Limits / guidelines on cable length -- solar panels

Options
RobertG
RobertG Member Posts: 28 ✭✭

I currently have the standard 4-way splitter and a 35' cable to bring power from my 3 Boulder 200's. Chasing the winter sun, it appears as if moving the panels onto some dormant raised beds further from the house would be necessary, and the 35' cable likely won't quite cut it (my Yeti is in a climate controlled cellar and the cable passes through a 1/2" hole drilled through the wall baseboard atop the concrete foundation).

My question is this. I am given to understand that DC power tends to get lost over longer cable runs, which is why our grid is AC and not DC; we'd need a power station in each neighborhood otherwise. Elsewhere I read that losses are less with DC; probably depends on what you're talking about exactly; it sounds like very high voltages transmit with less loss on DC vs AC, different gauges of wires matter, etc. Either way, there is loss.

How much of a factor is this if I add another length of the cable that GoalZero sells for these panels? For flexibility I'd buy another 35', for efficiency I'd might buy a shorter length, maybe 10', that would solve this particular placement issue. If the efficiency loss isn't very great, I'd probably go with the longer length.

Answers

  • RobertG
    RobertG Member Posts: 28 ✭✭
    Options

    OK well ... I am just going to buy another 35' I think and if that proves to be a problem I'll just point customer service back here [shrug]

  • jg164
    jg164 Administrator, Moderator Posts: 313 admin
    Options

    @RobertG,

    Each solar panel should only have its own extension cable before the combiner. Combiners are meant to be the last part of the circuit that is plugged into the Yeti. Any other arrangement than that will increase resistances, voltage drops and risk of damage to cables and combiners ( i.e. melting of insulation, separation of soldered wires ). Please do not combine and then extend. The parts are not made to handle that current.

  • ctc91711
    ctc91711 Member Posts: 5 ✭✭
    Options

    Thanks for this question and answer, but let me restate to make sure I understand since this is close to what I'm trying to do and I'm a total newbie at this!

    I want to mount 4 Boulder 100's on my roof that will charge a Yeti 1500X, 4 tanks, and home integration kit that are already set up in our basement. It sounds like you're saying I will need to get four really long cables to do individual roof-to-basement runs from each panel and THEN add merge them with a 4-to-1 high power port combiner down in the basement which then connects to my 1500X. Did I understand that correctly?

    Also, I haven't measured the roof-to-basement distance yet, but does GZ (or a third party) make standard or custom-built longer-haul cables that will help reduce loss I'd experience with multiple shorter cables plugged into each other?

    Thanks in advance for your assistance!