO - they should be reliable. But new models etc may have teething problems. And there may be differences between static mounted and mobile installations, but most should be SMT these days. (Surface Mount Technology.)

Hi ChipPunk,
Have seen that Oatley version advertised. Do you know it's final regulating voltage, and if it can be tweaked if necessary?
(s'pose I could ring them, I guess!)
Cheers,
Gerry

Gerry
suspect it's one of these.
http://www.wellsee.cc/ProContent_Editor.aspx?action=103

Wouldn't expect it to be adjustable, no display or whatever. Very basic information available.

Maîneÿ . . . posted:
..........
"Remember; ALL quality solar regulators have *load disconnect* switching capability ......"

That is simply untrue and shows a total lack of understanding.

Here we go again!

I know of many very high quality solar chargers that don't do that. Try an Outback MX60 for starters.

Some more info here.
http://www.027ws.com/10A-Solar-lighting-controller-WS-ALMPPT15.html

So is it a 15A or a 10A.

Thought it was Chinese but in these specs it says "Max Curry Current:10A "
Must be Indian. :-)

Boobook

No No No don't go there.........

Yeah Sorry

Lex, I just hit my head on a brick wall 10 times for doing that. Actually it was less painful than the last solar thread!

Mmmm, I like curry.
Thanks for that info, Rex
cheers,
Gelly :D

I'll avoid self induced loops....

It seems that it isn't adjustable - it's set for 14.4V.

But unless potted or PIC etc controlled, it should be hackable. Even then, it may be trickable (the same way many alternators can be tricked, tough decreasing output voltage requires complex circuitry).

But I suspect these circuits are based on typical SMPS controllers, and if you can get to the feedback resistors.....

For ~$30 it may be worth a sample.... I was merely going to add a FET to boost current anyhow.... (LOL!)

Lex,

I used to sell the Wellsee brand MPPT units and I currently have one 20 Amp one in my Jeep - the 140 watt panel charges my 100 aH AGM very well and I have had no problems with the regulator .. unfortunately I had a small falling out with the Wellsee supplier over a warranty issue and have now gone over to JUTA -

I am told that these are better performers than the Wellsee and I am waiting to hear back from some customers on how they performed .

But my 20 Amp unit produces 9.5 Amps during the Peak Period of the Boost phase .. Thats about 1.6 Amps above the rated value of the panel...

I think that is fairly resonable considering they are the cheapest MPPT around .

Cheers

steve

Hmmmmm. Thanks Mandrake.
9.5 out of a 140 Watt panel on boost is pretty close to 140W. Couldn't complain about that.

Be interesed in hearing how the Jutas perform.