ABYC and ISO Li reference diagram

[newhaul]

Originally Posted by rgleason

Thanks Newhaul!

No problem
I drink coffee and I know things

[goboatingnow]

Originally Posted by s/v Jedi

Citation for powering up in previous state? It is auto-releasing, just like the solenoid, which isn’t fail safe either, plus it requires another manual switch in parallel for manual override, which is built into the RBS. The extra cabling added to the manual switch and you are at the same price.



130mA is nothing? Do you realize that this is a 24x7 load? It’s more than 3Ah per day for a relay! It’s also a 1.5W heating element, I can assure you that it gets hot.

I can say it gets mildly warm that’s all

The TE solenoid is completely fail safe as of the coil power disappears the relay opens.

As I read the ML spec this will open happen of the control line opens. The trouble is if the 12v collapses the RBS will not change state.

The TE despite a measly 3AH a day is a better all round compromise

[goboatingnow]

Originally Posted by s/v Jedi

I held the diagram against ABYC recommendations and it appears that the manual switch violates 13.7.7



13.7.7 No electrical connections should be made directly to a lithium ion battery that would bypass a BMS or the protection relays.



The switch clearly bypasses the protection relays.

Firstly an open switch is not connected to the battery. That’s in plain sight.

Secondly both iso and ABYC recognise the need for overrides


“13.5.3 Consideration should be given to providing alternative power for critical systems (e.g., engine starting,
navigation lights, etc) if a BMS shuts down the battery.

“


Thirdly thd RBS ML has a integrated override that in theory violates your pedantry

It looks very much like you only accept your own ideas and no one else

[goboatingnow]

Originally Posted by newhaul

I have to agree the breaker / fuse is on the battery side and should be between the panels and the controller.

I see no point in fusing PV panels. They are current sources and the wire should be rated for Isc . The fuse can never blow

I’ve not seen any such fuses in the myriad of PV installs on boats around me.

There should be a fuse on the mppt output and at the battery. Victron have an output fuse. In my lightning strike these fuses saved the wire as the mppt output shorted

[goboatingnow]

Originally Posted by newhaul

A couple specific points I use a grp 27 flooded lead acid battery FLA for starting not a sealed lead acid . SLA .



As to the jump pack we'll the main thing I noticed running my auto repair shop was that most of my jump calls were because their jump pack was dead as well . Most people don't remember to charge it periodically.



You still haven't answered my question as to why not to parallel my FLA with my LFP for cranking up the engine ?

Drop in LFp and most BMS cannot handle engine start currents

[goboatingnow]

Originally Posted by newhaul

I have to agree the breaker / fuse is on the battery side and should be between the panels and the controller.

The output of any “ generator” connected to a battery should be fused at both ends. Thus includes mppt controllers.

On my case a lightening strike blew the output mosfet in the Victron mppt. The in-line fuse on the mppt output saved the day ax the battery was now seeing a direct short to ground via the mppt

Forget about panel side fuses.
The fuses shown are in the correct place.

[goboatingnow]

Originally Posted by rgleason

MPPT are fused at the Lynx Bus and 15a inline fuses are shown at the device, but I think they are on the wrong wire, shouldn't those fuses be on the solar panel wires? Also I need a switch there? (You advised me sometime ago about this, and I will find that thread and your excellent direction.)

Next revision will have a fuse on starter battery to Orion. Thanks.

The Orion Tr is now switched on and off automatically.


Sorry but this forum reduces the quality of the jpegs. I may try to split the sheets SK-1 and SK-2 next time.

You have them correct. Do not not change them.

[Sailmonkey]

Originally Posted by goboatingnow

You have them correct. Do not not change them.

I concur. The point is to fuse to protect the wire that can experience nearly unlimited current. This current comes from batteries. The solar panels are current limited, if the wire is the correct size they’re incapable of generating enough current to damage the wires.

[noelex 77]

Originally Posted by goboatingnow

I see no point in fusing PV panels. They are current sources and the wire should be rated for Isc . The fuse can never blow

Fuses are absolutely needed in some circumstances.

The simple rule of thumb is if you have three or more panels in a string, you need to include fuses on the solar panel side of the controller (in addition to fusing the battery side of the controller).

There is plenty of detailed information about this available, but unfortunately the myth of never needing to fuse PV panels keeps being repeated.

This is a link explaining how to calculate if fusing is needed:

https://www.explorist.life/how-to-**...y-not-need-to/

Even if fusing is not needed in a particular installation we need to make it clear that this is not always the case to avoid perpetuating this dangerous myth.

[Sailmonkey]

Originally Posted by noelex 77

Fuses are absolutely needed in some circumstances.



The simple rule of thumb is if you have three or more panels in a string, you need to include fuses on the solar panel side of the controller (in addition to fusing the battery side of the controller).



There is plenty of detailed information about this available, but unfortunately the myth of never needing to fuse PV panels keeps being repeated.



