Relay to disable solar when engine running

[sailingabe41ds]

Originally Posted by fredericks

I found a very simple and low cost solution to the exact same problem I had. A simple on/off switch between the solar controller and battery bank solved the problem. Turning the switch off prior to engine start and turning it back on again after shutdown solved the problem. I added switch movement to my engine operation flow.

Thats what I have...I usually keep mine off. I usually keep it off and only turn on when I am anchored.
Abe

[SOLAR SUPPORT]

Originally Posted by hlev00

I want to disable my solar when my engine is running to avoid the solar voltage targets from conflicting with the alternator targets. If both are running the solar seems to confuse the Balmar gear. If I am running the engine, the alternator (Balmar 100A + ARS-5 regulator) can supply plenty of charging current compared to my solar (2X 190W banks each with a Victron 75/15 MPPT controller). Some suggestions are to set the solar target voltages below the engine alternator targets but then the solar never gets the batteries (Trojan T125) to their proper voltages.

So I am thinking of using two relays (one for each solar bank) so that when the engine is running the solar is disabled, but as soon as I shut down the engine, the solar will do what it can. I would use the relay to disrupt the current coming from the panels to the MPPT controllers. Automotive relays are designed around 12V @ 40A (480W) which is a lot more than either solar bank can supply. Is it okay if the solar voltages are higher as long as the total Watts are less than 480W?

Thanks,
Harry

If you want to cut energy coming from your solar panels you can place a cheap two pole 110-220 Volt AC automatic cutter between the solar panels and the charge regulator which is good for the max amperage coming from the solar panels. This AC cutter will cut + and - leads simultaneously when you switch it off or on. Do not put any relay or switch between the solar charge regulator and your batteries. It is essential for the solar charge regulator to stay connected to the batteries when you cut the energy coming from the solar panels because solar charge regulator needs to set its operating voltage before it has loaded by the energy coming from your solar panels. It can't do that when energy loaded to its solar input terminals.

[goboatingnow]

Originally Posted by flightlead404

I have just discovered a problem with my new solar installation and my existing shore power charger. This problem could just as well exist with any two charging mechanisms (I think, still researching).



It appears that the solar controller charges at a high enough voltage to cause my shore power battery charger to think there is a fault/over voltage situation and to go into a failure state. To recover I have to shut off all power, DC, shore power, and solar, then restart the charger. It does not recover automatically.



I believe this could happen with any two systems where one chargers at a higher voltage than the other and where the lower voltage mechanism has a high voltage fault sensing mechanism.

Even if the chargers faults , so what. It will recover when voltage falls

No charger should fault if the charging voltage is appropriate for the battery tech.

No solar should be set so high as to deliver a voltage that causes anything to “fault. “

Remember loads set current. The battery terminal voltage is a function of the battery chemistry primarily not the charge device. Two charge devices together share charge when the battery is low as the battery determines the voltage , as the battery charges the charge source with a higher absorption voltage will deliver almost all of the charge , but it’s a small current so no one cares precisely what charge source both delivers & finishes the absorption phase.

The should be NO reason to normally disable a charge source. If your solar is faulting your battery charger something is WRONG. fix the problem not go around it.

[Shaneesprit]

Battery always wins on voltage - I often used to run my 16V laptop from a 12V charging supply, solar panels from memory can produce high voltages depending on how many panels connected in Series - I might of missed how many panels you have, but turning off. free energy to produce electricity from diesel? Really In the current climate!

Yes I run Diesel for propulsion if needed, but that’s more environmentally friendly than trying to replace the diesel with an optimistic and unworkable solution. As small as my solar is i could never imagine to disconnect it.

[flightlead404]

Originally Posted by goboatingnow

Even if the chargers faults , so what. It will recover when voltage falls

No charger should fault if the charging voltage is appropriate for the battery tech.

No solar should be set so high as to deliver a voltage that causes anything to “fault. “

Remember loads set current. The battery terminal voltage is a function of the battery chemistry primarily not the charge device. Two charge devices together share charge when the battery is low as the battery determines the voltage , as the battery charges the charge source with a higher absorption voltage will deliver almost all of the charge , but it’s a small current so no one cares precisely what charge source both delivers & finishes the absorption phase.

The should be NO reason to normally disable a charge source. If your solar is faulting your battery charger something is WRONG. fix the problem not go around it.

I don't disagree with you, I'm just posting one possible cause of a malfunction.

I'm still researching....