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RE: Your favorite way to charge tt batteries between trips
Solar.
You've already got it installed. I'd figure out a way to let it keep things charged, which it should do a fine job of.
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ewarnerusa
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06/16/13 11:05am |
Travel Trailers
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RE: Help with custom Morningstar Tristar PWM setup
Jim, my bad. I meant 0.1V but I can't recall at what amp. I see your point regarding how the drop will change. I could try disconnecting the sense wires. My wire length is about 5'.
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ewarnerusa
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06/06/13 09:32am |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
I Shouldn't have called it storage, I mean parked in the driveway not camping. I do try to use the inverter while parked at home for light duty power needs like recharging other small batteries.
I have voltage sense wires installed, the difference between the sense wires and at the CC is about 0.01V.
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ewarnerusa
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06/06/13 08:51am |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
I first witnessed the inverter fault while in storage, then it happened again during day 1 of a camping trip. Then, as you suspect, the batteries were discharged quite a bit by the next day and I was not at the setpoint (14.6V at that time with temp compensation still occurring at cool temps). No faulting observed in the discharged situation.
All the programming and investigating I've done has been since we got home from that trip and had things stored at home.
It is true that I may have made several charging program settings to work around a situation that is unlikely to occur during most of a camping trip.
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ewarnerusa
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06/06/13 06:51am |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
At what point in the day do you normally hit 14.25 volts?
Jim
Unknown. I haven't been home during the day to witness it and the batteries have pretty much been fully charged at all times anyway since we haven't camped in a few weeks.
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ewarnerusa
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06/06/13 06:23am |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
OP here.
I have my charging setpoint at 14.25V. HVD on the charge controller is 14.40V and it seems to work a bit faster at clamping down on the voltage spike. But I still get faults under the right circumstances. My inverter tripping at a low HVD is my only issue in my opinion. Claimed 15V but it seems to trip at around 14.8V. Everything else works like it is supposed to. My system may have been overcharging the batteries all their life so they may compromised as well.
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ewarnerusa
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06/05/13 08:05pm |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
...But not sure why inverter does not revert to normal when voltage drops below 15 instead of needing a reset. (IIRC the OP)
His 14.4 (if real and not like my 14.4 vs 14.6 nominal) is way too low below 15 to take care of this, so something else must still be going on there I guess.
I see my unloaded voltage is about 14.6, which is the high set point, so that means the loaded voltage is lower (natch!) as seen, so how come the OP's unloaded voltage goes over his set point---weird!!!???
Anyway, that's what I got for what its worth. Can't think of another way to test it out.
Thanks for doing your own study, it is great to read about different setups and behaviors and compare them to what I see with mine. Regarding why my inverter doesn't reset itself, I think it was pianotuna that suggested that only higher-end inverters auto-reset. Mine is certainly not high-end and it does not auto-reset, I have to cycle the power switch to clear the fault. That's why it doesn't automatically start working again once the battery voltage reading settles back down to below the inverter HVD. I wish it did.
As far as why my inverter faults at a voltage that appears to be a few tenths less than 15V, which is its claimed HVD? I don't have an explanation, but this is essentially the true source of my issues and I think the only piece of my equipment that isn't operating "normally". I suspect it is tied to the fact that my inverter is quite inexpensive for a 1500W PSW inverter and I don't expect it to fully deliver on all of its claimed specs. This isn't a name brand product, it is a direct from Asia unit from an ebay seller with a pretty Asian lady modeling the inverter in the auction listing. I believe she was holding the inverter in one hand and a hair drier in the other.
Regarding why my unloaded voltage goes over my setpoint, I think it is normal behavior based on what you observe with your tests with nearly charged batteries and higher resistance. I experience my inverter fault when it is loaded (lightly) but charging is still able to occur right at the max voltage setpoint. Then the load is removed and I experience the voltage spike. My CC does react to clamp the voltage back down to the setpoint, it just takes it up to a second. Not fast enough for my inverter which shuts down on HVD as it sees the spike. Why can't my cheap inverter have an associated cheap/slow HVD response instead of fast and at less-than-advertised??!! Then I bet I would not be having any issues.
