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ImmortalSoFar

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  • Thanks for this. If you'd asked me about ohms law, after dragging my memory, I'd have come up with V=IR as in "solve for voltage, current or resistance. 10/10. On to the next module." Funny how maths will get you through any number of subjects without actually teaching you anything useful. I learn best with "here's a problem, let's solve it." I want to know the voltage in the battery, I found the voltage divider, wondered at which combination of resisters would be better and found the "smallest" answer on stack overflow. That puzzled me so I asked a more practical group here. I appreciate your detail and I'm going over it making sure I get all of the details.The current measuring board is a small PCB which sits on the ground wire just before the battery. It h…

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    Thanks for this. If you'd asked me about ohms law, after dragging my memory, I'd have come up with V=IR as in "solve for voltage, current or resistance. 10/10. On to the next module." Funny how maths will get you through any number of subjects without actually teaching you anything useful. I learn best with "here's a problem, let's solve it." I want to know the voltage in the battery, I found the voltage divider, wondered at which combination of resisters would be better and found the "smallest" answer on stack overflow. That puzzled me so I asked a more practical group here. I appreciate your detail and I'm going over it making sure I get all of the details.The current measuring board is a small PCB which sits on the ground wire just before the battery. It has Gnd in and out on one end and +5V, data, Gnd on the other - apparently converting 0-50 amps on the power wire to 0-5V for the ADC on the Arduino. I'm hooking up a lot of different sensors in the battery box and broadcasting the measurements over Cat5 cable to anything that might be interested.I'm only using this for measurement, not for power, although with so many low power devices around, I might see how dumping the ground through them affects the readings so as to minimize the parasitic load on the system. I know it's negligible but it bugs me.

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  • How to Measure and Mark With Precision

    Thanks for this. I was beginning to feel that accurate measuring was a dark art. I know the theory but whenever I try to put it into practice, the results are worse than dead-reckoning. I just had to cut down plastic blocks by eye because the guide on the circular saw somehow didn't kept producing different results.

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  • How Electronic Switches Work for Noobs: Relays and Transistors

    A question from a tinkering maniac: I want create a new, switchable 200A circuit to drive a welder but which leaves the cells isolated otherwise. If I link the cells together with a 600A BUK454 (http://pdf.datasheetcatalog.com/datasheet/philips/BUK454-200A.pdf). Am I right in thinking that simply connecting them across all of the positive terminals and applying 3V to all of the collectors will create a continuous series connection that can handle this current?I'd kind of like to find out before I try welding with my battery pack!

    A question from a tinkering maniac: I want create a new, switchable 200A circuit to drive a welder but which leaves the cells isolated otherwise. If I link the cells together with a 600A BUK454 (http://pdf.datasheetcatalog.com/datasheet/philips/BUK454-200A.pdf). Am I right in thinking that simply connecting them across all of the positive terminals and applying 3V to all of the collectors will create a continuous series connection that can handle this current?I'd kind of like to find out before I try welding with my battery pack!

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  • Thanks, Downunder. Will do. Like suddenly realising that a cheap, plastic toolbox makes a great portable battery case, it seems to be a case of stumbling across the right area.

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  • Funnily enough, I've stumbled across some interesting solutions to some of these points. I'm still assembling the battery (in a Black and Decker, 19" tool box - £20 from Homebase) and I've put a couple of switches in the housing. One uses a DPDT switch to reverse the polarity of the middle of 3 batteries which should, in theory, go from 3 x 12V in parallel to 3x12V in series = 36V. I'm protecting that switch under a safety hood! I also ran the negative lines of the 3 balancing boards through a 3 circuit switch since the boards are rated for 50A, not the kind of welding amps. It's a simple little thing but I might post an instructable because the result is so pretty!Now I've got to figure out a way of creating an alterative route for unbalanced cell use which doesn't interfere with th…

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    Funnily enough, I've stumbled across some interesting solutions to some of these points. I'm still assembling the battery (in a Black and Decker, 19" tool box - £20 from Homebase) and I've put a couple of switches in the housing. One uses a DPDT switch to reverse the polarity of the middle of 3 batteries which should, in theory, go from 3 x 12V in parallel to 3x12V in series = 36V. I'm protecting that switch under a safety hood! I also ran the negative lines of the 3 balancing boards through a 3 circuit switch since the boards are rated for 50A, not the kind of welding amps. It's a simple little thing but I might post an instructable because the result is so pretty!Now I've got to figure out a way of creating an alterative route for unbalanced cell use which doesn't interfere with the balancing.

