Solar Controller for 1200 watts

[seandepagnier]

Personal rule of thumb, for a 1200w solar array you need at leat 1200 Ah of battery bank.

This is a really ridiculous rule to make up.



I have 40Ah battery and 700w solar. This is a good arrangement for me. 1200 Ah battery should have at 15-20kw solar. The reason, is solar output reduced to 10% in overcast must be sufficient to power normal loads.



When the sun is out, I use excess power for various things like 3d printing, cooking, charging ebike, even can power the boat. A watermaker filling tanks on sunny days is a good example too (but I don't have) When overcast (regardless of weather) still receive 70 watts generally don't run out of power because sufficient solar power is more important than battery capacity to ensure stable power from 100% solar.

[seandepagnier]

Originally Posted by ttex

No charge controller? You doing that right now?

yes, I have no charge controller at the moment, and perfect working system 100% solar plenty of power.


I also in the past have run few panels on controller and rest direct to battery to use a smaller controller. This worked with lead acid as the non controlled panels only boiled a bit of water you can add more. With lithium BMS does the same as charge controller.

[ttex]

Originally Posted by seandepagnier

yes, I have no charge controller at the moment, and perfect working system 100% solar plenty of power.


I also in the past have run few panels on controller and rest direct to battery to use a smaller controller. This worked with lead acid as the non controlled panels only boiled a bit of water you can add more. With lithium BMS does the same as charge controller.

Interesting. I reckon it depends on how much you trust the BMS.

[more]

Originally Posted by SKMT

Planning to install 1200 watts of solar on my flybridge hardtop. My battery bank is a 12v system.

Looking for recommendations for the solar controller. Are people using multiple small/cheap controllers or 1 big/expensive controller? I see Victron has a 150v/100a for $785 on amazon. Are there any cheaper brandss in that capacity?

You instal 4 Panel 300W I am right.
if you want victron 2x Victron BlueSolar MPPT 100/50
but check VOC your solar panel, location MPPT don't go to 40°C total over 60°C
you can combine Victron shunt and monitor.

if you on budget
4x
EPEVER MPPT Solar Charge Controller 30 amp 12V 24V Auto, 30A Solar Charge Controller Max 100V Input Negative Grounded
or 2x 50 A

or totally on budget 2x60A
https://www.aliexpress.com/item/3289...d117b85ekm064O

All this +- MPPT electronic part inside have around 3000-working hour life span on 100°C

But on boat solar panel doesn't last full life cycle, degradation is huge.

[Seriously Slow]

Shading panels is important. Apparently you have a powerboat. You still may be shading panels with radar, sat receivers etc. Separating the panels into 2 or 3 systems may improve overall performance. If you are using
flybridge in relation to a sailboat the mast and sails will add shading. Any shading will reduce output significantly of all panels connected together.

[SKMT]

Originally Posted by LingeringFox

1200w ? You don't say how big is your battery bank.
Better be very big otherwise you're wasting money not only on cables as said before but also on MPPT and solar panels !

You need to balance consumption, production and storage.
Consumption:
How much energy you need for a day ?
How many days without sunshine do you want to survive without cranking the engine or the generator ?
Do you have other sources adding to the production ?
These give you how much storage you need.

How quickly you want to charge your battery bank gives you the size of your panel array.

Personal rule of thumb, for a 1200w solar array you need at least 1200 Ah of battery bank.
If you don't, it will be full sometimes during the day and the MPPT will shutdown the array but you're may be still lacking energy before the night is gone...

My new bank will be 900ah lead acid. Actually i will have 1700w (because I already have 500w). Sure it's overkill for a sunny day, but not for a cloudy day. It's a 1 time cost for the panels, and I don't need to build anything to put them on. Excess power has advantages. Can leave inverter on 24/7. Can install a 120v chest freezer. Can use 120v appliances/tools anytime during the day carefree as opposed to trying to optimize when generator is on. Watch as much TV as I want. And batteries will last longer because constantly getting fully topped off.

[LoudMusic]

I have 2100W on three 100/50 controllers. It splits up the panels so that shading is less of a problem, reduces wire sizes, and provides load distribution in the event of failure. There is a small issue of them fighting with each other when the batteries near full and they all want to shut off, but if you have a BMV and put them in a bluetooth network with each other they'll cooperate on when to switch modes.

[SKMT]

Originally Posted by Seriously Slow

Shading panels is important. Apparently you have a powerboat. You still may be shading panels with radar, sat receivers etc. Separating the panels into 2 or 3 systems may improve overall performance. If you are using
flybridge in relation to a sailboat the mast and sails will add shading. Any shading will reduce output significantly of all panels connected together.

Yes trawler. I've studied any potential shading and by the time the radar can cast a shadow, the sun is basically setting.

[Scott Berg]

We have 4 panels (2x 315 and 2x 327); each with a dedicated Victron smart MPPT 100/30; perfect...

[sesmith]

You can't go wrong with Victron controllers. I've used them on 2 boats and an off-grid cabin and am really happy with them.

I would probably use a couple on a boat installation that size, just to split them for shading or better charging angle to the sun. Keep in mind if you put several in series, just a small amount of shading on one will really limit the output.

Multple Victron controllers can be set up on a network so they exchange information with each other and maximize charging without fighting each other. If you add a Vicron smart shunt you can monitor the battery bank. It also can be added to the Victron network. Do watch their video if you install a smart shunt, as there are some tweaks you will want to do in the setup for solar charging.