Using morningstar prostar 30 controllers in ways for which they were never intended.

My first non traditional application and use of a Morningstar prostar 30 controller is using it as a charge controller on my solar inverter hybrid generator. The solar panels for my solar hybrid generator have not arrived yet (which means its still just an inverter hybrid generator). The Morningstar has arrived, I installed it and it appears to be working as I intended. Which is powering it with a 240VAC input, 21.5 volt DC output battery charging power supply of my own making.
I made this 240 volt AC charger so it would mimic the output of a "12 volt solar panel" as closely as possible with 21 to 23 OCV and 18 to 16 volts working load.
I have not tried using this setup to charge a very low battery yet.
The soon to be solar inverter hybrid generator has had an AGM battery and 1000w Kisae pure sine inverter installed for a year or 2 now, so I know that all works great, but have to charge the battery with an external charger when it gets low.
Since the Morningstar does not have an AGM setting I placed the selector on "sealed".

Is "sealed" the best option for AGM?

Also when this machine is not in use I pop the main circuit breaker, cutting off battery power to the generator, inverter and the battery charge/discharge terminals to the Morningstar. But I leave the voltage "sensing" wires connected. The sensitive amp meter setting on my fluke 87 multi meter popped its fuse so I could not check if there was any tiny amp draw.

If I am going to let it sit for a few months should I also disconnect the Morningstar's sense wires too?

The next application I am considering is using a Morningstar prostar 30 to charge my LiFePO4 batteries, a 4 cell series bank of AMP20 cells using no more than a few hundred watts of solar.

I am thinking the "sealed" setting might be best for this too?
Has any one tried this?

I did not see it any where in the instruction manual and wondered if the Morningstar acts as a charge limiter by any chance? Would I be able to connect it to say a running vehicle electrical system to steal a charge or would that just over load the Morningstar and cause it to shutdown?

My 60 amp hour LiFePO4 battery gets very hungry when it runs low and likes to drain every extra amp of power a vehicle alternator can produce, causing the belt to squeal and the alternator to get hot. I would like to limit the charge with something other than a charge limiting resistor, unless I have to.
The LiFePO4 battery I made will draw 40 to 60 amps easy off a vehicle alternator and the vehicle alternators don't seem to like this very much.

Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

Comments

  • PNjunctionPNjunction Solar Expert Posts: 762 ✭✭✭
    oil pan 4 wrote: »
    Is "sealed" the best option for AGM?

    Depends on the model, but in your case yes. One should always go by the actual absorb voltage spec, and not just the canned settings or silkscreens. For instance, the SunSaver models have only sealed and flooded. In this model, "sealed" is about 14.1v, which is ok for gel, but will UNDERcharge a "sealed" agm. Thus, with that model, you choose flooded as a better choice in cyclic duties.

    If you KNOW what you are doing, and using very high ends agm's, you could get away with setting flooded on the prostar 30, BUT you had better use the remote temperature compensation probe.

    For now, your choice is ok.

    Remember to always connect the battery to the controller first, and to the panels last.
    The next application I am considering is using a Morningstar prostar 30 to charge my LiFePO4 batteries, a 4 cell series bank of AMP20 cells using no more than a few hundred watts of solar. I am thinking the "sealed" setting might be best for this too? Has any one tried this?

    STOP RIGHT HERE.

    Can you use it? Yes, but you had BETTER know what you are doing. It is not made for lifepo4, but you can put it into operation safely. That means using the GEL VOLTAGE setting of 14.0v. Obviously, this is not a gel, but we are going by voltage specs as a workaround. The reason for only 14v gel is that there is no reason to take lifepo4 to 100% SOC charge, and in your hacked together batteries, it is likely they are unbalanced. Setting it low for 14v allows a little wiggle-room.

    You know that you have to DISABLE any sort of temp-comp right? And with this controllers built-in ambient temp-comp transistor peeking through the front, that means you have to DESTROY or cut it out, relying on the controller to default to no temp comp like my 15a Prostar. Not all controllers will like having their temp-comp circuitry cut out and still function.
    My 60 amp hour LiFePO4 battery gets very hungry when it runs low and likes to drain every extra amp of power a vehicle alternator can produce, causing the belt to squeal and the alternator to get hot.

