Solar controller options

[xc-mark]

rock solid performance , easy to set up , built and tested to run for the long haul!

Victron energy is the industry leader , you will not be disappointed. I would avoid no-name brands .

https://battlebornbatteries.com/prod...r-mppt-100-50/


you set this unit up with your cell phone and the Victron bluetooth app. You can see what it is doing with the App and it will trend data. do your home works you will see a clear path to the one you want not based on price.

[paul65k]

Originally Posted by xc-mark

rock solid performance , easy to set up , built and tested to run for the long haul!

Victron energy is the industry leader , you will not be disappointed. I would avoid no-name brands .

https://battlebornbatteries.com/prod...r-mppt-100-50/


you set this unit up with your cell phone and the Victron bluetooth app. You can see what it is doing with the App and it will trend data. do your home works you will see a clear path to the one you want not based on price.

I have to agree with this completely.

We have a very robust Victron integrated system and I can see everything going on with my system batteries (both house and chassis) and charging (Shore/solar and alternator) all together on my smartphone or computer from anywhere I have internet access

I spend a lot of time on various Solar/solar RV forums and I almost never see people needing help/complaining about Victron MPPT smart controllers...... Renogy and other off brand controllers............. Not so much

[Mark_K5LXP]

Nice thread on 12V fridges. Still can't 'warm up' to the idea that I need to double my batteries and install a roof full of solar just to maybe keep up with one. But nice to have that background info in the event at some point I have to face it.

Originally Posted by hclarkx

I have three 40 amp MPPT controllers each with three 200W panels in series (72 volts open circuit provides good MPPT headroom). I like the reliability of multiple controllers and 40 amp is the sweet spot

Hopefully hclarkx sees this - I get how you can have separate sets of panels connected to individual controllers but are they sync'd, master/slaved in some way or simply put in parallel and they all just play well together? I get that multiple charge sources "works" but wondering if it was just as simple as a paralleled connection or if there's a particular technique or standard practice for multiple controllers.

Mark B.
Albuquerque, NM

[hclarkx]

Originally Posted by Mark_K5LXP

Hopefully hclarkx sees this - I get how you can have separate sets of panels connected to individual controllers but are they sync'd, master/slaved in some way or simply put in parallel and they all just play well together? I get that multiple charge sources "works" but wondering if it was just as simple as a paralleled connection or if there's a particular technique or standard practice for multiple controllers.

Mark B.
Albuquerque, NM

Mark,

The several sets of panels are each connected to a solar controller and the several solar controllers are connected to the battery. They are effectively in parallel on the output side. I usually keep the several controllers set similarly though that's not necessary. When they are set similarly all will stay in bulk to 14.4V then switch to absorb at 14.4V for 15 minutes, then switch to float at 13.5V.

While the solar controllers have a lot of digital in them, the voltage sensing and such is analog (with A/D conversion) so they don't agree on what 14.4V is. I.e., one will switch to absorb before the others, maybe seeing an actual 14.38V and taking it as 14.4V, But in short order the second and third will switch to absorb when their voltage setpoint is satisfied be it 14.4V or 14.42V. Similarly on the absorb time, they don't switch simultaneously to float, but nearly so. And when in float mode, they don't share the load current equally but if one hit's max output, another will pick up the slack. At about 13.45 or thereabouts all three will be putting out maximum available power and will continue to do so even if load gets higher and pulls voltage lower or the solar wanes and lets voltage drop.

The bottom line is that there is not a precise or inherent synchronization, but nonetheless, all three do their job through the three stages of charging and no solar energy is wasted.

PS: I switched to a 12V fridge after watching a Youtube video of a guy walking through an RV wrecking yard in the Southeast. A number of the RVs were intact other than a burned area around the fridge. They were mostly older rigs and maybe newer propane fridges are better, but I was surprised at the dust and debris mine accumulated around the burner. I got a halon automatic extinguisher but there was no room for it behind the fridge. I also liked the idea of more precise temperature control and going from a 6.8 cu ft fridge to a 9.1 in the same space made the DW happy and that was nice. Then there were the always cracking plastic shelf covers (the 12V has only wire shelves). And the propane tanks don't need to be filled as often. And the 12V cools down in three hours while we are loading up for an excursion.

[Mark_K5LXP]

OK, so it is just that simple. I get that once you've reached the end of bulk you're not going to need all the panel capacity for absorb and float anyway, so which of the controllers that dominates there is a minor issue. I was just wondering how well they played together and apparently they do OK that way. I kind of like the redundant nature of having panels dedicated to multiple controllers, not that they're all that unreliable in the first place but perhaps better than all or nothing with a single controller. Thanks for replying.

Mark B.
Albuquerque, NM

[hclarkx]

At my first significant upgrade, from 400W to 600W I went to two 300W arrays and two controllers largely for reliability.

Yes, when the voltage rises during bulk, the controllers just see the rising voltage; it doesn't matter that another controller is helping, all that matters is the voltage get to about 14.4V.

BTW, I'm ex-KA2R.

[Mark_K5LXP]

Thanks hclarkx. Pondering that a bit, beyond redundancy I'm thinking maybe independent controllers would also offer the option of more efficiently creating a system of disparate panels.



Mark B.
Albuquerque, NM

[Bobby F]

I think you'll also find that several smaller controllers are substantially cheaper than the one large controller.

[hclarkx]

Originally Posted by Mark_K5LXP

Thanks hclarkx. Pondering that a bit, beyond redundancy I'm thinking maybe independent controllers would also offer the option of more efficiently creating a system of disparate panels.

Mark B.
Albuquerque, NM

I agree fully. In my case the two sets of panels were each in its own plane on opposite sides of a crowned roof. So I avoided mixing panels with different angles to the sun as well as having two arrays where one might take maximum advantage of the sun when the other was degraded by shade.

In addition, and to this day (currently with three controllers) I don't turn on more controllers and their arrays than necessary to get the battery back to or close to 100%. As we speak, I still have the two 300W arrays and a 400W array (added when I went with a 12V fridge) which has been used only once or twice during cloudy weather back in February.

And, as Bobby mentioned, and the last time I looked, three 40A Epever controllers cost less than two 60A Epever controllers. Though the two circuit breaker/switches for a third controller uses up much of the savings.

[AnotherMike]

Originally Posted by Bobby F

I think you'll also find that several smaller controllers are substantially cheaper than the one large controller.

Another advantage: if one of the small controllers happens to die you still have a working system. Yes, it is degraded some, but not dead like if you had only one large controller.

Mike

[AlanTerry]

Interested in this