Solar Set Up Help

**NEOH** · 08-26-2019, 08:28 AM

Are you using a single 24v 300 watt PV panel ?
What size AGM Batteries ?
You size your inverter per your loads.
How are you going to power 12 volt loads with a 24 volt battery bank?

**tigerremod** · 08-26-2019, 08:37 AM

Originally posted by NEOH

Are you using a single 24v 300 watt PV panel ?
What size AGM Batteries ?
You size your inverter per your loads.
How are you going to power 12 volt loads with a 24 volt battery bank?

Yes a single panel
They are 200Ah batteries
A 300W inverter, only use to charge laptop/phone and maybe for a small kitchen appliance
And thats why I am wondering if I need a step down converter 24V to 12V

**SunEagle** · 08-26-2019, 09:23 AM

Having 12V loads powered by a 24V battery system will cause an unbalance and premature battery failure.

**littleharbor** · 08-26-2019, 09:32 AM

You need higher voltage than a single 24 volt panel produces to charge a 24 volt battery through an MPPT controller, at least for optimum charging.

Question, is the 300 watt panel a 60 cell or a 72 cell panel?

**tigerremod** · 08-26-2019, 09:40 AM

Originally posted by SunEagle

Having 12V loads powered by a 24V battery system will cause an unbalance and premature battery failure.

Right, so could I use a step down converter from the battery to the 12V loads?

**NEOH** · 08-26-2019, 09:45 AM

Originally posted by SunEagle

Having 12V loads powered by a 24V battery system will cause an unbalance and premature battery failure.

A 24 Volt to 12 Volt DC converter will easily solve this problem ...

**tigerremod** · 08-26-2019, 09:47 AM

Originally posted by littleharbor

You need higher voltage than a single 24 volt panel produces to charge a 24 volt battery through an MPPT controller, at least for optimum charging.

Question, is the 300 watt panel a 60 cell or a 72 cell panel?

I think 60, they're PERC solar cells, which I read were more efficient.

**tigerremod** · 08-26-2019, 09:50 AM

Originally posted by NEOH

A 24 Volt to 12 Volt DC converter will easily solve this problem ...

Thank you NEOH!
Now my next question is where do I put the converter in all of this? After charge controller? From batteries to fuse box?

**littleharbor** · 08-26-2019, 10:09 AM

Originally posted by tigerremod

I think 60, they're PERC solar cells, which I read were more efficient.

Then you have a couple issues. One, a single 24 volt panel isn't high enough voltage for an MPPT controller, and two, a 60 cell panel is considered more of a 20 volt nominal panel.

Easy solution. get one more panel. and series wire them.

**NEOH** · 08-26-2019, 10:16 AM

PV Panels => Fuse => Charge Controller => Fuse => 24 v Battery

24 v Battery Bank => Fuse => 24 v Inverter => Fuse => 120 V AC appliances
24 v Battery Bank => Fuse => 24-to-12 V DC down converter ( properly sized by amps ) => Fuse => 12 V DC devices

"Fuse" may be a Fuse or a Circuit Breaker
Use "DC Rated" fuses for DC circuits
Use "AC Rated" fuses for AC circuits

**NEOH** · 08-26-2019, 10:18 AM

Please reply with ...
a) The exact model # of the PV Panels
b) The exact model # of the MPPT Charge Controller

**SunEagle** · 08-26-2019, 10:39 AM

Originally posted by NEOH

A 24 Volt to 12 Volt DC converter will easily solve this problem ...

Yes. The OP could use that type of converter to generate 12V. But how big should it be? That will depend on the 12V loads.

Bigger problem is what littleharbor has pointed out. A single 24V panel will not be enough to charge a 24V battery system.

**tigerremod** · 08-26-2019, 12:44 PM

Originally posted by NEOH

Please reply with ...
a) The exact model # of the PV Panels
b) The exact model # of the MPPT Charge Controller

Not sure of exact model numbers but I can tell you what they are...
a) Renogy 300W 24V Monocrystalline Panel
b) Victron SmartSolar MPPT 100|20 Solar Charge Controller

hope that helps

**tigerremod** · 08-26-2019, 12:50 PM

I don't have room for another panel as this is going on top of my camper and the 300w is large, I know of people that have the same set up but their batteries are wired parallel, not sure if that makes a difference. I've heard that batteries should be wired in series.

Solar Set Up Help

Solar Set Up Help

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