Results 1 to 13 of 13

Thread: Inexpensive solar reg/charger

  1. #1
    Premium Lager

    Join Date
    Jan 2008
    Age
    57
    Posts
    4,784
    Thanks
    1,576
    Thanked 2,632 Times in 1,191 Posts
    Rep Power
    1102
    Reputation
    39166

    Default Inexpensive solar reg/charger

    Hi,

    Just looking into solarizing the 12v side of my shack.

    I have a few older solar panels, 37v.

    I see that chargers can be either 18v for a 12v off grid system or 36v for a 24v system.

    I donít want to run 24v batteries and then have to reg down to 12v so I am looking for a solar charger that will take my 37v (36v) panels and allow direct charging to 12v batteries.

    I have been looking at the various MPPT charges on eBay but just get confused with specs and donít want to buy the wrong one.

    A cheapy 30 - 60 A will suffice.

    Looking for recommendations.

    Thanks
    __________________________________________________ __
    Statistically, if you wait long enough, everything will happen!



Look Here ->
  • #2
    Crazy Diamond
    Tiny's Avatar
    Join Date
    Dec 2010
    Location
    Tasmania
    Age
    61
    Posts
    6,229
    Thanks
    10,588
    Thanked 5,150 Times in 2,561 Posts
    Rep Power
    1997
    Reputation
    83337

    Default

    Buy quality & buy once.
    I bought a cheapy (well not so cheap, $10 less than the replacement below) for my shed, from Jaycar, to do exactly what you are trying to do, drove me crazy with constant errors, it's in the useless equipment bin now.
    In it's place is the equivalent item from Victron Energy 100/30, works perfectly.
    Will take panels up to 100V & charge/regulate a battery of 12v or 24v. Max 30A. There is also a 50A version, see both at
    I'm running a 250w 24v panel into a 12v battery.
    Or go to the next size up for future panel or battery expansion of your system.
    Last edited by Tiny; 01-01-21 at 09:54 AM.
    Cheers, Tiny
    "You can lead a person to knowledge, but you can't make them think? If you're not part of the solution, you're part of the problem.
    The information is out there; you just have to let it in."

  • The Following 2 Users Say Thank You to Tiny For This Useful Post:

    porkop (01-01-21),tristen (01-01-21)

  • #3
    Premium Member
    wotnot's Avatar
    Join Date
    Nov 2019
    Posts
    1,274
    Thanks
    488
    Thanked 1,030 Times in 570 Posts
    Rep Power
    470
    Reputation
    20610

    Default

    Yeah, we used Victron gear in the camper trailer, hasn't missed a beat


  • The Following 2 Users Say Thank You to wotnot For This Useful Post:

    porkop (01-01-21),tristen (01-01-21)

  • #4
    Premium Lager

    Join Date
    Jan 2008
    Age
    57
    Posts
    4,784
    Thanks
    1,576
    Thanked 2,632 Times in 1,191 Posts
    Rep Power
    1102
    Reputation
    39166

    Default

    Ok, Im sold on the Victron regulators after all the research I have been doing.


    Which brings me to my next question.......

    Remembering that this is to charge a 12v bank of batteries, maybe a couple of 100AH or 3.

    Is it better to series up the panels....increase voltage, or

    Parallel up the panels, increase current?

    I have 8 x 36V panels.

    Thanks
    __________________________________________________ __
    Statistically, if you wait long enough, everything will happen!

  • #5
    Premium Member
    wotnot's Avatar
    Join Date
    Nov 2019
    Posts
    1,274
    Thanks
    488
    Thanked 1,030 Times in 570 Posts
    Rep Power
    470
    Reputation
    20610

    Default

    How many watts is each panel rated at?

  • #6
    Premium Lager

    Join Date
    Jan 2008
    Age
    57
    Posts
    4,784
    Thanks
    1,576
    Thanked 2,632 Times in 1,191 Posts
    Rep Power
    1102
    Reputation
    39166

    Default

    Quote Originally Posted by wotnot View Post
    How many watts is each panel rated at?
    They are 190W 36V @ 5A

    The roof space where I will be placing them, on my garage, should fit 4 of them.
    __________________________________________________ __
    Statistically, if you wait long enough, everything will happen!

