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Please Review/Critique My Plan

sunrise

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Jul 16, 2020
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I am very new to this, and this is the first version.

I am adding a 200W (I might add one more panel if roof space permits) solar system to my 16' travel trailer

2 4s 100A battery banks will be using JBD smart BMSs each. Note I don't want to draw over 100A from them as I think the existing inverter won't handle more than 100A, hence the 100A main switch and main fuse.

Note I didn't include wire gauge in this diagram, as I haven't figure out the length of the wires yet.

Thanks!Solar Schematics.png
 
What is the continuous watt rating of the inverter?
Make sure there is no loop between the inverter and the converter.
 
What is the continuous watt rating of the inverter?
Make sure there is no loop between the inverter and the converter.

I don't plan to mess with existing inverter and converter wiring, I hope I will be able to find existing lead-acid battery connectors and replace with the main outputs of the new LiFePo4 batteries.

My trailer has not been delivered yet, once it arrives I will know more. but for now I will have to work with the information I have.
 
I took the liberty to make a simplified version of you diagram
I added a shunt
Code:
primitives {
    |F| busbar fused position
    |U| busbar un-fused position
    <- uni-directional current flow
    -> uni-directional current flow
    <-> bi-directional current flow
    | aggregation point
}

batteries {
    pos = battery1.pos<->battery2.pos
    neg = battery2.neg<->battery1.neg
}
system {
    |F|<->batteries.pos              |<-panel1
    |F|<-victron<-breaker<-combiner<-|<-panel2
    |F|<->existing_trailer
    |F|->shunt_power

    |U|<->shunt<->batteries.neg      |->panel1
    |U|<-victron---------->combiner->|->panel2
    |U|<->existing_trailer
}
 
I took the liberty to make a simplified version of you diagram
I added a shunt
Code:
primitives {
    |F| busbar fused position
    |U| busbar un-fused position
    <- uni-directional current flow
    -> uni-directional current flow
    <-> bi-directional current flow
    | aggregation point
}

batteries {
    pos = battery1.pos<->battery2.pos
    neg = battery2.neg<->battery1.neg
}
system {
    |F|<->batteries.pos              |<-panel1
    |F|<-victron<-breaker<-combiner<-|<-panel2
    |F|<->existing_trailer
    |F|->shunt_power

    |U|<->shunt<->batteries.neg      |->panel1
    |U|<-victron---------->combiner->|->panel2
    |U|<->existing_trailer
}

@smoothJoey Thanks! I like this text based language/notation you use for the diagram - is this just a convention used in this forum, or there are tools can turn this into a graphical schematics?
 
@smoothJoey Thanks! I like this text based language/notation you use for the diagram - is this just a convention used in this forum, or there are tools can turn this into a graphical schematics?

Thanks its my own idea based on the way I described topology in my past lives.
Feel free to write the tool.
Just don't ask me for a formal definition... its still evolving. ;)
 
Thanks its my own idea based on the way I described topology in my past lives.
Feel free to write the tool.
Just don't ask me for a formal definition... its still evolving. ;)
Haha, that's cool, are you are software engineer? can't imagine folks of other occupation would use open/close bracket :D
 
@smoothJoey What's the purpose of the added shunt? the BMS already offers detailed monitoring, and the fuses breakers are protecting the SCC and battery.
 
I didn't reali
@smoothJoey What's the purpose of the added shunt? the BMS already offers detailed monitoring, and the fuses breakers are protecting the SCC and battery.
I didn't realize you were using a fancy bms. :)
The shunt is part of a battery monitor to do coloumb accounting so that you can accurately assess the battery state of charge.
 
A shunt would be useful if you were using a battery monitor like the Victron 712. It would abstract the individual batteries into a single entity that you can then get one state of charge reading from. Basically the same thing smoothJoey said in the post above, but in a different way.
 
A shunt would be useful if you were using a battery monitor like the Victron 712. It would abstract the individual batteries into a single entity that you can then get one state of charge reading from. Basically the same thing smoothJoey said in the post above, but in a different way.
The BMS I use has all the stats I ever wanted, including per cell voltage. so I think I will skip the shunt
 
The BMS I use has all the stats I ever wanted, including per cell voltage. so I think I will skip the shunt

But you'll have to combine the stats from two distinct BMS. My design will be taking into account that I may not be around and it might be my wife or one of my kids that needs to know the state of charge of the battery bank.
 
I also plan to add a 30A breaker between the main output (positive) and 'Aux Charge' connector wire of the 7-way plug from tow vehicle, to protect the alternator from frying given I have 200ah batteries, for peace of mind. I have seen testing video by Victron that at 65A the alternator smoked due to the fan was running at low RPM and could not provide enough cooling.
If the my car's circuit doesn't prevent backfeeding, then I will just use that as a switch to disconnect the Aux Charge.

I have a separated post on 7-way plug Charge connector, there doesn't seem to be a simple and absolutely safe solution so far. But since I have solar, the chance of I have no juice left in battery for engaging brake for a few seconds is fairly low I think, I think it's better to be aware and avoid this situation than spending a lot more for a more complicated system in TV.
 
But you'll have to combine the stats from two distinct BMS. My design will be taking into account that I may not be around and it might be my wife or one of my kids that needs to know the state of charge of the battery bank.

Yes, and I have a separate project planned for that - I plan to build a bluetooth monitor with LCD to combine the stats of 2 BMS and Victron MPPT SCC in display them in one screen.
 
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