PWM questions

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  • Slappy
    Slappy Solar Expert Posts: 251 ✭✭✭✭✭✭
    #32
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    Re: PWM questions

    run the "MSview" software, hook to your controller and see what your float cancel voltage is set to. I run a 12 volt system and if my batteries get to 12.4 V it will cancel the float stage for the next charging cycle. and for a 24 v system it is factory set to 24.8 v..... and for a 48 v system it is set to 49.59.............so if your batts reach that point it will cancel the next floating cycle and will operate in bulk and absorb.
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  • stoichiometry
    stoichiometry Solar Expert Posts: 27 ✭
    #33
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    Re: PWM questions
    Slappy wrote: »
    run the "MSview" software, hook to your controller and see what your float cancel voltage is set to. I run a 12 volt system and if my batteries get to 12.4 V it will cancel the float stage for the next charging cycle. and for a 24 v system it is factory set to 24.8 v..... and for a 48 v system it is set to 49.59.............so if your batts reach that point it will cancel the next floating cycle and will operate in bulk and absorb.

    Slappy,

    I assume you mean if the overnight (or actually the morning) voltage is less than 24.8 v it wont go to float? I didn't see this in my manual. My bat voltage is 25.2 this morning and when i turn on the coffee pot (fridge was running too)it dropped just under 24.8 for a second or two. Now it's back at 25.2v. So it's doubtful that even with a generator that I'll reach float?

    So my question to the group is should I have more batteries to prevent this? Is it possible that one battery is slow or marginal? (fwiw: I've got 1/0 running battery to battery and to the inverter.) Can (and should) I try to reset this lower voltage?

    Best,
    M
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  • stoichiometry
    stoichiometry Solar Expert Posts: 27 ✭
    #34
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    Re: PWM questions
    Cariboocoot wrote: »
    (Having just read the Morningstar manual and found it fastidiously avoids explaining its Absorb function time process ...)

    Got battery sense wires hooked up?

    Now I'm really out of ideas.

    Cariboo,
    I've got battery sense wire hooked up under the same lugs that are running from the charge controller. The inverter is hooked up to the other legs- I was hoping I'd avoid large voltage drops this way.

    Best,
    M
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #35
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    Re: PWM questions
    stoichiometry wrote: »
    Cariboo,
    I've got battery sense wire hooked up under the same lugs that are running from the charge controller. The inverter is hooked up to the other legs- I was hoping I'd avoid large voltage drops this way.

    Best,
    M

    Uh, that doesn't sound right.
    Inverter should be connected to battery terminals, not to charge controller.
    Heavy wire (the 4 AWG) goes from controller output to battery; carries the current to charge battery.
    Light wire (16 AWG) goes from "BATTERY SENSE" terminals to battery; it reports Voltage of battery to controller without the drop caused by handling high current.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #36
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    Re: PWM questions
    stoichiometry wrote: »
    I've got battery sense wire hooked up under the same lugs that are running from the charge controller.

    This part doesn't click with me, don't understand. Controllers I've had always have Battery voltage sensor connections that connect directly to the batteries, so the controller can "see" the voltage actually present at the battery, bypassing voltage drop on current carrying cables so the controller sees the real picture.
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  • Slappy
    Slappy Solar Expert Posts: 251 ✭✭✭✭✭✭
    #37
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    Re: PWM questions

    I assume you mean if the overnight (or actually the morning) voltage is less than 24.8 v it wont go to float? I didn't see this in my manual.

    it is not in the manual. I found this out through the software settings by using "MSview" software. But if it gets below the voltage set point long enough to get logged by the controller, it will kick out the float mode.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #38
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    Re: PWM questions

    Battery Terminal connections -

    I place the inverter cable on the battery terminal, and on the opposite side of the battery terminal, I place the charge controller, so the 2 high current cables, are on the battery post, not on each other. I put the Sense Leads on top of the charge controller lug, and then the thru bolts get tightned down.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • stoichiometry
    stoichiometry Solar Expert Posts: 27 ✭
    #39
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    Re: PWM questions
    Cariboocoot wrote: »
    Uh, that doesn't sound right.
    Inverter should be connected to battery terminals, not to charge controller.
    Heavy wire (the 4 AWG) goes from controller output to battery; carries the current to charge battery.
    Light wire (16 AWG) goes from "BATTERY SENSE" terminals to battery; it reports Voltage of battery to controller without the drop caused by handling high current.

    Sorry for the confusion. Let me try to explain what I've got at the battery bank. Imagine two strings of 4 batteries. Those two strings are paralleled together. This means that I could have two positive lugs (one each from the two strings)and two negative lugs. Mine are on a rack so I've an upper strig and a lower string. I've got the inverter on the "top" set of lugs (but with1/0 wiring so electrically it's mostly equivalent to being on "both"). The charge controller is on the bottom positive/negative lugs. The voltage sense wires are directly on these same terminals. Does this make sense?
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  • stoichiometry
    stoichiometry Solar Expert Posts: 27 ✭
    #40
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    Re: PWM questions
    waynefromnscanada wrote: »
    This part doesn't click with me, don't understand. Controllers I've had always have Battery voltage sensor connections that connect directly to the batteries, so the controller can "see" the voltage actually present at the battery, bypassing voltage drop on current carrying cables so the controller sees the real picture.

