high-voltage mppt controllers?

Intronics has a 75 amp, three stage (user selectable), 80 volt max MPPT controller, $240 + $16 shipping (if I remember right.) Made in the US. Hard to beat that.

Downside they are not networkable, if I recall correctly... but the price is good and can handle a couple 24 to 48 volts in series without issue.

The MS MPPT60 will handle 3 of the 270W panels. MS has a calculator and you can check the 290W panels. You'll rarely get over 800W and the controller will derate to 60A if needed, but look at the watts. If you're charging 14.4*60=864W and once past bulk the battery voltage and amps will drop. Something to consider

The biggest concern would be the 44.5 VOC on Big Bertha. You want to make sure you don't exceed 150V with any temperature and the specs are for 44C. The calculator will help.

I'd do a Midnite Classic with optional battery monitor. with a couple of these wired in serial. The Classic 150 will handle 150 volts solar input and is a 96 amp controller but you can limit this output. If you wire to achieve Voc near this 150 volts and you have a strange clear day with temperatures well below zero and your Voc exceeds this no worries. They call this HyperVoc and protect the controller if this happens.

A few of the panels I am looking at...

I call her "Big Bertha"
290w poly

Nice price on a mono panel
270w mono

Unyalli wrote:
How much battery are you trying to charge and how much power do you expect to use each day?
-Jeff

Jeff, I have about 900 amp-hours of battery and use about 200 amp-hours in a 24 hour period... I'll use my 2800 watt inverter to run the MW, waffle maker, electric kettle, as well as small stuff like the tv, laptop, etc.

Typically I can recharge with a 3-hour generator run with my Yam 2000, as long as I don't do much electric cooking while the recharge is running. I'm a heavy user of electricty and don't want to bother with conservation, so the more watts I can squeeze out of the sky, the better :)

pianotuna wrote:
Hi Gordon,
Try this: 250 watts with free shipping

I'll read up on the Rouge, but it looks to be undersized as well, by my math I'm really looking at atleast a 50 amp controller ... 500 watts / 12 volts = 42 amps, 600 watts / 12 volts = 50 amps.

Thanks for the link on the panel; it looks like they just built the shipping cost into the price of the panel... 250w should be closer to $225 - $250 plus shipping

BFL13 wrote:

Another aspect for Absorption and Float is that by then, your battery acceptance rate in amps is so low that one set of panel/controller could do it all anyway, even if it happened that one controller was at lower voltage than the other so it had dropped out of play by then.

These were "series" type controllers, not "shunt" type. With shunt type you have that on/off shorting of the panel where perhaps two of them could get out of synch, don't know. Each has its own panel anyway in this idea. With the series type that did not arise. MPPT controllers AFAIK are sort of bucked up series types---somebody maybe can confirm/deny that ????

The price is right on the eco-worthy, but with a maximum of 20 amps, a 250 watt panel would be right on the edge and the 270-290 watt panels would be too much. Sure, I'll probably rarely hit the max rated output of whatever panels I get, but I wouldn't want to hamstring the system with undersized controllers. Good points regarding parallel controllers; pushing that last few percent of capacity back into the battery is the slowest, and likely one panel's output would be all the battery would accept.

The idea of using multiple inexpensive controllers is interesting - do they network? I can see bulk charge working fine, but voltage dependent absorb / float modes, won't they sense each others voltage and flip/flop on and off? "

Can't say on all of them, but like any time there are two or more chargers on a battery, they share their amps best when each is at the same voltage. So it is best to have the same model controllers, but not necessary to get results.

They don't need to network but that might be a way used to better get them acting the same for voltage and charging profile.

I had two LandStar LS2024 20a PWM controllers on one battery bank where each controller was on a different sized 12v array. One did 12a and the other 8a and the total was 20a as seen on the Trimetric. It acted just like one controller, you couldn't tell it was two.

Another aspect for Absorption and Float is that by then, your battery acceptance rate in amps is so low that one set of panel/controller could do it all anyway, even if it happened that one controller was at lower voltage than the other so it had dropped out of play by then.

These were "series" type controllers, not "shunt" type. With shunt type you have that on/off shorting of the panel where perhaps two of them could get out of synch, don't know. Each has its own panel anyway in this idea. With the series type that did not arise. MPPT controllers AFAIK are sort of bucked up series types---somebody maybe can confirm/deny that ????

Wiring two controllers. I tried two ways, both worked. One is each controller has own wires to battery. Second way is to put a Y at the array end of a single fatter wire to the battery. Each controller is on its own array and then goes to its own leg of the Y. It all comes out the same at the battery end for total amps. (You can't tell which controller is doing what amps unless you had a clamp- on ammeter and did each leg of the Y before it becomes one wire to the battery)

Hi Gordon,

Try this: 250 watts with free shipping

GordonThree wrote:
Is all the solar shipping from California?

Trying to find a retailer that doesn't have a 200% or more markup over California in the great lakes area, not having much luck.

How much battery are you trying to charge and how much power do you expect to use each day?

-Jeff

Is all the solar shipping from California?

Trying to find a retailer that doesn't have a 200% or more markup over California in the great lakes area, not having much luck.

I will study up on the Morningstar products - thanks for the suggestion.

Midnight looks nice but like the Outback, it's too much controller for my small trailer, and my wallet :)

I have not decided on which panels yet, so many places to buy from. Watts per square inch make the big ones appealing. They seem to have some technology advantages too, like extra bypass diodes (3 to 6 is what I'm seeing), versus 1 or even none for the small panels.

The idea of using multiple inexpensive controllers is interesting - do they network? I can see bulk charge working fine, but voltage dependent absorb / float modes, won't they sense each others voltage and flip/flop on and off?