Hello. Can I get some help setting up my Morningstar Tristar 45 PWM controller with custom setpoints? I have been using it at the stock 14.6V absorption voltage profile with temperature compensation. I'm using the remote temperature sensor. Works great, but my inverter shuts down on high voltage alarm at around 14.8-14.9 V. So I want to set up my controller with a custom algorithm that basically mimics the stock 14.6V profile but doesn't go over 14.6V when temperature compensating. My plan for accomplishing this is to setup the minimum temperature for compensation at 25 degree C (77 degrees F). I believe that this means the controller will not bump up the voltage past 14.6V when the temp is below 25 degrees C, but it will dial it back as the ambient temp rises above that temp. I realize that this means my batteries will not get the advantage of temp compensation when it is below 25 degree C (77 degree F), but I'm fine with that. Having the inverter work when it is cool but sunny out is more important to me. I'm fine with it doing an equalization every once in awhile at a higher voltage. If someone has a better way of doing this, please straighten me out.So my concern is I don't know what to enter in all of custom options to make it mimic the stock 14.6V profile. Some stuff is easy:Absorption V = 14.6Float V = 13.4Equalization V = 15.3 for 3 hours, 5 hours maxMy questions are what is:"Transition to Float when duty cycle is ____ % or less" 30? For how long?"Exit Float when duty cycle is 100%" For how long?Low battery trip voltage and timer?Thanks.EdEDIT: I originally thought I was using the 14.8V stock profile, but I had been using the 14.6V one. I want to try to get a little higher than 14.6V, but not high enough to trip the high voltage shut down on my inverter.

EdWhy not keep it simple and try the HVD option?The Free MSVIEW Manual defines the settings

The manual is embedded in the MSVIEW aplication - use the help functionFrom the manual Transition to Float Duty CycleSpecify a duty cycle value between 0 and 100%. Duty cycle is roughly the percent of charge current that is being accepted by the battery. When the battery first reaches the Absorption setpoint, the duty cycle will be large (90% or more). As the battery comes to full charge at the Absorption setpoint, the duty cycle will decrease. The rate at which the duty cycle decreases depends on the amount of charging current, the size of the battery bank, the age of the batteries, and the amount of load current. Each of these factors can drastically affect the duty cycle value.The recommended value is 30% but this is a very system-dependent adjustment.High duty cycle setpoint values (90% or more) will begin the float timer almost as soon as battery reaches the Absorption voltage. While this makes for predictable float transition behavior, the battery may not be fully charged before dropping into float.Note: Duty Cycle adjustment is supported in TriStar firmware v1.04.08 or later._____________________I expect you have upgraded your firmware Also note the comment about being very system dependent They agree with what I have been saying the dip switches do not offer enough flexibility. You have a high end controller that can easily be customised to your needs.

KJINTF wrote:EdWhy not keep is simple and try the HVD option?...The Free MSVIEW Manual defines the settingsI've dug deeper into the MSVIEW Help tool and found better definitions and explanations than had before, thanks. The HVD options seems less simple in my opinion. Wouldn't that cut off the solar array anytime the voltage was above that setpoint? I would rather have the array charging at 14.8V than doing nothing at all. Wouldn't that also prevent the equalization from happening since that voltage setpoint would be greater than 14.8V?My current "solution" is basically doing just that, I trip the breaker I have between the array and the controller so that I'm not charging the batteries at all so I can keep the voltage below 14.9V and the inverter will stay on. It bothers me to be dumping my solar when it could be used for charging, especially while I'm using the inverter at the same time!

Just a suggestion .... Yes it will isolate the controller anytime the set point is acheived. Might want to look into an inverter that can handle 15.5 Vdc or higher... The problem goes away

KJINTF wrote:Just a suggestion .... Yes it will isolate the controller anytime the set point is acheived. Might want to look into an inverter that can handle 15.5 Vdc or higher... The problem goes awayThanks for the help, KJINTF. I think tweaking this sweet controller to clamp the charging voltage at 14.8V will be cheaper than buying a different big PSW inverter! I know you have mentioned a few times how I'll want to use custom settings vs the standard algorithms, and now I am definitely finding a need to.

Help with custom Morningstar Tristar PWM setup

161 Replies

ewarnerusa
Nomad
Jul 29, 2013
Update 7/29/13
After a couple of trips out I decided that my stock batteries were not performing adequately. A single day of normal use starting from full would knock them down to under 12V by bedtime and that was much worse than last summer. So I swapped them out for a pair of Costco 6V golf cart batteries. I think these have me at 220 Ah and I can definitely tell that I have a lot more capacity now. Now after a solid day's use starting from full still has me in the 12.3-12.4V range, and after a night of furnace use I'm still in the low 12's in the morning.