    Yeah, that happens because of the low internal resistance, the alternator just maxes out forever etc. Many marine guys have found out this situation too. Not just with lifepo4, but in some cases with very low IR "pure-lead" lead batteries as well.
    I would like to limit the charge with something other than a charge limiting resistor, unless I have to.

    Instead of a hack, how about a decent charger - again something that can be shoehorned into use as long as you use the right voltages. In your case, either a Samlex SEC1215ul (15a) or SEC1230ul(30a) charger. That keeps the cells at .5c or below during charge, and also set to GEL (14v) is a reasonably sane stopping point, especially for any battery hacked together with cells of unknown origin.

    Lifepo4 has been discussed elsewhere here, but I warn you to do a LOT MORE RESEARCH on the subject, and not just from "e-bike" or other forums that have no qualms about duct-taping unsafe crap/used/reject cells together. I'm personally using new GBS prismatics, although Winston or CALB are the other major players. No duct-tape crap on my bench.

    I was hesitant to discuss the morningstar for use with lifepo4, since it is not really made for it, but have a feeling you might plow ahead anyway and at least give you some guidelines for proper use - especially for homebrew stuff.

    I sure hope you did an initial top-balance on those cells.

    Maybe any sort of followup should be done in the new battery tech subforum, as lifepo4 threads and discussions always turn ugly unfortunately.
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Oh no I don't have to use a Morningstar controller, I just read on here pretty recently that there still were no dedicated LiFePO4 charge controllers on the market.
    The cells I bought were all new A123 cells made in korea, all with the same lot number. If they were rejects a least they were new and consistent rejects.
    I have a high budget for these things, I don't have to buy the cheapest most rejected unwanted mismatched junk like people on the ebike and scooter forums.
    I already know my LiFePO4 battery works, its been starting my diesel for about 2.5 years now.
    The LiFePO4 batteries have already lasted far longer than any lead acid batteries I ever had in my diesel between 2006 and 2012. Just about every year I was replacing a battery, some times both of them. I was not using the cheapest economy batteries.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • PNjunctionPNjunction Solar Expert Posts: 762 ✭✭✭
    oil pan 4 wrote: »
    Oh no I don't have to use a Morningstar controller, I just read on here pretty recently that there still were no dedicated LiFePO4 charge controllers on the market.

    You may want to look at Genasun for lifepo4 specific solar charge controllers. I've seen 'em at batteryspace and elsewhere.
    The cells I bought were all new A123 cells made in korea, all with the same lot number. If they were rejects a least they were new and consistent rejects.

    The new cells for the last few years have been made in the US in Livonia. You have to be careful with the Korean cells if you did not get them from an authorized dealer, as some early models were experimental, designed for differing customer needs, and can be generally hard to track down at this point for who/what they were really intended for. You may want to check with WB9K over on Endless-Sphere. Certainly I hope you don't have any missing the proper amount of kapton-tape, cut off cell tabs, missing zipper-fuses, and the like.

    Basically you got several year old new-old-stock or worse, so be careful.

    Personally, I'd ditch those questionable Korean cells, and start fresh from a REAL authorized A123 dealer. They ARE great cells, no question there. For our solar storage needs, perhaps a bit too much, but certainly they can be used.
    I have a high budget for these things, I don't have to buy the cheapest most rejected unwanted mismatched junk like people on the ebike and scooter forums.

    Ok, cool! At least do a sanity top-balance with a single-cell 3.7v charger. Or grab hold of an iCharger 306B, maybe a Cellpro PL8 and power supply for them. While a simple 4S / 12v battery setup like we are using doesn't need obsessive top-balance or bleeder boards (if used within reason), it is still wise to initially do the single-cell or totally automated hobby-charger with balance leads to a sanity check upon receipt or once in awhile.
    I already know my LiFePO4 battery works, its been starting my diesel for about 2.5 years now.
    The LiFePO4 batteries have already lasted far longer than any lead acid batteries I ever had in my diesel between 2006 and 2012. Just about every year I was replacing a battery, some times both of them. I was not using the cheapest economy batteries.

