charge batts cost$$$$

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sleepie

New Member
Hearth Supporter
Dec 2, 2007
65
elmira, new york
does anyone know --how much it cost to charge a 12v batt-----my ? is---is battery power cost effective if i use the grid to charge them?---i would like to figure this out-- i like using the grid at my conveinance---so i was thinking about batt power for the house and only use them for charging-----any thoughts? cheers --pat
 
What do you mean? Charge them up, then use an inverter to power 120V appliances? In that case, it would not be cost effective given the power losses during charging and discharging. Maybe if you could charge them up with solar panels....plus you have the cost of the batteries to absorb.
 
yes thats what i want to do----i heard the grid is going to install off peak meters---so i thought i would charge the batts at night--when my load is light and the electric is cheaper-----thanks pat
 
Read the post in this same room about off-grid, that will give you an idea of whats involved.

Why don't you figure out a way to take advantage of the cheaper off-peak rates?
 
i thought i was using off peak efficiently--i would charge the batts during off peak---i don't want to live off grid---what i want to accomplish is to lower the electric bill--i heat with wood---i pay about 125 month in elec----was looking for a way to lower it even more---have done all the energy things----but if it lowers my bill --to charge batts at night ----and consume the batts during the day---that is the question??and the goal----cheers pat
 
The inverter efficiency loss of 10 to 15% would more than offset any cost savings.
 
is it then cost effective to recharge with generator???? or is solar or wind the only costt effective option to lower the elec bill---cheers pat
 
I don't think you'll ever come out ahead charging batteries.

If you use electricity, your charger is maybe 80% efficient, and you'd be extremely lucky to find an 80% efficient inverter, so you've only got 64% of your original power, plus the cost of the batteries and the depreciation because of their use, plus the cost of the inverter. Don't forget that to get the max life out of lead-acid batteries, you don't want to drain them - you can only use the top 25-30% - so you need quite a stack of batteries.

A generator is substantially worse. Maybe 30% of your gasoline actually turns the generator - the rest is lost as heat, maybe 70% of your generator power gets to the batteries and 80 percent through the inverter - so that is a measly 16% of the energy in the gasoline, plus now you have wear/tear/maintenance on a gas engine, electric generator, batteries and inverter.

Solar might be a tad better, because the power is free, and the cells generally don't require much maintenance, but they have a high up-front cost and you still have feeble batteries and a lossy inverter to worry about.

Your best bet would probably be to invest in some timers and turn off as much load as possible during peak time and time things to come on during off peak hours.
 
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