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ewarnerusa
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06/05/13 12:20pm |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
This has little to do with the inverter issue. It is about water usage.
The low (10%?) duty cycle the battery is pretty much charged and can go to float in a short time (5 minutes?).
The idea is this will be reached quickly while in storage and you will be in float most of the day.
While in use and the battery is low on charge every morning it will take a long time to hit the 10% duty cycle and in effect you are in absorption most of the day.
I think the one hour at 30% in storage will have you at absorption voltage for much longer than needed causing the excess water use....
Thank you for this, it has really helped me grasp what the setpoints mean and what modifying up or down can do.
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ewarnerusa
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06/04/13 02:23pm |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
The lower absorption voltage will conserve water. 2 batteries, 2 yrs, 1 gallon seems like a lot of water. Another reason to cut absorption time to a minimum (5 to 30 minutes) while keeping the modulation % low (20% - 10%). In storage this will be reached quickly, while in use the time will be extended significantly before you move to float.
Also consider going 90 days and just 60 minutes on the equalize. I would also consider 14.8 - 15.0 volts range as I believe 15.3 is at the very max the fridge is supposed to tolerate.
Mine is set 14.9 and just manual operation.
Thanks for the advice. I'm a little confused regarding "Another reason to cut absorption time to a minimum (5 to 30 minutes) while keeping the modulation % low (20% - 10%)." I believe I've read that the MPPT programming is not identical to the PWM one. For instance, I cannot simply enter an absorption time or duty cycle. I can only set an absorption setpoint and tell it to transfer to float when the system is less than a certain duty cycle threshold for a certain length of time. Default is 1 hour at less than 30% duty cycle. I can change the time and the duty cycle threshold, but it is not equivalent to setting an absorption time or specific fixed duty cycle.
Also, since I've decided to use a HVD on the controller at 14.4V, I think this means I basically can't do an equalization at anything above that voltage level. So I'll have to set up a new controller parameter file and reprogram things when I want to do the equalization. I have submitted a tech support request to Morningstar to confirm/refute my theory that the equalization setpoint cannot be higher than the HVD setpoint. KJINTF has chimed in and said that this would be the case as well.
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ewarnerusa
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06/04/13 01:54pm |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
I gotta learn to click more carefully. Double post, sorry.
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ewarnerusa
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06/04/13 01:29pm |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
The controller does not control current. It doesn't care what the current is.
The charge controller (CC) controls voltage. But I don't believe the CC regulates voltage at 14.40V (as you think) just prior to the voltage surge. The CC is in boost mode, which means the charging battery current will cause battery voltage to rise until max boost voltage is achieved (14.8V). With the inverter load, there's more or less an equilibrium at 14.4V, preventing battery voltage to rise. As your first video shows, this equilibrium isn't maintained. All of a sudden all hell breaks loose and we see the battery surge to 14.8V. The CC does what it's supposed to do, that is charge to 14.8V and then drop to a lower voltage (absorption mode).
I've asked you to do a simple test that will tell us whether the inverter turning off is the cause or the effect of the current surge. That would be the number one objective. Only through further testing will we understand how to fix your problem.
Sal
I missed the bottom of page 11 posts, sorry.
Sal, the situation is as smkettner explains in the post following your's above. There is a single setpoint for bulk and adbsorption charging and it is currently set at 14.40V. At the start of my troubleshooting it was at 14.60V and I have been trimming down ever since.
It may not have been clear in the first video clip, but what is happening to cause the voltage spike is just as you stated in an earlier post.
....Spikes are usually generated when inductive loads are turned off....