  • #7
    Premium Member
    wotnot's Avatar
    Join Date
    Nov 2019
    Posts
    1,274
    Thanks
    488
    Thanked 1,030 Times in 570 Posts
    Rep Power
    470
    Reputation
    20610

    Default

    This is why we chose the victron 100/50 instead of the 100/30 on a 12volt storage system ...if you check this pdf -->

    On a 12volt system, the 100/30 you've got a maximum of 100volts/440W of PV input -- so, given the panels you have you can run 2 panels, either in parallel or series.

    Conversely, on the 100/50 controller, you've got a maximum 100volts/700W of PV input -- in this case (and this is how we went) you can run 4 panels ... 2 pairs of panels in series, parallel connected...ie;



    edit: yes, it means you 'appear' to have 100W of power you won't be able to use, but in practice it's neither here nor there -- if anything, you don't need clean the panels as much =)
    Last edited by wotnot; 25-01-21 at 08:16 PM.

  • #8
    Premium Lager

    Join Date
    Jan 2008
    Age
    57
    Posts
    4,784
    Thanks
    1,576
    Thanked 2,632 Times in 1,191 Posts
    Rep Power
    1102
    Reputation
    39166

    Default

    Thats great info and just the sort of advice I was looking for. I will do just that

    thanks
    __________________________________________________ __
    Statistically, if you wait long enough, everything will happen!

  • #9
    Premium Lager

    Join Date
    Jan 2008
    Age
    57
    Posts
    4,784
    Thanks
    1,576
    Thanked 2,632 Times in 1,191 Posts
    Rep Power
    1102
    Reputation
    39166

    Default

    so now that I have the charger and panel configuration down, I would like advice on an inverter (240v).

    So many to choose from on eBay, and mostly cheap Chinese shit.

    Looking for advice on quality brand in the 1000 - 2000 W pure sine wave models.

    Thanks again.
    __________________________________________________ __
    Statistically, if you wait long enough, everything will happen!

  • #10
    Premium Member
    wotnot's Avatar
    Join Date
    Nov 2019
    Posts
    1,274
    Thanks
    488
    Thanked 1,030 Times in 570 Posts
    Rep Power
    470
    Reputation
    20610

    Default

    What are you going to run off the inverter?

  • #11
    Premium Lager

    Join Date
    Jan 2008
    Age
    57
    Posts
    4,784
    Thanks
    1,576
    Thanked 2,632 Times in 1,191 Posts
    Rep Power
    1102
    Reputation
    39166

    Default

    Quote Originally Posted by wotnot View Post
    What are you going to run off the inverter?
    A few computers, Hand Held radio chargers, networking equipment, Wireless Access Points. 3D printers, TV. AC mains will be the primary, but I want the option if needed.

    Usual stuff you would find in a modern ham shack

    Regards
    __________________________________________________ __
    Statistically, if you wait long enough, everything will happen!

  • #12
    Senior Member
    bob_m_54's Avatar
    Join Date
    Jan 2011
    Location
    Newcastle, Australia
    Posts
    1,970
    Thanks
    979
    Thanked 1,021 Times in 622 Posts
    Rep Power
    540
    Reputation
    17578

    Default

    Quote Originally Posted by porkop View Post
    A few computers, Hand Held radio chargers, networking equipment, Wireless Access Points. 3D printers, TV. AC mains will be the primary, but I want the option if needed.

    Usual stuff you would find in a modern ham shack

    Regards
    And a smoker?

  • #13
    Premium Member
    wotnot's Avatar
    Join Date
    Nov 2019
    Posts
    1,274
    Thanks
    488
    Thanked 1,030 Times in 570 Posts
    Rep Power
    470
    Reputation
    20610

    Default

    Ok ... as you can imagine, with our setup in a camping trailer, just about all electrical gear is 12VDC ; if it comes to needing 240VAC, the 'likely candidate' devices are all happy to feed on a modified sine-wave AC source, and of course you already know there's a plethora of (cheap) units out there from CN, and we use these as 'consumables' ..ie; if you need 1000W, buy two cheap 2000W no name/little or no warranty inverters, and run one of them and see how long it lasts - keep the 2nd unit for redundancy.

