I almost feel silly asking such a simple question, but I wanted some
I have a SuperNova 250S battery charger and it has only leads to
connect to a 12v source. I want to be able to charge batteries in my
house, but don't want to rely on my little 12v lead acid battery.
I've tried connecting it to various transformers, but the ones that
are labeled "Output: 12v" really put out over 13v and the charger
won't operate on voltage that high.
What's the best way to connect my charger to household current? What
should the minimum mAh be of the transformer?
As mentioned in other posts you can convert a old PC power supply. A few of
us have built several of these and they work a treat.
For a 250S, assuming it was pushing the full 5Amps into the max amount of
cells (which as been previously suggested is unlikely) you'd want something
that can supply about 15-18Amps. Once you figure out which supplies are the
easiest to convert (AT style with the separate power button) grab one with a
rating of 200Watts and higher.
Depending on what you are charging, you want a fairly chunky transformer of
at least 3-4 Amps output or more. The voltage output of 13V or more
shouldn't matter - it may be more a matter of regulation (or rectification
to be exact) that the charger doesn't like - that is, it want's clean DC and
simple transformers often put out a little too much AC. Look around for a
regulated power supply designed for powering CBs and the like - they are
specced to output 13.8V or so at a couple of amps or more, which should be
ideal for your Supernova.
The SuperNova requires a DC source, your transformers are AC. Most "12
volt" DC supplies are actually 13.6 volts, so is your car electrical system
when running. I could give you more information on sources but your bogus
e-mail email@example.com precludes that. UP YOURS!
Red's R/C Battery Clinic
I would agree with this idea. You already have the lead acid battery and
the charger to top it up. Unless you specifically want to spend some
money then you have got what you need.
I have used this method to run a ham band transmitter and receiver which
on transmit had a current draw of 20 amps. As the receiver is in use
more than the transmitter the battery charger could keep up alright.
As long as the battery charger is firmly clamped to the battery
terminals then the equipment attached to the battery will never be
supplied with anymore than normal battery voltage... failsafe.
You could convert a PC power supply easily.... but your lead acid
battery will appreciate a workout anyway. Best way ti kill the lead acid
battery is to not use it for months at a time.
If I was him I would say UP YOURS TOO you prat !
You should respond to a query through the group, that way other people
would also benefit rather than you sloping off and having a conversation
out of sight.
Anyone sensible uses a fake email address on usenet... easier than
filtering all the junk that's gonna come your way. So, you are not
sensible... how did we guess that ?
Judging by your attitude any information you could give him may not be
up to much anyway...... get a life.
I tend to agree with Red on this one (though maybe not so strongly).
Back in the day it was common courtesy to provide a valid email so that
conversations that were about to diverge away from the main topic could
continue privately via email. Also extra info (as Red wanted to send)
was probably more suited to a private message. Sometimes it's also just
nice to personally thank and/or start up a friendship via email.
Yes, you will get spam. Who doesn't get that already anyway? That's what
message filters are for. You white list your friends and sort though
your spam box every now and then to find valid emails.
It seems though, common courtesy has gone out the window. People post
crap just because they can and seem to get some sort of thrill being as
belligerent as they can be. Part of the problem is that text doesn't
relate emotion well and many people don't follow common conventions
which ends up inadvertently starting flame wars over nothing.
Then again, some people obviously enjoy the flame wars. They end up in
| If I was him I would say UP YOURS TOO you prat !
Yes, that is definately the proper way to respond to somebody who's
trying to help. Uh-huh. Red's not always the nicest guy out there,
but he's definately come across better than you have.
| You should respond to a query through the group, that way other
| people would also benefit rather than you sloping off and having a
| conversation out of sight.
Putting a summary online and the details offline is a pretty common
way of doing things, actually. Asking how to get 12v in your house is
a very common question, one that we've seen and answered many times
| Anyone sensible uses a fake email address on usenet... easier than
| filtering all the junk that's gonna come your way. So, you are not
| sensible... how did we guess that ?
I guess I'm not sensible either, not by your definition anyways.
Not that what what you think really means much to me, at least not
now. For now, you're just another pseudo-anonymous twit.
| Judging by your attitude any information you could give him may not be
| up to much anyway...... get a life.
As a general rule of thumb, those who say `get a life' are those who
need to do so the most ...
| >> I have a SuperNova 250S battery charger and it has only leads to
| >> connect to a 12v source. I want to be able to charge batteries in my
| >> house, but don't want to rely on my little 12v lead acid battery.
| >> I've tried connecting it to various transformers, but the ones that
| >> are labeled "Output: 12v" really put out over 13v and the charger
| >> won't operate on voltage that high.
I'm sure your charger WILL operate on voltages that high. It'll
probably handle at least 13.5 volts -- the problem is that your
transformers either give AC, or give poorly recified DC, or not enough
And if you do get a transformer that generates enough power, and it's
rectified properly, it's likely to be very inefficient. Converting a
PC power supply as others have mentioned works very well.
Might have been better to show his comment rather than indulge in a bit
of selective editing !
So he is the only one entitled to slag someone off ???
Allowed to throw his dummy out of the pram due to some dispensation
which decrees he won't get kickback ?
I don't think so.
Trying to help ? Didn't demonstrate that too well did he ?
I understand your comments, but it still makes more sense to reply
through the group that way others, including lurkers and those who may
be a bit shy to ask a question, get to benefit. If someone asks the
question via the group then it is not much use to others if most of the
replies are sent by email.
Back a while it was perhaps not too problematic including a valid email
address, I certainly wouldn't do it now. I had to abandon the original
email account I had due to massive amounts of junk mail every day. That
address was used on newsgroup postings some 5 years or so ago. The email
addresses I keep out of the newsgroups do not attract any junk.
A new generation of virus is appearing. The companies who monitor and
sell anti-virus software are concerned to see new versions of virus
which are deliberately designed to evade detection by known means.
Then there is the Lazarus virus.... comes in two parts to defeat the
anti-virus software. One part is detected and removed by the AVS after
that the second package resurrects the first package and both packages
slip into your system.
Trouble is what may have been O.K a while ago is now decidedly more
risky. Time was when it was reckoned that a .jpeg could never carry
a malevolent load... that's just recently been blown out of the water.
So we have the situation where someone, quite possibly new to the hobby,
gets dumped on for taking a reasonable precaution. Guy doing the dumping
may well not be aware of the change in risk recently but blows off
because it isn't the way *he* thinks it should be done.
Sorry Red. I just get sick of the junk email from people that scan
these news groups. I prefer you reply to this question in the news
group anyway so we can all benefit from your knowledge and experience.
Here's my email address if you want to scorn me some more:
Thanks for your replies everybody. My "wall wart" transformer only
puts out 1000mAh, which obviously isn't enough to run my charger. I
can't even get the charger to power up when connected to the wall
wart, so I was guessing it was a voltage thing. I tried a different
wall wart in the past and it would at least power the charger and act
like it was going to start charging. Then it gave a message of
"Voltage too high" on the screen.
I think I will convert a PC power supply since I have a few of them
lying around. And I'll try not to neglect my lead acid battery
Advantage of the PC power supply is that you can then use your fast charger
to top up the SLA in your field box.
Of course, this assumes your charger is suitable for charging SLA (most
chargers have a function for this).