Solar MPPT recommendations

[Gary H]

Hi all,

It looks like my Blue Sky MPPT controller has finally died. I am looking for recommendations for a replacement. I have two 224 watt solar panels and my battery is a 700 Amp Hour LiFePO4 bank (so I need to be able to set custom charge voltages).

I've never been truly happy with the Blue Sky since it produces a lot of interference on AM and lower frequency HF radio. (Maybe all MPPT controllers do this?)

As always, the collective wisdom of this group is appreciated!

[jeepbluetj]

I'm a big fan of the Midnight Solar Kid. It's got very good adjustability and with the wiz-bang gizmo it'll use current (rather than time) for absorb. You have slightly too much wattage for it (but so do I, I have 2 250W panels feeding it)

The Midnight Solar classic is a good controller too.

Too bad Rogue quit making the 30A controller.

There's a few threads about MPPT feeding LiFePO4 banks here - you may wanna search em.

[Gary H]

I am taking a look at the Victron controllers - probably a 100/50. It looks like I would be able to program custom charge voltages with a PC.

Anyone have any experience with these?

[Maine Sail]

Originally Posted by Gary H

I am taking a look at the Victron controllers - probably a 100/50. It looks like I would be able to program custom charge voltages with a PC.

Anyone have any experience with these?

I sell and install a lot of them. Good little controllers, pretty fast tracking, but be aware they are "ambient air temp sensed" for temp compensation which requires them to be in very, very close proximity to the batteries for optimal operation. They only check ambient temp when the controller is idle (so not to adjust temp based on internal controller temp after working hard) so it is not real time compensation. If Victron would just add an external sensor as an option this controller would be very hard to beat value wise.

You will need a VE Direct cable to program via a PC and it's a very DOS based (read antiquated) control panel but not difficult. V 1.4 now allows you to program absorption time and temp compensation slope or even turn it off if you run LFP batteries.

By far the best way to program it is to add the BlueTooth dongle which allows programming from your phone or iPad and seeing real time performance..

[dirkdig]

We have the outback mmpt 80 running 980 watts of solar panels, since install 6 months ago it has not been looked at and its working perfectly


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[Gary H]

Originally Posted by Maine Sail

I sell and install a lot of them. Good little controllers, pretty fast tracking, but be aware they are "ambient air temp sensed" for temp compensation which requires them to be in very, very close proximity to the batteries for optimal operation.

You will need a VE Direct cable to program via a PC and it's a very DOS based (read antiquated) control panel. By far the best way is to add the BlueTooth dongle which allows programming from your phone or iPad and seeing real time performance..

I have LiFePO bank so temp comp is not an issue. With 450 watts of panels would I need the 100/50 or would the 100/30 be sufficient?

[GILow]

Pretty happy with my votronic (not a typo, it's a German design) so far. Simple and cheap with one programmable charge profile which you would have to configure for your setup.


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[Maine Sail]

Originally Posted by Gary H

I have LiFePO bank so temp comp is not an issue. With 450 watts of panels would I need the 100/50 or would the 100/30 be sufficient?

It absolutely is an issue if you don't have a controller that allows you to turn it off and many controllers do not allow for this. Victron only recently added the ability to turn off temp compensation.

Peak optimal before any MPPT boost:

450W / 13.8V = 32.6A

450W / 13.0V = 34.6A

The 50A unit would be the better choice.

[Gary H]

Sorry, I was not speaking precisely. What I meant is that I don't want temp compensation. I was able to turn it off on the Blue Sky, and it is good to know that I can disable it on a Victron unit.

Looks like I will purchase a Victron 100/50.

RC, are you a dealer? (or more accurately, do you make any money off selling Victron units?)

[pcmm]

If you want to go Victron, check out aliexpress, the factory that makes the Victron 100/50 sells a factory branded version (same firmware) for $66 USD!!

[Moontide]

Have been very happy with my Morningstar controller. probably 4-5 years old now with 15000 miles. Has put over 237000 amp hours in.

Features I like are remote wired battery temp sensor and ethernet connection. It tracks daily stats and I can download to a spreadsheet. Can also monitor real time to see effects of shading, tilt, swing, etc.

Have a 60 amp controller with 720 watts of solar. Occasionally hit the limit of 59 amps that I programmed.

Not sure about their current product but quality and features of my generation unit was very good and would buy again.
Bill

[Matt Johnson]

Originally Posted by pcmm

If you want to go Victron, check out aliexpress, the factory that makes the Victron 100/50 sells a factory branded version (same firmware) for $66 USD!!

That's not true. Read their own Q&A.... They say that they do not make the controllers for Victron or Outback, but have copied every detail with their own parts. The software they use is a pirated copy from Victron.

Matt

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[Gary H]

Thanks all for the responses. However, it turns out that my controller was not the problem. It had been giving erroneous voltage readings for a couple of days before shutting down entirely. The culprit? Undersized wiring to the battery. I guess I am still getting used to the tropics! Too much sun...

[ErikFinn]

Originally Posted by funjohnson

That's not true. Read their own Q&A.... They say that they do not make the controllers for Victron or Outback, but have copied every detail with their own parts. The software they use is a pirated copy from Victron.

Matt

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So the op resolved his issue, therefore we can direct attention to these chinese MPPT controllers without hijacking the thread.

Anybody ever bought these and had a chance to compare to a genuine original product?

FLEXmax 80 FM60 FM80 MPPT Solar controller Description,photos,FAQ on m.alibaba.com

Alibaba Manufacturer Directory

[Opie91]

Originally Posted by Maine Sail

I sell and install a lot of them. Good little controllers, pretty fast tracking, but be aware they are "ambient air temp sensed" for temp compensation which requires them to be in very, very close proximity to the batteries for optimal operation. They only check ambient temp when the controller is idle (so not to adjust temp based on internal controller temp after working hard) so it is not real time compensation. If Victron would just add an external sensor as an option this controller would be very hard to beat value wise.

You will need a VE Direct cable to program via a PC and it's a very DOS based (read antiquated) control panel but not difficult. V 1.4 now allows you to program absorption time and temp compensation slope or even turn it off if you run LFP batteries.

By far the best way to program it is to add the BlueTooth dongle which allows programming from your phone or iPad and seeing real time performance..

Thank you for the Victron feedback. I ended up getting one of their MPPT controllers an the bluetooth dongle. The bluetooth works awesome!!!

Must say it has only been a day but the power production increase appears to be substantial compared to the PWM controller.