I think you are under the impression that the voltage rise/spike is occurring at random. It is not, it occurs only when I remove a load from the inverter and I think this fits your definition of a "spike." The case of the video clips, I am unplugging my laptop AC charging cord while I'm using to power the laptop.
My controller says the controlling current IS what it does during absorption. Isn't it trimming the current (duty cycle?) so that battery voltage remains at the absorption setpoint? Quote from the Morningstar Tristar manual
"2. PWM Absorption: When the battery reaches the regulation voltage, the
PWM begins to hold the voltage constant. This is to avoid over-heating
and over-gassing the battery. The current will taper down to safe levels as
the battery becomes more fully charged. The green LED will blink once
per second."
Also from Morningstar: Why PWM? document:
"When in PWM regulation, the
current from the solar array tapers according to the battery’s
condition and recharging needs."
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ewarnerusa
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06/04/13 01:21pm |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
I don't think there is a problem with any of the equipment. I think the only issue I'm dealing with is an inverter with a low high voltage disconnect. I didn't point it out in the 2nd video clip, but the small inverter did not fault in high voltage when the large one did and it's high voltage range is also 15V.
We have identified some other weak points in my system like batteries may be going and my controller takes up to a second to put a clamp on a sudden voltage rise. But to me it seems that all equipment works fine.
A new/different large inverter would probably cure my issues. But right now I'm not interested in buying a new one and rather using the programmable controller to put a bandaid on the situation.
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ewarnerusa
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06/04/13 12:55pm |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
What time of day are you hitting 14.2v and 14.4? Do you know how many amp hours you are taking out and putting back per day? Toward the end of the day what mode it the solar controller in and at what voltage?
Jim
Unfortunately I don't have good info here. When in storage at home, it gets up to the setpoint by mid morning. But the batteries are pretty much topped off all the time anyway as it sits unused. While camping, I don't hit the setpoint until much later in the day if at all. I have no idea of the amp hours we use.
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ewarnerusa
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06/04/13 07:16am |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
Does the 14.4 HVD act fast enough?
I could see going 14.2 B/A & 14.3 HVD if needed.
It's better, but I can still force it. I don't know why I am reluctant to drop the voltage further, but it does seem like that is the going to be the way to solve this. Should I be concerned about the batteries not getting charged enough?
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ewarnerusa
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06/04/13 06:27am |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
I have walked through the MS View software several times and have suggested adjustments. New inverter is last resort.
Thank you, I believe I have implemented them. 14.40 HVD and 14.35V bulk/absorption set point.
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ewarnerusa
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06/03/13 05:16pm |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
Something has to cause the voltage surge. I'm fairly certain the surge is from a lot more current going into the battery. Where did this extra current come from? Are there other loads in your setup that disconnect?
You say the inverter shuts down when voltage approaches 14.8V. The video doesn't indicate the exact voltage when it quits. Why not connect a light to the inverter to get a better understanding when it quits. I think the light will go out just when the surge begins.
Sal
I am in agreement. Maybe my understanding of the current flow is incorrect, I certainly don't claim to be an expert! I just know enough to maybe get me in trouble... But in my mind what is happening is I have solar current going into the batteries and during the inverter load condition I have current going out of the batteries to the inverter to run that load. The system is in sort of an equilibrium with the controller deciding how much solar current to allow into the battery to allow for the inverter to "pull" the current it needs from the batteries and to maintain the battery voltage right at 14.40V by "pushing" in the right amount of solar current. When the inverter load gets removed, for a brief moment the controller is still pushing solar current into the battery at the same rate even though there is no longer current flowing out of the battery to run the inverter. So we get a brief period of voltage rise on the battery from the solar current pushing in without a corresponding draw from the inverter. The controller does do what it is supposed to and cuts the current so that the voltage falls back to 14.40V, but in the meantime the inverter has tripped on high voltage disconnect due to sudden rise that occurred. There is nothing peculiar about this type of rise, it is just normal battery charging behavior. But the problem is I have this finicky inverter that faults out at around 14.8V.
