Should my system be F MPTT at low power??

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

NorthGuy wrote: »

In your first post, you said they were 1.255/1.260 at noon. How long ago?

That was noon yesterday, Sunday. That was the initial reading as delivered. They are now 1.235

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

Is there a way to set the FX to EQ?
I am now under 200 watts solar (cloudy) and when I start the genny to EQ, it just drops down to 0 watts charging. I do notice the voltage on the MX rises anyway, I figure this is because the load in the house is carried by the gen and the solar array is going to charge the bank??

Cariboocoot · September 2013

Re: Should my system be F MPTT at low power??

Freewilley wrote: »

Is there a way to set the FX to EQ?
I am now under 200 watts solar (cloudy) and when I start the genny to EQ, it just drops down to 0 watts charging. I do notice the voltage on the MX rises anyway, I figure this is because the load in the house is carried by the gen and the solar array is going to charge the bank??

Yes, the FX can be set to EQ via the MATE.

I'm guessing "it just drops down to 0 Watts charging" is the MX when the gen is running and charging is being provided by the FX? This will happen if the Voltage settings for both aren't the same; the MX "sees" a higher battery Voltage (as provided by the FX) and thinks the batteries are full so it stops contributing.

But I'm doing too much guessing here as there are numerous screens on both the MATE and the MX60 and there are a lot of output readings for Volts, Amps, and Watts depending on which one you're looking at.

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

Cariboocoot wrote: »

.I'm guessing "it just drops down to 0 Watts charging" is the MX when the gen is running and charging is being provided by the FX?

Sorry, more specific...the generator drops down to minimal or no charging thru the FX. This actually is the way this has always performed as voltage has increased.
BUT I would like to tell the mate to go to EQ mode, that way the FX would keep up the charge to the bank.
I do not know how to do this, and until today it never occurred to me I could do this...

anybody help with the mate screen I need?

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

ignore that request, there is an outback youtube video that shows how to do it,,,you start by hitting the AC in button.
Wish I had googled it 5 years ago...
http://www.youtube.com/watch?v=ns6Z5-xm3PE

Cariboocoot · September 2013

Re: Should my system be F MPTT at low power??

You may be getting your current and Voltage confused. During Absorb stage it is perfectly normal to have the current drop off as long as the Voltage level is maintained. Shifting to EQ does nothing to this function, it merely ups the Voltage level. You can do the same thing by raising the Absorb Voltage. Again the settings for this on the two charge sources should match.

EQ is not the magic cure-all to every problem, although there are those who think otherwise.

zoneblue · September 2013

Re: Should my system be F MPTT at low power??

Hi . Ive scimmed your previous thread, and conclude as all the others have that something is not right.

What pricked my ears up, was at one point you say that you didnt have much loads only a toaster and a dishwasher. On a 12volt, 1kWp system these items should exist in one place only, the attic. Or else the system is less a renewable energy system than one powered primarily by a generator.

As such its possible that your new bank is also now well on its way out. Thats the most likely explanation for low terminal voltage and low sg, for what looks like adequate charging attempts. However without a closer look theres no way to know if theres a bad conection, failed hardware or something of that nature.

Like all folk in this situation, unless you are willing to throw yet more money at batterys, you have two choices:

1. get a professional in, highly recomended at this point.

2. work with us to see what we can do. If you go this route youll need at a mimiumum the following:
- write down in one place every spec of every bit of hardware, model numbers, date of purchase, settings, history etc.
- high resolution photos of the entire system
- known reliable dc clampmeter, dmm and hydrometer

good luck.

waynefromnscanada · September 2013

Re: Should my system be F MPTT at low power??

zoneblue wrote: »

Hi . Ive scimmed your previous thread, and conclude as all the others have that something is not right.

What pricked my ears up, was at one point you say that you didnt have much loads only a toaster and a dishwasher. On a 12volt, 1kWp system these items should exist in one place only, the attic. Or else the system is less a renewable energy system than one powered primarily by a generator.

As such its possible that your new bank is also now well on its way out. That's the most likely explanation for low terminal voltage and low sg

Have to agree. Unfortunately many folks aren't really aware of how much power some items consume. A toaster is pretty small, so how could it consume much power? And a dish washer? Especially if it has a booster heating element.
"Not much loads" would be 2 or 3 LED light bulbs, a radio and a cell phone charger.

