Dual Solar Controllers?

Two controllers will not work as good as one They keep telling each other that the batteries are full but it is only the current from each panel confusing each controler

You'll be pretty close to the steca's 20A limit, but I'd go that way and not use the new controller. As Phil says, the two controllers will probably confuse each other if you try to run them together.

If you do elect to run both controllers, I'd suggest installing the new one at the battery end of the panel cable, rather than at the panel - more efficient to have any cable losses "upstream" of the controller.

Cheers

John

Yes as previously stated you cannot have two controllers feeding the one battery bank. You need to disable one of the controllers and feed both solar banks into the one controller. Of course you will better from any controller that has MPPT capabilities provided you don't overload it.

Regards John Genge

Hi jd,

I agree with the other replies - you should have all your panels going through one reg.

If you do that I presume your portables and the roof-mounted will be connected in parallel. If so, have you thought about blocking diodes in the output of each set?

You need those to stop backfeed from one set of panels to the other if one set is in shade and the other in sun.

Cheers

Hi Guys
If you do your research you will find its OK to run multiple controllers in parallel to a battery bank.
If one decides to limit the current the other will make up for this shortfall.

And as well most modern controllers have blocking diodes fitted to stop this perceived feedback.
Its only the very older models that seem to allow feedback.
My suggestion is to have the two controllers of the same make and capacity.
Else as mentioned get a bigger model.

The Morningstar Prostar Controller is able to be paralleled with up to 300amps capacity.
this model comes in either 15 or 30 amps.

Morningstar’s ProStar is the world’s leading
mid-range solar controller for both professional
and consumer applications.

This second generation ProStar:
• Adds new features and protections using highly advanced technology
• Provides longer battery life and improved system performance
• Sets new standards for reliability and self-diagnostics

Standard Features:
• Versions available: 15 or 30 amp 12 / 24 or 48 volt negative or positive ground
• Estimated 15 year life
• PWM series battery charging (not shunt)
• 3-position battery select: gel, sealed or flooded
• Very accurate control and measurement
• Jumper to eliminate telecom noise
• Parallel for up to 300 amps
• Temperature compensation
• Tropicalisation: conformal coating, stainless steel fasteners & anodized aluminum heat sink
• No switching or measurement in the grounded leg
• 100% solid state
• Very low voltage drops
• Current compensated low voltage disconnect (LVD)
• LED’s indicate battery status and faults
• Capable of 25% overloads
• Remote battery voltage sense terminals Electronic Protections:
• Short-circuit — solar and load
• Overload — solar and load
• Reverse polarity
• Reverse current at night
• High voltage disconnect
• High temperature disconnect
• Lightning and transient surge protection
• Loads protected from voltage spikes
• Automatic recovery with all protections

If you buy quality then there will be no issues. They also come with a 2 year warranty

See GEMAC Solar and Power on this site. They are able to supply all this stuff

I have done something a little bit different. I have fixed panels on the van roof through a 30A Prostar regulator, all is good. I also have a foldup pair of panels. What I have done here is to have 2 pairs of cables from the panel. One pair direct from the panel output (ie. not through the panel's regulator) which I can connect into the van's Prostar which sees all 4 panels as 'one'. In this way I can boost house battery charging if necessary. The Prostar handles all 4 panels' output no problems. The other pair from the foldup is through the on board 10A Techtronics regulator. I can use these to top up tug battery, auxiliary battery, or whatever if I need to. I feel I get maximum flexibility from the system this way.

Mark

Unless you have two controllers that are designed, known and proven to work together I simply would not take the risk.

There are funky controllers that are specifficaly designed to be paralelled with like controllers.

That is one thing.

Trying to combine two controllers of unknown heritage is another all together, predicting how they will interact is little more than a lottery.

cheers

Just wanted to say thanks to everyone for responses.