Question sizing BMS and Victron Charge controllers 24v system

[Joshgabel]

Hey all!

Attached is a diagram of my system.
I have all the components in hand except one of the charge controllers.

I'm thinking that i may have to change it up but calculating the solar charge controller needs is making my head spin when trying to factor for the temperatures this mobile rig might see. (0deg F)

My desire to over panel is to allow for simultaneous battery charging while operating the mini split during peak Sun hours.

1. What would your recommendations be for charge controllers?

I dont mind running multiple smaller controllers as i think it might same some money. And have no objections to changing panel configuration or even dropping down to (6) panels.

2. How much PV charging do i need? The battery banks have 100A daly BMS on each of them.


Thanks in advance. Cheers!

 

[sunshine_eggo]

1. 2S of those panels has Voc too high for 100/30 unless it NEVER gets colder than about 60°F and 30A is too low. Recommend: 2X 150/60-75 or whatever currents are available in that range.
2. That depends purely on our energy needs as your solar harvest determines what you can use on an ongoing basis without continuously driving your batteries lower and lower.

Each of your batteries is limited to 2400W in or out due to BMS. Since flow is never divided perfectly, assume the two together can deliver/charge 4800W - 10% or 4320W or 2160W EA. You should also use a clamp ammeter to measure flow through each battery to confirm they are sharing the loads proportionally.

 

[Rocketman]

Use two of the 150/60 or a single 200/100 (I would use two 150/60’s).

 

[Rocketman]

On the line going to the 24/12v converter you have a on/off switch. You could consider adding a Victron smart BP65 (or BP100) and/or using the battery protect as the switch. This way you can select the voltage to shutoff the power before the batteries get critical (just in case lights, etc. get left on).

 

[Joshgabel]

At this point (cost of needed MMPT's) would it not be wise to just sell the multiplus, BMS's and 100-50 mppt and get a 48v all in one like the growwatt and a 48v-16s BMS?

Some of those that im seeing take PV up to 450Vdc @18a which would allow me to connect all panels in series.. ?

Am i crazy or is this the way forward?

 

[sunshine_eggo]

At this point (cost of needed MMPT's) would it not be wise to just sell the multiplus, BMS's and 100-50 mppt and get a 48v all in one like the growwatt and a 48v-16s BMS?

Sell a quality car and replace it with a Yugo?

Some of those that im seeing take PV up to 450Vdc @18a which would allow me to connect all panels in series.. ?

Are you sure that's a good thing?

Am i crazy or is this the way forward?

Personally, I would never replace Victron with Voltronix equipment UNLESS the Victron had failed, was out of warranty, and I didn't need to rely on the system, i.e., it's for a hobby project.

 

[740GLE]

If you can afford the Victron gamut of plug and play units Lego units.

Why put your eggs in one basket of a growatt?

I don’t think the OP was complaining of the cost or installation complexity of going with multiple Victron units.

I do agree that the system may benefit from a higher voltage, more PV and more storage, but couldn’t we all say that.