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

The offer of help is much appreciated. If there was a good solar tech in the area, I would have him/her in. There is not, I am in the boonies.

I DO NOT want to hijack my own thread and start a debate about loads in off grid living. Just be assured that I have lived off grid for 5 years and am ANAL about how much power is being used. I know what my loads are and am not shy to run the generator when the power is questionable. That is what a "hybrid" system is all about. Kick on the genny and run the toaster over breakfast and charge up the batteries at the same time. It works. Some people have an electric fridge off grid, now that would be hard to compensate for, it runs off and on all day and night. You can choose to run an energy efficient dishwasher on a no dry 1 hour cycle on a bright sunny afternoon, or if power is not pouring in, run the gen for that hour and reap battery charging without harming your system....my wife has been trained also. It helps that we only live off grid for the summer, have propane appliance, dc water pump, energy efficient washer, solar clothes dryer (100 feet), small lcd tv etc, etc.

As to equipment, I am missing the clampmeter...I will get one. My system is my sig....all I can really add is that it is 5 years old except the brand new batteries....do you really need the model number of my MX60? If so, I will find one...

My problem, is simple, the chargerS think that the batteries are fuller than they are. So far, the only opinion offered is that this is caused by sulphation and I should try a good round of equalization. Since the batteries have only been in less than 48 hours and there has been almost no solar here, I have yet to complete an equalization cycle. But sun looks good tomorrow on, so that will be done. In the meantime I am ensuring that the SG stays up as much as possible, over 1.200 or much higher. Once I run a good EQ cycle, if the problem is not better I will look at swapping out the MX60 since I have an FM60 on hand (for another array I am planning on). I had damaging "low" voltage (a little below 1.200) for a few hours only, I am not ready to throw in the towel yet.

thanks again!

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

One problem has come to light and been easily fixed.
Steve spent a long time reviewing my system yesterday with me (I cannot complain about lack of Surette service on this one!).
The MX was not adjusted for the .2 voltage drop from the bank. Now it is.
Interesting to see what that does for charging, it can only be good.

For now I am continuing with EQ, good session yesterday of 4+ hours and today is even better. I saw the SG rise to 1.250 and hope to fully charge today.
Then will go back to normal mode...I plan to set absorb to 14.8 and 4 hours for a trial period tomorrow ...

happy to hear your thoughts

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

Please tell me if this is normal, or a fault in my system....
Start out in the morning with 12.1 volts resting, start genny and run for 2 hours. Settings for the fx are normal, not in EQ mode.
Solar starts coming alive and turn off Genny. My MX is on EQ mode. I switch off EQ mode (because I want to start the timer) and the MX goes to FLOAT.
Voltage is at 15.8 when I stop the EQ. SG is 1.225.

Is that the way it works? No need for MX to go to absorb?

thanks, sorry for the dumb question, I just do not know what is normal and how these parameters work.

Cariboocoot · September 2013

Re: Should my system be F MPTT at low power??

Disable EQ on the MX. You do not use EQ unless the batteries are already fully charged, which they aren't. It is not a regular part of the charging process. The higher Voltage caused by the EQ is tricking the MX into going to Float.

You need to run it normally: Bulk, Absorb, Float.
Absorb Voltage at 14.8 would be a starting point; you may have to go higher yet.
Also make sure the Absorb time limit is set to its maximum, and watch the current during the Absorb stage to see where the plateau is. That will give you a clue for setting End Amps.

vtmaps · September 2013

Re: Should my system be F MPTT at low power??

Freewilley wrote: »

Please tell me if this is normal, or a fault in my system....
Start out in the morning with 12.1 volts resting, start genny and run for 2 hours. Settings for the fx are normal, not in EQ mode.
Solar starts coming alive and turn off Genny. My MX is on EQ mode. I switch off EQ mode (because I want to start the timer) and the MX goes to FLOAT.
Voltage is at 15.8 when I stop the EQ. SG is 1.225.

Is that the way it works? No need for MX to go to absorb?

