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Forum Index : Electronics : UPS + car batteries
| Author | Message | ||||
| domwild Guru  Joined: 16/12/2005 Location: AustraliaPosts: 873 |
Hi, Just entered this post twice and had it knocked back by Fieldlines.com. Do they have us F&P chaps in a black book or what is it?? I know Gizmo is busy, so I do not want to add to his work by posting too many questions here - anyway - here it is with apologies! UPS: Accupower Select 2000, 1500W, 2000VA, 36V DC in, 240 VAC out via four IEC sockets for four PCs. Three N7 car batteries, 600 CCA, an Aussie term for cold cranking amps, been told to divide by six to get AmpHours, so I have 36V DC @ 100 Ah, hope! Rest voltages: 12.64, 12.45 and 12.46. UPS claims via a LED "bar chart" to allow me to run a 60W 240VAC globe for 90 minutes. Q1.: Does this sound right? As this UPS is built for SLAs, it floats batteries only up to 40.6 V or 13.5 V per 12V battery. Q2.: Is it easy to find a trimpot to tune it to charge up to 14.5 V?? Without rising to heaven, of course! Mains OFF! With mains on, the DMM reads an output of 244 VAC. With mains off, the UPS feeds my $5 Bunnings DMM with 234V AC with the load being the 60 W globe. Been told the very cheap DMMs get confused by the harmonics of the square wave of a modified sine wave and read only 180 V. Can I assume this is a pure sine wave UPS??? Thanks. Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5031 |
Hi Dom Bruce would be the expert on using UPS's, but I might be able to help a little. The 60W lamp for 90 minutes would be for the UPS's built in batteries, if you increase this battery capacity by using your car batteries or another source there is no reason why you could not extend this time, however.... Most cheap UPS's are not designed for continous duty, they tend to cook, but this could be easily fixed with a well placed cooling fan. UPS's are also not overy efficient compared to inverters, but dont let this worry you unless your on a tight watts budget. And lastly most UPS's have a modified square wave output, ok for some stuff ( lights ) but a bit harsh on other stuff ( motors ). I'm sure the others will have some more info for you. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Gill Senior Member  Joined: 11/11/2006 Location: AustraliaPosts: 669 |
I too have posted several times to the Fieldlines forum only to have it vanish into the ether. I don't bother any more. One day I'll find that hole where all my stuff disappears to. was working fine... til the smoke got out. Cheers Gill _Cairns, FNQ |
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| domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873 |
Glenn, Thanks for that. That was quick! Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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