    Yep - they do great when taken care of. A123's are certainly made for SLI duties with their high-C burst ratings.

    Here though, from a solar storage standpoint, we don't need A123 like high-rate (10C and so forth) capabilities. The standard large-prismatic from GBS, Winston, CALB with only to 3-5C or so bursts are far greater than we'll EVER need! Not to mention, they are already pre-made for you! You can even get the cells fully wired with bussbars, compression panels and the like.

    So yes, I'm with you - lifepo4 has it's place if you can justify needing / paying for the capabilities at the outset.

    In reality, one can go far with lead with proper maintenance - or if you need extra oomph without wanting to pay for lifepo4, then a "pure-lead" agm, which is just under the rung for energy density and performance than lifepo4, may be worth a look. Like all things, they need proper maintenance to get the most from them.

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Next time I would much rather just buy already assembled batteries. White knuckle assembly of fully charged cells is not my idea of fun.
    The cells are held together in compression.
    The manufacture date on the cells was early 2012, I built the battery late 2012. They are a few years old now. I didn't get cells with cut off tabs, I saw no good way to connect them with out tabs and not have them burn up under short duration 20C use.
    When I first got them I charged them up to 3.7 or 3.6 volts on each cell with a home made adjustable low voltage power supply.
    I wanted to expand the roll of this battery or one like from just starting the diesel engine to also running more accessories like in an RV application but only intermittently and replenish the batteries with solar if the engine doesn't get started and ran for a while.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Hey that Samlex SEC-1230UL charger was pretty much exactly what I was looking for to put on my inverter generator for battery charging.
    Only problem I see with the samlex is its $200 and it doesn't look very water or weather resistant.
    If there was no way for me to have built my own 240VAC powered battery charger I would have totally gone with that 30 amp samlex charger.
    I am glad I found a use for all the junk that I built my 240VAC powered charger out of and building it saved around $150.

    When I was talking about charge limiting the LiFePO4 I meant charging with the vehicles alternator.
    On a piece of equipment that used NiCd aircraft batteries for engine starting we used a charge limiting resistor to limit the charge rate to 20 amps. I have one or 2 of these resistors in my junk collection. They were being pulled and tossed because the NiCd were replaced with optima batteries which can charge at 40 amps normally and up to 60 amps for short duration.

    I am not worried about charging the LiFePO4 batteries too fast when using solar or external charger. I was only ever planning to use a max of 15 to 20 amps of solar capacity, same with any external charger.

    The piece of gear that I built my own battery charging rig for was my inverter generator hybrid which will only ever use an AGM.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    I think the Genasun from batteryspace will do the trick. There is a 10 amp Genasun for $180 and another 60 amp controller made by some one else for $460.
    A little more than 10 amps would be nice but $460 for a 60 amp one that I will never be able to fully utilize is too much.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • PNjunctionPNjunction Solar Expert Posts: 762 ✭✭✭
    oil pan 4 wrote: »
    Hey that Samlex SEC-1230UL charger was pretty much exactly what I was looking for to put on my inverter generator for battery charging.

    Yep - I use a Samlex SEC-1215UL set for GEL because it is accurate to 14.0v, which is where I like to end up at with my 4S GBS bank. Definitely not outdoor use!
    I am not worried about charging the LiFePO4 batteries too fast when using solar or external charger. I was only ever planning to use a max of 15 to 20 amps of solar capacity, same with any external charger.

    While you are using A123 which can handle super-high charge current, with the typical large primatics from GBS, CALB or Winston, 0.5C is the recommended max, although you CAN exceed that if you are on top of things. Certainly no more than 3C - 5C for short bursts.
    The piece of gear that I built my own battery charging rig for was my inverter generator hybrid which will only ever use an AGM.

