PWM controller cut out

CraigE
CraigE Registered Users Posts: 4
Hi I dont know a lot about solar, but I have 2 panels 1 x 120w on my 4x4 with an EPHC PWM 10 amp controller and a folding 80w system for my camper.
The issue I have is the PWM controller cuts power from the panel when the battery voltage drops to around 11.1 volt. Is this normal? If so why as surely the objective is to keep charging the battery. I know the folding system does not do this. The problem with this controller is that it will only try to automatically reset a few times and then has a 24hr lock out and has to be manually reset. Part of the reason I have this on the 4x4 is it sits in an airport car park for over a week and the aim is to keep the batteries fully charged. Any advice would be appreciated. My intent was only to use this controller for a period of time and maybe upgrade to a better one. It is an EPHC PWM 10 amp unit.
Cheers
Craig

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: PWM controller cut out

    Welcome to the forum Craig.

    No, that is not normal.
    Normal is the PWM controller cuts power between the panels and batteries when the Voltage is up.

    Are you sure that what you are experiencing isn't the controller disconnecting LOAD terminals when the Voltage drops? That is normal for controllers that have such terminals.

    At any rate you do not want your battery Voltage falling that far. I think there's something wrong with your system. A single 120 Watt panel will produce about 6.8 Amps and an 80 Watt panel about 4.5 Amps so together they could possibly exceed the controller's capacity. Also, we do not know what size (in Amp hours) the battery is; 10 Amps may not be enough to keep it charged.

    Can you fill us in with more details?
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: PWM controller cut out

    Battery voltage of 11.1 is a dead battery and a lead-acid battery allowed to go that far into discharge will have an extremely short life.
    Many charge controllers do shut down if the battery is dead or not connected. How low (discharged) is too low a voltage will depend on the controller design. Just something to keep in mind.
  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    Re: PWM controller cut out

    The specs for that charge controller show an 11.1v LVD.

    My guess is that he has attached the battery to the LOAD terminals, the battery has self or parasitically discharged to 11.1v, disconnecting the panel from the battery - in any event attaching the battery to the load terminals is not going to work right off the bat.

    Or, if the battery is attached to the actual battery terminals on the controller, the battery is already shot or being drained by a parasitic load too much for the panel to compensate.

    Craig - how are you wired to the controller?
  • CraigE
    CraigE Registered Users Posts: 4
    Re: PWM controller cut out
    PNjunction wrote: »
    The specs for that charge controller show an 11.1v LVD.

    My guess is that he has attached the battery to the LOAD terminals, the battery has self or parasitically discharged to 11.1v, disconnecting the panel from the battery - in any event attaching the battery to the load terminals is not going to work right off the bat.

    Or, if the battery is attached to the actual battery terminals on the controller, the battery is already shot or being drained by a parasitic load too much for the panel to compensate.

    Craig - how are you wired to the controller?

    Hi Thanks for the replies.
    The system is wired up as the controller instructions show. Positive and earth wires from solar panel to controller and positive and earth from controller to Deep Cycle Optima Blue Top battery. The issue is more about when the controller cuts out and does not reset automatically. I cannot tell if it is cutting out at OVP or LVP. The problem is when I get back the battery has drained as there is some parasitic drain somewhere but is minimal voltage and so far cannot trace even with a clamp meter. May have to look at a controller that automatically resets. The issue is I am away for periods of time. The battery does charge up when hooked up to a battery charger and does hold charge.
    Thanks
    Craig
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: PWM controller cut out
    CraigE wrote: »
    Hi Thanks for the replies.
    The system is wired up as the controller instructions show. Positive and earth wires from solar panel to controller and positive and earth from controller to Deep Cycle Optima Blue Top battery. The issue is more about when the controller cuts out and does not reset automatically. I cannot tell if it is cutting out at OVP or LVP. The problem is when I get back the battery has drained as there is some parasitic drain somewhere but is minimal voltage and so far cannot trace even with a clamp meter. May have to look at a controller that automatically resets. The issue is I am away for periods of time. The battery does charge up when hooked up to a battery charger and does hold charge.
    Thanks
    Craig

    Controllers do not 'cut out' between battery and PV. They monitor battery Voltage and if it is too low they connect up the PV and charge the battery. When it reaches the proper charge level they switch on/off rapidly to maintain that Voltage (for Absorb and Float stages).

    If battery Voltage falls too low the controller may have no power to run from and so won't work at all. This sounds like what your problem is with a battery at 11.1 Volts, which is far too low for a 12 Volt system.

    If PV Voltage is too high the controller may fry. What these levels are depend on the particular controller.

    I think you have excessive loads draining the battery too far (very small capacity with a single battery) and a charge controller that frankly isn't very good.
  • CraigE
    CraigE Registered Users Posts: 4
    Re: PWM controller cut out
    Controllers do not 'cut out' between battery and PV. They monitor battery Voltage and if it is too low they connect up the PV and charge the battery. When it reaches the proper charge level they switch on/off rapidly to maintain that Voltage (for Absorb and Float stages).

