Run charge converter to bus bar or direct to battery?

[MReimler]

Should I run the output from my PV charge converter to the bus bar or direct to the battery? My thinking is, if it's to the bus bar and the battery disconnect is open, the batteries wont get any charge from the PV.

I already have the charge converter connected to the bus bar but this morning at 2:15am my brain woke me up and I started thinking about connecting direct to the battery. Please help me out so I can get some sleeping tonight.

Thanks!

 

[timselectric]

Buss bar is standard.
Either is fine.
Would recommend a disconnect somewhere between.

 

[MisterSandals]

my PV charge converter

Wondering what it is you have that you are calling a "PV charge converter".

 

[12VoltInstalls]

Buss bar is standard.

I’m doing that.

It was interesting the other day while coffeemaker was running that my clamp meter read 46.7A from the charge controller and 16.x from the battery bank cable.

 

[timselectric]

I’m doing that.

It was interesting the other day while coffeemaker was running that my clamp meter read 46.7A from the charge controller and 16.x from the battery bank cable.

That's great

 

[MReimler]

Wondering what it is you have that you are calling a "PV charge converter".

MPPT charge controller.

 

[MisterSandals]

MPPT charge controller.

Ok, thanks.

My thinking is, if it's to the bus bar and the battery disconnect is open, the batteries wont get any charge from the PV.

Its good to think along these lines, it shows a good operational understanding of your system.
One thing in addition to your comment/concern, is that by having different circuits from array to SCC and battery, and battery to bus bars, its easier to understand the wire sizing and fusing. You will know the amps, volts and wire length from array to SCC and battery so adding breaker or fuse & switch, is easy to size. Similarly, for your bus bar, presumably that is all or mostly loads. And the loads are probably governed by your inverter size, so wiring and fusing that is equally straightforward.

Both will work. I do my installs as i described for simplicity.

 

[time2roll]

All items to the bus. That is the purpose of the bus.

 

[MReimler]

Thanks for the input folks. I think I'll run the output from the charge controller direct to the battery (through a fuse) as the camper will sit unused a fair bit. This way I can disconnect all the 12V loads from the batteries (with the battery disconnect switch) and still keep the batteries charged via the solar.

 

[rmaddy]

Keep in mind that if you have a shunt then nothing but the shunt and the main battery fuse should be connected to the battery. Everything should be connected to the bus bars. If you want to have DC loads disconnected then put a disconnect switch between the bus bar and the DC fuse box.

 

[MReimler]

Keep in mind that if you have a shunt then nothing but the shunt and the main battery fuse should be connected to the battery. Everything should be connected to the bus bars. If you want to have DC loads disconnected then put a disconnect switch between the bus bar and the DC fuse box.

No shunt. Renogy "smart" batteries so the monitor connects to the batteries via Ethernet cable

 

[12VoltInstalls]

by having different circuits from array to SCC and battery, and battery to bus bars, its easier to understand the wire sizing and fusing

Or you just do what I do and make the main battery cable twice as big as you need it lol ?

 

[12VoltInstalls]

think I'll run the output from the charge controller direct to the battery (through a fuse) as the camper will sit unused a fair bit. This way I can disconnect all the 12V loads from the batteries (with the battery disconnect switch) and still keep the batteries charged via the solar.

You can do that with a busbar too. And then you don’t have any more complexity than necessary with keeping the cables balanced at the battery. I think that’s better imho

 

[rmaddy]

No shunt. Renogy "smart" batteries so the monitor connects to the batteries via Ethernet cable

Even without a shunt, the wiring I suggested is much cleaner and simpler.

 

[time2roll]

Thanks for the input folks. I think I'll run the output from the charge controller direct to the battery (through a fuse) as the camper will sit unused a fair bit. This way I can disconnect all the 12V loads from the batteries (with the battery disconnect switch) and still keep the batteries charged via the solar.

That is fine too. I turn components off and disconnect nothing. I have no switches. Sure there is maybe 100 mA draw. Solar keeps up just fine.

 

[HRTKD]

The power produced by the solar charge controller isn't always used to charge the battery. I make fairly heavy use of the power produced by my solar charge controller during the day. By connecting the solar charge controller to the common bus bars it has direct access to the loads without having to go through the battery cable back to the bus bar.

Connections at the bus bar, at least in my system, are cleaner than if I did them at the battery. I do have a shunt in my system so nothing but the shunt and the BMS is connected to the battery.

 

[12VoltInstalls]

The power produced by the solar charge controller isn't always used to charge the battery

Maybe I’m weird but I got all excited the other day when my solar output was 47A and my batteries were discharging at 20A or something while I was making coffee.

If I wasn’t charging at the busbar I wouldn’t have had as an easy of a time noticing that. More importantly, the 6ga cables from the SCC to the busbar are only like 10 inches. My line losses are probably not factorable cuz I’m 00 to the batteries.

 

[Jonathan123]

This is great information. I had the same question and the discussion here makes sense. But the setups I see using bus bars in this way seem to have a fuse at the battery but not at the busbar going to the scc and dc fuse box. Assuming a much heavier cable coming off the battery, why isn’t there a fuse at each of the smaller cables that connect to the busbar?

 

[12VoltInstalls]

setups I see using bus bars in this way seem to have a fuse at the battery but not at the busbar going to the scc and dc fuse box.

My current setup is lithium. 125A fuses antveach battery. SCCs have fuses in them. DC fusebox is rated to 100A and utilizes an 30A fused 8ga wire.

Assuming a much heavier cable coming off the battery, why isn’t there a fuse at each of the smaller cables that connect to the busbar?

Each battery (3 total) uses 1/0 cables and have a 100A bms, 2kW inverter uses 2/0
SCCs all have breakers, battery charging disconnect is a DC breaker.

In practice every wire is fused or breakered.

 

[Jonathan123]

Isn’t something like the scc’s fuse protecting that device itself, leaving the wire to it from the busbar vulnerable?