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Newbie to Forum

PostPosted: Tue Feb 13, 2018 7:17 pm
by jonda
Hi There,

I'm from Whyalla in South Australia. I have a 1.5 Kw grid tied Solar system. I cannot expand or modify it as adding panels will then exclude me from my very generous solar rebate. So, I have purchased 5 x 250 watt 24 volt Luxor 60 cell solar panels at a bargain price. I will have 575 Ah of AGM batteries shortly so looking to do something with this soon.
I currently have a 200 watt 12 volt system charging 3 x 115 Ah AGM batteries. I can run my large patio fridge for a day but it needs to charge for about 3 days to top the batteries up.

Cheers

Re: Newbie to Forum

PostPosted: Tue Feb 13, 2018 7:34 pm
by Gordon-Loomberah
Welcome to the Energy Matters Forums Jonda :)

Your existing 3 X 115AH batteries probably wont last very long if you run them to near-flat then take 3 days to charge them. Ideally they would be charged at a much higher rate, which is generally detailed in the technical specifications.

I'd suggest running your new system at either 24 or 48V, rather than 12V, which is better suited to portable camping set-ups, and you may need a few more panels if you wish to run a fridge continuously in cloudy weather.

Re: Newbie to Forum

PostPosted: Tue Feb 13, 2018 8:11 pm
by jonda
Thanks for that.
I make sure the AGM batteries never go past 50% discharge anyway, but all good.

One other question. Does a MPPT regulator allow you to have nominal input from the panels of 24+ volts and still charge a 12 volt battery bank at the correct charge of ~14.7? In other words does the MPPT automatically sense the voltage of the batteries and adjust the charging accordingly regardless of the input voltage of the solar panels. In my case 24 volt panels 12 volt battery bank.

Cheers again
Jon

Re: Newbie to Forum

PostPosted: Tue Feb 27, 2018 9:46 pm
by davidg
jonda wrote:One other question. Does a MPPT regulator allow you to have nominal input from the panels of 24+ volts and still charge a 12 volt battery bank at the correct charge of ~14.7? In other words does the MPPT automatically sense the voltage of the batteries and adjust the charging accordingly regardless of the input voltage of the solar panels. In my case 24 volt panels 12 volt battery bank.


Real MPPT charge controllers the answer is YES and potentially much higher input voltages. Fake ones or ones that are in actual fact PWM units NO.