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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) ...
Ecnerwal's user avatar
  • 218k
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 ...
Ecnerwal's user avatar
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28 votes
Accepted

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 ...
Reign of Error's user avatar
20 votes
Accepted

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 ...
Moshe Katz's user avatar
  • 2,705
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, ...
stmp945's user avatar
  • 696
17 votes

UPS / Battery Question

I think you're seriously looking for trouble if you try to use one set of batteries in two UPSes at the same time. In theory, discharge will be OK - the batteries will be supplying both loads at the ...
manassehkatz-Moving 2 Codidact's user avatar
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 ...
Chris H's user avatar
  • 6,700
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 ...
manassehkatz-Moving 2 Codidact's user avatar
12 votes
Accepted

Can a completely evaporated deep cycle battery be brought back to charge?

How did the electrolyte boil off in the first place? The typical reason is a very cheap battery charger that did not know how to charge the battery properly. Modern state-of-the-art battery chargers ...
Harper - Reinstate Monica's user avatar
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 ...
Fresh Codemonger's user avatar
10 votes

Are deep-cycle batteries for off-grid power tolerant of temperature changes?

Here is a solution that I think is CHEAP, easy and versatile. You don't need to light up the whole shop at work-level lighting. Install 12V LED ceiling lights that are enough to walk around safely, ...
jay613's user avatar
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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 ...
manassehkatz-Moving 2 Codidact's user avatar
8 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 ...
jwh20's user avatar
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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..
Keith's user avatar
  • 81
8 votes

Can a completely evaporated deep cycle battery be brought back to charge?

Assuming you want your sump pump to work in a power outage, new battery. If you have a different, deader, battery to trade in when you do that, feel free to hack about with this one, for some non-...
Ecnerwal's user avatar
  • 218k
7 votes
Accepted

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 ...
Michael's user avatar
  • 997
7 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 ...
jay613's user avatar
  • 39.4k
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 ...
TooTea's user avatar
  • 2,332
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 ...
jay613's user avatar
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7 votes
Accepted

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 ...
Moshe Katz's user avatar
  • 2,705
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. ...
DaveM's user avatar
  • 2,725
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 ("...
Harper - Reinstate Monica's user avatar
7 votes

Are deep-cycle batteries for off-grid power tolerant of temperature changes?

Ready made battery "power stations" are now widely available. They contain a pack of LiFePO lithium cells, a charger and an inverter. Most will output 5V, 12V and either 120V or 230V ...
Simon B's user avatar
  • 3,958
7 votes

Replicate "Behind Wall TV Power" - Idea or Explosion?

Inlet/outlet is perfectly reasonable here. A few things to consider: The typical "kit" will be a fixed, relatively short, length. So the right way to do this between floors is full-fledged ...
manassehkatz-Moving 2 Codidact's user avatar
7 votes

Restore capacity of cordless drill batteries (NiMH)

NiCds &/or NiMHs abandoned in the attic for years (or anywhere else for years) are recycling fodder, nothing else. Price new batteries. Then either buy them, or decide that buying a whole new tool ...
Ecnerwal's user avatar
  • 218k
6 votes
Accepted

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 ...
manassehkatz-Moving 2 Codidact's user avatar
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. ...
Harper - Reinstate Monica's user avatar
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 ...
IronEagle's user avatar
  • 1,372
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 ...
Greg Hill's user avatar
  • 30.8k
6 votes

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

Volts is the "pressure" or force behind electricity. Note that 240V power has 20 times the force of a 12 volt battery. Amps is the flow/volume of electricity. Power (the thing you ...
Harper - Reinstate Monica's user avatar

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