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Old 07-02-2008, 04:44   #1
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Rechargable Stuff

I was wondering about the draw of having small rechargeable stuff plugged in all the time, such a toothbrushes, razors, rechargable battery chargers, small vacumes, batteries for drills, laptops etc. and how much juice they take up. Does leaving them plugged in present any problems? I have seen some great items that will use solar for small items, but was wondering about the stuff you might want to use all the time. Thanks in advance for any imput.
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Old 07-02-2008, 09:35   #2
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world of "wall warts"

The proliferation of "wall cubes" or "wall-warts" to recharge various battery powered portable devices along with the proliferation of computers and displays created a significant harmonic powerline problem in business buildings. As a result the drive (requirement) has been for the manufacturers of such devices to use "switch-mode" off-line supplies which produce very low harmonics on the line. The result is higher efficiency.

What this means to you is that they draw minimal power. The "catch" is that when operating a power inverter one must monitor the battery current to determine if it is sufficiently low for your continuous energy budget. If you are motoring along with the inverter on and an alternator is keeping ahead of the inverter drain then you don't care.

Some inverters have a "on" mode which, when there is no ac load, draws only "idle" current. If a small load like a "wall cube" is connected that only draws a few watts it will pull the inverter out of the "no-load" mode which, in at least one case, carries an overhead current draw of 5 to 7 Amps even though the "wall-wart" might add only 0.1 Amp battery draw. Obviously in this case one might wait until heavier loads are operated (like an LCD TV and sound system) before plugging in the "wall-wart".

For convenience use a power strip to plug in all your rechargeables and use the strip's on/off switch to switch them off when you don't want the drain. Make sure that the power strip is either encased in metal or has the U/L 1459 revB (if I correctly recall the number). It is a designation that means if a power transient sufficiently high so as to destroy the internal transient protection devices an internal fuse will open rather than causing a fire. Boats and homes have had fires from such instances with devices not having such internal protection.
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Old 07-02-2008, 09:50   #3
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I have been choosing my battery chargers to run from a 12-volt source, for just this reason... most handheld radios and similar products offer a DC charger option, and some (like the Yaesu VX-6R and Icom IC-M72) have drop-in chargers that connect to the AC line with 12-volt wall warts (meaning you can just lose the wall wart and use your boat DC system). Likewise, there's a Ni-MH charger from Batteryspace that works like this.

Cheers,
Steve
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Old 07-02-2008, 13:09   #4
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Put your hand over it and see how much waste heat it is producing. That will give you some idea.

A more accurate measurement would be to plug it through the AC current setting of your multimeter and see how much current it is using sitting there doing nothing other than sucking down the watts. The current you measure (amps) times the volts will give you watts which is your true indication of how much power it is drawing doing nothing.

I would be willing to bet we waste billions of dollars now on those nasty little wall transformers. I know I have at least a dozen of them spread around my house and a number of them on the boat. Why they are not built with some sort of load sensor so they are completely off when not in use is beyond me.
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Old 08-02-2008, 07:05   #5
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Quote:
Originally Posted by Rick View Post
Make sure that the power strip is either encased in metal or has the U/L 1459 revB (if I correctly recall the number). It is a designation that means if a power transient sufficiently high so as to destroy the internal transient protection devices an internal fuse will open rather than causing a fire. Boats and homes have had fires from such instances with devices not having such internal protection.
UL’s minimum performance standard for surge suppressors is UL 1449. A major revision, also known as UL 1449 Second Edition, became effective in 1998.

You need more than just a UL listing. There are a lot of power strips listed by UL that have no surge protection components at all. They are listed only for their performance as extension cords.

On a UL listed surge protectors (UL 1449, 2ND Ed), you will find a couple of ratings.
Look for Clamping Voltage, Energy Dissipation, & Response Time:

Clamping voltage: This tells you what voltage will cause the MOVs to conduct electricity to the ground line. A lower clamping voltage indicates better protection. There are three levels of protection in the UL rating 330 V, 400 V and 500 V. Generally, a clamping voltage more than 400 V is too high.

Energy absorption/dissipation: This rating, given in joules, tells you how much energy the surge protector can absorb before it fails. A higher number indicates greater protection. Look for a protector that is at least rated at 200 to 400 joules. For better protection, look for a rating of 600 joules or more.

Response time: Surge protectors don’t kick in immediately; there is a very slight delay as they respond to the power surge. A longer response time tells you that your computer (or other equipment) will be exposed to the surge for a greater amount of time. Look for a surge protector that responds in less than one nanosecond.

Surge Protective Devices UL 1449:
Scope for UL 1449

The impact of UL 1449 - Second Edition
UL 1449
And:
UL-1449 2nd Edition Changes
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