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ooops, no my math WAS backwards!!! in Parallel the lsc will be 12.30A assuming lsc doubles with a parallel configuration in Series, the lsc will be 5.84A assuming lsc stays the same even while adding panels.

okay so the saga continues for those still interested;) Just went back to drawing board. current photo is set-up WITHOUT black neg up to windlass batt bus. I've got 9.4V everywhere except when volt meter lead is on black neg on small bus underneath charger with DC/DC charger OFF, obviously...

I've got 2X 170W solar panels that have about a 15' run to my MPPT charge controller. curious what size wire I will need. I've been advised 10AWG will suffice. Does this sound correct? and what about a 2' run from MPPT to Battery bank? thanks!

been reading of some other folks with RV setups having similar voltage drop issues. after all of this, I think the issue is the #8 cable from panel to DC/DC is insufficient. It's the same cable that's always been there yet it used to go to a Digital Echo charger for charging what was an AGM...

This is super helpful thank you! so the diagram you have with the non-isolated DC/DC is exactly the way we had it set up initially. The problem we were having was as soon as I powered on the charger the input voltage drops way down to 10V and automatically locks out (setting on Victron Orion)...

another beginner question here: the cables on my two panels are shorter than practical for connecting in parallel. Are there considerable downsides to installing short extensions to create more flexibility for mounting? panels are not far from charge controller. they sit on top of a bimini on...

FYI, the reason I have the small bus below DC/DC is that the yellow neg in and the black neg back out to windlass batt were too fat to fit into the GND port together.

1) panels are either or. not installed yet. 2) what is lsc? 3) battery bank is 12V

I've got a LifePO4 Windlass Battery that is totally separate (isolated) from the house LifePO4 bank. I use a DC/DC charger from main panel (house bank) to windlass battery. I originally installed a non-isolated Victron Orion DC/DC charger but was having problems popping the breaker at the panel...

I'd like to add a second MC4 disconnect in my wire run so that I can break solar panels down (semi-flexible on top of bimini) and stow them. Is it possible/appropriate/recommended to add another MC4 connector in the middle of the run from the panels to the charge controller? note: this is in...

Just installed a new Victron MPPT 100/30 controller and 2x170W panels. My system has an inverter/charger (shore power) and an alternator (engine running). Q: do I need to shut down the MPPT controller while I'm running the engine or when I'm connected to shore power? I'm assuming it's smart...

thanks for the lightening fast reply! Figured it would add resistance and cost efficiency, etc...will need to figure out alternative. Bimini is a covering over the aft cockpit of most sailboats, or even power boats. In my case, we like to take it down so solar panels would come down with it when...

Q: I've got 2x170W panels that I will likely wire in series to a 12v lead acid battery bank. Curious if a 30A/100V MPPT charge controller is sufficient. By my math, with 340W of power I'll be putting out 28.3Amps. is that enough margin for a 30A controller? Thanks!

Voc = 34.6v lsc = 6.15A not sure what open circuit voltage really means.

Victron MPPT 100/50 but wondering if the 100/30 would be suitable. it's cheaper.

I've got 2x170W panels I plan to wire in parallel going to a Victron 100/30 MPPT going to a 700Ah Lead Acid house bank. According to specs on my panels, Vmpp = 29.4V = 29.4V this stays the same in parallel Impp = 5.84A = 11.68A (this doubles in parallel) looking for consult on how I should...

Curious if there's a downside to using high quality marine grade tinned copper that is 10AWG 2 conductor (10/2) from panels to MPPT rather than single conductor cables. I'd prefer this as it's easier and cleaner for me to run 10/2 cable.

Hi, I've got 2x170W panels wired in parallel going into a Victron 100/30 MPPT controller and then into a 700Ah battery bank. Wondering what kind of protection is recommend before and after the controller. I'd assume 40A switch/breaker between controller and batteries but what about between...

yeah, it'll be 12.3A Isc. okay thanks. I'll look for one that is also a switch.

HA! Sailboats are only Off-Grid if they're not tied to the dock and shore power. We're kinda both. Winter=shore power and Summer=Off-Grid and no shore power;) lsc for 2X170W panels in Parallel will be 6.15A lsc for 2X170W panels in Series will be 12.30A that is if my series vs parallel math...

don't know the answer to that. are you suggesting three breakers? one for each panel and then one for the combined? I haven't seen anything like that before, but I'm really new to this stuff. on the steep side of the learning curve.

Isc is 6.15A was planning on running straight from the SCC to the battery. I have an inverter/charger but thought it wasn't necessary to go through inverter. at any rate, battery bank, inverter/charter, and SCC are all within about 15 inches of each other.

panels are SunPower 170W Monocrystaline flexible panels.

good point and thanks or the input! probably best to go with PV specific wire.

lsc of each panel is 6.15A

Thanks! so, what about running cable from SCC straight to batteries? is there a reason to go through Inverter?

I've got a Heart Interface Freedom 25. it's older but works like a champ.

another question: during AC (shorepower) charging or Alternator charging while running the engine, I'm assuming the MPPT SCC will read that there's already charge coming into the batteries and shut itself off?

gotcha. will check that out.

Sorry, FilterGuy, can't provide diagram at this time. Will try tomorrow. In the bigger picture, I'd just like a better understanding of the difference between Isolated and non-isolated DC/DC chargers and their application.