Re: [EVDL] EV Digest, Vol 19, Issue 44
jerry freedomev via EV wrote: I've used for many EVs just a 2 length of solid copper wire sized right for the load [as a fuse]. Higher voltage, use longer. Using SS bolt/nuts as terminals and support with distance and something to catch the molten metal if it blows. That works! :-) A fuse is indeed just a piece of wire. But if you make your own fuses, you need to *test* them to know the current at which they will open. You can't rely on someone else's #16 wire blows at 100 amps to work, because there are many variables that have a *drastic* effect on the fusing current: - the length of the wire - any insulation on it - heat being dissipated by the connections at each end - airflow around it - the surrounding air temperature - how long you expect it to carry the current before opening But if you have the patience, you can do the tests and figure it out. Another point Jerry mentioned. When a fuse blows, it scatters molten metal around. This needs to be contained, so it won't short something else or start a fire. Commercial fuses are packaged in glass, ceramic, or phenolic for this reason. Arcing is another concern. The arc in a DC circuit can stretch out a surprising distance. This is especially true in a fuse, because the melting metal provides conductive particles to help the arc. On DC, you'll need at least an inch per 100 volts to break the arc. Commercial DC fuses generally fill the inside with sand or some other noncombustible insulator. When the fuse blows, the heat also melts the sand, which flows into the space to help break the arc. I've made my own fuses for battery boxes. For example, a pair of 5/16 bolts on standoffs in a bakelite box. The fuse element is a strip of sheet copper between the bolts. I trim the width until it blows at the desired current and time. -- I view this year’s failure as next year’s opportunity. Failures are not something to be avoided. You want them to happen as quickly as you can, so you can make progress rapidly. -- Gordon Moore -- Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] EV Digest, Vol 19, Issue 44
From: Cor van de Water via EV ev@lists.evdl.org Common wisdom puts a pack fuse in the battery box before cables exit... My EV that was converted around 1995 by a now defunct converter company, has no overcurrent protection on the battery pack... any event that would create a short anywhere along the many feet of pack cabling, would cause a current only limited by the battery pack itself. Indeed, I still need to buy and install a fuse inline in the pack. I think you've convinced me to install a fuse! I was sorta hoping that the controller (Curtis 1231C-8601) had some sort of over-current protection, but that won't protect against a mechanical short between the pack and the controller. Indeed, if you have a split pack, you need a fuse for each segment to properly protect against mechanical shorts. In an accident, both ends of a partial pack could get pinched in frame metal. Sheesh. One more thing to buy. At best, it [conservation] means we will run out of energy a little more slowly. -- Ronald Reagan Jan Steinman, EcoReality Co-op ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] EV Digest, Vol 19, Issue 44
On Thu May 29 09:36:11 PDT 2014 ev@lists.evdl.org said: Indeed, if you have a split pack, you need a fuse for each segment to properly protect against mechanical shorts. In an accident, both ends of a partial pack could get pinched in frame metal. Sheesh. One more thing to buy. With my current update of the truck, I'm going to have 3 separate battery boxes. Probably have big Anderson connectors to each box - though I won't have a fuse in each box. What I will have is an 800A 3 phase breaker, using 2 of the phases to separate each box, and the 3rd will disconnect the + from the controller. The breaker is located in the back beside one of the battery boxes. (it is also in it's own box.) There are also contactors on both sides before the controller. The breaker has an electrical actuator as well as the big honkin lever. I'm looking at hooking the actuator up to a BRB in the cab. I may also hook up the big teleflex cable from the old Automatic Shift Lever on the steering column, to pull the lever on the breaker. Also, all the cables between the boxes will be run in places where it would take major trauma to the truck to damage them. (inside frame rails, etc..) -- Worlds only All Electric F-250 truck! http://john.casadelgato.com/Electric-Vehicles/1995-Ford-F-250 ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] EV Digest, Vol 19, Issue 44