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ewarnerusa
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06/03/13 02:16pm |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
What we're seeing is the battery voltage rapidly increasing from about 14.4V to 14.8V. It isn't a spike. Spikes are usually generated when inductive loads are turned off. In our case, the battery is not capable of taking the charge, resulting in rapid rise in voltage, or voltage surge. Given the battery capacity, there's too much solar.
You can verify this assessment by disconnecting 2 of the panels. Battery voltage will now rise at a slower rate.
It seems like the big inverter looses it at 14.4V, not at 14.8V. You can verify this by connecting an ac light to inverter. When does the light turn off, at 14.4V or at 14.8V?
Sal...
As shown in the first video clip, the big inverter runs fine at 14.4V and loses it when the voltage rise approaches 14.8V. It is only during the rapid voltage rise that happens when the solar charging status is at its max voltage (14.4V in this case) that the inverter faults. The same rapid voltage rise occurs when I'm not already at the max charging voltage, but that is no problem because all voltage movement occurs well below the inverter's high voltage disconnect. I only have 2 panels and I can't easily switch one off. But your description of the issue occurring sounds right on the money based on what I observe.
The big inverter seems to do fine as clouds come and go (affecting the available charging current). It is only during the load drop situation (or sometimes just flipping the inverter on) when I'm charging right at 14.4V that I get the high voltage disconnect from the inverter.
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ewarnerusa
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06/02/13 11:19am |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
Does the inverter have a 12v switch? Try it and look for the spike one more time.
Otherwise I suppose Sal is right. Do you have a good battery to temporarily put in parallel with the others for a final check.
Might be worth a call to Morningstar.
I'm not sure what you mean by 12V switch? It has an on/off switch. It can also cause a spike that trips itself when I flip it on while the solar is charging at 14.40. The resistance in the battery thing makes sense to me. Batteries easily got us through our one night of camping so far with the furnace cranked and plenty of TV time for the kids. I could see them being compromised, but they don't seem "shot".
AFter making the videos, I switched my charging program over to using the Morningstar's HVD at 14.40V. I set my bulk/absorption setpoint at 14.35V. I do think it clamps it down faster versus, but I can force a spike at the right conditions to fault the inverter. But it seemed better than before. I can set the MSVIEW to show me when it cuts it at high voltage and it definitely actively cuts it off.
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ewarnerusa
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06/01/13 10:24pm |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
Nice demos! I still think your battery is shot. How much solar do you have? What happens when voltage gets to 14.7 or 14.8V? Does the controller immediately drop down to a lower voltage? The fact that voltage can quickly change indicates the battery has high resistance.
I'm not sure what's going on in the first video. Why is the voltage all of a sudden taking off? Did the inverter disconnect the load first? Or is there an increase in charging current?
The second video makes more sense. The inverter load is removed and the voltage takes off.
Looks like the software displays charging current. Can you connect something like two 20W loads to the inverter (perhaps two 20W lights)? Toggle one of the loads on/off and measure battery voltage. The charging current should remain constant. The battery voltage should jump with each toggle. We should be able to determine the battery resistance with this test.
Sal
I have 280 watts solar with 12V panels. The exact thing is happening in the first clip as the second clip, the laptop is just being charged via the large inverter instead of the smaller one. It is just as you described, voltage spike from removing the load from the inverter. I guess I was zoomed in to far to see that. The current stays constant during the spikes from what I remember.
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ewarnerusa
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06/01/13 10:12pm |
Tech Issues
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RE: Help with custom Morningstar Tristar PWM setup
A gallon of water? So the plates were substantially exposed? The capacity of the batteries is probably greatly reduced, exaggerating the spike as Salvo mentioned.
Jim
I could barely see the tops of the plates. I was surprised almost a gallon fit in there actually.
I guess I may have an excuse to upgrade these fairly new batteries!
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ewarnerusa
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06/01/13 10:53am |
Tech Issues
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