When yu turn off the generator the battery voltage is elevated by surface charge. The MX, looking at battery voltage, sees a very high voltage and thinks the batteries are fully charged.

After you turn off the generator, if you wait awhile, or turn on a large load to drop the voltage down, the MX will then begin a bulk/absorb cycle.

One more thing that may be a consideration. I think that the MX used a charging scheme where the length of the absorb was related to the length of the bulk. When you turn the generator off, the battery was in or near absorb. Thus when the MX starts charging there is a very short duration bulk before the battery is ready to resume absorb. The MX may shorten your absorb to a matter of minutes under those circumstances. Does your MX have a setting for minimum absorb time?

--vtMaps

BB. · September 2013

Re: Should my system be F MPTT at low power??

Your SG at 1.225 seems too low... You should be upwards of 1.260 to 1.270 nominally for a "standard" deep cycle battery.

So, that leaves us with some things to puzzle out.

You are not in absorb long enough
Your hydrometer is not accurate
You are doing temperature correction correctly for SG readings
There is a typo in your SG reading (you said you had 1.250 in 1,000post)
Your batteries are getting "sulfated"
Your voltage readings are not accurate
A mix of "some of the above"

I noticed in your previous post that you have 0.2 volts wiring drop from the controller to the battery bank??? If so, I understand you corrected the reading with an offset--But, you really should look at your wire length/awg and see if you can get that down to the 0.05 to 0.10 volt drop range (on a 12 volt battery bank). It would will be more accurate voltage readings of the battery bank for your charge controller.

To look at your system... You have a 400 AH at 12 volt battery bank and a 1,000 watt array.

A 12.06 volt resting battery reading is ~50% discharged or you will need ~200 AH to recharge:

1,000 watts * 0.77 panel+controller derate * 1/29 volts charging = 26.5 Amps typical max
200 AH / 26.5 Amps = 7.5 hours (+2-4 hours equalization)

To recharge your battery bank back to full--You should need around 2 days of sun (and no further discharge) to get back to full--If my understanding/guesstimates are close.

So, what is your generator charging current/time? I guess it is 80 amps peak--But what are you seeing (i.e., 80 amps for 2 hours = 160 AH; 40 amps for 1 hour = 40 AH)?

-Bill

Cariboocoot · September 2013

Re: Should my system be F MPTT at low power??

vtmaps wrote: »

Does your MX have a setting for minimum absorb time?

--vtMaps

Yes it does. Normally it isn't used because normally the MX handles the full charging cycle and as such it isn't needed. You are correct about the Bulk/Absorb clock.

With the MX connected while charging via gen the clock will still run up because it will still see the Bulk cycle. There is no problem running the two charge sources together if there is insufficient sun for the MX to do the job on its own.

But the OP has got to stop obsessing with EQ. Shut it off, leave it alone, ignore it, don't use it.

These batteries need a proper Bulk/Absorb/Float regime with the correct Voltages and times in order to be charged, and they're not getting it.

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

vtmaps wrote: »

After you turn off the generator, if you wait awhile, or turn on a large load to drop the voltage down, the MX will then begin a bulk/absorb cycle.
--vtMaps

Now that is exactly what has not happened to date. If I go off EQ, the system will float. That is why I put in these 2 new batteries.

vtmaps wrote: »

Does your MX have a setting for minimum absorb time?
--vtMaps

Yes. It is set for 140 minutes. I have posted that setting and asked if it is right, no reply yet.

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

Cariboocoot wrote: »

But the OP has got to stop obsessing with EQ. Shut it off, leave it alone, ignore it, don't use it.

These batteries need a proper Bulk/Absorb/Float regime with the correct Voltages and times in order to be charged, and they're not getting it.

Well, since the batts have been acting as if they are sulphated, and since Surette says do an initial EQ cycle. Steve suggested I run that cycle That has not been completed yet, as I understand EQ will not be done until I get fully charged.
Unfortunately, the sun is not cooperating well.

Cariboocoot · September 2013

Re: Should my system be F MPTT at low power??

If the sun does not co-operate, charge it from the FX using the gen. Running a full charge cycle from the gen may be uneconomical on a regular basis, but doing it once to get the batteries fully charged won't hurt.

