How to add a "shunt" to a MPPT charge controller

[pmhayne5]

My panels charge my batteries though a charge controller (pretty ordinary i hear u say)

My charge controller "shorts" the panels when it determines the batteries are full (again i think this is normal)

My question is:
Can i attach a device (shunt?) between the panel and the controller which say when a short is i place, "shunt" the power to a "Grid Tie in" converter(not in place at the moment).

Reason:
Main purpose it to charge the batteries which it does great. That's the priority.
When, and only when, batteries are full, don't waste the excess power put it into the home grid.

I imagine there are expensive controllers which have this facility built in.
If you know if any please feel free to post a link

Any help appreciated.

[Sunking]

First when your battery is fully charged, your controller does not short out the panels, it does the exact opposite and opens and disconnects the panels like a switch.

There are charge controllers that have a Dump Load aka Diversion Load. Most that is used to wind mills to keep the turbine from flying apart by using the power to heat water. No grid tied as all grid tied systems use high voltage, not low voltage. Besides you should not be using Solar battery if you have commercial AC power. AC power from the POCO cost 11 to 12 cents per Kwh. From battery over $1 per Kwh. There is no demand for such a device as it would be foolish.

Now there are hybrid inverters that can do what you want, but very expensive.

[pmhayne5]

Thank you for your prompt reply.

My system is currently for fun not profit.

Guess i'll have to make something myself.

Detect open circuit voltage , 20 volts on my panels, then use a relay or something to divert power to the inverter.
Probably need a timer on there to check if panels are still at 20 volts.

any how rambling now

[SunEagle]

Thank you for your prompt reply.

My system is currently for fun not profit.

Guess i'll have to make something myself.

Detect open circuit voltage , 20 volts on my panels, then use a relay or something to divert power to the inverter.
Probably need a timer on there to check if panels are still at 20 volts.

any how rambling now

I don't understand. You have a system where solar panels charge your batteries. Once the batteries are "charged" you want to disconnect the batteries and use the solar to power something in the house?

As soon as you disconnect the batteries from the system they start to lose charge so why do it? Even if you did do this you can't back-feed the house AC system without a UL listed Grid Tie inverter. There is equipment called a Hybrid solar / battery system that does what you want but it is very expensive.

So with your current system, once the batteries are fully charged you can use power from them to run a specific AC load through an inverter and the batteries will still be connected and being charged if you draw them down a bit. Also with the batteries in the circuit you load will see a constant voltage supply which is not what you will get directly from the solar panels.

[inetdog]

The only GTIs that I am aware of that will work with an input voltage (Vmp) lower than 20 volts are unsafe and illegal plug and play inverters with very low power ratings. I cannot in good conscience advise you to use such a GTI or help you in connecting it.

[pmhayne5]

The only GTIs that I am aware of that will work with an input voltage (Vmp) lower than 20 volts are unsafe and illegal plug and play inverters with very low power ratings. I cannot in good conscience advise you to use such a GTI or help you in connecting it.

This is the one i saw. I would put my panels into a 24v configuration. voltage would then be 24v-40v

http://www.bimblesolar.com/ongrid/microinverter/GTI-500W

SunEagle.
My Rig is sized for winter. In summer i has alot of Excess power. Now i could buy more batteries i know.
Maybe i should have mentioned they they run my 12v devices and dont have a 12v to 230v inverter runnnig the house.

Also the batteries have very little load on them so i could safely charge them up from a night usage in one hour on a sunny day
Then use the rest of the day sun light with a tie in grid inverter, then recharge the batteries again the next morning for one hour (assuming its another sunny day)

Now i could use some kind of timer but id rather KNOW the batteries are charged before diverting power else where.


Any how thank you both for your comments, i shall go away now with my soldering iron and try not to blow myself up

bye

[Sunking]

This is the one i saw. I would put my panels into a 24v configuration. voltage would then be 24v-40v

http://www.bimblesolar.com/ongrid/microinverter/GTI-500W

Illegal to use in the USA.

All solar battery systems are designed for worse case winter sun hours. Or at least they should be.

[SunEagle]

This is the one i saw. I would put my panels into a 24v configuration. voltage would then be 24v-40v

http://www.bimblesolar.com/ongrid/microinverter/GTI-500W

SunEagle.
My Rig is sized for winter. In summer i has alot of Excess power. Now i could buy more batteries i know.
Maybe i should have mentioned they they run my 12v devices and dont have a 12v to 230v inverter runnnig the house.

Also the batteries have very little load on them so i could safely charge them up from a night usage in one hour on a sunny day
Then use the rest of the day sun light with a tie in grid inverter, then recharge the batteries again the next morning for one hour (assuming its another sunny day)

Now i could use some kind of timer but id rather KNOW the batteries are charged before diverting power else where.


Any how thank you both for your comments, i shall go away now with my soldering iron and try not to blow myself up

bye

That Grid tie inverter is not UL listed and can't be used legally in the US. And even if you live where it can be used it may not be safe.

If you want to use the excess power from your panels than maybe investing in a 12v to 230volt inverter to at least run something in your home.

[pmhayne5]

That Grid tie inverter is not UL listed and can't be used legally in the US. And even if you live where it can be used it may not be safe.

If you want to use the excess power from your panels than maybe investing in a 12v to 230volt inverter to at least run something in your home.

Im sorry but that is laughable. it would be illegal to sell something that is dangerous.
Also if installed improperly these things are dangerous!

I thankyou for your imput but i think i wont be looking at this forum again.

[Sunking]

I thankyou for your imput but i think i wont be looking at this forum again.

Don't let the door hit you in the butt on the way out. One thought to take with you. Can you buy cigarettes or alcohol where you live? Can they harm you? I did think so or else they would not sell it right? You a moron.

[russ]

Im sorry but that is laughable. it would be illegal to sell something that is dangerous.
Also if installed improperly these things are dangerous!

I thankyou for your imput but i think i wont be looking at this forum again.

Have fun with the garbage like this that apparently can be sold in the UK.

You are very wrong if you think dangerous, useless and or illegal items can not be sold on the market.

The same site sells wind turbines that are no more than boat anchors.

[SunEagle]

Im sorry but that is laughable. it would be illegal to sell something that is dangerous.
Also if installed improperly these things are dangerous!

I thankyou for your imput but i think i wont be looking at this forum again.

Sad to say but anything can be sold on the internet to anyone in the world even if it is dangerous or illegal in some places.

It comes down to buyer beware. It is up to the buyer to determine if what they are getting is allowed in their country. The seller doesn't care.

Good luck with your project and hope you don't get yourself or anyone else hurt.