Posted by B&B Musmon on October 4, 2007, 6:09 pm
I recently had a quote for a home propane generator backup for our
electricity. I guess it is alright, $3500 for a 7K installed with
switching and with the cost of wire, the length is pretty long about
45 feet and back 45 feet, I am told that is where a lot of the expense
is, I know wire has gone through the roof and I suspect it would be #6
wire for the whole house.
Ok, having said that, I really don't want to spend that much money and
what we really want it heat, I live in Maine and we loose our
electricity quite often, a lot of trees. We did loose it one time for
over 2 days and it was -10 F at night, we were lucky we didn't get
hypothermia. So I am thinking either go to a hotel and figure it is a
lot cheaper than a generator or try to do it cheaper.
Just for the heat alone a 4 zone forced hot water, I asked the guy
that put it in is about 1800 watts. I am thinking a 3KW inverter that
I have found for $450 that does have a built in charger. I want 2
days min or even 3 days which I know would need more than one battery.
I think the switch as to not back feed the line wouldn't be hard to
install and for one circuit pretty cheap. I am thinking it might take
3 to 5 batteries, I queried the people that sell the inverter, haven't
heard from them yet. But in any event a good idea or a bad idea? I
have seen a couple of different ways to wire the batteries. Inverter
+ with all the batteries wired of course + to plus in parallel and -
to minus and then the last battery to Inverter minus. We could if we
wanted to run a couple of extension cords to run some other things,
there should be plenty of overhead, but that isn't as important. I am
not worried about lights, we have plenty of auxiliary lighting and we
have a gas stove, we do have a water pump but storing some water isn't
a great big problem.
I am thinking under $500 with shipping for the inverter, $50 per
battery(unless they have gone up), $100 for switches and such.
4 batteries would make it about $800
Any comments, recommendations or plain old your dumb that would never
work would be welcomed.
Thanks,
Barry
Posted by bealiba on October 4, 2007, 6:39 pm
> I recently had a quote for a home propane generator backup for our
> electricity. I guess it is alright, $3500 for a 7K installed with
> switching and with the cost of wire, the length is pretty long about
> 45 feet and back 45 feet, I am told that is where a lot of the expense
> is, I know wire has gone through the roof and I suspect it would be #6
> wire for the whole house.
> Ok, having said that, I really don't want to spend that much money and
> what we really want it heat, I live in Maine and we loose our
> electricity quite often, a lot of trees. We did loose it one time for
> over 2 days and it was -10 F at night, we were lucky we didn't get
> hypothermia. So I am thinking either go to a hotel and figure it is a
> lot cheaper than a generator or try to do it cheaper.
> Just for the heat alone a 4 zone forced hot water, I asked the guy
> that put it in is about 1800 watts. I am thinking a 3KW inverter that
> I have found for $450 that does have a built in charger. I want 2
> days min or even 3 days which I know would need more than one battery.
> I think the switch as to not back feed the line wouldn't be hard to
> install and for one circuit pretty cheap. I am thinking it might take
> 3 to 5 batteries, I queried the people that sell the inverter, haven't
> heard from them yet. But in any event a good idea or a bad idea? I
> have seen a couple of different ways to wire the batteries. Inverter
> + with all the batteries wired of course + to plus in parallel and -
> to minus and then the last battery to Inverter minus. We could if we
> wanted to run a couple of extension cords to run some other things,
> there should be plenty of overhead, but that isn't as important. I am
> not worried about lights, we have plenty of auxiliary lighting and we
> have a gas stove, we do have a water pump but storing some water isn't
> a great big problem.
> I am thinking under $500 with shipping for the inverter, $50 per
> battery(unless they have gone up), $100 for switches and such.
> 4 batteries would make it about $800
> Any comments, recommendations or plain old your dumb that would never
> work would be welcomed.
> Thanks,
> Barry
There is a big difference between "dumb" and "ignorant"
Ignorant is just a lack of knowledge. And, well dumb is just dumb.
You have said " I asked the guy that put it in is about 1800 watts".
That 1800 watts is per hour. So, how many hours do you need to supply
this 1800 watts for? You have mentioned up to three days.
Now, lets say you need 1800 watts for the 72 hours and you use 24
volts for the batteries, you would be looking at a battery bank on the
order of 5400 Amp hours capacity. This does not take into account
losses, reality, closer to 7000 Amp hours.
Hours x Watts = Watt hours
1800 x 72 = 129600 Watt hours
Watt hours / Voltage = Amp hours
129600 Watt hours / 24 Volts = 5400 Amp hours
5400Amp hours is the capacity of your battery bank at 24 volts,then
you can add the losses.
I think you will find that the generator is a bargain.
Posted by RW Salnick on October 4, 2007, 6:56 pm
bealiba@gmail.com brought forth on stone tablets:
>
>>I recently had a quote for a home propane generator backup for our
>>electricity. I guess it is alright, $3500 for a 7K installed with
>>switching and with the cost of wire, the length is pretty long about
>>45 feet and back 45 feet, I am told that is where a lot of the expense
>>is, I know wire has gone through the roof and I suspect it would be #6
>>wire for the whole house.
