I have a boom-box (the make is Supersonic) that has an input jack so I can play CDs with it. But I want to use it in the car: The specifications label reads, at one point, “DC : 12V (UM1 or “D” x 8).” I know that the second part means you can play it with 8 “D” batteries, but what is “UM1”? (The device also has a regular AC cord, which is of no known use when I have it in the car…)
You can get a voltage inverter which will plug into your cigar lighter.
IIRC UM1 is another name for D cells
Please note that while a car’s battery voltage is nominally 12 volts, it can vary quite a bit from that and a direct connection might destroy your device. There’s also surges and such to worry about. An inverter is best but most $. There’s also car lighter dc-dc adapters but the ones I have would be for lower wattage devices as well as generally being crap.
That’s correct; there are a number of different ‘standard’ names for different sizes of cells; UM1 = D (other terms for this size - some of them completely obsolete - include HP2, LR20 and MN1300).
Your boombox may or may not be regulated for other “12V” sources like a car battery. Some devices like a few digicams can easily take a 50% overvoltage with no ill effects because of a switching power supply but don’t count on that for your boom box. Some devices can actually be destroyed by switching 1.5v alkaline cells for 1.2v NiMH or NiCad cells. I think the inverter is a much better idea.
A standard ‘D’ cell is 1.5 volts, 1.5X8=12, the same as a standard automotive DC. But as others have mentioned auto voltage can vary, as high as 14.4 volts. A small ac inverter is ony about $20 and should be a safe solution.
Aside – I did have an old boom box (8 D cells) that I used for years by connecting the battery terminals to the positive and negative wires of a truck (same basic electrical system as a car) and never had a problem, but if the radio died it would not have been a big deal either.
Where do I find an inverter at that price? I live in Southern California; the only one I’ve seen is at Radio Shack for $100. :eek:
As for your “aside,” well, I don’t have that kind of expertise–or courage. I have had problems galore with the battery and the ignition system and I’d rather leave that alone. Even buying eight “D” batteries periodically is less of a risk than that–for me.
That’s one of the reasons I don’t shop at radio shack.
I’ve seen them around $30 or so in a lot of different places. I just checked walmart’s web site and they list one for $29 and another for $17, but they are out of stock on the cheaper one (which I didn’t like the looks of anyway - too much weight on the cigarette lighter plug).
If it were my boombox, I’d wire it up to the car’s DC supply. Yes, the voltage is a little higher but there’s not anything in any boombox I’m familiar with that’s that sensitive to anything other than 12.0000VDC voltage sources. Don’t forget, those 1.50000 volt batteries are going to vary quite a bit themselves, potentially being quite a bit higher than their nominal values. What’s more, it’s doubtful the boombox’s internal DC supply was manufactured to ‘exacting’ specifications.
To be perfectly safe, you could either get the inverter as suggested or wire up a little regulator circuit to provide 12VDC.
I’ll check that out…they just opened a Wal-Mart a couple of miles from here (Harbor Gateway area, south of Los Angeles).
And I think I’ll go to Fry’s in Manhattan Beach too.
I have one like this – http://www.bestbuy.com/site/olspage.jsp?skuId=6291513&type=product&id=1072287374898, but I paid less than the $35 they list as the price.
I agree… I doubt the boom box will have a problem running at 14 V. All electronics are designed with some overhead in mind, and I would assume a boom box is no exception.
If you’re still concerned about it, stick a couple of high-current silicon diodes in series with the DC power cord. (They’re fairly cheap.) The diodes will knock the voltage down1.5 V or so.
I bought an inverter at Signal Electronics in Torrance; cost about $30.
The only thing I didn’t allow for is powering a portable CD player, which if course can’t be connected to the power source at the same time. So I’ll have to supply it with batteries… :sigh:
Because the inverter only has one outlet? If so, just connect a small power strip to the inverter. Or a short extension cord with two or more outlets.
If the CD player plugs into the 12V socket (cigar lighter socket) and the inverter is taking up that socket, you can get a splitter cable for it too. I think I got mine at Walmart.