    I like AGM too, provided you actually don't UNDERcharge them, which is easy to do with solar. Pure-leads like Optima, Odyssey/Enersys and so forth. I'm a big fan of very low IR. It was my gateway battery chemistry to lifepo4. :)

    The Genasun's are very expensive, but consider that they are designed for marine use, and are very hard core internally. The default for their lifepo4 series is at 14.2v, and if you wanted a custom voltage like I would at 14.0v instead, that would be a $50 custom addition to a special order.

    Of course there is also MasterVolt but we are starting to get into the stratosphere.

    You sound like you are on top of things though, and a Morningstar with the temp-comp sensor removed can be shoehorned into use with the right voltage adjustments. Not all morningstars will still function with that removed, so check to see where it specifically mentions in the addendum that if the sensor fails, it will still work, just sans any temp comp. Probably immediately voiding the warranty obviously.

  • PNjunctionPNjunction Solar Expert Posts: 762 ✭✭✭
    LOW VOLTAGE DISCONNECT

    Forgot to ask if you are implementing this at all.

    Typically at our solar discharge rate of about 0.1 to maybe 0.2C max (because we properly size our banks to last 8-12 hours or more like days!) the 80% DOD point for a 4S /12v bank is roughly 12.8v on a pack level, which is about 3.2v individually. Some may take them down to 12.7v. We can go lower, but that costs us cycle life, just like any other battery chemistry suffers with deeper DOD's.

    One way I incorporate it on my simplistic level is with a Powerwerx ITS-12 LVD. Designed for lead, it has a "hard" lvd of about 10.7v, BUT it conveniently has "timed" timeouts which start at 12.8v !! GREAT. The timeout is about 2 minutes before shutdown and only 5ma idle current draw. (150ma in use) There are many other settings you can choose.

    Again, the Powerwerx is designed for lead, but the higher voltage timeouts serve adequately for my lifepo4 stuff. Since my GBS cells are good quality, at the 80% DOD I don't have any *major* imbalance issues - which is a subject that can require a board to purchase an entirely new server just to contain. :)
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    I followed your recommendation and picked up the 10 amp genastar for charging my LiFePO4 battery. The deal is done, its in the mail on its way.
    I do have 20 watts of solar panels on there now since 2011, so if the genastar comes in tomorrow I could install it and use it for battery charging now.
    MPPT for something with solar panels that just passively sit flat on top of a vehicle just seems like it will work a lot better all around than PWM.

    I think what I will do is get two 80 watt "12 volt" panels, this is assuming I will never get more than 140 watts out of 160 watts worth of panels since they will just be sitting flat on the top of the vehicle.

    As of now I have nothing as far as low voltage disconnect for LiFePO4.
    But would really like to have something.
    I would split the loads 3 ways. The inverter would use its factory 10.5 shut down on the Xantrax so the inverter doesn't cut out on a start up load. So it will always have the ability to kill the battery. I plan on the inverter only being used occasionally and when it is used it will only be used intermittently.
    Second the starting system, it will always be wired to go when needed, that draws 100 amps for up to 12 seconds for glow plugs, 100 amps for up to 30 seconds for the intake heater, then 350 amps for 4 seconds for the starter. Depending on how warm the engine is, I may just use the starter only to fire the engine.
    The third group of loads would be everything else, I would not mind being able to automatically cut power to pretty much everything if battery volts get down to 12.8 or 12.7 volts.
    Saving the LiFePO4 with a discharge controller could save me hundreds of dollars and yes I have been playing with fire the last 2 and a half years. Somehow I have not accidently killed the batteries.

    At some point when LiFePO4 pure sine inverters with built in proper auto shut down for LiFePO4 (some set amount of time the input voltage goes below 12.7 volts) become popular I would get one of these. Till then I will just be real careful to not kill the battery with the inverter.

