MPPT Charger shuts down when....

[gizmoguy]

I have a 530 Watt solar array fed into a BlueSky 6024 MPPT controller that feeds a 24v 225 AH battery bank.  My solar location isn't perfect, so I'm augmenting it with a small hydro system wound for 24 volts.

The string is (4) 6V 225AH Golf Cart batteries in series.

When I feed the extra power into the batteries by hooking my rectified negative connection to the negative terminal at the end of the string (same negative post that the inverter is hooked to) and the rectified positive goes to the positive end of the string (also same as inverter hookup).  The Solar charge controller is also hooked to the same terminals.

What am I doing wrong?

Thanks!

Gizmoguy

[gizmoguy]

When I say that the controller shuts down I mean that no lights are on and my remote display shuts off so I can get no current/voltage readings.  When I disconnect the PMA and reset the MPPT it returns to normal functioning.

Thanks!

Gizmoguy

[ghurd]

Stray thought, may be way off base.

Sounds like the PMA is messing with the MPPT.

Any chance the wiring between the batteries is a bit too small?

Or one of the battery terminal connections is not as good as it should be?

No idea what kind of PMA you are using. Or where the rectifiers are. Or anything else.

If it is a single or 2 phase PMA, and the rectifier is near the PMA (not near the battery), it may help to add a large capacitor over the DC outputs at the rectifiers.

It is one of those things a simulation will probably not see, but I know I can measure the AC component and frequency at the battery terminals with a cheap meter.  If it can be measured with a cheap meter, there is a strong possibility the MPPT controller can see it too, which could confuse the controller to no end.

G-

[Simen]

I have a Steca solar controller that cuts the load output if the voltage at the batteries raises over a set voltage to protect the connected equipment, though it doesn't black out completely; it just gives me an overvoltage error.

Have you checked your rectifier diodes on the pma that they're ok?

Maybe, as Ghurd implies, the pma produces some harmonics or something that your controller doesn't like?

[gizmoguy]

Thanks for the help Ghurd.  I went and checked my connections and the Negative connection was a touch bit loose...but it didn't seem to change anything.

The connectors between the batteries are 1/2" thick x 1" wide solid copper bar, so I don't think the gauge is too small...but maybe I should use wire instead of copper bar?

The PMA is the Otherpower 10' with a 24v stator wound with 1 14 Gauge strand 70 turns.  It is 3 phase and the phases are rectified right next to the charge controller which is right next to the batteries.

The solar panels are 75' from the controller/battery bank and the PMA is 40' from the controller/battery bank.

I don't have a capacitor to test with yet...but I'll see if I can get one.  I also wondered if there was a pulse issue that the MPPT controller was seeing and getting confused about.

Thanks,

Gizmoguy

[ghurd]

"a touch bit loose" is often enough with MPPT.

"The connectors between the batteries are 1/2" thick x 1" wide solid copper bar"

Gosh!  You couldn't find something BIGGER?  LOL!

I doubt that's the issue, unless one of them has a bit loose/corroded/un-perfect connection.

May not take a huge cap to tell if it helps.  Caps can do some strange things, even in places where they should have 0 effect.

I have 'a few' spare 1000uF 63V axial caps.  Shoot me an email if they would be any help at all.

BlueSky's tech support is great.  Real people, without attitudes.

The issues you are dealing with are either very complicated or a simple fault, probably nothing in between.

I have a bit of a generic gut feeling the best guy to talk with is out until after New Years Day.

Never hurts to call and ask.

G-

[ghurd]

Also:

When resetting many of their products, it is a good idea to disconnect everything for a few minutes.  Solar, hydro, and battery.

Reconnect it in the order the manual states.  Then the hydro last.

You did not cut any corners adding the hydro did you, like connecting the hydro to the MPPT output terminals?

Really want the hydro connected as close to the battery terminals (or bus) as possible.

Don't run the MPPT and hydro through the same wire to the battery.

[Ungrounded Lightning Rod]

The PMA is ... 3 phase and the phases are rectified right next to the charge controller which is right next to the batteries.

Sounds like you've got the charge controller and the rectifier tied together than a common run of wire from there to the batteries.  This puts significant parasitic resistance and inductance in the connection between them and the batteries, letting the charge controller see a voltage ripple from the rectified alternator.

Try running separate runs from the rectifier directly to the battery terminals and from the charge controller to the battery terminals ditto.

Don't forget that both need a fuse to protect against shorts on the charging side pulling massive power from the battery and starting a fire.  DON'T share this fuse!  Use separate fuses for the genny and the charge controller!  The fuse is a MAJOR parasitic resistance at these currents so sharing one will also couple ripple from the genny to the charge controller.

[Ronnn]

The type of signal that comes from a pma or most wind turbines makes MPPT controlers go nuts. Some will handle it but no longer do mppt for any of their input. There has been discussion of this on the outback forum. I have two of their charge controlers. They don't even like signals from a mixed array. It's what I have two. Supposedly the extra juice is worth it. Some claim 30%.

Ron

[joestue]

They need to rework the entire control methodology if indeed it is that bad.

Even home brew units like Tim Noland's got a measurable 20% average gain, that was in 2003.