Hypothertical Power Question - Small Cabin Forum

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Small Cabin Forum / Off-Grid Living / Hypothertical Power Question


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hitanktank Member	# Posted: 30 Jan 2013 18:53 Reply This is hypothetical as I have a generator but curiosity got the better of me. If a person didnt have a generator, could they use a deep cycle battery and a lets say 3000W inverter to run power tools and then charge the battery when its low? Assuming no generator no solar.

hitanktank Member	# Posted: 30 Jan 2013 19:04 - Edited by: hitanktank Reply strong spelling of hypothetical by me in the title

PA_Bound Member	# Posted: 30 Jan 2013 19:34 Reply No generator... no solar... how would you recharge it? Are you planning to take it back-and-forth? I'm not sure a single deep-cycle battery would drive a 3000w inverter. Or, if it did, probably not for very long at anywhere near that wattage.

MtnDon Member	# Posted: 30 Jan 2013 20:09 Reply If you had said a 200 or 400 watt inverter I would have said, Maybe, but just what would you run, how long would you expect to run it, and how often do you want to buy a new battery? But the 3000 watt inverter indicates you expect to put some seriously large demands on that system. That wants me to say, NO. Forget the idea. But to be fair, tell us more. You have given incomplete information. All that will get you is an incomplete or inaccurate and therefore meaning less answer. We need to know: Amount of power to be used. Watts or amps and volts. Length of time that amount would be used (watts x hours = watt-hours, a very useful number. An idea on how often you want to buy a new battery; annual event, 2 years, 5 years That's all the same questions that need answers whether or not there is a generator or PV panels in the mix.

hitanktank Member	# Posted: 30 Jan 2013 20:27 Reply ok fair answer I didnt have accurate info cause it was hypothetical tools involved would only be a jigsaw and a circular saw would be hauling it back and forth for recharge dont feel the need to go deep into answering this as it is hypothetical, it was more curiosity in my brain than anything

MtnDon Member	# Posted: 30 Jan 2013 21:00 - Edited by: MtnDon Reply Well, hypothetically speaking it is possible. Small loads = a longer time to use; larger loads = a shorter time of use. The more the battery is depleted the shorter the interval in depleting the wallet as one buys replacement batteries.

TomChum Member	# Posted: 31 Jan 2013 12:57 - Edited by: TomChum Reply Quoting: hitanktank tools involved would only be a jigsaw and a circular saw What you propose would work to a point. A circular saw might need 2000W startup, and 1000W sustained. A Jigsaw probably half that. So a 3000W inverter would run that stuff, unless it's "junk" (labeled 3000w but actually 1500w). A 3000w inverter worth owning would cost a lot, more than $1,000. My 1000W inverter (Magnum Energy MMS1012) cost $850 and it was a "refurb"! But it included an integral 50W charger. A deep cycle battery would run those tools long enough. I predict you will quickly become tired of this arrangement, and move on to a better method, before you wear out the Deep Cycle battery. I would NOT recommend that route. I would get the big bag of DeWalt 18v tools for ~$700. And add the DeWalt Jigsaw ($120?), which is arguably the best Jigsaw I ever had (and I have a Bosch!). You can do a LOT of work with 18v tools, and you can use the Deepcycle battery to run the recharger. Use a small cheap 400W inverter to charge 18v batteries with the included 110v charger (1 hour). You could get the DeWalt 12v re-charger for your 18v batteries (but they're slow, 2 hours) but then you can charge 2 batteries at a time. I don't know what to say about 18v vs newer 20v stuff. I have 18v and it's working great. Get a 40A battery charger so you can use your generator to charge the deepcycle battery if necessary. Run the generator if you have some real power needs, the rest of the time use your quiet DeWalt stuff, and enjoy your build without earplugs! All of this costs less than the 3000W inverter and you will be very happy, instantly. You will need a normal 120v skilsaw that runs on the generator, for some operations, like ripping a board or 3/4" plywood sheet. Don't get talked into over-buying tools that a professional needs to generate a profit 50 weeks out of a year. These threads always steer people towards the absolute necessity of nailguns, sometimes before they've even swung a hammer. The DeWalt 18V set is more than adequate for a guy building his own cabin and will continue to be useful onward.

