Small solar MPPT reccomendations

[madlabs]

Hi All,

I have given up for now building my own MPPT controller. Just not enough time. So for now, I want to buy a small MPPT controller, plus I can take it apart and see how they did it.

Anyway, I am looking at the BZ MPPT250. I have a small bank of 6 panels that put out a max right now of 18 amps or so. Any reccomendations or feedback, either about the unit above or any other?

Thanks!

Jonathan

[Rover]

I have a
http://www.blueskyenergyinc.com/products/details/solar_boost_2512i/

Blue Sky unit, never gave me an issue, I don't have the "X" model with the extras, in hind sight I wish I did for equilibration and the small (10A) dump load)

I've measeured current before and after the unit , and it does what it says

[ghurd]

Seems like I recall some pretty poor reviews for the BZ stuff.

I put in some 2512iX controllers, and use one at the shop for a couple years.  No issues.
However, they are "12V in".  Meaning 12V PVs can't be strung in series.

I would probably lean toward the MorningStar SS-MPPT at this time, if the panels are under the rated amps.
G-

[DamonHD]

My Morningstar SS-MPPT seems to be working well.

My battery seems to more regularly get filled to to the hilt than with my older solar controllers, to the extent that I'm probably going to have to finally build my GHurd-magic-dump-controller I have as insurance to be able to dump the tiny excess from my turbine...

Rgds

Damon

[hydrosun]

the one BZ mppt controller I installed worked fine for a few years before the owner tried moving it and some stray wires shorted out and killed it. The design made it all too easy to do. I've used several Solar Converters mppt controllers and most died after a few years. I'm not sure why but one corner of the circuit board burnt on them.
 I bought a so called mppt on ebay that was built in China but it didn't even work. It switched on the negative lead at a low frequency  without enough storage of capacitors and inducters to actually charge and switch from higher to lower voltage. It actually produced less amperage than wiring directly. To add insult it disconnected at 13.7 volts before the battery was fully charged.
So that has been my experience with small lower cost mppt controllers

I've had great luck with Outback mppt controllers.  Xantrex has a good one. Bluessky seems to work well. Morningstar has a good reputation.
Chris

[madlabs]

Thanks for the input guys. Some of those controllers are awful expensive. Maybe it's time to try to build one.

Jonathan

[XeonPony]

I use the SS-MPPT from morning star with the comms interface and so far it has worked excellent! My vote would be for them.

[hayfarmer]

I use the blue sky Solar Boost 3048L 24/48V  on a small 700 watt solar system and it works great,best bang for the buck I have done with R.E.

saw an add on   flea bay  from a guy who was switching from off grid to grid tie and used it 6 months for only  $150  

 next improvement is to build a solar tracker. @ 8 am low sun angle I am running home making as much power as I am using.

  hayfarmer

[dnix71]

MadLabs, I have a BZ 250HV and a BZ 500. Both can handle 100v in. Stay away from the BZ's that can only handle 50v in like the cheaper BZ 250.

The HV version is only about $20 more anyway.

Both work well for me and both bring in more power than a direct connection. But you need to double up your panels for them to work correctly. They take higher voltages and buck up the current. Both BZ's have a 2 stage circuit depending on the power coming in. The BZ 250 relay kicks in pretty low so at dusk and dawn it clicks a lot. The BZ 500 does that in partly cloudy weather when clouds are passing.

You can kill either if you do not read the manual first.  You must always disconnect the panel side first (add your own inline car spade fuse). If you disconect the battery first when the sun is up the power has no where to go and it can easily go overvoltage internally.

I had trouble with the BZ 250HV out of the box because of a production run assembly issue. BZ sent me a replacement right away. The 1DioT assembler used standoffs that were too short and warped the board when it was screwed down. I told the seller, too, and he returned his stock and it all got fixed.

[madlabs]

dnix,

Thanks for the info. I'm still looking and hoping for a DIY solution. Now that summer is here and I'm a little less pinched for power I can wait and make a choice near the end of summer. If I don't find a diy I'll likely be getting the BZ and I'll get the HV version for sure.

Jonathan

[MagicValleyHPV]

Another vote for SS Morningstar (mine is the 15L). I particularly like the software monitoring add-on.

For DIY MPPT, here's a good read:

http://www.timnolan.com/index.php?page=arduino-ppt-solar-charger

 

[madlabs]

Magic,

Thanks for the link. I have read that on already. Alas, the power rating on that unit is too low. I have a total of 660 watts to control, and another 880 watts going up soon. Is sure wish I could find someone with a little more design experience than myself. I have access to a cnc router for PCB's, good test equipment and so on. It's just that all of my design attempts have wound up with a hot FET after 5-8 amps output.

Jonathan