2000k system only puts out 500 watt why?

[sensij]

The only setting I have ever changed was voltage on23.9/off27.0 set points and the display on/off because I like to be able to see the battery voltage when walking by without having to touch

Those voltage settings make no sense. Where did you come up with them? Among other things, the ON voltage needs to be higher than the OFF voltage for anything close to proper functioning. The ON voltage is the voltage at which the divert relay actuates, removing charging power from the batteries (and diverting it, if you had a dump load). the OFF voltage is the voltage to which the batteries need to fall before the relay turns off and charging power is connected to them again.

When you go to the P-3 setting, you should see live voltage first, high voltage (ON voltage) next, and the low voltage (OFF voltage) last. (Unless maybe the ONL setting got changed to ONH, which reverses the action of the relay)

[charles2,david000k]

That's the same issue a PWM controller has. They are either on or off; nothing in between. But by turning them on and off somewhat rapidly you can get an approximation of the correct voltage.

It rapidly turns on and off with it getting further apart as the battery get closer to being completely charged.


This next part is directly from the manual

This is the relay activity timer (RAT). Relay activity timer starts
countdown every time the relay turns off. The RAT time period is preset at 5 seconds. Explanation: Assuming the RAT is 005 (5 seconds), when the
relay has activity (turns on then off) the RAT will immediately start a countdown from 5 to 0 seconds. If the relay turns on again before the countdown
reaches 0 the relay will stay on for 10 seconds then relay off and RAT countdown starts from 5 to 0 seconds again, if relay turns on again before
countdown reaches 0 the relay will stay on for 20 seconds then relay off and RAT countdown starts from 5 to 0 seconds again, if relay does not turn on
again before RAT countdown reaches 0 then the next time the relay turns on again it will be on for 5 seconds. The relay must turn on again before the
RAT time reaches 0 otherwise the relays on time will stay at 5 seconds. The RAT's purpose is to hold the controller in divert for an increasing amount
of time because your controller is repeatedly diverting within a short period of time i.e. batteries nearing full. Referring to the example above, 20
seconds is the maximum amount of time the relay will stay on if the conditions continue to be met. If you change the RAT (the second set of 3 digits) to
20 seconds (020 on display) then relay on time will be 20 sec, 40 sec, 80 sec, 80 sec, 80 sec.... In most systems there is no need to change the RAT.



The only setting I have ever changed was voltage on23.9/off27.0 set points and the display on/off because I like to be able to see the battery voltage when walking by without having to touch

[sensij]

I thought so too but he said that the dump load (i.e. the solenoid/relay) was broken:

"No heating elements. The solenoid put the panels into float mode when voltage reaches a certain preset voltage. I pulled the old one apart and you could see where the contacts stuck. I tried to clean up the contacts but the wire coil had burnt up also and I have never rewrapped a coil I would lose count of my turns but I have the basic ideal."

Without a dump load, when the divert relay actuates, the PV circuit is just open, which shouldn't hurt anything.

Maybe now after reading about MPPT controllers, and hopefully more about the charge cycle in general, he would describe it differently. It never "changes modes" to maintain a float voltage of 27.2. It has a single mode that always allows the voltage to swing between 27.2 and 28.8 on a timer, so it is always swinging back and forth between float and absorb, if the charge current is available. The timer increments to help push the cycle time toward floating when the battery is truly approaching charged, but it is very coarse.

As for failure analysis... a burned up battery makes sense from what he's said. I read that as the solenoid wire had burnt, preventing it from ever actuating and opening the battery charge circuit, allowing the battery voltage to be driven too high. He's got 2000 W of panels, on a good day maybe spiking 70 A of current into a full 70 Ah battery.

[jflorey2]

There is not a typical PWM or MPPT CC in this system. It is a slow on/off mechanical relay that is performing coarse PWM-like control at charge voltage.

I thought so too but he said that the dump load (i.e. the solenoid/relay) was broken:

"No heating elements. The solenoid put the panels into float mode when voltage reaches a certain preset voltage. I pulled the old one apart and you could see where the contacts stuck. I tried to clean up the contacts but the wire coil had burnt up also and I have never rewrapped a coil I would lose count of my turns but I have the basic ideal."

