Best small MPPT?

[mikedefieslife]

Originally Posted by noelex 77

Mike, what you are saying is accurate. I thought this may prove to be a problem for people running “12v” panels in parallel (I cannot see it happening with any other configuration), at least for those boats with wind charging (raising the battery voltage overnight) and in hotter climates. However, I have never seen a report of a Victron controller starting late. Have you seen any examples, and if so can you give any more details?

I run the FlySolartech bifacial panels. These only give a Vca of 15.33 ICC of 9a. I run them in series to get higher voltages. The problem comes that they are on either side of a curved bimini. That means at times one panel whilst not shaded is facing away from the sun. As such the whole system then puts out very little. Yet in such a situation it is impossible to use the Victron controller and run them in parallel instead, even if one is in full direct sunshine, the voltage will never be high enough to start the controller.

For panels like these it seems PWM is a better choice.

Anyhow, I think that is getting off topic a little for the OP.

[noelex 77]

I have never done any measurements on bifacial panels, but (I think) Vca is Italian for Voc. If this is correct, then 15.33 v is a very low number. Voc is normally around 22-23v for “12v” panels. Even Vmp should be well above these voltages. A Voc of only 15.33v will not function correctly for most solar controllers. The panels would need to be in series to charge a 12v battery.

[noelex 77]

Originally Posted by a64pilot

Unless people had other controllers also on board to compare with, and were the type to watch closely, odds are they wouldn’t notice.
Cause they have to be starting late.
However was much power actually available earlier than when they started? I’d think not, so even if they are late, you didn’t miss much

It is not difficult to pick if your controller is starting at the correct point. The current at start up should (ideally) be zero. If it is significantly positive the controller has started late, if it is negative the controller has started early.

As you point out, you do have to be looking for this. It will be early in the morning when I am not at my best . The amount of power lost if the start up is incorrect is typically small and only expensive controllers have start up parameters that can be adjusted (although you can always change the solar panel wiring), but optomising various parameters such as this is still helpful in extracting as much power as possible.

[sparrowhawk1]

https://youtu.be/kF_cVEYxj3E
Will Prowse reviews several charge controllers. He also does a review on a dc-to-dc charger with built-in mppt controller in another video. I've had a tracer for over 10 years, working perfectly. unfortunately my model's lowest setting is for gel, which I know a lot of people go to 14.2 but I would prefer 13.8. I would definitely buy the model Will recommends.

[Jon Hacking]

Originally Posted by mikedefieslife

The Victron MPPTs do a job but there are far from the best IMO.

Some of the drawbacks are, if you use one controller per panel you have to bluetooth into each controller individually to see the data. Since they are networked why can't Victron just make all the data available at once? ...

The controllers will only start with input voltages 5v higher than the battery, but will continue to run if the voltage is 1v higher...

My pet hate is the position of the fuses. Very difficult to get to and to re-insert as there is no guidance there to help you ease it in. The fuse goes directly into two prongs on the PCB.

Thanks for this, Mike. You say the Victron is far from the best. Do you have a favorite? Why?

The +5v to start is, IMHO, a non-issue. If there's no current being drawn, the voltage will go up to Voc, which will start the MPPT pretty quickly, & before there's any real power to use.

But having to bluetooth into each controller would be a considerable pain for me. I like glancing at my wall display with it's flashing LED (to tell what stage it's in) & current.

And I agree with Noelex that your panels should be run in series to charge a 12v (nominal) battery. They must have fewer than the normal 36-cells. Were they designed to be connected directly to the battery with no controller at all? Even a PWM controller will have some voltage drop.

[Jon Hacking]

Originally Posted by sparrowhawk1

https://youtu.be/kF_cVEYxj3E
Will Prowse reviews several charge controllers. He also does a review on a dc-to-dc charger with built-in mppt controller in another video. I've had a tracer for over 10 years, working perfectly. unfortunately my model's lowest setting is for gel, which I know a lot of people go to 14.2 but I would prefer 13.8. I would definitely buy the model Will recommends.

Thanks for this, Sparrowhawk. I'll try to check it out. But those of us out in the boonies with marginal internet connections (& having to pay for each byte individually) don't like YT much. Wish he'd simply write down his report somewhere.

[sparrowhawk1]

Here's the winner. That's all that really matters. I've owned both a victron and a tracer. Victron: almost no heat sinks, terrible terminals; small and easily corroded terminals like stated earlier, overpriced. Tracer: huge heatsink(huge controller for that matter), nice remote display, big stainless steel terminals.
https://www.amazon.com/EPEVER-Contro.../dp/B07NVDJFD4

Here's his website where he discusses many things including the controllers https://www.mobile-solarpower.com/so...ntrollers.html

[Simi 60]

Originally Posted by sparrowhawk1

Here's the winner. That's all that really matters. I've owned both a victron and a tracer. Victron: almost no heat sinks, terrible terminals; small and easily corroded terminals like stated earlier, overpriced. Tracer: huge heatsink(huge controller for that matter), nice remote display, big stainless steel terminals.
https://www.amazon.com/EPEVER-Contro.../dp/B07NVDJFD4

Here's his website where he discusses many things including the controllers https://www.mobile-solarpower.com/so...ntrollers.html

And yet that page you link to says quite categorically

Victron MPPT
Best of the best
Easy to use, expensive, highest quality

[john61ct]

Yes Epever/Tracer is not terrible, but the kind of product you get included in a mass-market kit.