And it should only take once. If you can not fully charge the batteries in one day from a generator than either the charging source is severely undersized or the batteries are severely oversized or there is too much load eating into the charging power.

There is no need to have the MX's minimum Absorb time set. Run the charge sources concurrently, with the same Absorb Voltage (at least 14.8 ) and time (maximum for now) and the MX will 'follow' the FX in counting up Bulk time.

The test is not only that the proper SG is achieved, but also that it stays high; too short of Absorb and the SG will go down rapidly. If you are powering loads during/after charging this will defeat the process. Ideally you want the batteries to rest overnight and check again in the morning to see that the SG has remained high. Then you're good to go with getting the charge regime to work on a daily basis.

Vic · September 2013

Re: Should my system be F MPTT at low power??

Freewilley wrote: »

Please tell me if this is normal, or a fault in my system....
Start out in the morning with 12.1 volts resting, start genny and run for 2 hours. Settings for the fx are normal, not in EQ mode.
Solar starts coming alive and turn off Genny. My MX is on EQ mode. I switch off EQ mode (because I want to start the timer) and the MX goes to FLOAT.
Voltage is at 15.8 when I stop the EQ. SG is 1.225.

Is that the way it works? No need for MX to go to absorb?

thanks, sorry for the dumb question, I just do not know what is normal and how these parameters work.

Willey,

My MX-60 exits from an EQ into Float, even if the EQ is manually terminated by the user (from my memory)

And the MX here can quit charging from solar if there is another charger that has brought the battery voltage above the Absorb voltage setting of the MX. Then if that other charger is shut off, my MX goes to Float also.

If you do NOT have an EA setting entered into the MX, you should be able to do a Force Bulk in the MX, from the Misc menu (about the third screen in Misc IIRC), and the MX should start a Bulk, using solar power.

This is the I recall that my MX-60 works, with 5.10 or 5.11 (the latest rev FW).

Agree that you need to get the MX's daily charge routine set up correctly, and avoid the EQ, until the MX has fully charged the batteries to 1.265-ish SG. If there is not enough PV power to do this on a good day, then running the generator/OB 2512 to get to/near Absorption V and Forcing Bulk should work. When batts fully charged, then you could do your Commissioning EQ, at a voltage of 15.5 V, or just a tad above this.

Good Luck, and keep at it until you have the MX-60 charging figured out. Vic

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

BB. wrote: »

[*]Your hydrometer is not accurate

That is not the problem.
You are doing temperature correction correctly for SG readings
That is not the problem.
There is a typo in your SG reading (you said you had 1.250 in 1,000post)[/QUOTE]
Not sure of that reference....but my SG readings are low in the morning and go up during the day...of course....
Your batteries are getting "sulfated"
Yeah, the EQ cycle is about making sure we eliminate that as a problem.
Your voltage readings are not accurate
I am making those with a DMM, the MX and the Mate. When rested, the Voltage and SG do relate as expected.

So, what is your generator charging current/time?
Charging is 70 amps peak on the mx. Using 8 on the generator

Cariboocoot · September 2013

Re: Should my system be F MPTT at low power??

Freewilley wrote: »

Charging is 70 amps peak on the mx. Using 8 on the generator

That is a crazy amount of current for 400 Amp hours.
The MX60 should be limited to 40 for normal charging, and the charging AC Amps on the FX should be no more than 5 (it is a 10X factor).

High current is not the solution here, and may be detrimental to the batteries.

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

Thanks guys.

So, does it take less power to take a battery from 1.240 to 1.265 using absorption that EQ?

I am at the end of my solar day (4:30 and cloudy), so I forced BULK as suggested (SG is 1.240 after today 1.7kwh, 2 hours with genny charging at 800 amps, very little power usage in the house, a radio and a laptop and a small energy efficient chest freezer that runs a little.)
The MX immediatly showed F Mttp when I stopped EQ, voltage was showing 13.1.
I forced bulk and it soon went to absorbing. Wattage coming in from array is 40. Generator is only charging at 100 watts....Voltage is 14.9, which is what I have the Absorb setpoint at.

So, I will run the genny until bedtime, I guess? and then see if I am fully charged....but is it right that I only get that little bit of power out of the genny (I guess just enough to keep it at the Absorb set point?

