Beefing up my Marine Setup

[subsonic]

Hi there folks - Its great to be here!

Here is the setup on my boat - It is all Victron.

I have 1800W Solar mixed Series and Parrellel into 2 banks of 2 each to a Victron 100/50 MPPT Controller network to a Carbo GX and Connected Directly to my Battery Bank. I also have a Generator that is connected to a Victron Inverter Charger that can push out up to 120A.

If I run my Generator during a normal sunny day this could mean that I could have crica 190 Amps pushing into the batteries.

Now for my Question - I'm beefing up my wiring where I can to cope with the overall total possible amps. From the Charger to the Batteries I'm good (1/0 AWG Wire) however, from the Solar controllers I have a challenge. on the PV Side the amps are low so I am not concerned (80V+ at 7-9amps) on the Battery side it is 14.xx at 30+amps. I have 6 awg wire (the maximum that will fit in the controller) going from the controller to a 50A Thermal Fuse Switch/Breaker and then 2 Awg (good for 200A) running from the other side of the breaker directly to the batteries. With a total possible AMP Push of 190A I'm concerned that the maximum sized wire from the MPPT to the Hot side of the 50A Breaker is not big enough. Am I over thinknig this or to I need to bring the overall total possible charging AMPs down to the maximum the 6awg could theoretically handle so that the wires don't get too hot.

Thoughts?

 

[Suijkerbuijk]

Hi there folks - Its great to be here!

Here is the setup on my boat - It is all Victron.

I have 1800W Solar mixed Series and Parrellel into 2 banks of 2 each to a Victron 100/50 MPPT Controller network to a Carbo GX and Connected Directly to my Battery Bank. I also have a Generator that is connected to a Victron Inverter Charger that can push out up to 120A.

If I run my Generator during a normal sunny day this could mean that I could have crica 190 Amps pushing into the batteries.

Now for my Question - I'm beefing up my wiring where I can to cope with the overall total possible amps. From the Charger to the Batteries I'm good (1/0 AWG Wire) however, from the Solar controllers I have a challenge. on the PV Side the amps are low so I am not concerned (80V+ at 7-9amps) on the Battery side it is 14.xx at 30+amps. I have 6 awg wire (the maximum that will fit in the controller) going from the controller to a 50A Thermal Fuse Switch/Breaker and then 2 Awg (good for 200A) running from the other side of the breaker directly to the batteries. With a total possible AMP Push of 190A I'm concerned that the maximum sized wire from the MPPT to the Hot side of the 50A Breaker is not big enough. Am I over thinknig this or to I need to bring the overall total possible charging AMPs down to the maximum the 6awg could theoretically handle so that the wires don't get too hot.

Thoughts?

Oke again ABYC standard vs iso standard.
Download the Victron tools app.
Than you can calculate.

I use the same 100/50 model .
Its max is 16mm2 cable input .
Normal a mppt can have a 2 meter wire and its iso certificate with it.

See attach file.

Than again in the Manuel it tells you see the country rules .
If that means that the ABYC standard that cable can not be use .
Than simpel solution will be
A bigger cable to a busbar and from that busbar to the mppt with the 16mm2 cable in 0.5meter specs.

Now u use a breaker so how far away is that from the mppt.

 

[Rocketman]

6awg wire is rated for 50amps. So as long as each mppt has 6ga wire going to the larger wire - you are good.

 

[featherlite]

6awg wire is rated for 50amps

Temco fine strand, 6 AWG welding wire, is rated at 115A, which is the same spec for the Windy Nation 6AWG wire. Both have EDPM insulation rated at 105C.

I wonder what kind of insulation the 6 AWG wire rated for 50 amps has.

 

[jdege]

Temco fine strand, 6 AWG welding wire, is rated at 115A, which is the same spec for the Windy Nation 6AWG wire. Both have EDPM insulation rated at 105C.

But is it tinned?

 

[featherlite]

But is it tinned?

No, good catch!

But this below 6 AWG is tinned:

6 Gauge (6 AWG) Marine Grade Tinned Copper Battery Cable with Ends UL1426

www.batterycablesusa.com

 

[subsonic]

All good replies, thanks. The MPPT's are only about 1 Mtr from the Busbar and less than 2 from the batteries. The Breaker is only 6 inch from the MPPT's. I'm making sure that I have 6 AWG to the bus bar and then 2 awg from the bus bar to the Batteries.

 

[yabert]

Hi there folks - Its great to be here!

Here is the setup on my boat - It is all Victron

BTW, we like pictures

 

[l00semarble]

if you have 1800w of solar panels why do you only have a 50a MPPT? 1800w into a 12v system would be up to 150 amps. You are leaving up to 2/3 of your production off the table?!? Or maybe you are saying you have two MPPTs. Even then you are still well short of being able to produce anything close to 1800w and you are leaving up to 1/3 of your production off the table.

Since you say the inverter/charger will do 120a charging we have to guess that you have a Multiplus 12v/3000w. The cable sizing from batteries to bus bar and bus bar to multiplus is not limited by the charging current, it is limited by the inverting current plus house loads. The cable needs to be rated to support the 3,000w load plus surge capability which is near double. So this is 250 amps with surge up to near 500 amps. Then you have to add the 12v house loads to that for the battery to buss bar part of the install.

But even more importantly, especially on a 12v system, is to manage voltage drop to inverter at full inverter output. 1/0 AWG is not the correct cable. We can consult the ampacity table but ampacity is not the limiting factor here. You need to spec cable to meet voltage drop requirements and it will easily exceed required ampacity.

Then there is also the manufacturers instructions which you need to honor if you expect it to work properly per specifications and be supported by Victron/your dealer. If I'm correct about the model you have the Victron manual will tell you to use DUAL 1/0 AWG so literally double the cross section that you have now. Not sure why so many people simply ignore this and prefer to follow youtube or other sources rather than Victron's instructions that come in the box.

