I’m planning a refit of boat electronics to a Victron Lifepo4 setup, with Multiplus II, BMS NG, Distributor, Cerbo or Ekrano, multiple Orion XS’s, etc.
Most of the equipment I think I’ve decided on, but possibly installing solar panels and mppt is still very much open.
In the Nordics many shops sell Sunbeam panels for boats and the few distributors I talked to definitely recommended Sunbeam MPPT with sunbeam panels, because they can apparently start charging with only 0.1-1,5V difference to battery voltage. Victron they didn’t recommend because it needs +5V to start. Also sunbeam Tough/Tough+ are meant for parallel connection only, which is anyway more or less the only way on a boat since some panel(s) will be likely partially shaded so the easy solution of putting panels in series is more or less not possible/sensible.
I’m looking at 3 panels, around 111W/116W each, one in front of the mast and one on each side of the companionway so at least one of them is likely at least partially shaded by boom/mast/rigging/etc.
If I’d go with Victron MPPT, it seems there’s a risk that charging will not start or will start only on or near optimal conditions, but if it works then all the Victron systems will nicely communicate with each other.
If I’d go with Sunbeam MPPT, then I lose the comms and to get charging data to Cerbo/Ekrano, I might have to get a separate shunt?
I’d also need to set the absorption voltage a bit lower than the multiplus absorption setting?
Some discussion on the topic here, which is one of the reason I’m also thinking that Victron MPPT might not be ideal in this setup.
If anyone has Sunbeam MPPT in a Victron system (On a boat, preferably on the northern hemisphere or in the baltics) would love to hear experiences (good and bad). Suggestions and tips also welcome. I’m trying to decide on all the technical details first so everything ‘looks good on paper’ before buying the gear
Wow, they are asking 689€ for a 116W flexible panel and are not even providing a datasheet? I know that flexible panels are/were always more expensive, but you can get 450W rigid ones for under 100€ nowadays.
Personally i would use an MPPT for each panel, the 75/10 should do it. Since all three panels will get mounted facing different directions if i understood correctly. Then you also dont have to worry about reverse currents which can be an issue when using three or more panels in parallel. The PV does need to rise above Vbat+5V in order to start charging, but after that it keeps charging down to Vbat+1V.
The price is not (quite) that bad, although the Sunbeam flexible panels (of flexible panels in general) are still very expensive.
Right now there is a convention where you could get 111W Tough Black panel for 379€ (normally +100€) or the 116W Tough+ for 549€ (normally +150€).
I actually might not be able to fit 3 x 111W panels so likely need to go 2 x 78W and 1 x 111W, which would still make about 1k€ for 269W of panels. So yeah… Unfortunately I don’t have space for rigid panels.
And that’s why I want to be sure that the panels will work with the MPPT chosen. Victrons own calculator says for the 78W panel:
”This configuration works in most cases. To make sure charging works under all conditions, also when the battery is nearly full, you should increase the input voltage, for example by placing more panels in series.”
Unfortunately for the 111W panel it says:
**No matching controllers found.
**
It seems the 116W panel has slightly higher Voc so it gives the same result as the 78W panel in Victrons MPPT calculator (might probably work in most cases). However if I go to Tough+ panels it’s +500€ in cost (if discounts are still available).
Their all pretty low voltage, more voltage would be beneficial. Even though the list says not intend for series onnection, using two 39W in series would very likely perform much better than a single 82W. I wonder what the reason for that note is
