Excess power?

[inetdog]

So tell me how to do that. A human cannot do it. A PLC could if you had a vast assortment of load devices to tune the system, but I can see nothing but chaos of stuff getting switched on/off constantly.

Definitely not a manual operation, nor one that is supported by readily available US market CCs and inverters. I refer back, once again, to some UK-marketed systems which integrate the CC, inverter, and special heater loads into a single system. At that point you can either say that the microprocessor running the integrated system is doing the management, or you can say that there is a PLC hidden inside somewhere. The results are the same.

I agree 100% that trying to do this with discrete standalone CC, inverter and load control, even if they are all from the same manufacturer, is going to be a major circus and I would hate to be responsible for designing and engineering it. Definitely not a DYI project for the typical off-gridder, or even one with an engineering background.

PS: As I understand one of the systems, based on their literature, the load side involves essentially an inverse MPPT circuit which allows them to put a varying amount of power into a constant resistance heater.

[Sunking]

PS: As I understand one of the systems, based on their literature, the load side involves essentially an inverse MPPT circuit which allows them to put a varying amount of power into a constant resistance heater.

That is what I was thinking, a water heater and resistance heating at that. Not sure I would brag about that, but at least I now understand the point you are driving. e

[Sunking]

or even one with an engineering background.

Certainly not me, I would rather have a root canal.

[dkpro1]

Well my respomse was on here, it got deleted so let's try again.

dkpro simply does not know what he is talking about plain and simple. If he did he would know the first loss comes in the wiring, of 2 to 10 % burned off as heat. Next comes the charge controllers wiht MPPT being the lowest loss of around 3 to 5%, and with PWM at best 32% is lost and up to 50%. Then we have the batteries, FLA you loose 20% just with the charge/discharge losses. AGM is better at 5 to 10%. Then we finally get to the inverters where we loose at leat 10% and in some cases another 50%/

So at the very best if you could actually utilize every watt hour available which is IMPOSSIBLE, with a MPPT system 66% efficiency is as good as it can theoretically be on paper. With PWM you loose 50% or more. Now here is the real kicker. In real life application you are doing great if you can utilize just 30 to 40% of what is possible, but you CANNOT DO THAT, it is IMPOSSIBLE. A well designed system turns off just after solar noon when the batteries go into Absorb and Float mode. Technically you do not loose the power, it just gets turned off. Contrast that to a GT application and every watt hour is utilized by someone somewhere with only the line and equipment losses of roughly 20% making them 80% efficient.

So as you can see dkpro is just uniformed and does not really know what he is talking about.

most info is right here king but if you build a circuit that dump's extra power from array into a hot water heater when absorb is reached is it still lost king or are you lost?

[inetdog]

most info is right here king but if you build a circuit that dump's extra power from array into a hot water heater when absorb is reached is it still lost king or are you lost?

Several important points here:
1. As soon as you get to absorb? Then you run the risk of cutting back on the available absorb current, or else you are not using up all of the excess power.
2. With a more or less fixed array voltage (in the general area of Vmp) you have no way to modulate the power going into the fixed resistance heating element. Result is you either lose potential to charge the batteries or you do not use ALL of the potentially available panel power. Note my mention of the "inverse MPPT" output circuit.
3. Nobody (as far as I can see) ever said that you could not reduce the "waste" of potential panel power, just that it would never get as good as you can do with grid tie.

[Sunking]

most info is right here king but if you build a circuit that dump's extra power from array into a hot water heater when absorb is reached is it still lost king or are you lost?

I am not lost, you just do not know what you are talking about. Even beginners realize that in this thread. Read all the response, they get it and you don't. You lost the debate now get lost.

[AzSun]

Excess Power

Hello, please excuse me if my question is daft, but I would very much appreciate an answer. Having connected my batteries to the charge controller and inverter, how do I utilize the excess power produced by the panels (power not used for charging) there is a DC output on the controller for the excess power but if I connect that to the inverter as well as the batteries obviously I have a problem. Is it the case that I need to add a blocking diode of suitable size between the batteries and inverter, I have a battery monitor that places a shunt on the battery-inverter line, will this do the same job or am I barking at the wrong tree altogether? Thank you kindly for reading.

What make and model charge controller do you have Milo ?

Az

[Bucho]

Well my respomse was on here, it got deleted so let's try again.

dkpro simply does not know what he is talking about plain and simple.

That's a great response and all but it doesn't actually address what your experience with off grid solar is, have you ever been off grid?

[Sunking]

That's a great response and all but it doesn't actually address what your experience with off grid solar is, have you ever been off grid?

I design them professionally around 200 or so cell sites and a dozen or so weather and telemetry stations. I would never go off grid. I do have my ham shack that can run off-grid, but never ever been used except one night.

[dkpro1]

I design them professionally around 200 or so cell sites and a dozen or so weather and telemetry stations. I would never go off grid. I do have my ham shack that can run off-grid, but never ever been used except one night.

Talk is cheap King experience is not and you have none living off grid face it and eat it hot shot

[dkpro1]

IMG_20140316_111033785_HDR.jpg

I design them professionally around 200 or so cell sites and a dozen or so weather and telemetry stations. I would never go off grid. I do have my ham shack that can run off-grid, but never ever been used except one night.

unplug man and then shoot your numbers cell sites are far from living off grid

[SunEagle]

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unplug man and then shoot your numbers cell sites are far from living off grid

So what I see is a disagreement with someone that is living off grid and someone who understands the science behind battery charging.

dkpro1.

You believe that you are not really losing any energy because you have found a way to diverted excess power from the sun that is no longer needed to charge your battery system and instead is used to heat water or power some other load.

While you might feel that you are not wasting any energy you really are. It comes down to physics, science and math with respect to collecting, converting and using energy. There are built in "losses" that you can never recoup. You might be able to minimize those losses but never get rid of them completely.

Being able to happily live an off grid lifestyle has nothing to do with the math behind using the sun to charge batteries and run your appliances. Sure it can be done and a lot of people are living that way. Only most probably understand that there are "losses" in their system that can never be gotten back.

[russ]

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unplug man and then shoot your numbers cell sites are far from living off grid

We have been through this with dkpro1 before - he has a week to think about it.

[Sunking]

We have been through this with dkpro1 before - he has a week to think about it.

For the record I had nothing to do with it because I do not whine or take offense when some disagrees or is wrong. Call me any name you want. I am proud to wear the badges especially the label of RED NECK.

[SunEagle]

For the record I had nothing to do with it because I do not whine or take offense when some disagrees or is wrong. Call me any name you want. I am proud to wear the badges especially the label of RED NECK.

Just stay out of the sun and wear a hat. That RED NECK will go away.

Now I can't do that to stop from being called a Fl Cracker.