Nazo
2[H]4U
- Joined
- Apr 2, 2002
- Messages
- 3,672
Ok, so I just bought one of these: WeatherX RPS8807DT 200-Watt Portable Power System It was my hope to be able to use this thing to run my EeePC for extended periods of time off of this and this was one of the major reasons I bought it (though I would add, obviously not the only one as it has a lot of uses obviously.) But, most of the battery power sources of the nature I was looking for don't go up to a high wattage, do but have poor capacity, or cost a LOT. This one seemed a great balance with incredible running time for its price mainly just at the cost of being a lot heavier due to using a lead-acid battery instead of nickel-metal hydride or nickel-cadmium (or lithium-ion, though I don't think I've seen any of these in a power device of this nature yet.) So basically this thing is using the same type as a car battery, just on a much smaller scale. There's only one thing bugging me. To generate AC it runs a motor rather than the newer methods of using voltage conversion and generating a sine wave. This looses efficiency obviously by quite a notable margine (according to the product page, 60 watts will only get about 2 hours of power via AC and it will get about 3 hours DC.) Also, I was a little concerned at first because when lower powered devices are plugged in (for example, a LED nightlight) the produced voltage can go up to as much as 144V (but when I plugged in an AC powered fan that runs at some 350mA it dropped to 110V, so I feel less concerned about that now.) This could probably be risky with lower powered devices such as some chargers, right?
Anyway, for the moment my biggest concern is my EeePC. It can use up to some 22 watts or so (though a fair bit less when just charging while off -- I haven't gotten around to testing how much it really uses yet, but the plug is rated at 22 watts and I can run the EeePC off of my 16 watt maximum sustained supply if I pull out the battery or charge it if I leave the system off, so I think it comes close to that 22 watts when fully used, or at least I know it's more than 16) so I guess it would be ok in the voltage department as that should drop it really close to the rated 120V -- well within safety ranges. Of course, this still puts it at a high enough power usage that the efficiency difference has enough of a significant effect to be worth trying for something more efficient. Instead of going from DC to AC to DC again, perhaps I should just go from DC at approximately 12 volts to DC at the 9.5V the EeePC is rated at. Unlike in a car electrical system, the DC does seem to be somewhat reliable with the maximum being close to or very little over 12V, but at the same time I think this may mean that if it drops low enough it could maybe go belowe 9.5V?
Basically, my biggest concern here is that this thing has a LOT of capacity behind it. Not as many amps as a car battery, but definitely enough to do some serious damage if things went wrong. Also, I wonder if a normal voltage converter could handle that much power? Most importantly though, I must admit that I've never put together any sort of voltage converter before. I'm not really sure what the little voltage converters themselves are called to look them up on RadioShock/Mouser and I'm not really sure exactly how to use them as they usually have three pins rather than just an in and an out. If anyone could at least help point me in the right direction, I'd be grateful.
Also, just out of curiosity, what do you people think about plugging in a PC? Obviously it wouldn't be very often, nor for very long, but, it says that this thing can handle up to 200 watts. I'd have to get my video card in low power mode or something probably, but I could probably run even this PC on that as its normal voltage when not being pushed is in that vicinity and I have some older hardware that I'm almost certain would use less. The main thing is that the voltage would probably drop pretty low with that much load. Could the PSU handle that much of a drop?
Anyway, for the moment my biggest concern is my EeePC. It can use up to some 22 watts or so (though a fair bit less when just charging while off -- I haven't gotten around to testing how much it really uses yet, but the plug is rated at 22 watts and I can run the EeePC off of my 16 watt maximum sustained supply if I pull out the battery or charge it if I leave the system off, so I think it comes close to that 22 watts when fully used, or at least I know it's more than 16) so I guess it would be ok in the voltage department as that should drop it really close to the rated 120V -- well within safety ranges. Of course, this still puts it at a high enough power usage that the efficiency difference has enough of a significant effect to be worth trying for something more efficient. Instead of going from DC to AC to DC again, perhaps I should just go from DC at approximately 12 volts to DC at the 9.5V the EeePC is rated at. Unlike in a car electrical system, the DC does seem to be somewhat reliable with the maximum being close to or very little over 12V, but at the same time I think this may mean that if it drops low enough it could maybe go belowe 9.5V?
Basically, my biggest concern here is that this thing has a LOT of capacity behind it. Not as many amps as a car battery, but definitely enough to do some serious damage if things went wrong. Also, I wonder if a normal voltage converter could handle that much power? Most importantly though, I must admit that I've never put together any sort of voltage converter before. I'm not really sure what the little voltage converters themselves are called to look them up on RadioShock/Mouser and I'm not really sure exactly how to use them as they usually have three pins rather than just an in and an out. If anyone could at least help point me in the right direction, I'd be grateful.
Also, just out of curiosity, what do you people think about plugging in a PC? Obviously it wouldn't be very often, nor for very long, but, it says that this thing can handle up to 200 watts. I'd have to get my video card in low power mode or something probably, but I could probably run even this PC on that as its normal voltage when not being pushed is in that vicinity and I have some older hardware that I'm almost certain would use less. The main thing is that the voltage would probably drop pretty low with that much load. Could the PSU handle that much of a drop?