outback solar mppt controller

[ktmrfs]

anyone had any experience with the outback mppt controllers? I see solar blvd has a 10A for $99 and a 20A for $149.

the 20 A would be a nice update from the morningstar 15A at a reasonable price.

https://www.solarblvd.com/product_info.php?products_id=3065

[red31]

Front panel display/programming between 3 default charge profiles or user defined, use user defined for storage or vise versa. View Star by ep solar

[Almot]

BFL13 wrote:
About $125,--- here is an example of a PWM gone way overboard for "features" IMO. I am guessing the guys who invent these things get carried away with what is possible, never mind the poor RVer who just wants to get some sunshine on his panel to get the battery up some. Following the setting up instructions in the manual would drive me crazy.

http://www.midnitesolar.com/pdfs/10-293-1_REV-D_bratManual.pdf

In this case it makes the PWM more expensive than the Eco-Worthy MPPT.

Good point. Though, a bit of apples to oranges here :)... This Midnite is 30A. Eco is 20A. Features like remote temp comp are often necessary, and at high current a remote voltage sensing may also become necessary. Some other features of this model are just "bells", Christmas lights, I agree.

Poor Rver is an interesting angle. If they are in for something longer than a weekend, then financially it would make the most sense getting a system as big as possible, to avoid the use of generator as much as possible. This normally results in 24V panels and MPPT, space permitting.

OTH, if the purpose is getting "some" juice off the sunshine, i.e. solar as an auxiliary energy source when opportunity presents, and the panel is small - then one can get away with the simplest and cheapest controller. Proper charging algorithm or setpoints won't matter then, it's a temporary fix anyway.

More amps from 12V panel with MPPT... How much more and how often? 120W flat panel would harvest 40AH at best. With MPPT it will be what - 42AH? This is, if it's not too hot.

I never tried small single 12V panel. Wouldn't have much use for it in my situation - it would be like driving a car with one gallon tank. So, correct me if I'm wrong. You need 14V after controller. Panel can do 17V under perfect conditions. So there is 3V for conversion. If conditions are not perfect, you're getting less than 17V and have very little, if anything, for MPPT conversion. Ops - current the same as with PWM. Or less. Then it warms up and PWM wins. This is just one of possible scenarios. The point is - 20% gain expected by the OP with 12V panel (compared to PWM) is unrealistic.

[ktmrfs]

westend wrote:
I have the Morningstar MPPT-15. One of the better aspects of the controller is that a user can define all of the stage voltages and the duration of them. It is all done through the MS software and fairly intuitive, just select what you want and save that profile. It makes a lot of sense for storage situations.

that is one of the things I really like about the morningstar. I did similar based on our typical useage.

But with my panels I can get the morningstar to limit at 15A on sunny days with my panels, 3 80W panels. A 20A controller would be nice.

But previously the step UP to a bigger controller really was a big gulp to swallow in $$$$$$.

Outback 20A, Morningstar 15A, similar price = fast decision

[JiminDenver]

Another reason for a small MPPT controller is that there are smaller high voltage panels out there. I see them on CL with voltages too high for the Eco-W.

[westend]

I have the Morningstar MPPT-15. One of the better aspects of the controller is that a user can define all of the stage voltages and the duration of them. It is all done through the MS software and fairly intuitive, just select what you want and save that profile. It makes a lot of sense for storage situations.

[BFL13]

About $125,--- here is an example of a PWM gone way overboard for "features" IMO. I am guessing the guys who invent these things get carried away with what is possible, never mind the poor RVer who just wants to get some sunshine on his panel to get the battery up some. Following the setting up instructions in the manual would drive me crazy.

http://www.midnitesolar.com/pdfs/10-293-1_REV-D_bratManual.pdf

In this case it makes the PWM more expensive than the Eco-Worthy MPPT.

[JiminDenver]

The only reason MPPT was not suggested for smaller systems for so long was the cost vs improvement comparison. Now the small user can get better results with out breaking the bank. The 10a MPPT controller may sound expensive compared to the RJ specials but compare it to a name brand PWM controller with TC and adjustable settings and the difference isn't as much.

