Series or parallel solar

[GUMPY]

Thinking of fitting 3x 150w panels with 40amp MPPT controller that will handle up to 100volts, do I wire the panels in series or parallel? When boat is on its mooring the panels will never be in shade. 

[Robbo]

Check the voltage of the solar panels that in series it doesn't go over 100v.   MTTP works better with higher voltages.

[stegra]

Less voltage drop and (potentially) shorter overall cable length in series too. Riskier voltages though.

[smileypete]

Not a lot in it really but with series it saves getting MC4 splitters.

[Chewbacka]

Commercial panels are often around 37v (from memory) so 3 in series could give over 100V.

Have you considered a bigger controller as they often go to a higher voltage, or even a bigger controller with 4 panels, 2 in series pairs in parallel if you see what I mean.  

I went for 2 panels of 220W each, wired in series.

Take note of the caution above as 100V DC is more dangerous and needs better installation than your normal 12V.

[GUMPY]

Only room for 3 panels, so its either or.

100v well actually it will be about 60-70v which is low for me. Normal is 380v AC but have worked on 2.5kv DC at 1amp that will kill almost instantly. Its amazing the bang you get from that almost like thunder.

Edited March 27, 2017 by Loddon

[Jambo]

150W panels are '12V' normally aren't they? 

[larryjc]

I've got two, 250W panels and they were wired in parallel with a PWM and I've just gone over to a 40 MPPT from Bimble.  I did a thread here recently on it.  As the wires were already there and I couldn't face the hassle of changing them round to series I just kept as is.  I get load of lovely amps and can see how well the controller is doing with the remote guage - typically if the panels are producing 10 amps there is up to 15 going into the batteries.  Also as we travel a lot I like the idea of parallel as shadows should have less effect.

[Arthur Brown]

Read the data and instruct ions with the panels and the controller! Consider whether these will be your final panel array or whether you will want to increase the panels later.

[GUMPY]

22 minutes ago, Arthur Brown said:

Read the data and instruct ions with the panels and the controller! Consider whether these will be your final panel array or whether you will want to increase the panels later.

Yes have done that and it will happily work both ways;

Panel oc voltage 22.14v, Vmp 18.45, Imp 8.13a 

Controller 40amp max volt 100v.

hence my question.