6AWG marine 105c cable is fine for the 50a from MPPT to bus bars. The ampacity is fine and voltage drop over a short run is not a big deal since with Cerbo you can use DVCC which will perfectly compensate for the voltage drop MPPT to battery.

I don't understand how you seem to be describing that you expect the charger output to go through the breaker in the MPPT circuit. Why would it be like that?

As other states pics help a lot to understand what you are dealing with. And a schematic. Then we can really help.

 

[Suijkerbuijk]

if you have 1800w of solar panels why do you only have a 50a MPPT? 1800w into a 12v system would be up to 150 amps. You are leaving up to 2/3 of your production off the table?!? Or maybe you are saying you have two MPPTs. Even then you are still well short of being able to produce anything close to 1800w and you are leaving up to 1/3 of your production off the table.

Since you say the inverter/charger will do 120a charging we have to guess that you have a Multiplus 12v/3000w. The cable sizing from batteries to bus bar and bus bar to multiplus is not limited by the charging current, it is limited by the inverting current plus house loads. The cable needs to be rated to support the 3,000w load plus surge capability which is near double. So this is 250 amps with surge up to near 500 amps. Then you have to add the 12v house loads to that for the battery to buss bar part of the install.

But even more importantly, especially on a 12v system, is to manage voltage drop to inverter at full inverter output. 1/0 AWG is not the correct cable. We can consult the ampacity table but ampacity is not the limiting factor here. You need to spec cable to meet voltage drop requirements and it will easily exceed required ampacity.

Then there is also the manufacturers instructions which you need to honor if you expect it to work properly per specifications and be supported by Victron/your dealer. If I'm correct about the model you have the Victron manual will tell you to use DUAL 1/0 AWG so literally double the cross section that you have now. Not sure why so many people simply ignore this and prefer to follow youtube or other sources rather than Victron's instructions that come in the box.

6AWG marine 105c cable is fine for the 50a from MPPT to bus bars. The ampacity is fine and voltage drop over a short run is not a big deal since with Cerbo you can use DVCC which will perfectly compensate for the voltage drop MPPT to battery.

I don't understand how you seem to be describing that you expect the charger output to go through the breaker in the MPPT circuit. Why would it be like that?

As other states pics help a lot to understand what you are dealing with. And a schematic. Then we can really help.

View attachment 255549

On a boat you will never have that max out put from the solar.
Reason the mppt stay in tracking mode .
The panels are flat .

1800:14.2 volts is = 126a .
Minus the big lost we have by a moving boat .
126a - 35% lost = 82 a total output

See my mppt on the boat on still water

So no you can not use house calculation for a boat .

 

[l00semarble]

On a boat you will never have that max out put from the solar.
Reason the mppt stay in tracking mode .
The panels are flat .

1800:14.2 volts is = 126a .
Minus the big lost we have by a moving boat .
126a - 35% lost = 82 a total output

See my mppt on the boat on still water

So no you can not use house calculation for a boat .

At first I thought you had just one MPPT. With two it is more reasonable and it looks like you have intentionally overpaneled which is fine. But on the other hand....on a boat the quantity/size/mounting of the panels is the hard part. Adding a larger MPPT is relatively cheap/easy so personally I spec systems so that we can harvest all possible power from the panels.

Also you shouldn't spec cable by what your "average" or normal current will be. You need to spec cables based on the maximum possible. Under some conditions you may not lose 35%. As you said boats move so maybe it moves to the tropics and sun is perfectly overhead sometimes and the batteries don't always charge at 14.2v. If they are very depleted they will eat full MPPT output at a lower voltage and current will be higher.

Anyway - 6AWG is fine for MPPT to battery bus on a 50a MPPT. Still confusing why you are adding the charger output to this solar circuit.

 

[Suijkerbuijk]

At first I thought you had just one MPPT. With two it is more reasonable and it looks like you have intentionally overpaneled which is fine. But on the other hand....on a boat the quantity/size/mounting of the panels is the hard part. Adding a larger MPPT is relatively cheap/easy so personally I spec systems so that we can harvest all possible power from the panels.

Also you shouldn't spec cable by what your "average" or normal current will be. You need to spec cables based on the maximum possible. Under some conditions you may not lose 35%. As you said boats move so maybe it moves to the tropics and sun is perfectly overhead sometimes and the batteries don't always charge at 14.2v. If they are very depleted they will eat full MPPT output at a lower voltage and current will be higher.

Anyway - 6AWG is fine for MPPT to battery bus on a 50a MPPT. Still confusing why you are adding the charger output to this solar circuit.

Not my topic starter .

 

[yabert]

On a boat you will never have that max out put from the solar.
Reason the mppt stay in tracking mode .
The panels are flat .

I bet that can be different for you at 52e parallel and a guy, let say at 25e parallel in Florida

 

[l00semarble]

Not my topic starter .

Sorry I'm not paying attention.

 

[Suijkerbuijk]

I bet that can be different for you at 52e parallel and a guy, let say at 25e parallel in Florida

No not really.
Flat solar panels have that problem.
It have a lost ,it not face to the sun .

A boat move always by the wave of the water .
So the panels are not a fix position .
The angle degrees move by the waves .
So that means the panels move to .
So the volts go up and down to it .

Now with Victron have a fast track systeem
Other model like epever not .
So i dit see ingreas on charge over the day .
That the Victron make more than my epever's.
Reason i have sell both 150/20a epever's to Victron 100/50 and 100/20 model unit.
(More solar panels to the roof for the 100/50 model)
( 100/20 model still use the same 250watts panels what epever had so it see a big improvement on that setup)