    Perhaps my misuse of lugs is what is confusing . Per below-> "battery lugs"
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  • stoichiometry
    stoichiometry Solar Expert Posts: 27 ✭
    #41
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    Re: PWM questions
    mike90045 wrote: »
    Battery Terminal connections -

    I place the inverter cable on the battery terminal, and on the opposite side of the battery terminal, I place the charge controller, so the 2 high current cables, are on the battery post, not on each other. I put the Sense Leads on top of the charge controller lug, and then the thru bolts get tightned down.

    Mike,

    I've only got bolt posts, so I can't hookup to each side of te battery.
    Hmm... Perhaps i should use this controller as a load controller when I get my turbine up and get a new MPPT (per cbcoots recommendation).

    Best,
    M
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #42
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    Re: PWM questions

    For a moment it sounded as though the inverter was being run from the controller's charge output and the batteries were connected only to the "sense" terminals. :roll:

    Take a look at this page: http://www.smartgauge.co.uk/batt_con.html
    Note "Method 2"

    With two parallel battery strings you want all the negative connections to (-) of one string and all positive connections to (+) of the other string. This way the discharge and charge current is shared fairly evenly across all batteries. Both the inverter and the charge controller should "see" the same Voltage. I probably don't have to mention the importance of the battery interconnect wires being even length and large gauge.

    This may not, however, resolve the problem.
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  • stoichiometry
    stoichiometry Solar Expert Posts: 27 ✭
    #43
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    Re: PWM questions
    Cariboocoot wrote: »
    For a moment it sounded as though the inverter was being run from the controller's charge output and the batteries were connected only to the "sense" terminals. :roll:

    Take a look at this page: http://www.smartgauge.co.uk/batt_con.html
    Note "Method 2"

    With two parallel battery strings you want all the negative connections to (-) of one string and all positive connections to (+) of the other string. This way the discharge and charge current is shared fairly evenly across all batteries. Both the inverter and the charge controller should "see" the same Voltage. I probably don't have to mention the importance of the battery interconnect wires being even length and large gauge.

    This may not, however, resolve the problem.

    Great read! Thanks. My loads are on diagonals. Should my feeds be on the same diagonal or opposite?

    Best,
    M
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #44
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    Re: PWM questions

    (I'm posting this partly to try something out, so bear with me.)

    Your existing wiring looks something like the attached image, no? In this case "controller" being both the "charge" wires and another set for the "sense" terminals.

    Ideally load and charge and sense all connect to the same spot for both positive and negative.
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  • stoichiometry
    stoichiometry Solar Expert Posts: 27 ✭
    #45
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    Re: PWM questions
    Cariboocoot wrote: »
    (I'm posting this partly to try something out, so bear with me.)

    Your existing wiring looks something like the attached image, no? In this case "controller" being both the "charge" wires and another set for the "sense" terminals.

    Ideally load and charge and sense all connect to the same spot for both positive and negative.

    Honestly, yes the first three days they did. Then I had my problem and thought about resistances and loads. now they are on opposite diagonals. I think my problem has to do with the startup inductive load of the fridge (as you mentioned earlier). But I'm happy to learn something new and to ensure thaty battery hookup is ok. *grin*

    So - short of buying a new charge controller, is there anything wrong with staying in a fully charged "absorb" state moat of the day?

    Best,
    M
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #46
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    Re: PWM questions
    stoichiometry wrote: »
    So - short of buying a new charge controller, is there anything wrong with staying in a fully charged "absorb" state moat of the day?

    Yes: if the battery only needs two hours of Absorb holding it at the higher Voltage for a longer time will "boil off" water if it's an FLA and risk "popping the valve" on sealed/AGM's.

    Trying an attachment with "correct" diagonal wiring (these images are too small - need to work on that.)
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #47
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    Re: PWM questions

    Terminal : the metal part of the battery (post)

    Lug : tinned copper piece crimped to battery cable, and other end has hole for bolting it to the battery terminal.

    Wiring Check this site for how to wire battery banks.
    http://www.smartgauge.co.uk/batt_con.html

    The location you connect the charger to, is also the location you connect the inverter to. At the Battery or the Bussbar or the Star Bolt.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • stoichiometry
    stoichiometry Solar Expert Posts: 27 ✭
    #48
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    Re: PWM questions
    Cariboocoot wrote: »
    Yes: if the battery only needs two hours of Absorb holding it at the higher Voltage for a longer time will "boil off" water if it's an FLA and risk "popping the valve" on sealed/AGM's.

    Trying an attachment with "correct" diagonal wiring (these images are too small - need to work on that.)

    Alright, I'm convinced to save money for a new charge controller. What do you recommend?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #49
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    Re: PWM questions
    stoichiometry wrote: »
    Alright, I'm convinced to save money for a new charge controller. What do you recommend?

    I don't recommend things. You've got a fairly good-sized system so MPPT could be of advantage to you. Thus I suggest you look at some of these:

    Morningstar MPPT 60 http://www.solar-electric.com/motr60ampmps.html
    Outback FM60 http://www.solar-electric.com/oupofl60mpso.html
    MidNite Classic 150 http://www.solar-electric.com/mnclassic.html
    Xantrex XW MPPT 60 http://www.solar-electric.com/xaxwmp60amps.html

    Each has its own advantages and disadvantages so be sure and read all the specifications carefully, including price. Morningstar, for instance, charges extra for the display. Then there are the extra features on the MidNite which you may not need, so why buy them? Also some operational faults have been reported on the Outback FM series. The Xantrex has an odd way to its AUX function. But certainly any of them would work and allow for future expansion (charge controller is about the only part of a system that is adaptable to configuration changes).
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