Sanity check

[Scycle]

I've received a great deal of help from this forum and thought I was near done with my diagram then started to question my plan, so tell me if I'm overthinking or have information overload. First I was going to disconnect my RV converter/charger and using the transfer switch, feed the AC side of the panel with shore power or the inverter, then feed the 12v side with the existing wires from the panel to the battery bank. A separate charger for lithium batteries would be wired to the shore side of the switch to only function when on shore power. All this meant I would leave the converter connected but disconnect the charger. Does this sound practical?

I also forgot about the wires currently connected to my battery, so now they need to go to the Lynx, but out of space and not sure how to manage that.

 

[Browneye]

Seems reasonable.
Are your current battery cables not big enough for the new current loads? If not, why not just replace them?

Understand that a couple kw's may not be enough to run the whole coach? You might get a 15A load out of it. 200Ah of battery is really small - that means you might get an hour's worth of run time to a 15A appliance.

I would be looking at doubling the battery capacity. I run 230Ah and it just doesn't go very far, and I don't even run heavy 120VAC appliances off it - just a 600W inverter. Generator runs for roof air. The furnace blower motor pulls about 10amps, so over a cold night it might use 50-80Ah.
Everything else runs off LPG.

 

[justinm001]

Why not dump the inverter and charger and manual transfer switch then just get a MP 2x120 for $1100. Add a CerboGX or lite for another $220-290 and you'd have full control of everything from your phone with logging. I get its a bit more but it'll work and no issues. Plus if going to 2x120 you can get 50a/240v (12kw) power coming in and never have to worry about anything.

Victron 12V MultiPlus-II 3kVA 2x120V Inverter/Charger | Current Connected

Power, adaptability, and efficiency combined - the MultiPlus-II 2x120V Inverter delivers unparalleled performance for your energy system needs.

www.currentconnected.com

Victron Cerbo-S GX (Lite) System Controller | Current Connected

The Victron Cerbo-S GX is the "Lite” version of the Cerbo GX! This version removed the BMS-CAN port & tank/temp sensor inputs that most don’t use.

www.currentconnected.com

 

[Scycle]

Seems reasonable.
Are your current battery cables not big enough for the new current loads? If not, why not just replace them?

I think they are big enough, I just forgot I need to feed power to those connections already existing near the battery like the landing gear or slides-not sure whats there. It's more about space to connect all this stuff.

Understand that a couple kw's may not be enough to run the whole coach? You might get a 15A load out of it. 200Ah of battery is really small - that means you might get an hour's worth of run time to a 15A appliance.

I would be looking at doubling the battery capacity. I run 230Ah and it just doesn't go very far, and I don't even run heavy 120VAC appliances off it - just a 600W inverter. Generator runs for roof air. The furnace blower motor pulls about 10amps, so over a cold night it might use 50-80Ah.
Everything else runs off LPG.

Yes probably under powered, thought I'd start small then grow.

 

[Scycle]

Why not dump the inverter and charger and manual transfer switch then just get a MP 2x120 for $1100. Add a CerboGX or lite for another $220-290 and you'd have full control of everything from your phone with logging. I get its a bit more but it'll work and no issues. Plus if going to 2x120 you can get 50a/240v (12kw) power coming in and never have to worry about anything.

Victron 12V MultiPlus-II 3kVA 2x120V Inverter/Charger | Current Connected

Power, adaptability, and efficiency combined - the MultiPlus-II 2x120V Inverter delivers unparalleled performance for your energy system needs.

www.currentconnected.com

Victron Cerbo-S GX (Lite) System Controller | Current Connected

The Victron Cerbo-S GX is the "Lite” version of the Cerbo GX! This version removed the BMS-CAN port & tank/temp sensor inputs that most don’t use.

www.currentconnected.com

I thought about all-in-one, but like the idea of individual components for replacement. I've started buying components as money allows and have the inverter, lynx and some small stuff, most of which is required for any system.

 

[Scycle]

I also need to figure out wire management to connect it all together, since the lynx only has 4 positions which I have configured to hold fuses. Could I add bus bars with fuses in the line? I would like to keep it neat without buying another lynx for the cost.

 

[justinm001]

I thought about all-in-one, but like the idea of individual components for replacement. I've started buying components as money allows and have the inverter, lynx and some small stuff, most of which is required for any system.

An MP isn't an all in one it's a professional inverter that'll do exactly what it's designed to do and last decades as it's built with high quality components. It has built in features that eliminate the need for a transfer switch and separate charger. You put it in front of everything and you'll have power as long as you have enough battery. Nothing turns off when switching from shore to battery, completely undetectable.

 

[Scycle]

I looked at MPs and other inverter/chargers and still may go that way, but I'm stuck on figuring this out if nothing else for an education since I'm new to this, it bugs me that I can't wrap my head around it. The main issues revolve around the existing panel converter/charger. This is what is running through my pea brain:
1-If I disconnect only the charger in the panel. When on shore power; it feeds the AC in panel including the converter supplying the 12v side and the separate charger, while 12v comes from the battery-BUT! the charger is putting up to 14.6v in to the Lynx from which the 12v is coming from and back to the panel, maybe too high for 12v system?
2-Disable converter/charger, use shore for panel AC and separate charger, then supply panel 12v from battery. When no shore, inverter will power panel AC and panel 12v will come from battery.
3-Disconnect 12v wire from battery to panel and charger in panel. Then when on shore the panel AC, converter for panel 12v and separate charger are powered. When no shore the inverter will power panel AC and converter for panel 12v. This seems like a waste of inverter energy powering the converter for 12v.

 

[justinm001]

14.6v is not too much for the 12v panel it's normal charging voltage everyone uses it. It's 12v nominal, anything 12v can accept 11-15v ish safely. When you're on shore you'll need to have that charger on to run 12v loads.

If you get a MP and a cerbogx you'll be able to see everything and have a full understanding of what's doing what and can learn. The mppts will record solar, the shunt will show battery so and the MP will show how much power is coming from shore and how much 120v is being used. It's all displayed nice and neat on a web page and logged so if any issues you know what it is.

Also that ac charger is only 30a/360w which isn't much for DC loads. I have a larger RV with lots of led lights and can easily pull 300-350w of DC. Without any DC loads it'll take 8 hrs to charge the batteries from dead. I'd be worried it won't charge enough. The MP is like 120a so plenty to charge and use without even thinking about it.

 

[henrys]

The main issues revolve around the existing panel converter/charger. This is what is running through my pea brain:

I have a setup similar to your diagram but use an automatic transfer switch. I wired the converter to the shore power input side of the transfer switch so it only comes on while connected to shore power.

 

[Scycle]

I have a setup similar to your diagram but use an automatic transfer switch. I wired the converter to the shore power input side of the transfer switch so it only comes on while connected to shore power.

I have the manual transfer switch for now, mainly for reliability and cost. Do you have the charger connected in your panel? Do you have lead acid or lithium?
I'm thinking that my #1 or #2 scenario above is the better option, but using the separate charger for the batteries and feeding the panel 12v from the same connection as the charger seems unusual although what justim001 said makes sense.

 

[henrys]

My charger is not connected to the panel at all. The input is connected to the shore power side of the transfer switch and the output goes directly to the battery bank (fused of course).