I need a Victron Solar Panel Kit for my Boat that will allow for the maximum charge rate and possible future expansion of battery bank.
I have a Bavaria 42C (2005) and having shipped the vessel to the Med I now need a solar-panel set-up (previously in the UK it had none).
I would like to purchase a Victron kit because I can be assured of all components being compatible and from a reputable source.
The Bavaria has 2 x 140 Ah (660Wh) house batteries and a 60Ah cranking battery.
I need to spec a Victron Panels and Controller/cables Kit suitable for my vessel.
I’m looking to mount the (rigid) panels on the roof of the Bimini - above the sunbrella material and probably secured to the cross-hoops of the bimini by using U-clamps.
I also need the kit to support the most efficient charging of my existing battery set and allow for some future expansion?
What battery voltage, how much power will you use daily, do you expect the panels to generate this power at all times of the year. This info may allow us to recommend a panel power and MPPT controller but panel size will depend on physical layout.
These were your questions which I have tried to answer. Hopefully there’s enough information here to spec. a kit.
What battery voltage? - 12V
The Bavaria has 2 x 140 Ah (660Wh) 12 V house batteries and a 60Ah cranking battery (I think I should exclude the cranking battery because it will be used to start the engine and will then be immediately replenished by the alternator. So total 280 Ah house batteries.
How much power will you use daily?
No idea - I can try to calculate by taking all the 12V consumers and work out what the requirement might be. But it’s only going to be an estimate.
Do you expect the panels to generate this power at all times of the year?
Yes.
The boat is on the Med so it will have many long hours of unshaded exposure - even during winter. We will need 12 V when anchoring but we can also start the engine to charge the house batteries which has a high output alternator.
I have seen a Victron Kit - as follows:
Victron 300W Mono Solar Panel Kit with two rigid panels
1580 x 680 x 35 - we have enough real estate above the Bimini to accommodate these and indeed possibly six of these panels depending upon weight.
That kit also has an MPPT 100 | 30 Victron SmartSolar Charge Controller with bluetooth.
That would appear to fit the bill for us but is 300w enough? So to answer that I used an on-line solar panel size calculator and it says that to charge the two lead/acid 140 Ah house lead-acid batteries from 50% to 100% with 300w of solar panels it would take around 8 hours - in winter - even on the Med that’s a long time.
To charge them from 50% to 100% in four hours I would need 800 watts.
What are the highest output panels of dimensions 1580 x 680 x 35 that Victron sell to produce around 800W. Also what MPPT controller and cables would this need?
OK, I have found in the UK on our boat that 700W covers our daily needs from late spring to early autumn unless weather is poor and that we use around 100Ah daily, which would fit with your battery bank size. Therefore, the 800W would be reasonable in the Med with a SmartSolar 100/50 MPPT or 150/60 MPPT depending on your panel voltage and arrangement.
Have a look at the Victron solar panel SPM042152402, 215W, 1580 x 705 x 35. You would have a peak of 860W and need the 150/60 MPPT. You would connect these panels with two in series and 2 in parallel.
Have a look at the Victron solar calculator, it has the details of all the panels, you can put your location in and it will estimate year round production and recommend the MPPT to use with the panels. You can of course use panels from other providers. The second link takes you to a prediction for the set up I have mentioned, I picked Ibiza for the Med and this give a good solar yield the full year. Obviously for a lot of the year there will be more than enough solar.
Many thanks PWfarnell - this all starting to make sense now and I’ve used the Victron Calculator - which is great.
Two questions just now:
For my possible six panels - I have put to the configurator as 3 in series in two strings - that seems to be correct?
Also - if I purchase 24V panels - will the Controller still output to charge the batteries in 12 volts?
If you have 6 Victron panels, of 150W or 175W with the 150V controller you can do 3 panels in series at the max voltage is less than 100V even when cold. The 215W panels I linked to can only be used as 2 in series because when cold the voltage is over 50V per panel so 3 would be over the 150V limit.
The MPPT controller will convert the panel voltage to the 12V battery voltage so a 24V panel is fine, and by putting them in series you generate 80V to 100V which is converted to 12V.