hitanktank Member	# Posted: 1 Feb 2013 00:04 Reply Quoting: TomChum What you propose would work to a point. A circular saw might need 2000W startup, and 1000W sustained. A Jigsaw probably half that. So a 3000W inverter would run that stuff, unless it's "junk" (labeled 3000w but actually 1500w). A 3000w inverter worth owning would cost a lot, more than $1,000. My 1000W inverter (Magnum Energy MMS1012) cost $850 and it was a "refurb"! But it included an integral 50W charger. A deep cycle battery would run those tools long enough. I predict you will quickly become tired of this arrangement, and move on to a better method, before you wear out the Deep Cycle battery. I would NOT recommend that route. I would get the big bag of DeWalt 18v tools for ~$700. And add the DeWalt Jigsaw ($120?), which is arguably the best Jigsaw I ever had (and I have a Bosch!). You can do a LOT of work with 18v tools, and you can use the Deepcycle battery to run the recharger. Use a small cheap 400W inverter to charge 18v batteries with the included 110v charger (1 hour). You could get the DeWalt 12v re-charger for your 18v batteries (but they're slow, 2 hours) but then you can charge 2 batteries at a time. I don't know what to say about 18v vs newer 20v stuff. I have 18v and it's working great. Get a 40A battery charger so you can use your generator to charge the deepcycle battery if necessary. Run the generator if you have some real power needs, the rest of the time use your quiet DeWalt stuff, and enjoy your build without earplugs! All of this costs less than the 3000W inverter and you will be very happy, instantly. You will need a normal 120v skilsaw that runs on the generator, for some operations, like ripping a board or 3/4" plywood sheet. Don't get talked into over-buying tools that a professional needs to generate a profit 50 weeks out of a year. These threads always steer people towards the absolute necessity of nailguns, sometimes before they've even swung a hammer. The DeWalt 18V set is more than adequate for a guy building his own cabin and will continue to be useful onward. this answer is pure gold---awesome

PA_Bound Member	# Posted: 1 Feb 2013 08:29 Reply I don' t know Tom, about your thoughts on nail guns. I started my cabin out with a hammer (and used a hammer for everything in the past). Not long into it I had a friend up to help me for a day. He brought his Pasload framing nailer. I was schooled very quickly in how much work and effort they save, and how much faster you can move. Yes... they're not "old school". But I think the old-schoolers would have used nail guns if they were around back then. On my way home that night I stopped by the local Lowes and bought my very own set of air nailers and a compressor. I didn't by Pasload, as that is a little to "rich" for my blood. But, a year later, I consider air nailers a staple of my tool set.

MtnDon Member	# Posted: 1 Feb 2013 10:14 Reply I didn't think past the OP as to what power might be used for. I agree completely on getting a cordless tool kit for building where there is no grid power. We built our cabin that way. The inverter generator was used to pump up air and run a table saw for a few things. An air nailer is not necessary but they are very nice for speed. Be careful with them though. A lot of people develop a lot of bad habits with them; trip and nail themselves someplace, drive a nail through a hand that was holding the work in place, and so on. A finish nailer is the way to install trim and T&G 1x boards. If an air nailer won't break the bank I'd get one. I still have my original Senco's, bought circa 1987. A

TomChum Member	# Posted: 1 Feb 2013 11:26 - Edited by: TomChum Reply Quoting: PA_Bound I started my cabin out with a hammer (and used a hammer for everything in the past). Then give this fella the same opportunity (a couple years). There's PLENTY to learn. How to rig up an efficient toolbelt is FAR FAR ahead of a nailgun. Getting used to a 'speed square'. How to mark a board & cut straight, and not cut yourself either (ever!). Not arriving at the top of a ladder with no tape measure and no pencil. A nailgun that adds speed, before a guy even knows sensible construction sequence, is just not the right tool to introduce. For the life of me I cannot figure out why experienced people always suggest it as a first tool to a new carpenter, except that they've never been around a "new" carpenter. It doesn't get you "started out right". Maybe it allows you to make your mistakes faster, then you learn how to tear wrong stuff out quicker. Suggest a good nail puller too then. (all this from a guy with a LOG cabin) My father-in-law (RIP) was a master carpenter. I learned a lot from him, very much enjoyed working with him. Also about nailguns, which he had every size and style, and I have them all now. If there's a big stack of plywood and OSB in the materials, and if you are building a "house" (not a "small cabin") and if carpentry and high-speed tool usage comes natural to you, then a nailgun is inevitable. Other than the fact that a generator has to yell all day long (8 or 10 hours) to support nailguns, I'm not against nailguns. With regards to the topic, I can almost GUARANTEE that the direction this thread was going to go..... "hypothetical power question" is not workable because a battery cannot support a compressor and an nailgun. Nailguns get a lot of attention.

MtnDon Member	# Posted: 1 Feb 2013 12:58 Reply Quoting: TomChum it allows you to make your mistakes faster, That is for sure. Cutting nails off at the joint line with a reciprocating saw is easier than pulling. Much of the time it is easier.