[BFL13]

Almot wrote:

BFL13 wrote:
I have a 100w 12v panel which I sometimes use. I have tried it with my $102 (US) Eco-Worthy MPPT and I do get more amps out of it than its Isc

Always?

Same as in Salvo's graph.

[Almot]

BFL13 wrote:
I have a 100w 12v panel which I sometimes use. I have tried it with my $102 (US) Eco-Worthy MPPT and I do get more amps out of it than its Isc

Always?

[time2roll]

Almot wrote:
I wonder if my Rogue 30 is the only MPPT with automatically adjusted Abs time.

Morningstar Tristar MPPT and Bogart PWM both adjust absorption time as needed.
I assume most of the better controllers do. Well worth it IMO.

[BFL13]

Language, language! Input volts being near output(ie same as battery) volts is when the MPPT controller is the most "efficient." 12-12 and 24-24 etc is more efficient than 24-12 and that is more efficient than 48-12.

I have a 100w 12v panel which I sometimes use. I have tried it with my $102 (US) Eco-Worthy MPPT and I do get more amps out of it than its Isc similar to what Salvo gets with his 12-12 set-up with his MPPT as shown above.

Locally, you see PWM controllers going for over $100 when you can get the Eco-W MPPT for the same or less price. I can see where somebody would want the extra AH from the MPPT from his small 12v panel.

Even if he went on Ebay instead of the local $100 job, and he bought a $15 PWM that would also run the panel, it would depend on his whole situation for how long if it would be "worth it."

[Almot]

I don't remember whether among all those just-for-fun-of-it experiments by BFL there was any testing of a small cheap MPPT on 12V panel. This is not something that people normally do, so it might not be on the top of the bucket list at his research center 😉

But - I do know that MPPT are not very efficient when input volts are close to output volts.

Also - with PWM you're getting not Imp but Isc, which is higher than Imp. About 10% higher, for 120W panel.

And - yes, heat does affect MPPT system more than PWM.

I view MPPT as a necessity for those with big solar arrays. With 24V panels one has no choice but MPPT.

[BFL13]

KD4UPL wrote:
What do you mean "much confusion"? You just did all the math to prove my point. The MPPT controller gives you more amps out in both of your calculations.

By the way, increased panel temperature, wire loss, and controller loss all come into play with PWM controllers too.

Ok you were not confused. 🙂 However the PWM is not affected by the panel heating since the Isc goes up with higher temps, so you still get rated Isc for your amps with panel aimed.

The lower Imp for the panel has no meaning with PWM. Your higher panel Isc rating is the "expected amps" to the battery at STC with PWM.

[KD4UPL]

What do you mean "much confusion"? You just did all the math to prove my point. The MPPT controller gives you more amps out in both of your calculations.

By the way, increased panel temperature, wire loss, and controller loss all come into play with PWM controllers too.

[BFL13]

KD4UPL wrote:

Almot wrote:
Educate me, people - why would anyone want a 10A MPPT?

So you can get the maximum output of your solar panel. A 120 watt panel normally has an Imp of about 7 amps. If you use a PWM controller and the panel sees battery voltage of about 14 volts the most power you'll get is 98 watts. You give up the other 22 watts unless you use an MPPT controller.

Much confusion here. A 120w panel (mine did) has a Isc of 7.6 amps, which I got with the panel aimed at a high sun using PWM with batt voltage around 13.5. it was a little less in amps when batt v got higher, then fell off the knee cliff at 15v.

so with an MPPT controller on the same aimed panel, you would see the panel reduced (by heating) in voltage and so watts by about 8.6% to 110w. Now you have at best, 1% wiring loss between panel and controller =1w so now you have controller input =109w

Controller efficiency is approx. 95% so output watts is say 103.5w NOW you divide that by battery voltage at the time to get your charging amps.

At 13 v, it is 109/13 = 8.4 (more than the 7.6 Isc that PWM gives you)
At 14 v, it is 109/14 = 7.8 (near the same as PWM gives)

But let's say the Rver has such limited roof space he can only fit a 120w panel no bigger. He can get more out of it by going MPPT while the battery voltage is still low. He can also get more out of it in the shoulder hours as seen in Salvo's diagram (where his 130w panel amps are near 8.2 max, so a 10a controller would be ok.