Charging circuits

[rascacio]

All my reference material is on board in Spain, and I'm in the UK, so I need some help with a circuit diagram / information to install an mppt solar controller.

What I'm not sure about is, can the panels be connected to the existing alternator charging circuit directly or do I need to switch them to off (isolate ) when the engine is running ?

Or is it possible to have them permanently connected to the charge circuit so they are working full time, and if so are diodes etc needed ?

It sounds simple but I can't find the answers I need after much searching. Any diagrams or pointers etc would be much appreciated.

I'm returning to the boat very soon and would like to have everything I need for the job with me.

 

[sarabande]

I don't know the mppt controller, but it won't be very different from my Steca.

Manual and diagrams here.
http://www.shop.solar-wind.co.uk/acatalog/steca_pr_digital_controllers_archive.html

It is important to connect the charger, batteries, and controller in a specific sequence, otherwise the system won't add up how much charge it has delivered, and may otherwise just give you Radio Three


I am not sure from your description that you should be joining the solar panel and the alternator circuit together directly. ??? More details perhaps please ?

EDIT

Doh ! MPPT controller manual here
http://www.shop.solar-wind.co.uk/acatalog/mppt_solar_charge_controllers.html

Sorry !

 

[rascacio]

I don't know the mppt controller, but it won't be very different from my Steca.

Manual and diagrams here.
http://www.shop.solar-wind.co.uk/acatalog/steca_pr_digital_controllers_archive.html

It is important to connect the charger, batteries, and controller in a specific sequence, otherwise the system won't add up how much charge it has delivered, and may otherwise just give you Radio Three


I am not sure from your description that you should be joining the solar panel and the alternator circuit together directly. ??? More details perhaps please ?

EDIT

Doh ! MPPT controller manual here
http://www.shop.solar-wind.co.uk/acatalog/mppt_solar_charge_controllers.html

Sorry !

Thanks for that. Not quite what I'm looking for though.

A bit more info, I'm upgrading my existing on board system with a second alternator to give a total of @150 amps, controlled with a Sterling alternator to battery charger system and new batteries, so basically we have a more powerful but essentially standard wiring layout. I also have a Sterling pro digital mains charger - 30 amp.

If I connect 2 solar panels into the batteries through any type of controller and at anchor the solar panels are working away grand but it's time to move on. If I fire up the engine and start blasting 150 amps into the batteries what happens to the solar controller / panels with this current ? Do I need to manually isolate them, fit heavy diodes, or is there another option that I don't know about, or does it not matter at all ?

 

[rogerthebodger]

I have just connected my solar, wind, mains and alternator all to the some set of batteries all the time with no problem.

The only thing is in the solar, wind and mains charger I fitted circuit breakers to protect the cables if a short should happen in any of the circuits. The alternator 120 amp does not as is normal in a car.

 

[rascacio]

I have just connected my solar, wind, mains and alternator all to the some set of batteries all the time with no problem.

The only thing is in the solar, wind and mains charger I fitted circuit breakers to protect the cables if a short should happen in any of the circuits. The alternator 120 amp does not as is normal in a car.

Sounds like we're getting somewhere. Anyone else with the Full Monty connected ?

 

[gasdave]

I don't have my final system installed yet but it will include a Smartbank connected across my batteries (essentially a VSR) and this will handle all charging sources at all times.

Not sure if this answers your question? The MPPT is there more to optimise the solar charge output for your batteries. I don't know if it offers any protection although certain controllers will block reverse current using diodes or open circuit. If diodes, I guess you would need to check spec to confirm they were up to 150A. If open circuit, what opens the circuit - this may well be a low PVC voltage, in which case you are not protected from alternator output if running the engine during daylight.

Perhaps you need to consider a relay from your engine starting circuit which will open the solar charging circuit (or even redirect the solar charge to another load separate from the alternator - water heater maybe?).

 

[William_H]

Charging

There should be no problem with the solar charger connected directly to the batteries. The alternator controller and indeed any step controlled charger will check the voltage of the battery. If this is already high due to solar charging then it will immediately or quite quickly reduce the charge voltage to float. Similarly the MPPT controller if it is set up for stepped charge voltage will simply sense a high battery voltage and throttle back to a float type voltage. If it is not a stepped type charging regime then no worries it will simply present 14v to the battery. If the battery is already at 14v due to other charging sources then simply no current will flow into the battery from the solar controller. good luck olewill

 

[ianj99]

All my reference material is on board in Spain, and I'm in the UK, so I need some help with a circuit diagram / information to install an mppt solar controller.

What I'm not sure about is, can the panels be connected to the existing alternator charging circuit directly or do I need to switch them to off (isolate ) when the engine is running ?

Or is it possible to have them permanently connected to the charge circuit so they are working full time, and if so are diodes etc needed ?

It sounds simple but I can't find the answers I need after much searching. Any diagrams or pointers etc would be much appreciated.

I'm returning to the boat very soon and would like to have everything I need for the job with me.

The solar panel regulator or panels without one won't be damaged when the alternator or mains charger are operating as they block reverse current.

 

[Stu Jackson]

Any input from any charging source are hooked up the same way. You alternator and shorepower charger go to somewhere in your system. Just land the solar input at the same place. The controller simply modulates the solar voltage and has nothing to do with any potential "backfeeding" or the like. Input to the battery banks is input, the batteries don't care what the source may be.

 

[rascacio]

Many thanks

Thank you all very much. It looks like I can just connect in my solar panels and controller into my system and not worry about them blowing up when 150 amps of charging current is running through my batteries !!

I like to keep things idiot proof so, irrespective of what system is running I don't have to throw switches and levers or worse expect someone else to do it if I'm not aboard for a few hours.

The main use for the panels is to keep the batteries up to par when leaving the boat for extended periods but it would be nice to harvest as much extra power as possible as you can never have too much can you !!! ?