transforming 36V solar panel to 18 volt for 12 volt system

[1611]

At the moment there are some good deals to be had in Greece on solar panels which are directed at the domestic market under gov subsidy.
Some of the larger panels however are ( 185W and upwards) rated at 36V open voltage giving 5.5 amps at 24V. Is it possible to transform the open voltage to 18v and so deliver 11amps at 12V. Where in the system would I fit it and would my 15amp rectifier cope.

 

[TopDonkey]

You need an MPPT regulator, these generally accept big voltages and convert it to 12v or 24v to charge your battery, I have a 250w 48v panel that puts out close to 60v and it charges my 12v batteries perfectly

Be aware, that a decent mppt regulator will probably cost more than your solar panel !, mine certainly did

 

[ccscott49]

At the moment there are some good deals to be had in Greece on solar panels which are directed at the domestic market under gov subsidy.
Some of the larger panels however are ( 185W and upwards) rated at 36V open voltage giving 5.5 amps at 24V. Is it possible to transform the open voltage to 18v and so deliver 11amps at 12V. Where in the system would I fit it and would my 15amp rectifier cope.

Whereabouts are you and where did you see the cheap deals please, I need a couple more 80 watt panels or bigger.
I'm 24 volt so do nicely for me.

 

[grumpygit]

Whereabouts are you and where did you see the cheap deals please, I need a couple more 80 watt panels or bigger.
I'm 24 volt so do nicely for me.

+1 It would be good to know please

 

[staarek]

Hi there,

It's my first post (even though I've been browsing forum for quite a while now) so hello everyone!

Most decent MPPT controllers accept voltage input of around 50V or more (which is not a case with PWM controllers, especially cheap ones)
I have recently changed my PWM Controller for MPPT, i bought one from Conrad UK (30 amp model, around £100). My setup is 3 panels with total wattage of around 450 watts. The increase of daily power harvest is around 15-20% which is not bad. I don't know what the difference would be using more reputable Morningstar though.