Solar Disconnect & Alternator Interference

[Be Free]

Originally Posted by donradcliffe

I always put fuses between the controller and the battery, and I have blown them more than once.....

Maybe a bigger wire and a bigger fuse? Sounds like you are leaving amps on the table.

[nuku34]

To Charlie J:
Here's the quote from my post regarding solar controller damage:
2) Victron says do NOT put any switches or fuses between the controller and the battery (you will find this warning in the manual). If you disconnect the controller from the battery for any reason while the panels are producing any output, you will damage the controller beyond any repair.
I also said:
3) Yes, good idea to have a fuse in the pos line from controller to panels to protect that wiring.
You will find what 3) Yes, good idea to have a fuse in the pos line from controller to panels to protect that wiring.


You'll find the citation on page 12 and 13 of the manual for the Blue Solar 70-10 which can download from the Victron website.



I have 3 different brand solar controllers and they ALL say do not disconnect the battery from controller when panels are producing output. With respect, why don't you give it a try with your own controller and let us know the result?

[donradcliffe]

Originally Posted by nuku34

To Charlie J:
Here's the quote from my post regarding solar controller damage:
2) Victron says do NOT put any switches or fuses between the controller and the battery (you will find this warning in the manual). If you disconnect the controller from the battery for any reason while the panels are producing any output, you will damage the controller beyond any repair.
I also said:
3) Yes, good idea to have a fuse in the pos line from controller to panels to protect that wiring.
You will find what 3) Yes, good idea to have a fuse in the pos line from controller to panels to protect that wiring.


You'll find the citation on page 12 and 13 of the manual for the Blue Solar 70-10 which can download from the Victron website.



I have 3 different brand solar controllers and they ALL say do not disconnect the battery from controller when panels are producing output. With respect, why don't you give it a try with your own controller and let us know the result?

I don't know what you have been smoking, but I find that the Victron manual clearly states the size of the fuse to put in the wire from the controller to the battery in Section 4.2 on Page 9.

[NYSail]

I have a breaker between panels and controller. Comes in hand when I need to turn off the power. And yes when panels and engine are running after a few hours my tach will stop. They don’t play well together…. At least my last controller which was a Renogy 40 amp mppt. Just bought a 100/50 I stalled for this season. So i turn panels off when powering long distances1+ hours.

Greg

[Wotname]

Originally Posted by nuku34

To Charlie J:
Here's the quote from my post regarding solar controller damage:
2) Victron says do NOT put any switches or fuses between the controller and the battery (you will find this warning in the manual). If you disconnect the controller from the battery for any reason while the panels are producing any output, you will damage the controller beyond any repair.
...........

You'll find the citation on page 12 and 13 of the manual for the Blue Solar 70-10 which can download from the Victron website.



I have 3 different brand solar controllers and they ALL say do not disconnect the battery from controller when panels are producing output. With respect, why don't you give it a try with your own controller and let us know the result?

With respect, you are providing erroneous advice, please stop. Not only is your advice incorrect, it is potentially dangerous to suggest not having a fuse between the battery and solar charge controller (located close to the battery). But don't take my word for it, check the various Victron manuals e.g. page 4 of https://www.victronenergy.com/upload...R_DE_ES_SE.pdf

or page 11 and 14 of https://www.victronenergy.com/upload...ual-pdf-en.pdf

Screenshots attached.


Consider the worst case scenario.
1. Fuse fitted and blows - destroys solar charge controller
2. No fuse - fault in wiring (or controller) burns boat to the waterline

Me - I'll take my chances with #1 but never with #2

[OS2Dude]

Originally Posted by Gone Gypsy

Any comment based on experience on installing breaker switches on panel cables before controller? Good idea? Waste? Thanks.

You can't use any old breaker in a DC system, it MUST be a DC breaker. Breaker is a good on/off switch to disconnect panels before disconnecting bank from controller.

Section 4.2 of the Victron MPPT 100|50 manual states you MUST have a fuse between battery and controller.
4.2. Battery
The battery supply must be protected by a fuse as per the below table.
Solar charger type Minimum battery fuse rating Maximum battery fuse rating
MPPT 100/30 35A 40A
MPPT 100/50 55A 70A

Every connection to a battery should be fused. It -may- harm the controller if the fuse blows while the array is operating but even if it does it is better than risking a fire.

[CharlieJ]

nuku34:

2) Victron says do NOT put any switches or fuses between the controller and the battery (you will find this warning in the manual)

Please provide the citation for your assertion/interpretation. And while you are in the manual, read it closely and review the illustration.

[Gone Gypsy]

Thanks everyone for your input. I have planned DC disconnects on both legs between panels and controller. I had planned a 40 amp fuse between Victron 100/50 controller and battery because I am only delivering 27 amps max but understand 70 amp fuse would be appropriate for full 50 amp output.

We are leaving boat so I can order and be home for delivery of the goodies in 3 days. Will keep you updated on install. Will post install to the popular solar picture string in this forum.

Thanks again,
Gone

[robbjd]

Seems some of this forums contributors are dyslexic or just plain dumb! Read your manual and it clearly shows protection between the panels and controller, and the controller and batteries. I have 1-230 watt panel feeding through a 40A double pole breaker to a Victron 100/30 Smartsolar charge controller, which then feeds my LiFePo batteries via a 40A fuse. Depending on your panel setup,without the breaker or fuse upstream of the controller you could expose yourself to a high enough voltage to do yourself harm, or worse.

[mroc]

Hi All,
I did a major redo of my Bene 331 which had quite troublesome DC system. My observations:
-solar doesn’t interfere with my Balmar 120A alternator and 618 regulator- it pumps 90A onto batteries that are low on SOC no problem
- fusing is a must and do it if you want to be safe and alive
- I have a couple of switches that allow me to do solar’s parallel or in series but I found parallel more efficient most likely due to shading

[Gone Gypsy]

mroc,
I pushed the button and ordered. Order includes Y connectors for parallel so I can test series against parallel in my exact application. Not a switch like your setup for quick comparison, but capable. Victron in particular says series will deliver higher total energy when coupled with panels that have diodes. From my reading most cruisers - More than 80%, say parallel is the way to go. This number I think is weighted by lots of Bimini installs that have considerable shading. Our install is on davits with minimal shading using diode panels. We’ll see!

[Wotname]

Originally Posted by Gone Gypsy

Thanks everyone for your input. I have planned DC disconnects on both legs between panels and controller. I had planned a 40 amp fuse between Victron 100/50 controller and battery because I am only delivering 27 amps max but understand 70 amp fuse would be appropriate for full 50 amp output.

We are leaving boat so I can order and be home for delivery of the goodies in 3 days. Will keep you updated on install. Will post install to the popular solar picture string in this forum.

Thanks again,
Gone

Sounds like a good plan. Just make sure the fuse between the solar controller and battery is placed as close as practicable to the battery end of the wire.