Hi guys, hope you have all got in some trips in postI am just about ready to hook up my solar and have decided to purchase an mppt controller (following on from advice from some of you guys!) Pretty keen on a victron unit, but what size? I am thinking 100/30 would suit but happy to be set straight! I have 2x300w panels and 1x 150ah lithium battery. Its likely i will add another battery in the future and i do have another 200w panel which might end up on the roof..and i have 160w blanket for a backup!. Also with the victron..i know i have asked before but... series or parallel? Which is best for poor light/ shade? Still confused about that one! Give me an engine to build I'm fine...electrics..not so good!
18' Series Which controller?
- Thread starter Linc
- Start date
Incoming shortly form @Boots in Action and @mikerezny for sure.............................
. After this trip I will be swapping out my PWM Morningstar controller, while it would be one of the best PWM units, going to a Epever MPPT reg may mean I won't have to add an extra roof panel, while I don't really run short of power other than a few days of heavy cloud I like to have plenty of HP in reserve.... I looked at the Epever because it has a display and seems to do all the things the more expensive Victron units, I'm not interested in any bluetooth capability, my power station office is inside a steel box so could be problematic and who needs another damn app on the phone.... The Morningstar will go on to my shed to run my shed panel.
. After this trip I will be swapping out my PWM Morningstar controller, while it would be one of the best PWM units, going to a Epever MPPT reg may mean I won't have to add an extra roof panel, while I don't really run short of power other than a few days of heavy cloud I like to have plenty of HP in reserve.... I looked at the Epever because it has a display and seems to do all the things the more expensive Victron units, I'm not interested in any bluetooth capability, my power station office is inside a steel box so could be problematic and who needs another damn app on the phone.... The Morningstar will go on to my shed to run my shed panel.
Hi @Linc, The Victron 100/30 indicates it can handle up to 100 volts input and give up to 30 amps in output at whatever battery voltage is. I have mine (2 X 200w panels and 1 X 180w portable panels) connected in Series to a 120ah AGM battery. I have seen up to 23 plus amperes into battery when load has been high and battery voltage around 12.3 volts in good sunny conditions.
If connected in Series, you rely on VOLTAGE rather than AMPS. Also, if connected in Series, amperage is limited to the lowest output of any panel but voltage is highest. If in parallel, amperage from EACH panel is cumulative but voltage is limited to the average output of all panels. There is much less loss of current with the higher voltage when in Series and one can use thinner wiring. If in parallel, voltage losses need to be considered in connecting panels to controller, especially if distance is involved. Each panel has a open circuit voltage of around 22.5v and a "working" voltage of approx 18.0 volts, but this drops as load is applied to approx 16 to 17 volts. My panels have a "working " voltage of 18.3 to 18.5 volts when under light charging load (battery fully charged and in Float mode) hence up to 56 volts possible and low input amps to charge or carry light load. So you could connect up 4 panels in series and your MPPT controller can handle up to 100 volts.
For your setup, and with all the panels, I would consider that a 40A unit would be preferable as you did indicate that you may connect extra panels, which I guess would then have to be connected in PARALLEL. You cannot connect one set of panels in SERIES and then connect extra panels in PARALLEL to the same controller. Examples of operation to consider:-
In series, I tend to get more current from controller to battery/ies especially if light is low or changing frequently, but if one panel is shaded or partially shaded, current drops off but voltage stays high. Only 1.98A total from all three solar panels (measured with clamp meter) at 56 volts (on clamp meter and controller) still gave me over 7A output from controller into battery when battery voltage was 14.0 volts - the advantage of an efficient MPPT controller.
However, if I had the panels connected in parallel, I would need to get approx at least 2A from EACH panel or more from the ones not shaded or partially shaded and have heavier wire from my solar panels to reduce voltage losses to controller. With flat panels on roof, you are going to have to place van in sunlight for best results as max solar generation is between 10.00am and 2.00pm. Before and after that, solar generation is considerably less. Or if in shade or partial shade, voltage is more important.
@Crusty on this forum has his panels connected in Series, has great results in low light and max generation when in full sun. I believe you will get good feedback from a member with REAL experience in solar generation with a MPPT controller and fixed flat panels on roof of van. As mine are all portable and I am able to follow sun as necessary, my experiences are not necessarily the same.
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I have 3 x 200w fixed panels on the van, 1 x 160w on the car, another 1 x 160w for the lid of the roof top tent along with a fleet of superceded glass and blanket panels of varying sizes. The 3 on the van are connected in series, and that has been good to me. I regularly get 60v plus, and can nudge 30 amps on a good day. I can harvest ample charge in overcast and the harvest can start before 7am and be still charging after 7pm. Partial shade is not a huge issue, the 3 x panels are each 2 X cell modules which helps to minimise partial panel shading, but with 600w on the roof even a couple of hours of on/off sun will recharge what we use
I run each panel into its own controller because all my panels are different specs: A 120w plus projecta IDC25 in the tug for its AGM batteries, a couple of cheap ($100) mppt units from china for the 120w and 150w on the van roof, and the original TPS pwm unit that now connects to an external socket for my portable panel.
My batteries in the tug can be (and usually are) in parallel with the van so they can all be charged by something so long as one panel is in the sun and they all share the load at night.
The projecta is usually ok but has nearly flattened the cranking battery a couple of times when confused - ok after a reset. It works well in low light conditions.
The chinese ebay mmpt have worked well and pretty efficient - better with higher panel voltages as in series
The TPS is basic but I like its ability to top up from the portable in the low evening sun
My batteries in the tug can be (and usually are) in parallel with the van so they can all be charged by something so long as one panel is in the sun and they all share the load at night.
The projecta is usually ok but has nearly flattened the cranking battery a couple of times when confused - ok after a reset. It works well in low light conditions.
The chinese ebay mmpt have worked well and pretty efficient - better with higher panel voltages as in series
The TPS is basic but I like its ability to top up from the portable in the low evening sun
Thats what I meant about "Incoming", a long informative narrative.............................. ya daft bugga.............lol.