I get no charge

eddieeddie Registered Users Posts: 12
Hi to all,

Yes Im a newbie and having issues with my solar panels. I have two panels of 36 cell each cell is .5 vlts. I get 16+ out of each panel. I hook them up in parralel to my charge controller and battery. Once connected my volts drop to 4.5 and I get zero charge info on my controller. The panels do not send out enough volts/amp to charge the batteries. At first I thought I had a bad controller so I purchased a new one with LCD Display. When I connected it I get no readings from the panel. Idisconnect the wirings to check reading direct from the panels and I get 16 plus volts. What could be going wrong? Everything is connectd correct. Why when I hook up the wires to controller I lose voltage from the panels and it would even give me any readings on my charge controller? Any help?

Thanks!:confused:

Comments

  • petertearaipetertearai Solar Expert Posts: 406 ✭✭✭✭
    Re: I get no charge

    Are these home made panels?
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . victron battery monitor . 24 volts 450 ah surette batterys . off grid  holiday home 
  • eddieeddie Registered Users Posts: 12
    Re: I get no charge

    Yes they are home made..
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: I get no charge

    Homemade panels strike again. :roll:

    First clue: 36 cells * 0.5 Volts ought to be 18 Volts Voc, not 16. Right there four of the cells seem to be missing from the circuit. Improperly soldered, solder in backward, accidentally skipped or bypassed. Something. Hopefully you haven't sealed them up with goop and can still get at them to check connections.

    Disconnect and inspect. Systematically test each cell individually to make sure it is defective (those cells you buy on E-bay are ones discarded by manufacturers as being not up to snuff).

    Despite the claims of the Internet hucksters, making your own panels is not easy nor cheap and only fun if you're a masochist.
  • mike95490mike95490 Solar Expert Posts: 8,497 ✭✭✭✭✭
    Re: I get no charge

    Connect panels one at a time, and discard/repair the bad ones.

    Do you have a volt meter you can use to test each panel before connecting it?
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • eddieeddie Registered Users Posts: 12
    Re: I get no charge

    Yes I have a meter. I will check each cell today and post the results.

    Thank you.
  • eddieeddie Registered Users Posts: 12
    Re: I get no charge

    Just finished checking my panel. one cell was cracked , fixed it. all reading .4-.5 volts. I connected again to the charge controller and down went the volts as well as the amps. i disconect it from the charge controller and I get 17.4 vlts and 3.33 amps. I can turn on a 12v fan direct from the solar, but can't charge a battery. Wow! any other ideas or test I can do? this is really weird. I wish i can post a video. :cry:
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: I get no charge

    Okay, it's panel testin' time! :D

    Couple of bits of background info in case someone reading this doesn't already know:
    Photovoltaic cells are current sources, not Voltage sources. They don't behave like batteries.
    Every panel has three Voltages: the "nominal" (as in 12 Volt or 24 Volt), the Voc, and the Vmp.
    Most people hook up their DVM and read the Voc and think all is well because there is plenty of Voltage there. This is not so. A panel can have quite a normal Voc and still not be able to produce enough current to charge a penlight battery.

    The thing you want to test for with a PV panel (or its individual cells) is current, not Voltage. You can't do this against a variable load like a fan or a battery (which may or may not need charge). Fortunately there's a couple of other numbers for panels; Imp and Isc. The first is very important, and nearly impossible to test for. It's the amount of current the panel will produce at maximum power. This usually works in conjunction with Vmp: Imp * Vmp = panel Watts. Theoretically, anyway. The real world tends to ignore such neat mathematics and mucks up the calculations with variations in temperature, et cetera.

    Which brings us to about the best test you can do: Isc. That is the current at short circuit. Basically, you short the (+) and (-) of the panel and read the current. Best done with a clamp-on DC Ammeter, but if your regular meter can handle the potential (at least 10 Amps) and you know how to read it you can connect it in series with the panel's output and see what you get in full sun.

    Once again I'll point out that those cells you buy from various sources are the ones the manufacturers already discarded as not being up to snuff. Ideally you should test each one individually before you solder it in to your panel, and test the whole thing as you go. It's all too easy to damage them along the way or solder them poorly.

    The next time someone tells me how you can build your own panels cheaply and easily I'm going to point to the three threads in the past week that prove otherwise. Or maybe I'll just laugh.
  • eddieeddie Registered Users Posts: 12
    Re: I get no charge

    Cariboocoot,

    You are aboslutely correct! As a newbie I thought this was going to be easy, and it isn't. LOL... I'm about to thrash what I got and buy a real , professional panel. I would like to share this video(my first) I went through alot creating an account on youtube to post. Two videos, one me testing the equipment and the other dispaying how I can use the panel to turn on a simple 12v fan.

    here they go >>> http://www.youtube.com/watch?v=QIiiggxwWIQ

    http://www.youtube.com/watch?v=IGyOAz_oHe4
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: I get no charge

    Did I mention that the Voc on a "12 Volt" panel should be somewhere around 22 Volts? And you should get that even on a cloudy day. Without a lot of bright sunlight panel don't produce much power, and when they do produce power it comes as Amps at the expense of Volts.