    If battery Voltage falls too low the controller may have no power to run from and so won't work at all. This sounds like what your problem is with a battery at 11.1 Volts, which is far too low for a 12 Volt system.

    If PV Voltage is too high the controller may fry. What these levels are depend on the particular controller.

    I think you have excessive loads draining the battery too far (very small capacity with a single battery) and a charge controller that frankly isn't very good.

    Thanks for the reply.
    What I actually have is a dual battery set up in a Land Rover Defender 110 TD5. The main cranking battery is an AC Delco Calcium sealed battery and the second battery is a Optima Blue Top deep Cycle. These are set up with a dual battery system. The solar panel via the controller is set up to the deep cycle Optima Blue Top. When fully charged all is ok.
    At this stage I am honestly not sure whether it is cutting out at Low Voltage or Over Charge. I think the problem may actually be over charge and then the controller not auto re setting and requiring a manual reset. I have attempted to find a parasitic drain, but so far not found. I have done this using a clamp meter and a volt meter and found no drain from either battery, but there must be one somewhere. Even so the solar panel should more than compensate. The plan was to be able to leave my car fridge running in the car full time. I may have to look at a better controller that can charge both batteries and will reset automatically at certain voltage. The EPHC 10 will only attempt 4 resets I think and then you must wait 24hrs and manually reset. This is ok if you are in the car every couple of days, but when the car is left in a car park for 1 to 2 weeks not practical.
    Cheers
    Craig
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: PWM controller cut out

    You might want to consider a SunSaver Dual for this application. It will connect to and charge two batteries separately, so the 'house' and 'auto' batteries remain isolated for solar charging. Then if you need to connect the two for some reason you can do so manually. http://www.solar-electric.com/modubachco251.html
  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    Re: PWM controller cut out
    CraigE wrote: »
    The system is wired up as the controller instructions show. Positive and earth wires from solar panel to controller and positive and earth from controller to Deep Cycle Optima Blue Top battery.

    Good choice for that application. However this still doesn't answer the question if you have accidentally wired up the blue top to the "load" terminals accidentally, or to the "battery" terminals on the controller.

    If you don't have a parasitic load, it may be somewhere in the dual battery switching setup. I wonder when switching, the switch is merely breaking the blue-top wiring to the controller, yet still leaving the panel attached to it, thereby confusing the controller, which wants to see the battery first, and THEN the panel. Some guys I know with just simple switching actually have two switches, one dedicated to the batteries, and one solely for the panel, which they switch into circuit last.

    The fastest way to cut down on the variables would be to totally isolate the blue top wiring. Attach the controller to it. Then attach the panels. This isolates it from the Rover completely just to see if it still trips that way. If so, we know it is not anything to do with the vehicle. That's what I'd try first.
  • CraigE
    CraigE Registered Users Posts: 4
    Re: PWM controller cut out
    PNjunction wrote: »
    Good choice for that application. However this still doesn't answer the question if you have accidentally wired up the blue top to the "load" terminals accidentally, or to the "battery" terminals on the controller.

    If you don't have a parasitic load, it may be somewhere in the dual battery switching setup. I wonder when switching, the switch is merely breaking the blue-top wiring to the controller, yet still leaving the panel attached to it, thereby confusing the controller, which wants to see the battery first, and THEN the panel. Some guys I know with just simple switching actually have two switches, one dedicated to the batteries, and one solely for the panel, which they switch into circuit last.

    The fastest way to cut down on the variables would be to totally isolate the blue top wiring. Attach the controller to it. Then attach the panels. This isolates it from the Rover completely just to see if it still trips that way. If so, we know it is not anything to do with the vehicle. That's what I'd try first.

    Hi,
    Definitely have controller set up to battery. That side of things is fairly simple. Set up for this controller looking at it is from Left to Right Panels (power in), Battery and then Load as shown by light symbol for light. I think the main problem for this particular controller is it will only auto reset 4 times over about a minute and then you must wait 24hrs and do a manual reset. OK when I am driving the car every day, but at times it will sit for a week or two. May look at using a CTEK dual battery and controller system.
    Cheers
    Craig
    Cheers
    Craig
  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    Re: PWM controller cut out

    Oh yeah, the CTEK D250S Dual. I like CTEK stuff, although I don't have any experience with the D250S.

    I'd still recommend totally isolating your Optima from the vehicle, and testing your solar charging that way, just to prove that the existing dual-switching setup, or something else in the vehicle is at fault.

    Just note that the D250S is set up for 14.4v, and although this will work with the majority of conventional agms, the pure-lead types like Optima like to see 14.7v once in awhile at the very least. CTEK also provides chargers that you can specifically set for 14.7v so if the D250 works, think about an external charger when you have the time to pop it on.