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31

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) with one filament broken for free.


20

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 other answer says, you should have a second pump. However, instead of connecting it to your inverter, your second pump should be one that is designed to run ...


18

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, the batteries are isolated from any other metallic objects and protected. I don't see any advantage to complicating matters by installing stem protectors simply ...


14

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 resistors. A 3 Ω resistor would dissipate 48 W at 12 V, so wiring 3 in parallel would work and allow you to adjust the load. I'd buy 100 ...


13

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 switching back and forth between two tools by yourself. Not having to switch batteries every 5 minutes will make a big difference. Plus using two batteries has ...


11

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 wide spread. Because you didn't provide the model it isn't possible to give you a more specific reason why it has failed. My opinion is that when you were having ...


10

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 sump sensor. This way the battery one only runs if the water reaches above a high spot. This will also give the added benefit that if the household sump pump ...


8

Large rubber stopper or buy a pair of baby's socks..


7

Since you have an old car battery, the cost of damaging it by overcharging isn't much ($40?) and that would only happen if it got a lot of sun over weeks. A small home solar system might have thousands of dollars of batteries, so standard practice has long been for those to always have charge controllers. For small systems the cost of a charge controller ...


7

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 holder, discard the rest of the tool. If you happen to cut so that the two halves of the shell come apart,glue them together. Remove wires coming from the battery ...


7

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 but that won't undo a 50% increase. You can charge one while you use the other. Your tools will be lighter and easier to use. If one fails, you still have ...


6

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 your devices. If power goes out (technically: voltage out of range) then it uses an inverter to power your devices from the battery. All automatically. You ...


6

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. Second, you can't get 100 amp-hours out of a 100Ah lead-acid battery, at least not for very many cycles. That would be 100% depth of discharge, and that is very ...


6

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 of 20W or so if you want to refine your testing.


6

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 routinely require a "dummy load" for testing radio transmitters without actually transmitting anything. These are basically high-power 50 ohm resistors. On its ...


6

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 wire there capable of supplying its power needs without too much voltage drop in the line. While you could do this with a large AWG wire at 120V, you can use a ...


6

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 of some soft material like foam inside it, and I didn't have any foam handy. Then I made the decision to make the caps entirely out of duct tape and paper. The ...


5

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 substained rate of about half. I found on Amazon this 3kW inexpensive inverter, check if it may be good for you. Anyway, with an inverter it's important that the ...


5

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 characteristic (The resistance increases when it gets hot). If you really want constant current you would need to build something electronically. That is ...


5

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 system this small, you want all the loads to be DC. It might be tolerable if you only spun up the inverter for the second per day the pump was actually in ...


5

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 bottom of the cover and gently pull outward to loosen and slide the cover down to remove. Below is a picture you can reference. But strangely, the picture didn't ...


5

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 buy actual corded tools. Just the ones that you actually need for such big jobs. Plan B would be to buy more, bigger, batteries and a multi-battery charger ...


5

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 some very rough numbers: Cost of electricity per kWh: US average is around 13 cents. Let's round up a bit to make the math simple and call it 20 cents per kWh. ...


5

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 you'll always be able to get replacement batteries and watch out for counterfeits (Amazon).


4

You have the basic concept down. Your challenge will be sizing. What's the minimum possible load you can put on the system? For instance, don't use an inverter to run lighting. Run the lighting direct off 12V, and there's a huge variety of 12 volt LED lighting: from screw-in bulbs, spot or flood lights, LED strips that let you freestyle your lighting, ...


4

The Powerwall is/will be based on the lithium ion battery technology used in the Tesla cars, so instead of a few large lead acid batteries (like in PV battery banks) it will contain a zillion tiny 18650 cells, which work better if you put them in series and let the voltage soar. This keeps the current low while still allowing the same amount of power output ...


4

The neck style battery pack typically held an extra 1-2 NiCad cells in that neck portion. With the transition to higher voltages, they want to make at least some change in design so you can't use the wrong battery like @Henry Jackson stated. But the main reason you don't see any is the way lithium-ion packs are constructed, yes they do still have a few ...


4

There have been a lot of changes in batteries for tools over the years. Different chemistries, voltages, capacities. Obviously the tool makers don't want you sticking a 20V lithium battery into an old 12V nickel-cadmium drill, so they make the shapes different. Maybe some of the discount manufacturers try to turn over their battery types regularly to force ...


4

Measure each battery individually, you can still do that with the wires you have added attached to the battery. I suspect your batteries don't have a full charge. Your logic is correct.


4

That charger device clearly states that it is for NiCd and NiMH rechargeable batteries only. It would be a risky proposition to put other batteries in that unit whether they be lithium or alkaline types. I think it would be just too easy to put the unit into the wrong mode. What you want to do instead is get yourself a digital multimeter that can measure ...


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