    Did I mention that charge controllers eat up a bit of power themselves?

    Did I mention that the Vmp for charging a 12 Volt battery should be in the 17-18 Volt neighborhood?

    Did I mention it's a lot easier to spin over a fan motor than to force current into a lead-acid battery?

    Did I mention that to get a really good idea of what's going on you need two DVM's so you can measure the current and Voltage simultaneously (and thus get some idea of the Watts the panel is putting out)?

    What else did I forget to mention?

    Oh yeah; this stuff isn't as simple as some people would have you believe.
  • eddieeddie Registered Users Posts: 12
    Re: I get no charge

    Cariboocoot

    True that, you 100% correct... I give up. I will use the panel to run a small attic van while the sun is out lol. Now, can you guide me to where or what type of panel I can purchase that would work with my charge control and charge my battery, lol...:D
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: I get no charge
    eddie wrote: »
    Cariboocoot

    True that, you 100% correct... I give up. I will use the panel to run a small attic van while the sun is out lol. Now, can you guide me to where or what type of panel I can purchase that would work with my charge control and charge my battery, lol...:D

    That would depend on what the battery is.
    For full recharging capability you're looking at a peak charge current target of 5%-13% of the battery's Amp hour capacity. The middle 10% is a good thing to try for. So a 100 Amp hour 12 Volt battery would like 10 Amps of current @ 14.4 Volts which is 144 Watts. Panels don't put out their nameplate rating, but rather an average that' somewhat lower. How much so depends on things like insolation, temperature, and elevation. We use 77% efficiency as the "ballpark" calculator, so that 144 Watts turns into a 187 Watt panel.

    Since batteries are the heart of an off-grid system the Battery FAQ's is a good place to start: http://www.windsun.com/Batteries/Battery_FAQ.htm

    I've never seen one of those charge controllers before; what are its specifications?
  • eddieeddie Registered Users Posts: 12
    Re: I get no charge

    Below ae the specifications:

    Model
    VWG2008V2-12V/24V

    Rated power
    600W

    Max Wind Input Power
    500W

    Max PV Input Power
    100W

    Rated Battery Voltage
    12V 24V

    over voltage protective voltage
    17.5V 35V

    Battery over charge protective voltage
    14.32V 38.64V

    Battery over discharge protective voltage
    10.98V 21.97V

    Over discharge voltage recovery
    12.44V 24.88V

    Rated charge current
    40A 20A

    No load loss
    ≤40mA

    Protection Type
    1,Over charged protection; 2.Over discharged protection. 3. Reverse polarity connection protection. 4. PV Panel reverse current protection. 5. Short circuit protection. 6. Thunder and Lighting protection

    operation Ambient tempreture
    -10C~50C

    operation Ambient humidity
    0~90%

    Size(W×H×D)mm
    228×133×75mm

    Weight(KG)
    1.

    The battery I'm using is an 12v 8D
  • Solar GuppySolar Guppy Solar Expert Posts: 1,962 ✭✭✭
    Re: I get no charge

    connect the PV direct to the battery and see what you get for a charge ( use a DVM to measure the current ). Sounds like your fancy / funky wind solar charger is busted if its loading the PV down to a few volts yet the battery is 12V. Maybe is set to diversion load not solar mode
  • eddieeddie Registered Users Posts: 12
    Re: I get no charge

    Okay, This morning I checked the panel reads 17.45. I repositioned the panel. However the amps. Only reached 0.70. The panel should be producing 3.8 max. I have another panel set a side . That one reads 14.75 vlt and 1.79 amps. I install the 12v fan and it runs high speed. I'm now understanding, if correct. That the AMP= Current, correct? Therefore the more amps produce, the fastest the fan win run, correct? So if the panel is not producing enough amps, the panel will not be able to charge my 12v 8d battery, correct?

    Now, would there be a way to fix my amp problem? I'm not trying to beat a dead horse here. However, I'm trying to get the best out of this project. Worse case, I see the panel would make power source (daytime eventually) for an attic fan.:roll:

    The key here is to not get upset and work with what I got.....;);)
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: I get no charge

    Are you familiar with Ohm's Law? You really need to be.

    I = V/R

    Where 'I' (the 'I' from an old term "Intensity") is Amps, Amperes, current. 'V' is Voltage. 'R' is resistance in Ohms.

    With a battery, you apply 'V' to 'R' and get 'I'. With a solar panel you apply 'V' to 'R' and 'V' drops as 'I' comes up according to the panel's capacity which is rated in Watts: I*V.

