120vac timers - to reduce net load from phantom load devices

Keith Birchfield
72 Posts
May 7, 2008 09:09 pm
120vac timers - to reduce net load from phantom load devices

Goal: Reduce total net consumption for a very specific set of devices. ( primarily battery chargers for tools )

Question: Is it possible to connect a power strip to an a/c timer, and set the timer to only run during specific hours during the day ( peek pv production times )

Here is part of what I have ...

I have 5 battery chargers that draw roughly between 6 watts and 30 watts during standby, trickle charge and full charge modes.

I want to put these chargers on a solar+battery powered circuit.

But, the chargers running 24x7, put quite a net load on the power supply. ( mostly phantom / standby power draw ).

So, my thoughts are that If I can find a timer that draws very little to none during standby, and then have it turn on while the solar panels are generating at near peak ( about 4 hrs per day ) ... then I would put the least possible load on the supply, while, hopefully, keeping the batteries charged and ready to go.

My worry is that any 'good' timer would end up drawing just as much power in standby as the chargers ... but I'm having a lot of trouble seeing that kind of specs associated with the timers for sale online.

Anyways ... Any comments or suggestions would be greatly appreciated.
 
 
John B
163 Posts
May 7, 2008 10:22 pm
Re: 120vac timers - to reduce net load from phantom load devices

Keith,

I believe the Intermatic electronic timers draw less than 3 watts, and they should be available at your local hardware store.
http://www.intermatic.com/

You just need to make sure that your chargers have good diodes to prevent the batteries from discharging back through the charger when the power is switched off.


John
 
 
James Rosenberger
11 Posts
May 7, 2008 11:50 pm
Re: 120vac timers - X10 or smarthome...

Personally I use X10 devices to control loads on a timer basis.  I use an appliance module which has a relay to switch the 120V device.  The only power draw is the controller unit.  Depending on the controller unit you get it can draw almost nothing. 
I use an alarm clock type of control unit which I just checked with my "kill A Watt" and it reports 1 Watt.  This can control up to 8 modules on different on/off time schedules or many more than 8 modules if you want to switch at the same time.

www.x10.com or www.smarthome.com  Radioshack used to sell them under the "Plug 'n Power" brand,  but not sure if they do anymore.
 
 
Keith Birchfield
72 Posts
May 8, 2008 06:42 am
Re: 120vac timers - to reduce net load from phantom load devices

Quote from: john bodden on May  7, 2008  10:22 pm
... You just need to make sure that your chargers have good diodes to prevent the batteries from discharging back through the charger when the power is switched off.

Thanks,

Since a couple of these are simple off the shelf black and decker chargers ... I wouldn't expect them to be expensively made.

So, how do I determine if I have 'good chargers'?

 
 
John D
184 Posts
May 8, 2008 09:16 am
Re: 120vac timers - to reduce net load from phantom load devices

You might be better off with an Iota DLS-series battery charger.  Be sure to get the IQ-4 option.  These are three stage (bulk, absorption, and float) chargers.  I understand that you can leave them connected and power applied.  To protect your batteries, and to avoid wasting power, this seems like a much better option than to use timers.

 
 
 
Keith Birchfield
72 Posts
May 8, 2008 10:40 am
Re: 120vac timers - to reduce net load from phantom load devices

Quote
... You might be better off with an Iota DLS-series battery charger.  Be sure to get the IQ-4 option.  These are three stage (bulk, absorption, and float) chargers.
...
John,
Thanks, but I'm not certain I understand.

I'm looking for a way to lessen the impact of keeping my yard tools charged ... and household batteries like double As etc ...

How would your recommended charger work with my riobi and black and decker tools?

These tool chargers will be connected to a solar powered circuit that already is in place ... and that has a pretty good mppt charge controller on it. and a relatively good true-sine inverter.
« Last Edit: May 8, 2008 10:42 am by Keith Birchfield »
 
 
John B
163 Posts
May 8, 2008 04:27 pm
Re: 120vac timers - to reduce net load from phantom load devices

Quote from: Keith Birchfield on May  8, 2008  06:42 am
Since a couple of these are simple off the shelf black and decker chargers ... I wouldn't expect them to be expensively made.

So, how do I determine if I have 'good chargers'?

Keith,

One easy test would be to unplug the charger after the battery is fully charged, but leave the battery in the charging cradle. If your battery discharges overnight without any use then leaving it plugged in with a timer is not doing you any good. I think the instructions on some of the cheaper B&D models actually tell you to remove the battery from the charger after the battery is fully charged. This is usually indicated by the light changing from red to green. If the instructions for your chargers do not specifically tell you to remove the batteries after charging then you might be OK with what you are doing.

The 3-stage chargers that John D mentioned are the best. I have a Makita 18V cordless drill and that can be left plugged in at all times because the charger is a 3-stage model. After the battery is fully charged the light on the battery charger switches to blinking green and very little energy is being consumed. I was a bit reluctant to purchase it because of the higher price, but in the two years that I have been using it I probably would have gone through 2 or 3 B&D cordless drills.

John
 
 
Keith Birchfield
72 Posts
May 9, 2008 06:43 am
Re: 120vac timers - to reduce net load from phantom load devices

Ok, and thanks.
I believe my b&d chargers are going to be a problem. Bummer.

So, do I understand that I could use something like the DLS charger to charge off the shelf 18v b&d batteries? How would you do this, with alligator clamps? More than one battery at a time? Even though they would be at different charge levels?

This seems like a complicated solution, but its starting to sound like my options are severely limited for these 'cheep' 18v chargers.
 
 

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