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

Well, Steve at Surrette specifically told me that total charging at 8 amps was fine.

Someone else on this board said 6 was fine.

The surrette manual actually uses 2 s530 batteries charging at 60 and 80 amps as the two examples when calculating absorption times.

*** do I know....just muddling along.

Cariboocoot · September 2013

Re: Should my system be F MPTT at low power??

There's a limit to how much you can exchange time for Voltage. Higher Voltage puts more stress on batteries, this is why EQ is to be avoided unless necessary.

If the world were perfect your batteries would have come with instructions saying how to do an initial charge for RE systems. It would have given information like "do not connect any loads", "Absorb @ 14.8 Volts for 4 hours", and "then check specific gravity of all cells and equalize for 1 hour at 15.4 Volts" or some such.

Lots of people, btw, miss out on this first charging altogether. With some batteries it won't make much difference; they'll just make it up next time 'round and lose the tiniest portion from their lifetime. Surrettes seem to be needy for initial charging.

Yes, running the gen for the low power demand of the Absorb cycle is a lot of fuel for a few Watts. But this is not something you'll have to do every day.

I don't suppose you have any old car batteries lying around that you could run off overnight to save all drain on the new batteries?

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

LOL, I have 4 old S530s to run off, but I could never get them close enough to hook up.

I have turned the freezer to very cold and will disconnect it tonight. Nothing else really runs here at night, I will cancel all the appliances that steal a little power while turned off....

Tomorrow I am going to swap out the MX60 for that new FM60 sitting on the shelf. I wanted to get this system right but it is time to see if the FM will perform differently...now, folks with an FM, I looked at the manual and it said to connect at the PV- screw. My MX has no wire there, so I asked Steve and he said the FM is bonded as well and I can connect the FM exactly the same as my current MX wiring...he comes from Outback so he should know, but since the manual says otherwise I though I would run it thru you guys.

thanks

Cariboocoot · September 2013

Re: Should my system be F MPTT at low power??

There's very little difference between an MX and and FM. The negative terminals are "pass through"; all the "activity" takes place on the positive side. Oh, the FM apparently does not have a minimum Absorb time setting (at least I've never found it).

vtmaps · September 2013

Re: Should my system be F MPTT at low power??

Cariboocoot wrote: »

the FM apparently does not have a minimum Absorb time setting (at least I've never found it).

I think there is no minimum absorb time on the FM because there is THE absorb time. The MX would vary the absorb time depending bulk time, hence the need to be able to override it with a minimum absorb. I don't think the FM varies the absorb time depending on bulk time.

The FM absorb time is really a maximum time. The only thing that overrides it is end amps.

I've never had an MX, so what I've written here is based on what I remember reading in history books.

--vtMaps

Freewilley · September 2013

Re: Should my system be F MPTT at low power??

Playing with the MX to try and get it to awake and show mode....I went thru misc menu to the third screen where it shows REBULK and a voltage setting. My setting was 9.
Is that right??? I changed it to 11, but I wonder if it should be much higher?
The next setting on that page is END and my setting is 00.

And how do you make the MX wakeup so you can see the mode?

vtmaps · September 2013

Re: Should my system be F MPTT at low power??

Freewilley wrote: »

Playing with the MX to try and get it to awake and show mode....I went thru misc menu to the third screen where it shows REBULK and a voltage setting. My setting was 9.
Is that right??? I changed it to 11, but I wonder if it should be much higher?

The rebulk voltage tells the controller when to start a second bulk cycle during the day. In other words, if you reach float during the day and then discharge your batteries to the rebulk voltage, the controller will start a the second bulk cycle of the day.

When the controller wakes up in the morning, it will start the FIRST bulk cycle of the day regardless of the rebulk setting.

If you run your generator long enough in the morning and get the controller to read "F MPPT" when you shut off the generator, it means that the controller will not start a bulk cycle until the battery drops to the rebulk voltage.

--vtMaps

Cariboocoot · September 2013

Re: Should my system be F MPTT at low power??

9 is an extremely low setting for re-bulk. Crank it up over 12 at least.

Should my system be F MPTT at low power??

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