>>
>>Ok, having said that, I really don't want to spend that much money and
>>what we really want it heat, I live in Maine and we loose our
>>electricity quite often, a lot of trees. We did loose it one time for
>>over 2 days and it was -10 F at night, we were lucky we didn't get
>>hypothermia. So I am thinking either go to a hotel and figure it is a
>>lot cheaper than a generator or try to do it cheaper.
>>
>>Just for the heat alone a 4 zone forced hot water, I asked the guy
>>that put it in is about 1800 watts. I am thinking a 3KW inverter that
>>I have found for $450 that does have a built in charger. I want 2
>>days min or even 3 days which I know would need more than one battery.
>>I think the switch as to not back feed the line wouldn't be hard to
>>install and for one circuit pretty cheap. I am thinking it might take
>>3 to 5 batteries, I queried the people that sell the inverter, haven't
>>heard from them yet. But in any event a good idea or a bad idea? I
>>have seen a couple of different ways to wire the batteries. Inverter
>>+ with all the batteries wired of course + to plus in parallel and -
>>to minus and then the last battery to Inverter minus. We could if we
>>wanted to run a couple of extension cords to run some other things,
>>there should be plenty of overhead, but that isn't as important. I am
>>not worried about lights, we have plenty of auxiliary lighting and we
>>have a gas stove, we do have a water pump but storing some water isn't
>>a great big problem.
>>
>>I am thinking under $500 with shipping for the inverter, $50 per
>>battery(unless they have gone up), $100 for switches and such.
>>
>>4 batteries would make it about $800
>>
>>Any comments, recommendations or plain old your dumb that would never
>>work would be welcomed.
>>
>>Thanks,
>>Barry
>
>
> There is a big difference between "dumb" and "ignorant"
>
> Ignorant is just a lack of knowledge. And, well dumb is just dumb.
>
> You have said " I asked the guy that put it in is about 1800 watts".
>
> That 1800 watts is per hour. So, how many hours do you need to supply
> this 1800 watts for? You have mentioned up to three days.
>
> Now, lets say you need 1800 watts for the 72 hours and you use 24
> volts for the batteries, you would be looking at a battery bank on the
> order of 5400 Amp hours capacity. This does not take into account
> losses, reality, closer to 7000 Amp hours.
>
> Hours x Watts = Watt hours
> 1800 x 72 = 129600 Watt hours
>
> Watt hours / Voltage = Amp hours
> 129600 Watt hours / 24 Volts = 5400 Amp hours
>
> 5400Amp hours is the capacity of your battery bank at 24 volts,then
> you can add the losses.
>
> I think you will find that the generator is a bargain.
Using your calculations, B & B, a group 31 deep discharge 12V battery
can deliver about 50 amp hours
(that's at 50% discharge - you don't want to go much below this if you
want to keep using the batteries).
So, very roughly, a total of 5400/50 * 2 = 216 batteries. Wow.
BTW Barry, 1800 watts at 110 volts out of an inverter means more like
1900 watts need to be fed into the inverter.
If you are feeding from a single battery, that means that it will need
to supply 1900/12 = 158 amps, or about twice what the starter on a big
V8 draws to crank the engine. A single battery isn't going to last very
long...
bob
s/v Eolian
Seattle
Posted by B&B Musmon on October 5, 2007, 7:04 am
Thank you both for your posts and help. I guess everyone has
convinced me this is a bad idea, would take far to many batteries and
terribly inefficient. Well, you don't know unless you ask, I guess.
Thanks,
Barry
>bealiba@gmail.com brought forth on stone tablets:
>>
>>>I recently had a quote for a home propane generator backup for our
>>>electricity. I guess it is alright, $3500 for a 7K installed with
>>>switching and with the cost of wire, the length is pretty long about
>>>45 feet and back 45 feet, I am told that is where a lot of the expense
>>>is, I know wire has gone through the roof and I suspect it would be #6
>>>wire for the whole house.
>>>
>>>Ok, having said that, I really don't want to spend that much money and
>>>what we really want it heat, I live in Maine and we loose our
>>>electricity quite often, a lot of trees. We did loose it one time for
>>>over 2 days and it was -10 F at night, we were lucky we didn't get
>>>hypothermia. So I am thinking either go to a hotel and figure it is a
>>>lot cheaper than a generator or try to do it cheaper.
>>>
>>>Just for the heat alone a 4 zone forced hot water, I asked the guy
>>>that put it in is about 1800 watts. I am thinking a 3KW inverter that
>>>I have found for $450 that does have a built in charger. I want 2
>>>days min or even 3 days which I know would need more than one battery.
