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Help a girl with her electricity please?
29 May 2013, 12:14,
#1
Help a girl with her electricity please?
Well I'm good at some things but I can't quite get my head around power and I think I've made some duff purchases.

I know that UK voltage is 230-240v AC
I know that car and leisure batteries are 12V DC
I've got an inverter that turns 12vdc to 240v AC 1000W

Now help a girl out here will ya.
What is a WATT
What is an AMP

My inverter is 1000W
My hand cranked battery backup gives 240V at 100W

My eventual idea is NOT to run a whole load of 240V equipment
but standardize on 12V DC kit. Should I buy half a dozen/dozen car batteries, tie them up together, and then charge them from a solar (pretty useless in the UK I would have thought) - or generator??

Ideas please peeps!


Thanks
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29 May 2013, 13:09, (This post was last modified: 29 May 2013, 13:16 by Binnie.)
#2
RE: Help a girl with her electricity please?
An amp is a measurement of current flow

a watt is a measurment of current consumed


Your inverter can pump out 1000w, using Watts law we know the voltage, and the wattage, you can work out the amps, (google/wikipedia for a good description of the forumla)

1000w divided by 240v is 4.16amps.

take this in the case of a 3kw heater, which is the largest you will find available for domestic use

3000w divided by 240 is 12.5A (or more precisely 3000 divided by 230v is 13.04A)


This pretty much explains why 3kw heaters are the largest you can buy for domestic use, as 3kw @ 230v is 13A, our plugs are only rated and fused for 13A max.




most appliances with 5A fuses in the plugs should be ok with your 1000w inverter

play around with the numbers a little,

a car starter motor can be rated as high as 3kw @ 12v, how many amps? (this explains the CCA rating on batteries)

a 60w 240v bulb? (pretty much bog standard house bulb) how many amps?
a 55w 12v bulb? (bog standard car headlight bulb) How many amps?


What you use to charge would depend on consumption.

do you intend to only use 12v lighting only when its dark,

or do you want to use 12v hairdryer and straghteners etc?



Personally i'd go for as large a bank of batteris as i could afford,
in some cases, those with the least to say, say the most.....
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29 May 2013, 13:34,
#3
RE: Help a girl with her electricity please?
I would go for second hand fork lift truck batteries with a mixer of solar and a small genny to put extra charge in when needed.
Failure is NOT an option
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29 May 2013, 14:00,
#4
RE: Help a girl with her electricity please?
good shout on the forklift batteries
in some cases, those with the least to say, say the most.....
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29 May 2013, 17:24,
#5
RE: Help a girl with her electricity please?
Golf cart batteries are good too (deep cycle) - if you can find them that is...
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29 May 2013, 20:03,
#6
RE: Help a girl with her electricity please?
since most of the domestic appliances are made for 230V AC so it is more economical to use 12V-230V inverter.
with your 1000W inverter you can power light bulbs, refrigerator, radio, tv, computer as long as total consuming power is not exceeding 1000W. one classic light bulb has 60W power, modern LED bulbs are 7 to 14W, refrigerator has 300 (bigger ones 600W) when its compressor is on, modern tv has about 100W. so you can calculate how big inverter you need or how much light or appliances you can switch on.

batteries, on every 12V battery you can see its capacity shown in AMP per hour (A/h). usual family car battery has more or less 60A/h capacity. means that you can get 60AMPs of current for the 1 hour or 6AMPs for 10 hours.
now we know that one Watt equals one Volt times one Ampere (1W=1V x 1A).
so for running your 1000W inverter on full power you need at least same power coming from your battery. 1000W divided by 12V is 83,33AMPs. this means your battery is only good for about 45 minutes. more batteries you have connected in parallel the more battery capacity you have the longer you can use your lights or refrigerator.
this means you have to cut on electric consumption and use as many solar batteries as you can afford to charge your batteries.
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29 May 2013, 20:58,
#7
RE: Help a girl with her electricity please?
@ErikEst

Thank You So Much - just what a girl wanted

I assume that when I connect batteries in parallel you mean connecting all the pos together and all the neg together
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29 May 2013, 21:11,
#8
RE: Help a girl with her electricity please?
(29 May 2013, 20:58)River Song Wrote: @ErikEst

Thank You So Much - just what a girl wanted

I assume that when I connect batteries in parallel you mean connecting all the pos together and all the neg together

@ ErikEst.... I also think that is a great post, I have saved that one as it is very easily digested,.. thanks
A major part of survival is invisibility.
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29 May 2013, 23:04,
#9
RE: Help a girl with her electricity please?
Great reply's big help to me many thanks folks
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29 May 2013, 23:29,
#10
RE: Help a girl with her electricity please?
(29 May 2013, 20:58)River Song Wrote: @ErikEst

Thank You So Much - just what a girl wanted

I assume that when I connect batteries in parallel you mean connecting all the pos together and all the neg together

yes, if you connect them the other way you risk blowing your inverter or worse still, the things connected to it
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