MPPT Controller Question

[jopparocks]

I'm going to replace my very cheap solar battery controller with a more decent victron mppt but not sure what size to get. I have two 75 watt solar panels and two 110 amp batteries (non lithium although I may upgrade to lithium in the future). Any advice would be welcome.
Cheers Martin

 

[headlight]

jopparocks The Victron 75-15 MPPT is rated to 220 watts of solar so will be fine with your 2 x 75 watt panels.
I use the 75-15 with 2 x 100 watt panels and 2 x 100 AH leisure batteries.

 

[Guigsy]

If you wanted to penny pinch, the 75/10 is good for 145w. So in the very rare instance of full sunshine at lunchtime in summer, you'd be throwing away a few watts. Yes, this is fine to do, as long as you don't go over the voltage limit, which you won't with only 2 panels. Worst case scenario, you'd waste only a couple of Ah over the whole day. Most days it'd make zero difference.

The 75/15 gives you a little more headroom... If you were even thinking of adding another identical 75w panel, it'd make sense.

If you were even thinking about upgrading to bigger panels, the 100/20 might be worth considering... Although I think it is a bit more cash!

 

[jopparocks]

If you wanted to penny pinch, the 75/10 is good for 145w. So in the very rare instance of full sunshine at lunchtime in summer, you'd be throwing away a few watts. Yes, this is fine to do, as long as you don't go over the voltage limit, which you won't with only 2 panels. Worst case scenario, you'd waste only a couple of Ah over the whole day. Most days it'd make zero difference.

The 75/15 gives you a little more headroom... If you were even thinking of adding another identical 75w panel, it'd make sense.

If you were even thinking about upgrading to bigger panels, the 100/20 might be worth considering... Although I think it is a bit more cash!

Thanks Guigsy - prob go for the 100/20 as there's loads of room on my van for more panels.

 

[I2C]

We have a Votronic MPPT charge controller, reason we went for that one was that it also has an output to charge the vehicle battery.

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[Guigsy]

Thanks Guigsy - prob go for the 100/20 as there's loads of room on my van for more panels.

Even the 100/20 is only good for 290w. If you were going to put a barn door of panels up, then you have to go to the 100/30. Which I think is a different design and much more expensive.

 

[Lenny HB]

If you are going to fit more panels in the future worth considering that different size panels and different manufacturers the output voltage will be slightly different.
If more than ½ volt different best to run through seperate controllers.

 

[jopparocks]

Even the 100/20 is only good for 290w. If you were going to put a barn door of panels up, then you have to go to the 100/30. Which I think is a different design and much more expensive.

100/30 is £160 on Amazon

 

[jopparocks]

If you are going to fit more panels in the future worth considering that different size panels and different manufacturers the output voltage will be slightly different.
If more than ½ volt different best to run through seperate controllers.

Thanks as always Lenny.

 

[Guigsy]

100/30 is £160 on Amazon

Not as bad as last time I looked.

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[Lenny HB]

Not as bad as last time I looked.

Even cheaper from our own RogerIvy he gives 10% discount to Funsters.

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