If the system is still working at all he has to have a working charge controller _somewhere._ And given that he claims that his controller disconnects the array - "The charge controller I use now will rapidly turn on and off until the bank is fully charged then stays off until bank voltage falls to 23.9" - I assume it's a more standard type.

This would all be a lot simpler with a few pictures or accurate drawing of the system. (The original drawing has nothing other than a diversion load, and has two wind turbines.)

[sensij]

I don't think he does. He said "The charge controller I use now will rapidly turn on and off until the bank is fully charged then stays off until bank voltage falls to 23.9 before charging start over again." That tells me he has a PWM charge controller connected conventionally, to interrupt the connection between the solar array and the battery. In that case he does not need a separate dump load.

(If he had an AC-coupled system that regularly went off-grid, then he might need a dump load to deal with the excess - but that doesn't sound like it's the case.)

There is not a typical PWM or MPPT CC in this system. It is a slow on/off mechanical relay that is performing coarse PWM-like control at charge voltage.

I think the definition of "rapidly" is subject to interpretation. The relay is NC, powering open the battery charge circuit (and diverting, if a dump load circuit is connected) once 28.8 V is reached and closing battery circuit again once 27.2 V is hit. There are incrementally increasing timers on each state change on the order of 5 seconds (user adjustable) to prevent relay chatter, and help prevent overcharging, but it will force the duty cycle lower than what I think a good PWM would support (something like 5 sec charge / 20 sec divert looks like a likely outcome with default settings if there is sufficient charge current). I think the slow switching rate is generally wasteful of the energy that would be available during the adsorb stage.

[inetdog]

Meter set to DC current with black wire in com port and red in well whatever that port is called. But with my meter set like it shows in the photo I then take my black to - feed bar in combiner box and red to + feed in combiner box and it read 64 amp on set up.

It is all but impossible to read the meter information from that photo.
Most if not all multimeters have a separate, third, jack to which the red lead is connected just for high amp measurements. (e.g. 10A range).
If you leave it connected to the normal Volt-ohm-milliamp connection point you CANNOT use the 10A range even when you select it on the range switch. Instead you will blow the lower current milliamp range shunt fuse.
And with the fuses blown you will probably be measuring voltage more than anything else, in other words something proportional to Voc.
If you do not read the meter instructions carefully, you can literally have it blow up in your hand. You were lucky.
That meter is now toast for all but volt and ohm measurement until you have replaced the fuses or the meter, whichever is cheaper.

[jflorey2]

You do need a dump load if your hybrid inverter is there just to integrate with a generator and there is no grid connection. The OP stated, I believe, that there is no grid connection at this time.

I don't think he does. He said "The charge controller I use now will rapidly turn on and off until the bank is fully charged then stays off until bank voltage falls to 23.9 before charging start over again." That tells me he has a PWM charge controller connected conventionally, to interrupt the connection between the solar array and the battery. In that case he does not need a separate dump load.

(If he had an AC-coupled system that regularly went off-grid, then he might need a dump load to deal with the excess - but that doesn't sound like it's the case.)

[jflorey2]

Meter set to DC current with black wire in com port and red in well whatever that port is called. But with my meter set like it shows in the photo I then take my black to - feed bar in combiner box and red to + feed in combiner box and it read 64 amp on set up.

You blew the fuse in the meter and the readings are now nonsensical.

Might want to look into a mode called HBX. A few inverters support this mode. It uses battery power first, then transfers back to AC in when they get too low. This allows you to use mostly solar power and minimize utility use.

[charles2,david000k]

And trying to put through 60A on the 10A range will blow an internal fuse.
Once the fuse is blown it is not at all clear what if anything the meter is measuring if one tries to use that range.

Photo_00031.jpg

Meter set to DC current with black wire in com port and red in well whatever that port is called. But with my meter set like it shows in the photo I then take my black to - feed bar in combiner box and red to + feed in combiner box and it read 64 amp on set up. I got a mess load of old DC power supply just through in a box do you think I could test my meter by trying to take a reading from one of them? I opened the meter up again today to check the board inside for burnt connections the only thing on the entire board I could find that looks odd is some bubbling on the 300mA port but nothing that would break through the green shellac finish and no breaks in the electrical pathways on the computer board. The buble spot feels solid though I am thinking it could just be to much solder on that spot before the manufactur shellac the board.

