Dual victron 150/45

[Sportzfann]

I have a mix of wire: marine grade stranded 2/8 to top CC from POS buss thru 30a fuse to batt terminals on controller.
2/10 on lower controller POS buss to 30a fuse to batt terminals, they both go thru a 30 a fuse on way to the buss.
I did use some #8 thhn about 2’ long between fuse and CC ?
When I get back home I could change out the THHN to the same stranded wire I used for the solar. I guess the different wire could change the resistance a little, I didn’t think much about that it’s such a small difference, but I guess a couple tenths of volts makes a big difference when working with DC volts.
I checked the connections and they are all pretty tight.

 

[Q-Dog]

I have a mix of wire: marine grade stranded 2/8 to top CC from POS buss thru 30a fuse to batt terminals on controller.
2/10 on lower controller POS buss to 30a fuse to batt terminals, they both go thru a 30 a fuse on way to the buss.
I did use some #8 thhn about 2’ long between fuse and CC ?
When I get back home I could change out the THHN to the same stranded wire I used for the solar. I guess the different wire could change the resistance a little, I didn’t think much about that it’s such a small difference, but I guess a couple tenths of volts makes a big difference when working with DC volts.
I checked the connections and they are all pretty tight.

I'll just leave this here.

 

[Sportzfann]

I'll just leave this here.View attachment 195719

Great thanks I will look at that. Could be the issue.

 

[Q-Dog]

By the way, these no name stereo store breakers are not very good quality. We have seen a few fail in PV systems. Try genuine Blue Sea or Bussman instead.
.

 

[Rocketman]

I have a mix of wire: marine grade stranded 2/8 to top CC from POS buss thru 30a fuse to batt terminals on controller.
2/10 on lower controller POS buss to 30a fuse to batt terminals, they both go thru a 30 a fuse on way to the buss.
I did use some #8 thhn about 2’ long between fuse and CC ?
When I get back home I could change out the THHN to the same stranded wire I used for the solar. I guess the different wire could change the resistance a little, I didn’t think much about that it’s such a small difference, but I guess a couple tenths of volts makes a big difference when working with DC volts.
I checked the connections and they are all pretty tight.

#10 wire is rated for 30amps
#8 wire is rated for 40amps
#6 wire is rated for 50amps

At noon with 650watts of solar power your solar charge controller will produce: 650w / 14.2v = 45amps

If you try shoving more amps down a wire rated for fewer amps - it heats up and resistance increases. The wire has a temperature rating that allows for a certain amount of heat - but that heat doesn’t go into the battery as amps.

You should probably change all the wiring from the solar charge controller to the bus bars to #6 on both charge controllers for best production and fewer future issues.

The wire from the panels to the solar charge controller runs a high volts low amps, so that wire doesn’t matter as much.
The wire from the solar charge controllers to the buss bar/batteries is low voltage high amps so that one is very important to be correct.

 

[Sportzfann]

Rocket, Q-dog
Thanks for the responses I did see a drop across the one fuse holder, when I get back home I will change out the wire to a better quality stranded
#6 and remove the THHN wire completely.
I will put a couple new 50a fuse holders in there place. I didn’t realize how critical the voltage is in these 12v systems. A couple 10ths of a volt makes a difference.

 

[Sportzfann]

#10 wire is rated for 30amps
#8 wire is rated for 40amps
#6 wire is rated for 50amps

At noon with 650watts of solar power your solar charge controller will produce: 650w / 14.2v = 45amps

If you try shoving more amps down a wire rated for fewer amps - it heats up and resistance increases. The wire has a temperature rating that allows for a certain amount of heat - but that heat doesn’t go into the battery as amps.

You should probably change all the wiring from the solar charge controller to the bus bars to #6 on both charge controllers for best production and fewer future issues.

The wire from the panels to the solar charge controller runs a high volts low amps, so that wire doesn’t matter as much.
The wire from the solar charge controllers to the buss bar/batteries is low voltage high amps so that one is very important to be correct.

