DTSFab.com (Desert, Trail and Sand)
UTV's Off Road ( RZR, YXZ, Mini Buggy, Carts,etc.) => UTV Controls and Electrical => Topic started by: fabr on October 26, 2009, 08:46:34 AM
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OK ,this was discussed before but, what,if any, negatives are there to placing the main battery cutoff in the negative battery cable. I was swayed by our Aussie members that that is a better place for it than in the positive cable. Is there ANY reason to NOT put it in the negative cable other than sanctioning bodies here in the U.S. want it in the positive?
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I'm not too sure Master but I think it has to do with the computer, I'm sure someone will jump in any moment and tell how wrong I am but that's something I sorta remember, I think, but my memory isn't what it use to be... ::) Too many blows to the head. :-\ 5:
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If you do your toilet will flow anti-clockwise. (Backwards.)
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Maybe so for memory? Needs + always available?
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Maybe so for memory? Needs + always available?
Ya also need - for the + to work for memory. Try going out to your truck and unhooking the -. See if your radio and clock keep thier settings...
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I know and understand what you're saying .I don't think it is a problem with the bike motor cars but those of us running data loggers like Innovate DL-32's I think you have a good point on why not to do a negative main switch.
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I believe the reason you are supposed to disconnect the neg first when removing a battery, is so if your wrench slips and hits the frame or something it won't arc. When it comes to main disconnect switches, I don't think it makes a damn bit of difference which wire you kill as long as it is as close to the battery as possible. As for the Datalogger, you might consider a standalone power supply to run it that is charged up by the vehicles charging system, but continues to supply power to the datalogger alone if the batt is disconnected. A small nicad pack or something similar would provide hours or days of backup power.
I kinda see it like the extra battery I install in trailers. They are tied to my pickup through a relay that is triggered by the switched ignition power. That way, the batt in the trailer is being charged when the truck is running, but when the key is off, it is it's own separate system. In my gokart trailer, this allows me to use the interior lights even when it is not hooked up to the truck. With my dump trailer, I will have the same type of deal allowing me to run the winch or hydraulic pump with or without the truck attached. It also means that I don't have to run big bulky wires from the pickup to the trailer. Charging is done via a 12awg wire in the plug.
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If I had any idea where they got them from, I'd link you to a very nice battery isolator switch that my old work fitted to a bunch of trucks we sold to somebody the oil/gas industry.
They cut off both sides of the circuit, were sealed up good enough to be able to use a steam pressure cleaner on them, were rated to something like 1000 amps constant draw at 24 volts, and were also hooked up to an impact/rollover switch, so if the truck was in a significant impact or if it fell on its side, the battery circuit would be shut off automatically.
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Bet they're pricey too.
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Yeah they were a couple hundred bucks each from memory.
Real nice units though!
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I bet but since a busa only makes approx. 33 amps max it might be a bit overkill both in cost and maybe size.
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I Haven't Read the whole argument, but didn't anybody point out that current flows from negitive to positive?
Just put it on the negitive! LMAO
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It may well do so but i admit i don't understand that. You guys need to do some splaining as I was not taught that but I may have had a mistaken teacher. Enlighten me. I remember this coming up before but I didn't understand it then either.
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Yes, electrons flow from negative to positive, but you have to have both for them to flow at all. Also the way circuits are wired makes a difference as the positive is usually the switched side of the circuit.
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I dunno if they still make it but they USED to make a battery with a remote control pendant. The battery would literally cut the juice itself yet still send enough power for radios clocks and the ecu's that needed it but not enough power to start the car.
They may still make them? Not sure if it would accomplish what you wish either. Call the local battery shop and ask.
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I bet but since a busa only makes approx. 33 amps max it might be a bit overkill both in cost and maybe size.
Alternator might only put out that much, but what about starter motor draw?
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Starter motor draw wouldn't matter in a battery isolator used for the charging circuit. At least that is my understanding. I could be very wrong about that though. At any rate it is a moot point for us as I doubt anyone here is going a dual battery route due to the extra weight and complexity.
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Clearly Us Aussie are right, you guys still work in imperial! P= V x R came AFTER that age ;D
I was going to come over that way for a scholarship, Until I remembered you guys are imperial, there's no chance Im studying engineering in imperial!
On the subject of main switch's, have any of you found any good quality switch's that dont play up in the dirt?
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I found some real cheapies ,I don't remember where, but they are open construction or unshielded that will handle 50 amps continuous plastic and brass-never had a problem. Mud/dirt/sand just dries up and falls free. Only cost like 4 bucks. They might have been HF junk for all I remember but they work.Red and black plastic they are.
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Starter motor draw wouldn't matter in a battery isolator used for the charging circuit. At least that is my understanding. I could be very wrong about that though. At any rate it is a moot point for us as I doubt anyone here is going a dual battery route due to the extra weight and complexity.
Isolators I'm talking about have both battery leads going into them. What used to bolt onto the battery terminals now bolts onto the output terminals of the isolator.
Dunno about a dual battery setup, I just don't want to see you fit up an isolator that could be too small and weld it up solid when you hit the starter. ;D
The alternator may only charge at 33 amps, for which a 50 amp isolator would be fine, but how much is being drawn through the battery leads at startup?
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Damn sure not a thousand. Max could only be CCA of the battery being used.
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i dont know if you guys remember as i have not read the entire post either but vw did switch grounds ccts in their cars OEM
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It may well do so but i admit i don't understand that. You guys need to do some splaining as I was not taught that but I may have had a mistaken teacher. Enlighten me. I remember this coming up before but I didn't understand it then either.
Join the Navy! They take the first two weeks of any electrical school and reprogram you to understand that electricity flows from negative to positive. rofl
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I just got ripped for being an idiot over at GD for having the gall to say that. LOL!!!! Well,actually I said that a negative side main kill switch is preferable to a positive side main kill. I admit that that runs contrary to what we generally accept here in the US.
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I hear you. Most of the guys in my class had atleast a basic understanding of electricity so that little nugget of info made us laugh since we assummed the instructor was messing with our heads.
I don't know wether it actually changes anything unless you're designing circuit boards or something, but it doesn't necessarily change troubleshooting or running wires that I know of. Unfortunately, working in my job rarely requires troubleshooting circuits so I have lost a lot of what I once knew over the last 15 years, but I can't see any reason cutting off neg. makes a bit of difference.
I drink too much beer to retain info that I don't use. dd:
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Using - as the main kill completely isolates the battery. Another thing to consider ,especially if you are running in excess of 50 amps continuously from the battery ,is that most of the kill switches we use are rated at 50 amps continuous. If using the - for the main kill there is fewer amps drawn through the switch since some of those amps are "consumed" by the device being run such as a fan.
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Consider starter motor current draw across the kill switch when positive is used as the kill circuit also.While cranking there will be anywhere from 100 or so to upwards of 800 amps drawn through the kill switch depending on engine/compression/cid etc.. If I recall correctly most are rated approx 250 amps intermittent.