Jan Steinman via EV wrote: I think you've convinced me to install a fuse! New high-current fuses are expensive. But I have a decent collection of surplus fuses. Here are some examples. Note that AC rated fuses should only be used up to 1/4 of that voltage on DC. Write me off-list if you'd like one. qty price description --- - --- 1$1 2a, 415vac 250vdc, English Electric NIT-2, 1.375 x 0.5 2$1 2a, 440vac, Dorman AAO-2A, 2.125 x 0.75 1$1 5a, 600vac, Bussman KAC5, 1.875 x 0.625 1$1 10a, 415vac, 250vdc, GC NIT-10, 1.375 x 0.5 2$1 15a, 440vac, Federal 20B15, 1.375 x 0.5 3$1 15a, 600vac, English Electric GSB-15A, 2.125 x 0.3125 3$1 25a, 550vac, 250vdc, GC TIA25, 2 x 0.875 2$1 32a, 550vac, 250vdc, GC TIA32, 2 x 0.875 2$2 40a, 550vac, 250vdc, HRC MEM-40SB4-40A, 2 x 1 2$4 63a, 660vac, 460vdc, GC TBC63 or MEM63SF4, 2 x 1 1$5 80a, 660vac, 460vdc, GC TC80A, 2.5 x 1.3125 1$5 100a, 660vac, 460vdc, GC TCP100A, 2.5 x 1.3125 1$5 160a, 660vac, 350vdc, GC TF160A, 2.5 x 1.3125 1 $10 200a, 550vac, 250vdc, GC TF200A, 2.75 x 1.5 2 $10 200a, 600vac, Littelfuse JLLS200, 1.625 x 1 4 $10 250a, 250vdc, Bussman FWX250, 1 x 0.875 I was sorta hoping that the controller (Curtis 1231C-8601) had some sort of over-current protection, but that won't protect against a mechanical short between the pack and the controller. No, it doesn't. Without an input fuse, it explodes in a fiery burst of debris if anything inside fails shorted. At best, [conservation] means we will run out of energy a little more slowly. -- Ronald Reagan Conservation is important because it gives us *time* to look for other options. It's a second chance, to do it better the next time. But, second chances are only valuable if we change our behavior. We need to stop doing what got us into the situation in the first place. -- I view this year’s failure as next year’s opportunity. Failures are not something to be avoided. You want them to happen as quickly as you can, so you can make progress rapidly. -- Gordon Moore -- Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] EV Digest, Vol 19, Issue 44
On 2014-05-29, at 13:37, Lee Hart wrote: Jan Steinman via EV wrote: I think you've convinced me to install a fuse! New high-current fuses are expensive. You're right, they are expensive! What about fusible link wire? From an Amazon listing: A fusible link is a special section of low tension cable installed by an OEM and designed to open a circuit when subjected to extreme current overload. Its purpose is to minimize wiring system damage when such an overload accidentally occurs in those circuits protected by the fusible link. A short circuit causes the fusible link to act as an element in a slow-blow fuse. A fusible link is not intended to be used in place of a fuse but only where a fuse cannot be economically employed. Our fusible line wire meets the requirements of SEJ-156 and the insulation has the characteristics as listed for EAE, SE J-1128Type SXL. The vehicle manufacturer should be consulted about questions on fusible link length and size. General practice has been for a fusible link to be 4 gauges smaller than the circuit wire. Example: if the circuit wire is 12 gauge, use a 16 gauge fusible link. It appears to me that a fusible link is nothing more than a SHORT section of under-sized wire, with a coating that contain the shrapnel. Seems it wouldn't be too difficult to cobble up. I haven't found any formula for wire sizes versus current capacity -- anyone know how to size these suckers? At best, [conservation] means we will run out of energy a little more slowly. -- Ronald Reagan Conservation is important because it gives us *time* to look for other options. It's a second chance, to do it better the next time. But, second chances are only valuable if we change our behavior. We need to stop doing what got us into the situation in the first place. I'm with you, and change my behaviour at every opportunity. But I'm afraid we've gone solidly into overshoot. The time for a Manhattan Project or Apollo Project effort would have been in the 70s. But instead, we got Morning in America. The first rule when you find yourself in a hole is to stop digging. But the message hasn't gotten out yet... (And the following came up totally at random.) A change to a different way of living -- a low energy way -- is not negotiable. We need to reduce our use of fossil fuels or we will die. -- Pat Murphy Jan Steinman, EcoReality Co-op ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