[inetdog]

Woah there; you don't need a dump load if you have a hybrid inverter. You program the inverter to sell back to the load when X happens. X is usually "voltage over sell limit" which works well with most battery systems.

You do need a dump load if your hybrid inverter is there just to integrate with a generator and there is no grid connection. The OP stated, I believe, that there is no grid connection at this time.

[jflorey2]

I was thinking about why did I buy a dumpload charge controller and I remembered I was going to wire the charge controller so that when it did dump it would just switch the incoming power from charging the batteries to a grid tie inverter

Woah there; you don't need a dump load if you have a hybrid inverter. You program the inverter to sell back to the load when X happens. X is usually "voltage over sell limit" which works well with most battery systems.

but then came the whole battle with my power co-op over a $1,000 connection fees just for them to log it in their system plus they only give me back a .02 credit which I can't use and turn around and charge me .10 cents for the same Kwh i just gave them.

So you are paying .08 cents a kilowatt-hour for storage. How much will the same amount of battery cost you over the lifetime of your system? A T105 can be cycled ~500 times to 50% without serious degradation, which means you can get .6kwhr 500 times for about $100. Sounds like that would cost you around .33 cents for the same service from a (cheap) battery Even if you can get to 1000 cycles you are still at .16 cents per kwhr.

Sounds like your battery is ripping you off, compared to the utility!

[charles2,david000k]

Thanks for posting all of the additional information. A couple of quick thoughts...

There is no need for a dump relay / solenoid in a PV system. It does not put your system in "float", it disconnects the array completely. A "charge controller" of this type is capable of completing only the "bulk" stage of a traditional charge cycle, which means you will never get more than 80-90% SOC, gradually less as chronic undercharging reduces the capacity over time. With only the battery to regulate the array voltage, it won't be operating at its maximum power point very much of the time. There are inexpensive MPPT controllers that will do a much better job for you.

If you want more battery capacity (and based on the loads you want to run, that is a good idea), get away from the 12 V batteries. 6 pairs in parallel will be impossible to balance and will not last very long. To get 420 Ah at 24 V, you should look at 4 x 6 V batteries, 420 Ah each, creating a single 24 V string. The 370 Ah Trojan L16RE-B, or something like it, would be a much better choice.

I did look into the trojan battery line before but what had put me off was the price+shipping. I do like the ideal of lead acid so you can just top off the battery if needed but somewhere along the line someone had told me sealed AGM was the best not so sure about that now! But life is all trial and error. Also just by looking at the weight of the battery you can tell the plate have to be big which = more conductive surface.

I was thinking about why did I buy a dumpload charge controller and I remembered I was going to wire the charge controller so that when it did dump it would just switch the incoming power from charging the batteries to a grid tie inverter but then came the whole battle with my power co-op over a $1,000 connection fees just for them to log it in their system plus they only give me back a .02 credit which I can't use and turn around and charge me .10 cents for the same Kwh i just gave them. Which is something else I been meaning to ask is what does your local power company pay residential green power providers? Cash in hand credit does not count because you can't buy replacement parts and upkeep etcetera with a power credit.

[Mike90250]

I am liking what I have been reading on the MPPT charge controllers.

Will this meter work for reading my system http://www.sears.com/craftsman-digit...FdgUgQod5EwDbg

My battery bank does hold a charge of 25.6 to 26 volts when not in use. The charge controller I use now will rapidly turn on and off until the bank is fully charged then stays off until bank voltage falls to 23.9 before charging start over again.

Yes, I have had 2 of those (first one stopped working) and they are pretty good for the price, the next better one for DC is quite expensive.

[charles2,david000k]

I am liking what I have been reading on the MPPT charge controllers.

Will this meter work for reading my system http://www.sears.com/craftsman-digit...FdgUgQod5EwDbg

My battery bank does hold a charge of 25.6 to 26 volts when not in use. The charge controller I use now will rapidly turn on and off until the bank is fully charged then stays off until bank voltage falls to 23.9 before charging start over again.

[jflorey2]

How does a diversion controller get through absorb? If the array is making more power (current) than the battery can take, the voltage will rise and trip the relay. If the array is generating less current, it will trickle charge, but not truly top off.

That's the same issue a PWM controller has. They are either on or off; nothing in between. But by turning them on and off somewhat rapidly you can get an approximation of the correct voltage.