    My generator hybrid with AGM will use the built in 10.5v shut down on the Kisae inverter to keep the inverter from totally killing the battery. Then any other DC loads such as lights, are ran through the Morningstar "load" terminals which shut off at 10.5 volts.
    The only thing that can kill the battery dead is the generator electric start.
    I think the generator hybrid fairly well protected.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • BB.BB. Super Moderators, Administrators Posts: 32,212 admin
    Remember that a lead acid battery running at 10.5 volts is effectively dead (if not supplying large surge currents at that time). I would suggest using 11.5 volts as your cutoff voltage (ideally with some sort of time delay of seconds to a few minutes to allow for surge current).

    10.5 volts is really to protect the inverter and wiring (inverters are constant power devices P=V*I -- As DC voltage falls, DC current must rise to keep the AC loads running).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PNjunctionPNjunction Solar Expert Posts: 762 ✭✭✭
    Definitely BB for lead acid.  I hate it when I see guys using the inverter cutoff as the cue to stop, when it should have been done well beforehand.

    Lifepo4 with an SLI application may not have a problem with a very shallow dip to 10.5, especially with the A123 cells.  But your advice is well taken - when using lifepo4 for continuous draw applications, then stopping at 12.8 or just below near 80% DOD is a wise idea.

    Under a slow draw condition, going down to 10.5v would be really taxing on the lifepo4, even though many new users see 2.5v/cell as the minimum on the spec sheets.  3.0v/cell is the practical minimum when doing slow "sub-c" current draw.  Going deeper to 2.5v is going to cost you.

    So I'm glad you brought that up as the situation is kind of the same, even though the chemistry and absolute voltages are a bit different.

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭

    With AGM and other lead acid I consider 11 volts at very low C rate of draw past time for a charge.

    The AGM battery is connected to a generator with solar panels and a big battery charger, I really don't have any reason or excuse to run the battery all the way down.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    I got the genasun in, it is a very nice piece.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭

    Lets just say the 10 amp genasun turns out to not be big enough....

    I wont know this for a while, first I will need to get all the solar panels up to see if I even have room for more than 10 amps worth, then I will have to wait until summer to see how much they can really produce.

    I was thinking that if I have to much solar capacity maybe I could use a 15 amp Morningstar sunsaver tristar set up for gel (14v) or AGM (14.3v), no equalize, no hooking anything up to the load output because the highest voltage the load shut off will activate is at 11.5 which makes for a really dead or damaged LiFePO4. Then stick a resistor in place of the remote temperature sensor to trick it into thinking the battery temperature is always the same, thus putting out the same voltage.

    I have no idea as to what the ohm value of this dummy resistor should be, can anyone help with that?

    Or I will just have to buy my self a remote temperature probe and analize it with a DMM?

    Or don't mess with the remote temperature sensor at all and simply use the 14.0v "gel battery" setting in the summer and the 14.3v "AGM" setting in the winter?

    If I put go with a Morningstar for this application I already have a job elsewhere for this 10 amp genasun.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • vtmapsvtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    oil pan 4 said:
    then I will have to wait until summer to see how much they can really produce.
    I have to wait until winter to see how much power (watts) my panels can produce.  I have to wait until summer to see how much energy (kwh) per day my panels can produce.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • BB.BB. Super Moderators, Administrators Posts: 32,212 admin
    OK, some basic electrical equations:
    • V=I*R
    • P=V*I=V^2/R=I^2*R
    To calculate the resistance, need to know the voltage and current, then R:
    • R=V/I
    • R=14 volts / 10 amps = 1.4 Ohms (example)
    Next, you need a resistor "rated" to dissipate that much heat:
    • P=V*I=V^2/R=I^2*R
    • P=14 volts * 10 amps = 140 Watt resistor (example)
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭

    Unfortunately these panels have to lay almost flat.

    If these panels were pointed at a much more ideal angle to the sun I would expect more amps in winter and more over all power due longer summer days. Laying flat I am not sure what will be better, cooler panels with less direct sun or hot panels with more direct sun.

    Lets say I have the budget and room for say 220 watts worth of panels and they typically produce 200 watts any time the sun is high in the sky. Can I make the Morningstar acceptable to LiFePO4 as stated above?

