I can run these in series or parallel as both V & A are within the controller spec for either set up.
For my purposes I'll run in parallel to keep the panels independent of each other. Been on too many tree branch shaded sites to have the whole show pulled down by an errant branch.
https://www.renogy.com/learn-series-and ... LgjlkM5pL6
This means (a teaching moment) that my Amps will increase. Handy reminder below.
It also means Iin theory that i'd be using larger DC cables than if I ran the panels in series (in which case the Voltage would rise). As i wish for my two panels to output independently of each other my choice is parallel.
Going back to my panel chart I have a choice. My Voltage remains the same at a Voc of 23.7V while my Amps in parallel double from a max current of 9.85A to 19.7A.
This is close to the limit of the Victron 100/20 (20A max) but it is within spec. The short circuit Amp value for the panels is 10.5A or 21A in parallel so I'll make sure my cables are rated to at least 21A.
I've been reading up on the load output function on the Victron 100/20. I could save a few quid and go for the controller option that doesn't have that function but it's only a fiver difference so in this case I'll have the unit with the load option terminals and it can be a neat way to connect in the hypothetical 5V system leaving the heavy load gear to a T off inverter mounted close to the controller. This last for physical siting rather than load draw point.
The DC cables from Victron 100/20 to battery & inverter are a different story and I've not worked that out yet as to their size. They will be 12.8VDC with enough current being drawn to supply 1kW & 240VAC. I'll have to check the lowest VDC likely to be seen at the bottom of the Lifepo4 charge and spec cables from there rather that at 12.8VDC.
I hope the above isn't too boring but I like to plan these things through so i get it right at the first pass and it's nice to leave a wee learning read for others passing through. Feel free to rip into any glaring inconsistency.
Now that I've mentally committed to the wild freedom of parallel PV I'll need a couple of branch connectors to bring 4 cables down to two cables for the pass through of the RV monocoque.
The beauty of doing it piano piano is that I can spend a few quid more only and a large section of the work will be complete and safe. I.E PV installed up top and power brought into the utility cupboard in the van and terminated at a DC breaker.
The three items above were £34 and that combined with one carefully applied holesaw through the monocoque
will get us inside the van and into the utility cupboard. I resisted the call of the super cheap versions as they'll see a fair bit of movement and UV. Hopefully I can fit the panels close enough to each other that I can hook them up without intermediate cables.
I'll need some aluminium flat bar & s/s bolts along with Hellerman UV resistant Ty wraps. Put all that together carefully and it should hopefullu be a fit & forget system.
Running total
£165 Bifacial 195W panels 2 of
£34 DC isolator, cable entry & Y's
£199
I'm £8 under my original estimate and got the DC isolator thrown in too.
Looking forward to seeing what a good rummage provides in the way of PV cable and mc4's back in the workshop. I have no real recollection of what we've got..
That's as much joined up thinking as I can do in one go. The wind has dropped so I'm away down to see if we can get a couple of shore dives in today.
