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32 votes

Easy way of generating a 50-150W load @12V

Automotive headlamps are the obvious, easy 12V choice, being typically in the 45-55W range (don't get LED headlamps.) If you ask the right folks you can often get dual-filament bulbs (high/low beam) ...
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32 votes

I turned a breaker off, and now the security alarm system won’t stop beeping

Most alarm systems have a backup battery. It would appear likely that yours is indicating failure and need of replacement. I would expect a competent alarm monitoring service to advise you of that (or ...
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26 votes
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FirstAlert smoke detector low battery warning continues after opening battery drawer and replacing batteries

The problem was that, when I initially removed the old batteries, I damaged one of the terminals within the battery drawer. All the terminals are thin metal plates that deform easily; there are no ...
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20 votes
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Sump pump automated battery backup

Another answer by Fresh Codemonger suggests having two pumps, one on regular power and the other on your inverter. I would like to suggest a similar option that I think is more efficient. As the ...
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  • 2,451
18 votes

How to make a cap to cover the battery terminals of Ryobi batteries?

In my opinion the easiest solution would be to simply store your batteries, alone, in a smaller bag. You could store this smaller bag within your larger tool bag or carry it separately. Either way, ...
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14 votes

Easy way of generating a 50-150W load @12V

You don't need to step up to mains voltage, in fact for experimenting it's best not to. There are such things as 12V car fan heaters that are typically 120-150W. Or you can buy wire-wound load ...
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13 votes

Multiple small AH batteries vs one large battery

If you are getting 'x' tools, where x > 1, and 'y' batteries, 'y' should be at least 2. Very simple - you will have times where you are using two tools at once. Maybe with a helper. Or maybe just ...
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11 votes
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What could cause a battery hedge trimmer to have white smoke come out of it?

Your hedge trimmer sounds like it has died or is in the process of dying. A quick google search confirms that this can occur with Black & Decker hedge trimmers, although it does not appear to be ...
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10 votes

Sump pump automated battery backup

I think the easier thing to do is to have two sump pump connected. The first on household power and the second on your battery. The first would have a start sensor at a lower spot than the battery ...
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9 votes

I turned a breaker off, and now the security alarm system won’t stop beeping

This is typical. The alarm system is normally powered by your home AC power. It may be hardwired, though typically for small alarms use a plug in adapter with low voltage wires routed through the wall ...
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8 votes

How to make a cap to cover the battery terminals of Ryobi batteries?

Large rubber stopper or buy a pair of baby's socks..
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  • 81
7 votes
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How to change battery in garage door keypad?

I found this page which stated: The second oldest style keypads have a pin hole at the bottom of the keypad cover. You will have to insert a small Phillips screw driver into the small hole at the ...
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  • 547
7 votes

How to make a cap to cover the battery terminals of Ryobi batteries?

Ask around on Facebook/Craigslist/local Ryobi retailer/local recycling yard for a discarded Ryobi screwdriver or a similar compatible tool. Cut across the handle using a hacksaw,keep the battery ...
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  • 1,665
7 votes

Multiple small AH batteries vs one large battery

Two 1.5AH batteries is definitely better than one 2AH one for equal money if they are the same brand and chemistry. Yes you are getting 50% more capacity. You can question the precision and behavior ...
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7 votes
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Suggestions for connecting a small UPC (battery backup) to a single receptacle/outlet that will power a wifi mesh router

A common name for a male-to-male power cord as described in your second idea is a "suicide cord". It's an incredibly bad idea. The problem with your first idea is that extension cords are ...
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  • 2,451
7 votes

I turned a breaker off, and now the security alarm system won’t stop beeping

You need to find your user's manual for your alarm system, and see what it has to say. If you don't have one, then talk to your alarm company. Yes, it's likely it's complaining about the battery. ...
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  • 2,466
7 votes

How to prevent discharging car battery completely?

That's the wrong way to go about it. Your engine starting battery is absolutely sacred - never "steal from it" for appliance power. In other words, don't be Jesse in Breaking Bad ("...
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6 votes
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How can I make my home internet router work with a battery?

Get a UPS No, not that UPS. An uninterruptible power supply, also known as a battery backup. This is a box that takes normal AC (e.g., 110-120V in the US) and uses it to charge a battery and power ...
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6 votes
Accepted

Inverter Power draw from 12V battery

You've got a few problems/misconceptions. First there's no such thing as a 100-amp battery; however 100 amp-hour would be typical of a car-battery-sized thing. An amp-hour is an amp for an hour. ...
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6 votes

Easy way of generating a 50-150W load @12V

For 12V DC, you are probably looking for halogen bulbs, not incandescent. You should be able to get a few hundred watts of 12v halogen bulbs for about $10 online, and you could even get them in units ...
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  • 1,355
6 votes

Easy way of generating a 50-150W load @12V

As you know the battery voltage will fall as its charge depletes. Depending on how constant you want the load to be it may need to self-adjust to hold a steady load (wattage). Ham radio enthusiasts ...
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  • 20.2k
6 votes

Why do well pumps need 240V when the wattage is not that high?

Need is not the right word here. Preferred is probably a better choice. 240V is preferred because submersible pumps are often well away from the house and deep down in the hole and you must run a ...
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  • 20.5k
6 votes

How to make a cap to cover the battery terminals of Ryobi batteries?

I first explored the opportunity of using a toilet paper shell for this but the problem is that a shell is too large to stay on the terminals and to reduce it inner diameter, I would have to put lots ...
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  • 227
6 votes

Suggestions for connecting a small UPC (battery backup) to a single receptacle/outlet that will power a wifi mesh router

You fail to provide details on what, exactly, your "tiny WiFi puck" is, but since virtually all such things that are not inherently POE operated (truly the best solution - one UPS at the ...
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  • 137k
5 votes

"power buffer" in front of generator for peak power shaving?

Buy a (petrol-fired) air compressor and pneumatic tools, or go for a bigger generator. (Good) Inverter can cost nearly as much as a generator, also remember that an inverter rated for 2kW has a ...
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  • 2,099
5 votes

Easy way of generating a 50-150W load @12V

Officially what you are actually asking for is a constant current sink: something which uses the same current even if the voltage drops. A light-bulb does that somewhat as it has a PTC thermistor ...
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  • 191
5 votes

Sump pump automated battery backup

You don't want to do that. An inverter powerful enough to start a sump pump will also have high standby losses. It will burn your battery down in short order. When you're dealing with a 12V ...
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5 votes

Powering battery powered tools from the power grid

No reasonably-sized and priced 20V PSU will be able to deliver the power that your 20V tools need. You are trying to design a corded tool that can last through a big job. The correct solution is to ...
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  • 17.8k
5 votes
Accepted

Is it possible to make an "energy harvester" that drains old batteries?

Is this possible? Of course it is. But is it practical? Not at all. The comparison is not to the cost of batteries. Batteries are expensive. The comparison has to be to the cost of electricity. Using ...
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5 votes

Multiple small AH batteries vs one large battery

I wouldn't consider a 1.5AH battery small and a 2.0AH battery large. I'd go with the 2- 1.5AH setup. It's more bang for your buck and it's also a backup if one goes bad. Stick with a reliable brand so ...
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