Still have the same inverter and while I haven't done the troubleshooting to see if these new batteries experience the same voltage spike, the inverter still faults out at voltages approaching 15V.

Based on the rule of thumb on these forums of charging Trojan 6V GC's at 14.8V, I want to try and hit that level on these Costco 6V GC's regularly without impacting my inverter usage too much. My charging profile is still 14.25V for the bulk/absorption setpoint, switching to float when duty cycle is <15% for 10 min (same profile as before). No temp compensation at below 75 degrees F. But now I'm using the auto-equalize feature to do 14.9V for one hour every 5 days (also bumped up the HVD to accommodate this). That way I know that at least weekly it should hit that higher voltage charging level (assuming the batteries are "full" with regards to the 14.25V charging profile as it sits parked at home), but it shouldn't be so often that it impacts a camping weeking too much. Plus it is easy to cancel the equalization if needed by hitting the reset button on the controller. I can also initiate the equalization via the reset button which I have done the day before setting off a couple times now, just for piece of mind.
HiTech
Explorer
Jun 06, 2013
Knowing the voltage drop between batteries and converter before the shut off and then what it is at inverter at shut off can give you an idea how much the sense wire is contributing to the voltage jump the inverter sees.

But even just disconnecting the sense function and then seeing if the problem goes away might be Interesting. If it does, seeing what higher voltage values you can go back to without triggering an inverter cutout would be as well.

Sense wires don't do anything for low current top charge anyway, though voltage sensing helps with the higher current charging (once the voltage rises high enough that voltage even matters, but you can also program to compensate for that).

Jim
ewarnerusa
Nomad
Jun 06, 2013
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'.
HiTech
Explorer
Jun 06, 2013
Ewarnerusa is it easy to see if removing the sense wire temporarily will reduce alarming in the inverter? If it eliminates it entirely, it might even let you sneak the set points up a bit. I believe having voltage correction will amplify the effect of a voltage jump caused by a reduced load, due to the change in voltage drop on your main charge controller wires, before the load drop and after.

Any rough estimate on how long those 4 gauge charge controller wires are? .01v at what current flowing? The voltage difference from controller to battery will approach 0 as current drops to 0, but be larger with more current flow. This is the effect i am talking about that can exagerate the voltage jumping when using a sense wire and a controller that is a little slow on the draw with voltage correction. You posted a .1v drop before. Was that with more current flowing maybe?

Jim
time2roll
Nomad
Jun 06, 2013
Mine is also a short feed and I skipped the sense wires just to reduce clutter on the batteries.
ewarnerusa
Nomad
Jun 06, 2013
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.
HiTech
Explorer
Jun 06, 2013
Good suggestion. "In storage" is not a clear term. better might be when not camping, but using the unit lightly. In other words, the situation OP has outlined as the time when he gets his faults, other than day one of camping. I use my camper in the storage lot so I think of anything I do while out there as "in storage". E.g. Full to the top batteries, and light usage for a short time, vs actually camping.

Jim
pianotuna
Nomad III
Jun 06, 2013
Hi,

With respect, the OP is hardly likely to have the inverter fault when his RV is in storage.

I suggested the voltage sense wire be added or removed as a test of the system.
HiTech
Explorer
Jun 06, 2013
ewarnerusa wrote:
I'm basically wired up like the diagram. 4 gauge from controller to batteries (parallel 12V) with about 5' wire run. Separate 0 gauge wiring for the inverter, also about a 5' run. Both wire runs terminate right on the battery posts. I am using voltage sense wires as well. I have about a 0.1V drop between the controller and batteries which the controller compensates for.

Someone else suggested this, but you might try disconnecting the voltage sense line for storage. The reason is we know the charge controller is a little slow responding. So if you start with an extra .1v of charge to compensate for line losses, then reduce the current the inverter is drawing, the current the system is drawing from the charger will drop, reducing the correct compensation to, say .01 v. But with the lag, the controller will keep the .1v compensation going for a couple of seconds, making the natural voltage overshoot of a charged battery even worse.

If this helps, larger or shorter cables from the charge controller to the battery could help.

Also you could cheat and just put a switch in the voltage sense line, off for when using the system when fully charged in storage and on for camping.

Jim
HiTech
Explorer
Jun 06, 2013
I wonder if the changes you have already made would pretty much eliminate the issue with camping, and a different set of settings with just little more voltage reduction would handle it in storage situations as well?

I bet you could test a typical camping scenario with your normal camping loads (left on for about the same time) and see if you hit any problems. You may already have your day one issue put to bed.

Jim

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Help with custom Morningstar Tristar PWM setup

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