This is a link explaining how to calculate if fusing is needed:



https://www.explorist.life/how-to-**...y-not-need-to/

You’re correct, I keep forgetting about multi-panel arrays.

[goboatingnow]

Originally Posted by noelex 77

Fuses are absolutely needed in some circumstances.

The simple rule of thumb is if you have three or more panels in a string, you need to include fuses on the solar panel side of the controller (in addition to fusing the battery side of the controller).

There is plenty of detailed information about this available, but unfortunately the myth of never needing to fuse PV panels keeps being repeated.

This is a link explaining how to calculate if fusing is needed:

https://www.explorist.life/how-to-**...y-not-need-to/

Even if fusing is not needed in a particular installation we need to make it clear that this is not always the case to avoid perpetuating this dangerous myth.

Let’s dispel your myth

Firstly the link you provide refers to NEC code for land based systems none repeat NONE of this is relevant to a boat

Secondly even NEC realises you don’t need to fuse a PV panel.

“Solar arrays having higher current availability (parallel strings of solar panels) than the maximum overcurrent protective device rating specified for the panel shall be protected from overcurrent. EXCEPT when the short circuit currents from all sources do not exceed the ampacity of the wires and maximum overcurrent protective device size rating specified on the PV module nameplate.”

You have no business undersizing wires on a boat

Hence PV wiring should be able to carry Isc

Therefore fuses are rated over ISc and will never blow.

You need to read your own links you post

[goboatingnow]

Originally Posted by Sailmonkey

You’re correct, I keep forgetting about multi-panel arrays.

No he’s just wrong and nec code recognises it

Solar arrays having higher current availability (parallel strings of solar panels) than the maximum overcurrent protective device rating specified for the panel shall be protected from overcurrent. EXCEPT when the short circuit currents from all sources do not exceed the ampacity of the wires and maximum overcurrent protective device size rating specified on the PV module nameplate.

On a boat all panel wiring should be capable of handling the array IsC. That’s just safety first ,

On very large voltage arrays whereas conscious decision is made to undersize the wiring or less the array Isc , then yes fusing has a role ( as it has in all power source wiring ) but on a typical boat this is not the case.

[noelex 77]

Originally Posted by goboatingnow

Let’s dispel your myth
Firstly the link you provide refers to NEC code for land based systems none repeat NONE of this is relevant to a boat

Secondly even NEC realises you don’t need to fuse a PV panel.
“Solar arrays having higher current availability (parallel strings of solar panels) than the maximum overcurrent protective device rating specified for the panel shall be protected from overcurrent. EXCEPT when the short circuit currents from all sources do not exceed the ampacity of the wires and maximum overcurrent protective device size rating specified on the PV module nameplate.”

You have no business undersizing wires on a boat

Hence PV wiring should be able to carry Isc

Therefore fuses are rated over ISc and will never blow.

You need to read your own links you post

The “wires” most at risk are the wires inside the solar panel. These are the wires that are most likely to be subject to overcurrent and need protection.


The link you referred to:

“Solar arrays having higher current availability (parallel strings of solar panels) than the maximum overcurrent protective device rating specified for the panel shall be protected from overcurrent. EXCEPT when the short circuit currents from all sources do not exceed the ampacity of the wires and maximum overcurrent protective device size rating specified on the PV module nameplate.”

specifically states the “PV module nameplate” needs to be consulted to determine the capacity of these wires. This should make it clear it is not the wires that the boat owner installs, but the wires inside the solar panel that are at risk.

It does not help to advise boat owners “not to undersize the wiring” we have no control of the wire size used by solar panel manufacturers. These wires, like all wiring on a boat, needs overcurrent protection if a fault condition can supply more current than these wires can handle.

We need to stop perpetuating the myth that fusing of solar panels is never needed.

[s/v Jedi]

Originally Posted by goboatingnow

I can say it gets mildly warm that’s all

The TE solenoid is completely fail safe as of the coil power disappears the relay opens.

As I read the ML spec this will open happen of the control line opens. The trouble is if the 12v collapses the RBS will not change state.

The TE despite a measly 3AH a day is a better all round compromise

Explain that again for the diagram attached. There is only one control line, only when it has +12V the solenoid is on.

Are you trying to say that when the battery goes dead so that when there’s no power at any of the big terminals, it won’t change state anymore? It doesn’t say that but would be interesting to test. But it doesn’t matter, when there is no voltage, it can’t be switched on or off either.

No, I find these arguments weirdly weak

[Baronkrak]

Originally Posted by goboatingnow

…Secondly both iso and ABYC recognise the need for overrides….

“13.5.3 Consideration should be given to providing alternative power for critical systems (e.g., engine starting,
navigation lights, etc) if a BMS shuts down the battery….

“Alternative power" is not overriding or bypassing safety devices.

Originally Posted by goboatingnow

Thirdly thd RBS ML has a integrated override that in theory violates your pedantry

Originally Posted by s/v Jedi

I remove the loads, then switch the battery back on the bus manually,...