Not even close to Victron in features, efficiency and build quality.

Not saying Victron is "the best" in all use cases either, but IMO delivers the best value for most.

[sparrowhawk1]

There's no argument that victron uses high quality components.I'm just putting the info and my personal experience out there. I have no dogs in this race. PS if you have the bandwidth I highly recommend you watch the video because he points out the problems with the victron clearly and why the tracer is his favorite. Not so much on his website.

[Jon Hacking]

Thanks, all. Yes, we were able to find some WiFi to watch the video. Fairly well presented, with little extraneous fluff, but his goals are not quite ours. Interesting that he's doing it from his land-yacht.

The Victron is small enough that we'd have to get 2, & not having an external display is knocking it out of our personal running, despite its features & heritage.

The 40A Epevar is also in that strange category of being bigger (& therefore, more $$) than necessary for a single 400W panel, but not really big enough to handle 2, so we'd have to get 2 of them.

We're still looking, but at present the front runner for us is one of the 2 that Will calls "rebranded" (SRNE ML2430 or ML4860). He claims that they're difficult to program, & we'd have to do that for our LiFePO4 batteries, but I'm a geek & hopeful that I can sort that out. I'd only have to program them once, & they're readily available here in the Philippines. Good terminals, available remote display, good MPPT & conversion efficiencies, & relatively cheap.

One thing he didn't test is how FAST it finds the new MPPV when something changes, like some cells get shaded. Or how often it makes an MPP voltage sweep, looking for a possible 2nd (better) MPPV, & how long that takes. This is more important when panels are wired in parallel, or something gets shaded, but a slow sweep is time when it's not working very efficiently. If a controller does it too often or too slowly, it affects overall efficiency, but not very often means it may miss a better 2nd MPPV. It's a design trade-off when the units are programmed at the factory, but those numbers don't seem to be published anywhere.

I wish he'd tested what happens when you shade a single cell of a panel. Many folks have said that this shuts the whole panel down (or similar) but I can't see that happening. I'd think it would drop the panel voltage (by 1.2v/shaded cell) but the current shouldn't be affected significantly, but I haven't tested it as my panels have always been wired in parallel (a situation I'd like to repair).

[Jon Hacking]

One annoying thing I'm noticing is that NONE of these units measure the current into the battery. Therefore, they can't know the state of charge of the battery. They all seem to be voltage &/or time driven. This is OK (though not optimal) for our LiFePO4 batteries, but lead/acid batteries (all types) really need that input, so they can transition to Float at the correct time. Our ancient (c2001) Blue Sky SB50 has this input (I actually bought it when the company was still RV Power Products) but I think it's been ripped out of their newer offerings, as a friend has an SB30 & it doesn't have this feature.

[noelex 77]

Originally Posted by Jon Hacking

The Victron is small enough that we'd have to get 2, & not having an external display is knocking it out of our personal running, despite its features & heritage.

The Victron range includes some quite large controllers. Even the Smartsolar series has models which will handle up to at least 100A.

So although many prefer multiple controllers, a single controller can be chosen for even a large array if you prefer.

There are also many display options if you do not like the bluetooth connection. The SmartSolar Control Display or the Victron MPPT control display are only a couple. Personally, I use a Pico battery monitor that shows the output of my three panels on the main display. There are other cheaper third party products that can monitor solar output.

[noelex 77]

Originally Posted by Jon Hacking

One annoying thing I'm noticing is that NONE of these units measure the current into the battery. Therefore, they can't know the state of charge of the battery. They all seem to be voltage &/or time driven. This is OK (though not optimal) for our LiFePO4 batteries, but lead/acid batteries (all types) really need that input, so they can transition to Float at the correct time. Our ancient (c2001) Blue Sky SB50 has this input (I actually bought it when the company was still RV Power Products) but I think it's been ripped out of their newer offerings, as a friend has an SB30 & it doesn't have this feature.

This is true. A simple controller can usually be adjusted to reasonably accurately charge a lead acid battery, but this needs the default parameters altering and few users take the trouble.

Using measured end amps is a better system. Traditionally this has been the domain of a few expensive controllers such as Outback and MidNite and even then it requires optional extras. There has been some progress lately and I believe Victron can now send information from battery monitors to the controller, but I have not installed this system so others will be able to advise exactly what hardware is required and how well the system functions.

[daletournier]

Originally Posted by Jon Hacking

One annoying thing I'm noticing is that NONE of these units measure the current into the battery. Therefore, they can't know the state of charge of the battery. They all seem to be voltage &/or time driven. This is OK (though not optimal) for our LiFePO4 batteries, but lead/acid batteries (all types) really need that input, so they can transition to Float at the correct time. Our ancient (c2001) Blue Sky SB50 has this input (I actually bought it when the company was still RV Power Products) but I think it's been ripped out of their newer offerings, as a friend has an SB30 & it doesn't have this feature.

John, of course this is all abit out of my league but the bluesky 2512-HV 's I use measure the current through the IPN pro remote, at 25 amp they are probably abit small for your needs and they maybe limited to 36 cells?