    That is to say, for modified sine-wave inverters, you can often buy 2 or 3 'cheap' branded units for the cost of 1 'good' unit (that usually has a 5 year warranty), and we've found if you only drive the cheapies to 50% of advertised rated output, they seem to last 4-5years without trouble -- when they die, toss into ewaste, fit spare unit, and then look to source a replacement (and technology/choice/costs will be different years later, and you can avail yourself of those aspects rather than repairing older units...etc etc) The *big* caveat to this approach, is that those appliances/devices connected to the modified sine-wave inverter aren't really susceptible to any spikes on the AC feed that might occur when an inverter decides to let out the magic smoke (that said, most dead ones I see here, it's usually the input DC chopper mosfets that go boom).

    There's other forms of 'slight of hand' you can play with here ...ie; a 12VDC ->> 120VAC inverter can be cheaper than a 12VDC ->> 240VAC ; some devices are dual/mutli-range AC voltage -- a local I know with an off-grid house has lots of US appliances and several small 12v>120ac inverters, (almost 1 per appliance), to form a contingency strategy should one inverter fail. The rationale is purely a numbers game - the population of the US is a big marketplace, and devices aimed at that market are typically cheaper (wrt cheap but sometimes quite viable Chinese units, you shop on ebay.com instead of ebay.com.au and swallow equivalent shipping rates...ie; it's all coming from CN, even the US ebay listings =)

    Computer...a few years ago, you'd be hard pressed trying to think of a way around the 240V jug corded ATX PSU ... now.... now we're starting to see PC mainboards that only have a 12VDC power input, and the PSU for the other voltage rails are built onto the mainboard itself (go figure =)....like, I wouldn't have thought this was a question, but I have to ask exactly what the peak wattage usage of your PC is, because things like this now exist > ...who would've thought ..<grin>...little doubt there's better/bigger examples out there...just saying.

    You will pay good money, for a decent pure sine-wave inverter (whereas modified sine-wave units are cheaper) -- my advice would be to take a closer look at your loads -- which appliances/devices are 'sensitive' units that you want pure sine-wave for, and what other appliances/devices are there that will be happy with modified sine-wave instead --- add up the total wattage for each group, (factor in max wattage for each unit). Once you have the numbers, surf the tombs and see what's out there in pure/modified sine-wave inverters, and figure out is there's any cost advantage for having a 'good' inverter for your sensitive gear, and a cheap inverter for the rest....ie; why pay for 2000W of pure sine, when you might only need half that. For the most part it's an exercise towards putting oneself in a 'knowledgeable' position =)

    Not that I'm expressly advocating victron products, but when it comes to 12v->240ac inverters, their product range is quite extensive (including units that can be ganged together) ; once you know exactly how many watts of pure sine AC you need/want at hand, it'd be worth checking out their range, even if only to know the ballpark figure of what a good inverter @ wattage costs...(with a 5year warranty that'll still be around in 2026 =) ...you could choose worse, victron gear is 1st world stuff. Sort of goes with the territory when you're involved in the marine sector ; it has to be well made to survive that working environment.

    footnote:

    For the sake of thoroughness wrt the above image ('coz buying a 100/50 is like buying the base model without accessories)...the black CB/Switch next to the controller, is just a service switch to disconnect it's output to the battery bank (6 x 2.2v/240Ah) -- the blue rectangular box with 7seg LED, is a battery monitor/protector ... ...and that's there because the MPPT 100/50 doesn't have the facility to do this itself (some other models do) ; the black cable you see descending at the corner of the controller, leads back to one of these (wires coming out of terminal block on battery protector go to this as well, as does the current shunt sense just under it) .. ..

  • The Following User Says Thank You to wotnot For This Useful Post:

    porkop (29-01-21)

  • Bookmarks

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •