Advice on controller for my panels

[Greggo]

I have four of these https://www.homedepot.com/p/Grape-S...-Star-100W/204211365#product-section-overview Would this be a good match ? Victron SmartSolar Bluetooth MPPT Solar Charge Controllers - SmartSolar 100/20 12V-48V ? It will have a 200ah ampere time lithium phosphate 12 volt pulling a constant 200 watts for 10 to 12 hrs per night.

 

[12VoltInstalls]

I can’t remember exactly victron’s proprietary nomenclature and didn’t look it up >sorry<
But it seems to me that’s not nearly enough battery and barely enough panel watts at nominal. (if it’s actually enough at all- “enough” is loosely applied.)
Orange juice comes in quarts and if you pour an 8oz glass you’ll have 24oz left. Usable electricity comes in watt hours; if you use 600Wh out of 2400Wh you don’t have 1600Wh left due to efficiency losses, and some other things like pukert with lead acid. And that’s without cloudy days. Lithium batteries might do that but I don’t think the panels will.

 

[Greggo]

I can’t remember exactly victron’s proprietary nomenclature and didn’t look it up >sorry<
But it seems to me that’s not nearly enough battery and barely enough panel watts at nominal. (if it’s actually enough at all- “enough” is loosely applied.)
Orange juice comes in quarts and if you pour an 8oz glass you’ll have 24oz left. Usable electricity comes in watt hours; if you use 600Wh out of 2400Wh you don’t have 1600Wh left due to efficiency losses, and some other things like pukert with lead acid. And that’s without cloudy days. Lithium batteries might do that but I don’t think the panels will.

Thanks for your reply and I should have said for about 10 to 12 hrs per day at 200 watts

 

[Greggo]

I would be using it for camping and also have a 2000 watt honda to charge with as well.

 

[12VoltInstalls]

also have a 2000 watt honda

never knew a civic had only 2.7HP!

10-12 hours is better, but still tight imho

Is that amperethyme a lithium? That might do ok without failing out

 

[Greggo]

never knew a civic had only 2.7HP!

10-12 hours is better, but still tight imho

Is that amperethyme a lithium? That might do ok without failing out

HaHa that would be a honda generator and yes lithium...Thx

 

[Greggo]

I'm just unsure about the panels being too much for the 100/20 controller. Amps at maximum on the panels is 5.23 and I have 4

 

[12VoltInstalls]

Amps will just not all be used but voltage is where to be 85% of max voltage

 

[rmaddy]

400W of panels with a 12V battery means about 33A. If you get a Victron 100/20 you are potentially throwing away usable power since you can only get a maximum of 20A from that controller. You might consider the 100/30 which would take better advantage of the panels.

 

[rmaddy]

I can’t remember exactly victron’s proprietary nomenclature

It's simple actually. It's max input voltage / max output battery current.

 

[rmaddy]

The rest of the math:

Your battery is 12.8V x 200Ah = 2560Wh.
Your proposed usage is 200W for 12hours = 2400Wh. That's 94% of your battery each day. That's a bit too much.
400W of panels with 5 good hours of sun is 2000Wh. And you'll never get 400W out of the panels. So you can't recharge the battery in a day.

You need a bit more battery capacity to run 200W for 12 hours.
You need more solar to recharge that usage.
None of this even begins to deal with one cloudy day.

 

[Greggo]

The rest of the math:

Your battery is 12.8V x 200Ah = 2560Wh.
Your proposed usage is 200W for 12hours = 2400Wh. That's 94% of your battery each day. That's a bit too much.
400W of panels with 5 good hours of sun is 2000Wh. And you'll never get 400W out of the panels. So you can't recharge the battery in a day.

You need a bit more battery capacity to run 200W for 12 hours.
You need more solar to recharge that usage.
None of this even begins to deal with one cloudy day.

I was actually overestimating my usage of 200 watts for 10 to 12 but this helps. My thinking is the 100/20 would be max controller for the 4 panels.

 

[Greggo]

Open circuit is 23.1v x 4 and 5.23a x 4 panels

 

[rmaddy]

My thinking is the 100/20 would be max controller for the 4 panels

The 100/20 isn't really big enough for those 4 panels and if you get more solar to meet your needs, then it will really be undersized.

With a Voc of 23.1V, you can't put all 4 in series because that would be too much for the 100V max input of the 100/20 (or any other 100/XX). But you could put the panels in 2S2P. Though that doesn't change the fact that 400W at 12V is 33A. So even at 2S2P you would want the 100/30. If you need more panels you need something even bigger.

 

[Greggo]

The 100/20 isn't really big enough for those 4 panels and if you get more solar to meet your needs, then it will really be undersized.

With a Voc of 23.1V, you can't put all 4 in series because that would be too much for the 100V max input of the 100/20 (or any other 100/XX). But you could put the panels in 2S2P. Though that doesn't change the fact that 400W at 12V is 33A. So even at 2S2P you would want the 100/30. If you need more panels you need something even bigger.

Was trying to get out of more money spent but thank you. Much appreciated.

 

[12VoltInstalls]

usage is 200W

fact that 400W at 12V is 33A. So even at 2S2P you would want the 100/30

Thank you for correcting that.
Somehow i miscalculated by 50% and I don’t know how other than I needed to hit the sack?