Solar panel regulator output voltage

Discussion in 'Mech Tech' started by pkrboo, Apr 4, 2016.

  1. sANDYbAY

    sANDYbAY On benefits-won't sponsor!

    You've got me curious now so I've checked on the waeco cr50. According to waeco it draws 1.7 Ah/hrs at + 32 deg C ambient and 1.4 Ah/hrs at 25 deg C ambient. I'm not sure if that's averaged out over the duty cycle or not.
  2. Cr50 draws 5.7a when running so 1.7ah/hrs would be around a 30% duty cycle

    Sent from my Nexus 6P using Tapatalk
    sANDYbAY likes this.
  3. sANDYbAY

    sANDYbAY On benefits-won't sponsor!

    All I could see on their website was the voltage 12/24 but obviously we're on 12v and 40 watts which gives us three and a bit amps, (I think).
  4. Book says...
    5.7A rated current.
    40w average power consumption.
  5. I bet they have quoted the ah/hr values on 24v. I wonder if mine is actually 1.5ah/hr average then. Off to check now.... Sneaky buggers

    Sent from my Nexus 6P using Tapatalk
  6. Oh well I'm at a loss. The spec for mine says 35w with 0.44ah/hr at 20c or 0.67ah/hr at 32c and draws 5a at 12v or 2.5a at 24v. So even if that is 24v it doesn't add up to match the ah/hr to the wattage. Probably safe to assume it's 0.88ah/hr and 1.34 on 12v

    Sent from my Nexus 6P using Tapatalk
  7. Yea ..go and pull ya pork...:p
    paradox and theBusmonkey like this.
  8. Guys you're all over thinking it!
    Specs are complete plums until you've actually tested your systems! Power audit first and then work out what is needed.

    It's really simple, 200w from a panel will keep it all going (assuming compressor fridge)....if you're in the Med in summer!

    The biggest variable is the solar input in the UK,..& who's going to take a punt on that?
    Bertiebot and pkrboo like this.
  9. Woodylubber

    Woodylubber Obsessive compulsive name changer

    This is my fridge, does anybody know how many amps this would pull.

  10. 3.5 if that 42 W is the watts
  11. Woodylubber

    Woodylubber Obsessive compulsive name changer

    So would a 100w panel cope with that
    Last edited: Apr 30, 2016
  12. 100w will give theoretically around 8 amps on full chat. So yes it should keep the battery charged whilst the sun is shining.
    Woodylubber likes this.
  13. sANDYbAY

    sANDYbAY On benefits-won't sponsor!

    @theBusmonkey or possibly @matty or maybe @Bertiebot its been like Christmas here for the last two days and I'm now in possession of my controller and two panels plus some wire extensions.
    I'm currently looking for some inline fuse holders and I'm not sure which value of fuse I need. I've found one site which recommends a fuse for each panel plus a common fuse on the wire into the controller.
    They also recommend another one between the controller and battery but quite near to the battery.
    Apparently the output from the panels is cumulative and I have 2 X 100 watt panels and the wires are 2.5mm sq.
  14. sANDYbAY likes this.
  15. Bob, you're on the limit with that cable TBH. Splice in 4mm sq to the connector boxes if you can.
    The cable is rated 20 to 30 amps (depending if it's run in conduit or not) & your panels could put out a theoretical 15amps.

    All in all not an issue & it'll work safely but I'd be looking at using no more than a 20amp fuse at each of the recommended points. There is no point in going higher as the panel would be malfunctioning if it put out over 20 amps, the wire could get hot &......:eek: armageddon that's why the fuse is there.

    look at something like this:

    30 amps is the minimum fuse size for the strip fuse holder like @matty has & that's a little big for your wire gauge. I use those on my battery to battery connections where the amp transfer is much higher.

    Now, I'd like @matty & @Dicky to verify what I've said above... but I think that's the way to go for you.

    The fuse holder on the top of my battery is the + in from the charge controller. It has a 20 amp blade in there & no issues at all.
    matty likes this.
  16. Sounds good my bad
    I have bigger cable and fuses as I am using a ctex controller that takes input from the panel and the alternator to charge the battery's so need to carry a higher load
    sANDYbAY and theBusmonkey like this.
  17. sANDYbAY

    sANDYbAY On benefits-won't sponsor!

    Thank you
    after reading all the earlier posts on this thread I'd decided to go for 4mm cable but prior to that I'd already ordered 2.5mm extensions with the connectors on and they've already been delivered. Also a quick look at the junction boxes on the panels themselves showed them to be really well sealed and therefore tricky, if not impossible, to remove without causing some damage which would invalidate any guarantee from the manufacturers.
    Because of that I thought I'd go with the 2.5 that the panels came with and see how it worked.

    That sounds like a plan.
    I'm thinking it would be neater to connect both panels together on the roof leaving just one pair of cables entering into the bus so I'll just put one 20 amp fuse inside the bus on the cables going into the controller and then another 20 amp fuse between the controller and battery?

    Thanks for the link, I've just had a look at them, would it be best practice to solder the wires into the wire clamps and would they be ok on the roof so I could fuse each panel separately.

    Sorry for all the questions but I'm a bit of a simpleton when it comes to proper electrics.
    theBusmonkey likes this.
  18. Yep best way is to link outside the bus and only have the two wires running in through the roof skin. Have a look at my thread for the way I did it.

    I don't have fuses in my solar panel side just on the battery side(output from controller)
    sANDYbAY and theBusmonkey like this.
  19. Sounds good, both panel tails into 2 separate MC4 connectors & then fuse the +feed.
    LOL, whatever works for you aesthetically. Just fuse the single +feed into the controller & stick another fuse close to the battery on the cable from the controller to the battery. So long as any through-metal cables are tightly grommeted you'll be fine.
    Solder's OK if you can be bothered. It gives conductivity but can also form a brittle joint so there are the inevitable 2 schools of thought:rolleyes:.

    I simply used good quality crimp on connectors and a decent ratchet crimping tool..
    sANDYbAY likes this.

Share This Page