>>>I think the switch as to not back feed the line wouldn't be hard to
>>>install and for one circuit pretty cheap. I am thinking it might take
>>>3 to 5 batteries, I queried the people that sell the inverter, haven't
>>>heard from them yet. But in any event a good idea or a bad idea? I
>>>have seen a couple of different ways to wire the batteries. Inverter
>>>+ with all the batteries wired of course + to plus in parallel and -
>>>to minus and then the last battery to Inverter minus. We could if we
>>>wanted to run a couple of extension cords to run some other things,
>>>there should be plenty of overhead, but that isn't as important. I am
>>>not worried about lights, we have plenty of auxiliary lighting and we
>>>have a gas stove, we do have a water pump but storing some water isn't
>>>a great big problem.
>>>
>>>I am thinking under $500 with shipping for the inverter, $50 per
>>>battery(unless they have gone up), $100 for switches and such.
>>>
>>>4 batteries would make it about $800
>>>
>>>Any comments, recommendations or plain old your dumb that would never
>>>work would be welcomed.
>>>
>>>Thanks,
>>>Barry
>>
>>
>> There is a big difference between "dumb" and "ignorant"
>>
>> Ignorant is just a lack of knowledge. And, well dumb is just dumb.
>>
>> You have said " I asked the guy that put it in is about 1800 watts".
>>
>> That 1800 watts is per hour. So, how many hours do you need to supply
>> this 1800 watts for? You have mentioned up to three days.
>>
>> Now, lets say you need 1800 watts for the 72 hours and you use 24
>> volts for the batteries, you would be looking at a battery bank on the
>> order of 5400 Amp hours capacity. This does not take into account
>> losses, reality, closer to 7000 Amp hours.
>>
>> Hours x Watts = Watt hours
>> 1800 x 72 = 129600 Watt hours
>>
>> Watt hours / Voltage = Amp hours
>> 129600 Watt hours / 24 Volts = 5400 Amp hours
>>
>> 5400Amp hours is the capacity of your battery bank at 24 volts,then
>> you can add the losses.
>>
>> I think you will find that the generator is a bargain.
>Using your calculations, B & B, a group 31 deep discharge 12V battery
>can deliver about 50 amp hours
>(that's at 50% discharge - you don't want to go much below this if you
>want to keep using the batteries).
>So, very roughly, a total of 5400/50 * 2 = 216 batteries. Wow.
>BTW Barry, 1800 watts at 110 volts out of an inverter means more like
>1900 watts need to be fed into the inverter.
>If you are feeding from a single battery, that means that it will need
>to supply 1900/12 = 158 amps, or about twice what the starter on a big
>V8 draws to crank the engine. A single battery isn't going to last very
>long...
>bob
>s/v Eolian
>Seattle
Posted by z on October 4, 2007, 7:35 pm
How about a propane heater ? Or a wood stove.. you say you've got lots of
trees. Heating using electricity -- be it from batteries or a generator is
pretty terrible use of the power. With a propane heater and a smaller
generator you could have lights and heat regardless of the weather.
could you plumb in a propane water heater so it could circulate through
your house? Maybe an on=demand water propane water heater that you could
just turn some valves and switch over.
Or like my nieghbor has a propane fixed heater with a thermostat and all
that. It cranks out the heat.. i'd keep you from freezing to death thats
for sure.
just my 02 cents
XML site map
> electricity. I guess it is alright, $3500 for a 7K installed with
> switching and with the cost of wire, the length is pretty long about
> 45 feet and back 45 feet, I am told that is where a lot of the expense
> is, I know wire has gone through the roof and I suspect it would be #6
> wire for the whole house.
> Ok, having said that, I really don't want to spend that much money and
> what we really want it heat, I live in Maine and we loose our
> electricity quite often, a lot of trees. We did loose it one time for
> over 2 days and it was -10 F at night, we were lucky we didn't get
> hypothermia. So I am thinking either go to a hotel and figure it is a
> lot cheaper than a generator or try to do it cheaper.
> Just for the heat alone a 4 zone forced hot water, I asked the guy
> that put it in is about 1800 watts. I am thinking a 3KW inverter that
> I have found for $450 that does have a built in charger. I want 2
> days min or even 3 days which I know would need more than one battery.
> I think the switch as to not back feed the line wouldn't be hard to
> install and for one circuit pretty cheap. I am thinking it might take
> 3 to 5 batteries, I queried the people that sell the inverter, haven't
> heard from them yet. But in any event a good idea or a bad idea? I
> have seen a couple of different ways to wire the batteries. Inverter
> + with all the batteries wired of course + to plus in parallel and -
> to minus and then the last battery to Inverter minus. We could if we
> wanted to run a couple of extension cords to run some other things,
> there should be plenty of overhead, but that isn't as important. I am
> not worried about lights, we have plenty of auxiliary lighting and we
> have a gas stove, we do have a water pump but storing some water isn't
> a great big problem.
> I am thinking under $500 with shipping for the inverter, $50 per
> battery(unless they have gone up), $100 for switches and such.
> 4 batteries would make it about $800
> Any comments, recommendations or plain old your dumb that would never
> work would be welcomed.
> Thanks,
> Barry