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • BB.BB. Super Moderators, Administrators Posts: 32,212 admin
    Depending on where exactly, it appears that roughly a 11 degree tilt from horizontal is ideal for year round production... And in any case, I would suggest a minimum of 5 degree pitch so the panel is more or less self cleaning (leaves, dust). Panels mounted flat may tend to keep dirt on the surface better.

    Panels only work in direct sun--Shade, pointing away from sun, etc. is just going to kill the output. You can play with this link and see how different positions affect the output: Find the city closest to the installation:

    http://solarelectricityhandbook.com/solar-irradiance.html

    I am not a LiFePO4 expert--But I believe you want the charge controller to not have temperature correction for proper charging. I am not sure that charge controller can disable Temp Comp.

    What size of battery bank (voltage/AH/peak wattage/peak amperage) rating are you thinking of? Also--What is the planned power usage (AH or WH per day, etc.).

    There are many ways of killing a battery bank--And Li banks are not cheap. It is unfortunate that NiCad chemistry batteries are one of the most rugged against abuse--But are usually considered to poisonous to use in most applications (proper recycling/disposal of Cadmium).

    -Bill





    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭

    This is a vehicle mounted solar system, so far 90 watts are installed, 60 more watts of solar panels on the shelf ready to go on and so far it is working better then I planned. There is definitely room for at least 180 watts of panels. 

    My existing LiFePO4 battery is around 65ah. I have the cells to expand it to 85ah. Just need to do it. Expected usage is no more than 10ah per day. I do have a 900 watt Xantrex pure sine inverter to power tools and what not or run the LED light bar at night with the engine off, so occasionally I might use 20, 30 maybe 50ah of capacity. 

    No temperature compensation and no equalize seems to be the big definer for a LiFePO4 vs AGM and Gel charger controller.

    I am going to buy the tristars temperature probe and analyze it, hopefully it is a thermistor, could be an RTD but I doubt it. Its only $36 with shipping. Then I can resell it because I don't see my self having any use for it.

    If I can get it to work maybe we can make a "how to hot wire a Morningstar sunsaver tristar for LiFePO4" guide.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭

    I checked the 90 watts I have installed to see what they are doing, since this is the first time in a while that I have not been working.

    Laying flat with a little bit of dust they are producing 45% of rated with the MPPT controller and the MPPT controller is sending all but 1 watt made by the panels to the batteries. When they say 97% efficient, they are not screwing around. I calculate 97.5% efficiency.

    That 10 amp genasun MPPT controller is worth every penny of the $180 I paid for it.

    Sooo, if the panels are only going to produce around 50% of rated laying flat under the low  winter sun I might not need to worry about not having enough charge controller capacity. Guess now all I have to do is wait till summer to make absolutely sure.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    edited November 2015 #22

    The RTS came in and I ohm checked it. At 75'f to 76'F it was reading 10.1k ohms or 10,100 ohms.

    Stick a 10k ohm resistor on the RTS terminal board and that should trick the controller into seeing the battery temperature as unchanging. Thus disabling temperature compensation for use with LiFePO4.

    So, anyone want to buy a Morningstar RTS?


    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • PNjunctionPNjunction Solar Expert Posts: 762 ✭✭✭
    Or, just know that I use my Prostar 15 with LFP by physically removing the temp-comp sensor from the board.  NOT ALL Morningstars will continue to work with that removed, BUT for this model, a neat fallback is to continue working, just without temp-comp.

    Perhaps the Prostar 30 would work the same way.

    I got the idea when reading the manual, and noticed that it did say the unit would still function if the sensor went bad, sans temp-comp.  TADA!
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭

    If I remember correctly, the manual that came with the morningstar RTS says to remove the temperature sensor on the prostar and replace it with the RTS.

    The tristar (the one I have) the built in temperature sensor is affixed to the circuit board, and you install the RTS on a little 2 spot auxiliary terminal board, or in my case install a resistor or pot in place of the RTS trick the charge controller into seeing the remote battery temperature as fixed, thus fixing the output voltage.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

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