Re: Battery charging circuit

From: Damn Dan (a_at_a.com)
Date: 10/19/04

  • Next message: Damn Dan: "Re: Battery charging circuit" 
    Date: Mon, 18 Oct 2004 18:59:18 -0700

    "Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote
    in message news:10n7f92rkhicha4@corp.supernews.com...
    >
    > "Ross Herbert" <rherber1SPAMEX@bigpond.net.au> wrote in message
    > news:ptr6n0hbnfpbro61itov63eqrupmuc6nnr@4ax.com...
    > > You are starting from the wrong end...
    > >
    > > You need to determine the charging requirements of the 165V battery
    > > itself before anything else. Only then can you determine what is
    > > required of your charging circuitry and design it accordingly. The
    > > fact that you want to use a 12V (nominal), 80W solar panel as the
    > > charging source simply because that is what you have on hand is not
    > > the way to go about the problem. Once you know what the charging
    > > requirements of the battery are you can then determine how many solar
    > > panels you will require in order to charge a 12V,24V or 48V battery to
    > > power a suitable dc - ac inverter/rectifier/charging arrangement.
    >
    > I don't buy that at all. Firs off, he doesn't need to know the charging
    > requuirements of the 165V battery because it can charge at anywhere up
    > to hundreds of amps for short periods. And he will never be able to buy
    > enough solar cells to do that, let alone the next problem.
    >
    > And the next problem is that the solar cells will put out anywhere from
    > max to min to zero depending on the time of day, and the weather,
    > cloudy, overcast, etc. So he needs a converter that can handle a large
    > variation in input power. Why should he need an intermediate battery,
    > 12V, etc. to charge? That's just a waste of efficiecny.
    >
    > What he needs is a converter that monitors the input voltage to see if
    > it drops below a threshold, as long as it stays at about 12V, pull as
    > much current from the solar cells as it can. Then monitor the output
    > voltage to make sure it doesn't go much above 200V, so that if the
    > converter is not plugged into the battery, it shuts down.
    >
    > What I would do is start with a standard Dc-Dc converter like those used
    > for running tube equipment off 12V. Add an overvoltage monitor to the
    > output, and under voltage to the input. And fuses, of course.
    >
    > And he can put a large capacitor across the solar cell, to hold enough
    > charge to run the converter for a second or two. If the converter
    > charges in spurts, that's okay, too.

    Right, getting enough panels to produce that much voltage would be
    financially and physically impossible. The second problem you mentioned is
    actually the very reason I went for the 12V battery as a middle-man.
    Originally I wanted to hook the panel directly to the 165V battery through
    the converter. But my main constraint is that I'm trying to do this El
    Cheapo style. I did a bit of research but found no reasonably cheap (i.e.
    less than $50) 12V-200V DC-DC converters. If you happen to know of one,
    please let me know! The inexpensive solution I have come to is using a
    regular car inverter that you plug into your cigarette lighter. That gives
    me 120Vac. I step that up with a international power converter that you can
    buy at any Radio Shack. The 200 or so volts out of that gets rectified to
    DC. All in all, it cost just over $50. So now the reason I'm attaching the
    car inverter to the 12V battery is all car inverters have safety mechanisms
    that shut off power if the inverter detects a "weird" voltage input. The
    solar panel outputs between 15V and 20V, which it considers "weird", so it
    doesn't work. The 12V battery keeps the voltage at an unweird level. It
    also accomodates for any variation that the solar panel will give due to
    weather conditions and time of day. Plus, it keeps a steady, predictable
    current into the 165V battery. But like I said, if you know of any
    off-the-shelf, cheap converters that would accomplish the same goal, I'm all
    ears.

  • Next message: Damn Dan: "Re: Battery charging circuit"

    Relevant Pages

    • Re: Battery charging circuit
      ... > required of your charging circuitry and design it accordingly. ... > requirements of the battery are you can then determine how many solar ... And the next problem is that the solar cells will put out anywhere from ... cloudy, overcast, etc. So he needs a converter that can handle a large ...
      (sci.electronics.components)
    • Re: Converter not charging house batteries
      ... It has 3 deep cycle 12V batts for house, and a single battery for ... When I plug into 120V, the transformer in the converter hums and all, ... How do I go about diagnosing whether or not the converter is charging ... look up Progressive Dynamics and buy a unit with the built in Charge ...
      (rec.outdoors.rv-travel)
    • Re: Battery charging circuit
      ... |> required of your charging circuitry and design it accordingly. ... |> requirements of the battery are you can then determine how many solar ... |> panels you will require in order to charge a 12V,24V or 48V battery to ... whatever converter is used in order to raise the actual output above ...
      (sci.electronics.components)
    • Re: Progressive Dynamics 9200
      ... battery for charging, and the current converter still runs the house ... As for the size of charging wire, you don't say what you have ... integrated with the converter. ... Looking at the 'basic operation' document, other than the transformer and diode rectifiers which provide power both to the coach loads and to the charging section, the parts involved in charging are the charge control board, the current limiting resistor, the scr, and the auto-reset circuit breaker. ...
      (rec.outdoors.rv-travel)
    • Re: Question about battery charging, etc. Problem Fixed!
      ... I also have the Aux battery on and have the MH plugged into AC power. ... Now, I thought that when the converter was on, it should keep the house charged. ... You are correct that the batteries should charge when shore power is plugged in. ... You can replace the entire power distribution center with one that has a regulated charger built into the converter or you can add a charger and rewire the whole mess, which probably needs to be done anyhow. ...
      (rec.outdoors.rv-travel)