Victron Energy: Alternator/Solar Charging - LFP Battery System

[dreadlocks]

for inspiration here's my diagram

 

[Rando]

Diagrams I look at depict a fuse between PV and SC, unless your PV array is big, then a breaker. wire gauge off the PV is prob 10g, and your SC choice has screw terms accepting 8g in and out. If you have more than one PV, you'll want a combiner box, then into SC. I'm reading a BP for charge circuit prior to battery. a 'thick'(2/0 ?) cable off battery negative to shunt, then all negatives branch from there...partial thoughts...i'm consumer level, consuming ideas...i've seen 3/8ths inch pos and neg freestanding terminal posts so that only one attachment to your pos battery terminal.

I am not sure what the purpose of the fuse is on the PV to charge controller wires would be? The max current the panels can put out is Isc, which is not that far from Imp and far, far away from the current carrying capacity of the wires. I can see an argument for including a manually switchable breaker to use to isolate the charge controller, but a switch would also suffice.

 

[dreadlocks]

I just crimped on some power poles to a little pigtail plugged right into SmartSolar.. if I need to disconnect them for work I can just unplug em, no sparks or risk of shorting.. and simple.. I put a locking pin in em so I dont even consider it a point of failure..

 

[TantoTrailers]

DL that diagram is art! Definitely inspired =)

 

[shade]

While researching the BMS 12/200, I came across this important example of why you shouldn't try to feed reverse current through a BatteryProtect.

mvader (Victron Energy Staff) answered · Feb 19 at 6:52 AM · ACCEPTED ANSWER
Hi, here the official answer:
The BatteryProtect is not at all designed in a way that the current can flow both ways.
Doing so might result in fire. Do not do it.

 

[hour]

I just crimped on some power poles to a little pigtail plugged right into SmartSolar.. if I need to disconnect them for work I can just unplug em, no sparks or risk of shorting.. and simple.. I put a locking pin in em so I dont even consider it a point of failure..

I also have powerpoles on my charge controller. Is that to say I've been wasting my time and looking like a doofus putting a blanket over my roof when doing work? I always heard to not connect/disconnect under load. That makes sense if you're undoing screw terminals, but is it a null issue with something like powerpoles?

If it's fine to do like that then I'd consider upgrading my charge controller from the 75/15 to the 100/50 (even though I'm limited to 200w solar) and carrying around a 600w 24v PSU to run off the generator. Swap PV for PSU when warranted.

 

[dreadlocks]

These are not huge loads were talking about, nothing the powerpole cant handle.. if you wanted to cut power suddenly pulling it off the high voltage side would be the safest way to do it.. wont cause a potential voltage spike.. some people put switches, those connect w/load safely.. dun see how this is much different.

If you were to say run a solid wire from a fixed panel to your controller, whats going to happen if your controller needs replaced or you need to work on an de-energized electrical system? you'll have some hot wires dangling from solar that need to be reattached half an inch apart w/no stray touching.. that would be bad.. what if you need to manually reboot the solar controller out in BFE, you pulling out a screw driver and yanking out wires? or just unplug the solar panel? Put plugs or some way to disconnect solar if your doing a fixed+hardwired setup or you'll regret it.

 

[hour]

These are not huge loads were talking about, nothing the powerpole cant handle.. if you wanted to cut power suddenly pulling it off the high voltage side would be the safest way to do it.. wont cause a potential voltage spike.. some people put switches, those connect w/load safely.. dun see how this is much different.

If you were to say run a solid wire from a fixed panel to your controller, whats going to happen if your controller needs replaced or you need to work on an de-energized electrical system? you'll have some hot wires dangling from solar that need to be reattached half an inch apart w/no stray touching.. that would be bad.. what if you need to manually reboot the solar controller out in BFE, you pulling out a screw driver and yanking out wires? or just unplug the solar panel? Put plugs or some way to disconnect solar if your doing a fixed+hardwired setup or you'll regret it.

Good to know. I installed the powerpoles years ago just because I hated fiddling with two wires so close together in screw terminals that could wear out. Just was unsure of whether "do not disconnect under load" applied here, and played it safe with a blanket over the roof this whole time.

Looks like I have a nice way to charge from generator now, better if I go ahead with the 100/50a SmartSolar. Thanks

 

[Hillbilly Heaven]

for inspiration here's my diagram

First off @dreadlocks an excellent drawing!! My question concerns the post about using the Smart Protect backwards. Are you not using it backwards since you have charge sources and load devices connected to same side of Smart Protect? I haven't studied the Smart Protect yet so it is kind of confusing.

 

[Rando]

Agree with Hillbilly, there is something amiss with the Smart Protect in dreadlocks diagram.

The Smart Protect is just a high current MOSFET and a microcontroller. Read up on how MOSFETs work.

With forward current the MOSFET works much like a conventional relay.

Reverse current flows through the MOSFET body diode and it acts like any other diode, regardless of the state of the MOSFET. The issue here is two fold, current will flow backwards regardless if the smart protect is on or off, and importantly this reverse current will experience a ~0.7V voltage drop. If you are pulling 20amps backward through the Smart Protect it will be dissipating 0.7V * 20A = 14W. This is what leads to the device melting. Small reverse currents are OK, but large reverse currents are not.

 

[Hillbilly Heaven]

Thanks for the explanation of the device. Yes Mosfets in the off state act as a diode and only can absorb so much reverse current.

In my opinion if you are going to use the smart protect you should use two. One installed in the charge side and another installed in the opposite direction for the load side.

 

[1leglance]

Well I spent 3hrs at Northern Arizona Wind and Sun yesterday between picking up my 360w LG panel, misc bits and figuring out how to wire all this Victron love together.
I am working on a new draw.io diagram as there are power, ground and communication leads running around.

 

[b dkw1]

Great video. One thing I noted is the alternator often has a smaller pully so engine RPM does not = alternator RPM.

I was thinking that also. Most alternators are over driven at 4 or 5-1. I think the one on my 6BT is spinning about 2600 at idle. With the giant power robbing mechanical fan blowing on it, I doubt the alternator ever gets that hot.

 

[Alloy]

Well I spent 3hrs at Northern Arizona Wind and Sun yesterday between picking up my 360w LG panel, misc bits and figuring out how to wire all this Victron love together.
I am working on a new draw.io diagram as there are power, ground and communication leads running around.
View attachment 541424

Maybe fuses/disconnecs aren't shown if not some could be added....and a chassis ground for the buss bar.

 

[1leglance]

Maybe fuses/disconnecs aren't shown if not some could be added....and a chassis ground for the buss bar.

Yeah I am working on labels, there are 3 circuit breakers with disconnect switches built in....
Ford batteries to Buck Boost DC-DC charger 60A
Solar controler to pos bus 30A
BatteryProtect (after pos bus bar) to Aux Fuse box 30A

Chassis ground from Shunt/neg bus bar gotta add that one, thanks