    Your fan has one value for 'R', and it's probably pretty high. This means it will not draw a lot of 'I' or sink the panel's 'V' low. A battery will have a different value for 'R' (in charging a battery is a load and thus has resistance) which will change according to its state of charge. It is entirely possible for the battery's 'R' to be low enough to sink the panel's 'V' to a point where it won't work because the panel no longer has sufficiently higher Voltage than the battery to cause any current to flow.

    Follow Solar Guppy's suggestion to take the charge controller out of the circuit and see what the panel will produce against the battery directly. Be careful: even a discharged battery still has enough power in it to weld metal, to say nothing of making lots of fire-starting sparks. Do not try to measure a battery's resistance with a meter!
  • eddieeddie Registered Users Posts: 12
    Re: I get no charge

    Okay, let me try Guppy's suggesstion and I'll post the results.

    Thanks
  • eddieeddie Registered Users Posts: 12
    Re: I get no charge

    Hahaha... I got it to work. I tried Guppy's suggestion and the same. Well, I then hooked up my other panel which was on 30 cells not 36 for 18v. My other cell only throws max 15.4vlt and amp 2.55. I learn how to properly use the multimeter with this video.

    http://www.youtube.com/watch?v=bF3OyQ3HwfU&feature=related

    Anyway, final my charge controller is reading amps and volts. One thing I discovered. you need to find the best position for the panel. Moving it aroung brings up or down the amps. I'm going to try to get it to 3.5. In which the panel should reach that limit. I will keep posting my finding and pehaps a small video.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: I get no charge
    eddie wrote: »
    One thing I discovered. you need to find the best position for the panel. Moving it aroung brings up or down the amps.

    Boy oh boy is that ever true! That's what the fancy word "insolation" means btw; how much sun is falling on the panel. Voc will shoot right up with just some illumination from any angle, but to get the current to peak you need to be straight on to the sun in both directions.

    You can use a shadow stick to check this: a short, straight stick exactly parallel with the panel and raised about 1" off. In the sunlight it will cast a shadow on the panel (normally something to be avoided). If the shadow is directly below the stick and the same length then the panel is spot-on to the sun. These two angles change with time of day and time of year, of course. For most systems you pick a compromise point; one that gives the best over-all power at the time when you need it most or the best average throughout the year. Or you buy a one- or two-axis tracker. Kind of silly for a single small panel, though. :p

    P.S.: You could have read the instruction manual that came with the meter. Does anybody do that these days? :p
  • eddieeddie Registered Users Posts: 12
    Re: I get no charge

    LOL...No, I'm guilty of that. I'm more of an visual learner. LOL. Well. going back to my project and hopefully get it to work on 2.0 amps or better. I'll keep evryone post. I'm going to post a link to a small video on my progress, lol. I'm just glad I haven't given up!

    lol :D
  • eddieeddie Registered Users Posts: 12
    Re: I get no charge

    :D Here is the update video. Finally I see movment on my charge controller. :D

    I'm still making improvements. Hopefully things get better. By the way, my location is Florida.

    http://www.youtube.com/watch?v=xvoLkIPcHJw
  • System2System2 Posts: 6,290 admin
    Re: I get no charge

    Hello. When I read the beginning of this post, I thought "this is exactly what's happening with my panels and charge controller".
    But I have 3 panels that aren't home made.
    I checked the output of each panel, and they were at 17 volts, or so. Nevertheless, when I hook them up in parallel, the voltage drops to something like 6 volts.
    When I connect one panel to a battery (without a charge controller), it charges fine. But when I use a charge controller, voltage drops to 3 volts.
    I'm writing this to see if you can clarify the outcome of your problem? And what specific steps taken if you managed to make things right?
    Thanks
  • BB.BB. Super Moderators, Administrators Posts: 29,812 admin
    Re: I get no charge

    Are you sure about the polarity of the solar panels?

    Next, when you connect them to a load/battery/charge controller... Their output voltage is pretty much set by the load/battery bank.

    Say you have a "dead" 12 volt battery at 6 volts. If you connect a 17.5 volt Vmp solar panel to such a battery, the output will be 6 volts--and slowly rising (if the panel is supplying charging current).

    One other test you can do, see what the Isc (short circuit current) is for the solar panel. Say it is 5 Amps. Set your DMM (digital multi-meter, amp meter, current meter, etc.) to 10 amps full scale and connect the leads to the output of the solar panel. If the panel is in full sun, you should be reading around 4-5 amps. If you are reading much less than 4 amps in full sun, then you have a problem with the panel wiring/cells/etc.

    Note, you can only connect your current meter across "smaller" solar panels safely (meter has to be rated for higher current than the panel can output).

    You cannot and should not connect a current meter across a 12 volt battery bank or your 120 VAC house wiring. Current Meters are basically a dead short and will cause sparks/fires/worse if you short out a large battery bank/AC house wiring, etc...

    It is only safe to "short" solar panels because they are "current sources" and not voltage sources with lots of available current (100's to 1,000's of amps for a good sized car/truck/deep cycle battery / battery bank).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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