One for the electricians...

[Andy Bav]

Boat is in Med and I am looking at ways to keep batteries topped up without having shore power attached 24/7. Solar panels are the obvious answer, and I would likely get a qualified local to fit but would appreciate comments before I engage anyone, to ensure I get it done properly

I have seen some kits where the power is "pushed" through the 12v socket but assume that this would keep the house battery topped up only.

My shopping list would include panel, cables to regulator and cables from regulator to battery bank (or existing regulator ?)

Question is whether this is a new system to connect to existing battery or whether existing regulator could take 2 "feeds". Currently in UK so can't get name / photos of existing charging set up, but some initial advice would be welcome as I am sure it's an easy fix ... But likely easier to get wrong

Boat is 3 year old Bavaria..

 

[VicS]

Boat is in Med and I am looking at ways to keep batteries topped up without having shore power attached 24/7. Solar panels are the obvious answer, and I would likely get a qualified local to fit but would appreciate comments before I engage anyone, to ensure I get it done properly

I have seen some kits where the power is "pushed" through the 12v socket but assume that this would keep the house battery topped up only.

My shopping list would include panel, cables to regulator and cables from regulator to battery bank (or existing regulator ?)

Question is whether this is a new system to connect to existing battery or whether existing regulator could take 2 "feeds". Currently in UK so can't get name / photos of existing charging set up, but some initial advice would be welcome as I am sure it's an easy fix ... But likely easier to get wrong

Boat is 3 year old Bavaria..

Options include a single solar panel large enough to maintain both battery banks and a dual output controller. (For purely maintenance charging the solar panel may not have to be all that big.) Or if more convenient separate solar panels and controllers for the two battery banks.

Definitely connect directly to the batteries ( via fuses) so that the main isolator switches can be OFF

 

[5teve]

Is there a VSR or other dual battery control between the banks?

If so - then by connecting a panel or panels to one bank of batteries, the VSR should allow the charge to flow to the other bank, keeping both topped up.

Steve O

Edit - in my small tinny (6m) I have the crank battery connected to solar - and the VSR (dual battery controller) then ensures the crank is upto 12.5v and then opens to the house battery - in practice the controller is never closed now with a fixed panel.

 

[Andy Bav]

Thanks 5teve. Think a photo of the arrangement is required ��

From what I can see the mains comes into a regulator (possibly a VSR) and distributes from there. We are back out in 2 weeks so I'll post a picture.

 

[Portofino]

Andy Bav -what's the rational for not having the shore power hooked up and left on ?

 

[Andy Bav]

Andy Bav -what's the rational for not having the shore power hooked up and left on ?

This time of year it is plugged in all the time but I am looking towards end of season where she could be left for 4 - 6 months. Have heard a few instances of lightening strikes and regulator failures. Last Sept we left her unplugged and when we went back in April and after an overnight charge all was well, but I would prefer an isolated trickle charge for good battery management, especially as when we arrived in September after a 6 week break the shore power was fried - I think due to a bad connection - and we were running around in failing light wiring up a replacement. Agree that a permanent plug in is an option but am looking at a lower risk option...

 

[symondo]

I've no experience of solar charging, but I would suggest panel to a regulator/controller to give smooth regulated power to the batteries correctly. Wire direct to batteries with a fused connection.

I would be inclined to wirewire to all batteries and spread the charge As you suggest it maybe left unplugged for a month or more I don't think you'd have much issue with all batteries turned off and trickle fed in this manner

 

[vas]

my only Q is why bother charging the engine batteries?
They never seem to drain (as typically nothing is hooked up to them...)

I'm about to install 2X280W panels through a Victron PPTwhatever thingy and feed the charge to the 2X2X180Ah service bank, directly. This way I hope all my electronics gizmos and one fridge will be fully working and batteries charged throughout the season. Boat is in a marina but no easy access to shore power (nor I want it tbh)

cheers

V.

 

[BartW]

my only Q is why bother charging the engine batteries?
They never seem to drain (as typically nothing is hooked up to them...)

Vas, when left alone for 4 to 6 months it is better to top up the engine batteries,
they will drain from internal resistance...even when nothing is connected (especially when they get older)

to OP,
I would install the solar panels with a dedicated regulator, (Victron fe, but I gues there are others )
and connect this directly to the domestic battery's, in parallel with their charger, and alternator.
Then I would add a Victron Cyrix battery combiner, this is a "intelligent" relay that conects the domestic and engine battery's in parallel if the conditions are OK.
meaning, it only switches ON when on one side the volatge >12,7 V (a charger is working)
it does NOT switch ON when the voltage on one side <12V (abnormal condition / broken battery, etc...)

have a plan to add such a solar system to our boat.

 

[rbmatthews]

If it is any help, here's the wiring diagram for ours, which has the solar panel keeping the domestic battery topped up and a dual sensing VSR which then connects it to the engine battery to keep that topped up. Priority is given to the domestic as most of the demand is on that rather than the starter battery.

https://shetlandf4.files.wordpress.com/2013/12/wiring-diagram1.gif

Seems to work OK.

 

[Andy Bav]

Many thanks all - at work at present so firewall prevents me opening wiring diagram !

Another reason for the solar panel is that during the winter months, I can't nip to the boat to make sure that the anodes haven't been eaten up and, whilst I understand that stray currents are not a feature in SCM, if they do become an issue, it may be too late before I find out .. so a self contained solution should work.