Paul Member	# Posted: 1 Feb 2013 13:37 Reply I have been debating the same set up you want to do tank, but only using my truck instead of a battery charger. I dont know if you considered it but you could add a second battery(deep cycle) to the car/truck you drive to your property. The truck will charge it on the drive and if you start to run low on power start your truck back up and it will recharge. BE CAREFUL you need a battery isolator like used in a boat or an old ford starter solenoid would work too. Just do your research and there is a ton of it on the interwebs. It is very popular with truck campers so you could maybe start there if interested. I think you guys worry waaay too much about deep cycle battery life. I have been a foreman of a roofing company for 8/9 years now and I have worked here for 13 years. We have multiple tandem axle dump trailers. Each has a deep cycle battery that is used to power the hydraulic pump to raise the bed and dump the trash. We always run the batteries to no power or almost no power. They still last many years even depleting them and recharging them weekly. When you think about it, most deep cycle bats get ran all the way down on everything else except solar set ups(boats, trolling motors, power wheels, etc.) Solar seems to be the only subject where people complain about battery life. I'm sure it does have an effect on the battery life but so does how well its made and how you use it. Cordless tools work great and are very handy. The problem is that EVERY MAKER'S batteries dont hold a charge very well after a year or two. It doesnt matter who's tools you buy they all last about the same. Contractors use dewalt because of its availability, we dont have to pay for them customers do, and the dewalt reps work much harder than any anyone else at retaining and finding new customers. If you want to use a certain company great, but dont buy one or the other because of the name. The porter cable set I have at home does the exact same thing as the dewalt sets we have at work for a fraction of the price.

hitanktank Member	# Posted: 1 Feb 2013 17:55 Reply Im all about old school Got a hammer and goin to town. Most sophisticated thing I have is a mitre saw.

hitanktank Member	# Posted: 3 Feb 2013 19:09 Reply on a different note If I hook up a 12 volt battery directly to a 12 volt fridge what gauge wire is best to use?

exsailor Member	# Posted: 4 Feb 2013 10:22 Reply Over drawing batteries on a continual basis, such as trolling motor use does destroy batteries. My brother-in law has a stack of quality batteries ruined by trolling motor abuse. My nephew believes in buying the best but not taking care of it.

TomChum Member	# Posted: 4 Feb 2013 11:39 - Edited by: TomChum Reply Quoting: hitanktank If I hook up a 12 volt battery directly to a 12 volt fridge what gauge wire is best to use? 12v does not go far, you need big wires if the device is far from the battery. That's why hi-tension powerlines use 500,000volts (and DC has much more losses than AC) Consider positioning the fridge so the wire length is short as possible. There are lots of free calculators on the internet for this. You will need to know the length of the wire and the power requirements of the fridge (look at specifications in the owners manual).

TomChum Member	# Posted: 4 Feb 2013 11:48 - Edited by: TomChum Reply Quoting: Paul Each has a deep cycle battery that is used to power the hydraulic pump to raise the bed and dump the trash. We always run the batteries to no power or almost no power. They still last many years even depleting them and recharging them weekly. When you think about it, most deep cycle bats get ran all the way down on everything else except solar set ups(boats, trolling motors, power wheels, etc.) Solar seems to be the only subject where people complain about battery life. I've often wondered about that. Deep cycle is a strange name for an battery that the general wisdom concludes is best utilized only in "shallow cycles". Maybe the usage you describe works because they are run hard and charged hard? Are they allowed to "sit" in the depleted state or charged immediately?

rayyy Member	# Posted: 4 Feb 2013 12:00 Reply A fully charged 12 volt deep cycle battery wouldn't last you very long running any kind of power tool on an inverter.Infact,once you discharge a 12 volt battery down below 10 volts it takes it's toal on the poor thing.If you do this enough times it will kill your battery life drasticly.A 18 volt tool kit would do you much better.You can pick up a circ saw/drill motor combo with 2 batterys and a charger very reasonably.Plug that into your generator and it will be ready for you when your first battery gets week.Iv'e built everything with these tools for the last 10 years.You can also get other tools like jig saw,flashlight,vaccuum cleaner,grinding wheeles,recip saw,extra battery's and chargers.

TomChum Member	# Posted: 4 Feb 2013 18:09 Reply Quoting: Paul The problem is that EVERY MAKER'S batteries dont hold a charge very well after a year or two I've had some DeWalt batteries lasting 4 years, some lasting less than a year. NiCad, NiMH, and Lithium all behave differently. It would be impossible for me to state a preference. I have hated "NiCad" in the past, but then discovered that my DeWalt XRP batteries, that have worked the best, run the longest, are in fact NiCad. Note that DeWalt batteries are warranteed 2 years since the manufacture date. Look for the mfr date burned into the battery case. The local DeWalt rep simply replaces any non-performing battery (less than 2 years), which has increased my satisfaction in DeWalt a LOT.

Paul Member	# Posted: 5 Mar 2013 19:44 Reply Quoting: TomChum Note that DeWalt batteries are warranteed 2 years I have never heard anything about that before. after some news like that I feel like I owe you a steak dinner! Quoting: TomChum Maybe the usage you describe works because they are run hard and charged hard? Are they allowed to "sit" in the depleted state or charged immediately? I'd estimate the batteries get 6-8 "dumps" per charger. It varies by weight and material. if they seem low or wont push the pump then they get put on a charger at night. It is usually set to trickle charge. sorry I left you hanging, I lost track of this thread.