Rocket, I have ordered the #6 stranded and 2-50a blue sea breakers, hopefully they show up on time, I will be in Yuma next week so I’m hoping to get them installed next Wednesday. I turned off the solar to one of the chargers it was getting warm and the cheap inline fuse I bought was getting warm also, so not taking chances.

Right now I’m getting 440w/31.9 amps out of 1 CC battery is 13.55 v
Renogy shunt says I’m 100% ?

Some confusion on my part what voltage is 100% full on Lifpo 12v 400ah system?
I read some charts say 14.4-13.6 is 100%
Thanks, Sportz

 

[Sportzfann]

By the way, these no name stereo store breakers are not very good quality. We have seen a few fail in PV systems. Try genuine Blue Sea or Bussman instead.
.View attachment 195727

Q-dog, i did order some new blue sea 50a breakers and #6 wire I checked that stereo inline fuse and it was getting warm so I shut it down.
Gonna have to change out that wire,breakers etc.
Thanks for the heads up.

 

[Rocketman]

If you need the solar watts from the one that’s getting warm - Victron allows you to derate the solar charge controller.

The second line of the settings Max charge current- you could drop it to 25 to 30 amps- that way you get some solar from it.



Voltage and 100% full…

If a system is charging when the voltage reaches the absorption voltage- 14.35 in my system, the charge controller will hold the voltage there for 30 min. I call that full (or close enough) - my BMV712 resets to 100% after it is absorbing mode and tail current is under 4% for a few minutes.

Now after a few minutes of float the voltage drops to 13.5v - it is still 100% full.

 

[Sportzfann]

Okay great that’s what I was thinking,
once I reach 14.4 it’s pretty much 100%. I just saw my CC go from bulk to absorption at 14.4 v
Still producing but it is tailing off the amps.

 

[Sportzfann]

I set the amperage down to 20 amps for the second controller, the one that was getting warm.
when the chargers get to the absorbing phase will 1 controller take the lead and restrict the other controller ?
I couldn’t find information about dual operation.
Thanks,

 

[Rocketman]

In absorbing phase all charge controllers hold a steady voltage and let the battery take the amps they want. It will start out high and then slowly drop to a few amps (4% of the amp- hour rating is considered full). So a 500ah battery- once it hits 20amps for less- thats4%.

In bulk the charge controllers give full amps trying to raise the voltage to the absorbing voltage- say 14.3v.

There won’t be a real conflict having 2 (or more) charge controllers running at the same time.

 

[Sportzfann]

In absorbing phase all charge controllers hold a steady voltage and let the battery take the amps they want. It will start out high and then slowly drop to a few amps (4% of the amp- hour rating is considered full). So a 500ah battery- once it hits 20amps for less- thats4%.

In bulk the charge controllers give full amps trying to raise the voltage to the absorbing voltage- say 14.3v.

There won’t be a real conflict having 2 (or more) charge controllers running at the same time

Rocket, I saw you have a multiplus 2x120 do you know if I can control the multiplus with a Cerbo 50/70 touch ?
I would like to be able to change settings on all the devices without having to use a laptop inside my front compartment. (Multiplus)
I can modify a couple settings with my phone on the multiplus but not like I can with the solar chargers.
It would also allow me to see what’s going on at a glance.
What do you use to monitor your system?
Thanks

 

[Rocketman]

Yes the Cerbo can adjust the input amps for a Multiplus from shore/grid/generator, also change its status: on/off/inverter only/charger only.

I have the CCGX - which is like the Cerbo - but older (I doubt they make it anymore). I would love to move to a Cerbo & touch but the wife says nope!

Usually you setup all the settings once of a Multiplus- then don’t change them much. For me, I just used my laptop, but now you can do it with a Cerbo (I think it needs internet).

The process is you download settings in VRM - make the changes and upload them. I haven’t done it yet - just because I haven’t needed to.