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  • How to Assemble a HHO Generator and Why It Works

    Okay, I'm getting kind of interested. I'm turning my van into a full time travel home which means I have 180AH of battery storage and, more importantly, 50A of solar panels on the roof. Now, assuming I'm driving in daylight, I can bypass the batteries completely (with their associated power loss) and dump the entire solar array into one of these and feed it directly into the diesel engine!It's not that high on my priorities right now but since I can get a 25 plate setup for £85 on eBay, it might be tempting in the near future.

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  • SIMPLE Polarity Reversing Switch

    Am I right in thinking that if I have 3 x 12V batteries connected in parallel and then I switch the polarity of the middle one then they'll now be connected in series and give me 36V?

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  • How do you know your enemy? You study, you send in a few probing attacks and you *ask questions* - especially when trying out a new tactic. I couldn't see why it wouldn't work, I just figured it was better to ask stupid questions than to make stupid mistakes. Electricity and I have had a few minor skirmishes in the past, like the martians in War of the Worlds, it has released its black smoke!The upcoming battle has more at stake with 600W of 24V solar, 180Ah of 12V batteries, a 50W charge controller, 3 balancing boards and a 5KW inverter. While none of these are on my side, I am hoping to set them up to tame each other.I've lived in RVs for the past 13 years and the wiring is a nightmare - thick bundles of thin wires buried in the walls and under floors making tracking down breaks an abso…

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    How do you know your enemy? You study, you send in a few probing attacks and you *ask questions* - especially when trying out a new tactic. I couldn't see why it wouldn't work, I just figured it was better to ask stupid questions than to make stupid mistakes. Electricity and I have had a few minor skirmishes in the past, like the martians in War of the Worlds, it has released its black smoke!The upcoming battle has more at stake with 600W of 24V solar, 180Ah of 12V batteries, a 50W charge controller, 3 balancing boards and a 5KW inverter. While none of these are on my side, I am hoping to set them up to tame each other.I've lived in RVs for the past 13 years and the wiring is a nightmare - thick bundles of thin wires buried in the walls and under floors making tracking down breaks an absolute mess, even with a circuit diagram (which you never get).Thinner wires may be cheaper but they run everywhere, there's the voltage loss problem and they break more readily, usually in the most inaccessible place. DownUnder makes a good point, though, and so two lines running from the back down either side of heavy gauge cable should minimize the power loss. With junction boxes every, say, 250 or 500 cm, I should be able to hook in wherever I need to using thinner, short lengths of wire. Of course, keeping everything easily accessible without disassembling the entire vehicle.There is no circuit diagram because I'm building a framework for whatever I decide to add later on.As my ex once said "a software engineer's project is never completed - you just have to take it away from them". Mike.

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  • How to Build Arduino Weighing Scales

    I'm doing a self-conversion of a van into a full-time camper, fixing all of the annoying things I've put up with in pre-built ones. As well as networking the entire system to simplify wiring and modularise the system, I'm correcting the damned water gauges.Normally, these have three electrodes up the side of the tank to show which third the fresh/gray water is currently covered. For my version, I have two 40L detachable tanks and I'm going to use the weight (1L of water weighs 1Kg) to more accurately indicate the state of water, broadcasting the result across the internal network.Just another possible use for this.

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  • Thanks for that. I figure there has to be a product or component like this and was hoping someone could point me in the right direction but the image search is a good idea!

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  • "Linkage" is apparently the term I was looking for and there's a simulator at http://blog.rectorsquid.com/linkage-mechanism-designer-and-simulator/. Thanks anyway.

    Good thought. There are over-cab beds and it should be okay so long as it locks out of the way and doesn't affect the structural integrity but I'll definitely look into that.Thanks.

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