battery operated gadgets

krisman Solar Expert Posts: 57 ✭✭✭✭
I am starting to use rechrgeable batteries and a battery charger to cut down on energy costs. Was wondering if anyone had any ideas on what gadgets could cut down without draining batteries? i have already though of an analog clock which should save about 5 watts per hour compared to a clock radio, an electric toothbrush that wont save a whole lot but a lot better than a manual toothbrush. now i need more ideas.


  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: battery operated gadgets

    I'm not sure that using rechargeable batteries will " will save on energy costs" Unless you are charging your batteries from PV then the energy has to come from somewhere and it has a cost. Additionally, batteries require more energy to charge than they can give back. There are always loses.

    As for gadgets. Go to They sell all kinds of stuff for off grid Amish. Hand washing machines, coffee grinders, etc. If you are serious about cutting energy costs, look to see what the folks use use no electricity do. The reality is, mostly hard(er) work.

    Wind up clocks!

  • BB.
    BB. Super Moderators, Administrators Posts: 33,409 admin
    Re: battery operated gadgets

    I am not quite sure what you are asking for... For AC power, a Kill-a-Watt Meter (versions also now available for other countries) is a great start.

    For smaller DC loads, one of these Amp*Hour/Watt*Hour meters used by RC guys (Remote Control planes/cars/etc. hobbyists) would be handy too.

    Looking for battery powered appliances (like the old Boom Boxes--portable radio/tape/cd players) would usually indicate something designed for more efficient power consumption.

    Lighting--there are lots of options out there such as CFL and LED... However, they vary so much in consumption vs light output vs beam characteristics--That you almost have to purchase one of each and test with a Kill-a-Watt or DC Amp*Hour/Watt*Hour meter to see how much power each unit actually uses vs how much use you get from it.

    And making your use as local as possible... A CFL may be the better room light. But an LED based lamp would be better for spot/work bench lighting.

    I stopped using the big stereo (my old one even used 20 watts on standby) and replaced it with a cheap battery powered AM/FM radio with ear buds and uses a single AAA or AA battery.

    Much in the way of conservation requires some modifications to our own behavior--as well as doing our own testing/qualification for efficiency based on yours or mine specific uses.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • krisman
    krisman Solar Expert Posts: 57 ✭✭✭✭
    Re: battery operated gadgets

    i do have a solar generator that will be running the battery charger, so no need to worry about any impact on the environment. anyway, would a coffee grinder save money? or just be too much work for too little savings? also, trying to figure out how anyone could make coffee without using so much darn energy.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,409 admin
    Re: battery operated gadgets

    When I was young (may decades ago :cry:), my parents simply used a hand cranked coffee grinder for their coffee (frequently powered by us kids fighting for the chance to turn it).

    For a small device like a coffee grinder, assume that it takes 100 watts and runs for 1 minute:

    100 watts * 1 min * 1 hr/60 min = 1.67 Watt*Hours = 0.0017 kWhrs per use

    However, to heat your 2 cups of hot water... Say 1,500 watt electric tea kettle for 5 minutes:

    1,500 watts * 5 min * 1/60 = 125 Watt*Hours = 0.125 kWhrs per two cups

    And, if you want to relax in a warm room in front of an electric heater for an hour while enjoying the coffee+paper/laptop reading Google News:

    30 watts * 1 hour = 30 Watt*Hours = 0.03 kWhrs for the computer

    1,500 watts * 1 hour = 1,500 WH = 1.5 kWhrs for 1 hour of electric heat

    So--you really need to evaluate each usage for a cost/benefit ratio... $1-$2+ per kWhr is a realistic estimate for the cost off your off-grid system power (remember that battery needs to be replaced every 4-8 years or so--there is a definable ongoing cost for off-grid power). Using alternatives for heating (propane, solar thermal, etc.) is generally much more cost effective vs using solar electric/PV panels.

    The coffee grinder, less than a penny to run it per day. The laptop, perhaps $0.03-$0.06 per hour. The electric heater (I know, just an example) will cost $1.50-$3.00 per hour of use.

    Since you have a a solar panel + battery + inverter (?) -- you can estimate how much useful power it will generate per day, and plan your loads accordingly. Some days, you will generate more power than average, and others less than average. It does require monitoring of the battery state of charge + available power from the panel(s) to ensure that you do not draw more power than is available over time (deficit charging) and kill your battery in a few months.

    The Kill-a-Watt and Amp*Hour meters I suggested earlier will help you with load planning and monitoring.

    A Battery Monitor will help you manage the battery state of charge (and a good quality hydrometer+thermometer if needed, and is flooded cell battery) help you better understand your system and your eventual needs (assuming that you want to go with a larger off grid system in the future).

    Here is a nice thread about installing solar in a small RV Trailer (Kevin from Calgary). Includes photos and links to video (including a Battery Monitor).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Brock
    Brock Solar Expert Posts: 639 ✭✭✭✭
    Re: battery operated gadgets

    In a way I have been doing this as well. Take for example the kids music, they had a kids "boombox" plugged in and often left it on, but with the volume turned all the way down. I threw it on the kill-a-watt to find it was consuming 2 watts even in the "off" position and 4 watts on, but turned all the way down. So I took the cord off and put NiMH's in it, 6 AA cells with spacers to "C" size. For about two weeks I had to change / charge the AA cells about every other day and slowly they learned to turn the unit off when they weren't using it. I bet it has been 6 weeks since I changed them last.

    So if an appliance has an option I use batteries.

    To me it's the stand by losses or phantom loads in appliances that kills me.

    Oh another one is our cordless phones. Granted the wall wart only consumes about 1 watt and puts out 9vdc to the phone base. I now have the base plugged in to a 6 AA battery pack. It last about 10-14 days, but I just swap them out every week. And it is truly “cordless” now :)
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI