robin craig Posted May 28, 2011 Share Posted May 28, 2011 Well, The other week the Stormer was a "no start", not surprising, but regretable. It sounded very much like the starter drive had come forward to engage the ring gear and then run out of juice to do anything more. A quick look see proved I was correct and the starter drive was stuck nearly to the ring gear. So, I popped out the Supacat as a ready source of good 24 volts to slave it from. It is a "fire first time" machine, wobbled it over and slapped the slave cable on to the Stormer, sadly a voltage check on the Stromer when connected did not show any appreciable rise in the batteries at the drivers side. Cranking the Stormer yielded the same dead sympton. So, for some reason the Supacat, despite being a 24 volt with two reasonable sized MV batteries and itself being a good starter would not slave the Stormer. So jump in the truck, womble 7 kilometers to the other site and get the Hagglunds BV 206 out, another sure fire vehicle and drive it down past the sleeping populace as it is now after 10pm. Hook it up using the very same same cable and the Stormer comes alive electrically and Bob's your uncle on first attempt the Stormer bursts into life. What is puzzling me is that read at the slave socket afterwards while running the Supacat shows 27 volts at the slave socket. Im thinking that should be 28 volts. Could it be a sign that the alternator is on its way out? Any handy dandy simple idiot proof tests I can do on the Supacat? Or is it just not "man" enough ie amps to fire the Stormer? R Quote Link to comment Share on other sites More sharing options...
robin craig Posted May 29, 2011 Author Share Posted May 29, 2011 I'm surprised no one has commented at all so far R Quote Link to comment Share on other sites More sharing options...
Paul Drake Posted May 29, 2011 Share Posted May 29, 2011 Robin, A wild guess, I assume it may have something to do with the amperage. I had a similar problem with Land Rover batteries, showing 24 volts but would not start the Landy. A battery load tester showed there was insufficient power in the batteries i.e. the lack of amps. Quote Link to comment Share on other sites More sharing options...
Zero-Five-Two Posted May 29, 2011 Share Posted May 29, 2011 Sounds like not enough ampage, even though you have more than 24 volts. It might also be an earthing problem. I remember on some of the RE plant you had to "touch" the two vehicles together to make a full circuit. Plant kit is quite solid, you could scrape the buckets or blades together to get a connection without doing any damage. Quote Link to comment Share on other sites More sharing options...
Grasshopper Posted May 30, 2011 Share Posted May 30, 2011 I know Sirhc had the same problem jumping a Sabre, when he put the A frame on to tow it it made the earth circuit and the vehicle jump started fine. Likely cause was a bad earth somewhere. You do get strange symptoms with earth faults. Quote Link to comment Share on other sites More sharing options...
sirhc Posted May 30, 2011 Share Posted May 30, 2011 The problem we had was trying to start a dead 432 with a Sabre. The socket on the 432 wasn't earthing, with the A frame from the Sabre to the 432 it fired right up. Once we figured this out it was easier to touch the 2 vehicles together rather than mess around with an A frame or jump lead! Quote Link to comment Share on other sites More sharing options...
robin craig Posted May 30, 2011 Author Share Posted May 30, 2011 So, If what I can deduce is correct, your saying that the Supacat has an issue with its wiring, most likely a bad ground on it somewhere. As no vehicles were 'touched" together and the Stormer and the cable were a constant that would be the logical deduction I should make? R Quote Link to comment Share on other sites More sharing options...
sirhc Posted May 30, 2011 Share Posted May 30, 2011 Robin, Was the Supacat running when you tried jumping from it? What size is the alternator on it? Maybe it just wasn't kicking out enough amps to turn over the Stormer. Chris Quote Link to comment Share on other sites More sharing options...
robin craig Posted May 30, 2011 Author Share Posted May 30, 2011 The Supacat was running with me keeping it above an idle at around 1800 rpm while a mate was running the Stormer end No idea how big the alternator is. R Quote Link to comment Share on other sites More sharing options...
Tony B Posted May 30, 2011 Share Posted May 30, 2011 Isn't the Supercat mainly fibreglass? Quote Link to comment Share on other sites More sharing options...
robin craig Posted May 30, 2011 Author Share Posted May 30, 2011 Tony, no it is 1" square hollow structural steel clad in aluminium sheeting. Were you thinking of an Argo perhaps? R Quote Link to comment Share on other sites More sharing options...
andym Posted May 31, 2011 Share Posted May 31, 2011 I'm surprised no one has commented at all so far R Sorry Robin, too busy swapping 432 packs! As has already been said, this is more about current than voltage, although voltage can help understand what's happening. Firstly, what sort of batteries does the Supacat have? All MV batteries are not created equal even though they may look the same. For example, the conventional 6TN flooded cell battery will only deliver around half the starting current (CCA) of a 6TNMF Hawker. It may just be that the Supacat batteries can't deliver the sort of current required - a stalled starter on a big diesel needs a LOT of current! Secondly, what state are the Supacat batteries in? I'd expect them to be around 26V to 27V fully charged, rising to 28.5V when the engine is running. If it's any lower than this I'd put them on a battery tester to check. Failing that, the alternator may not be putting out the correct voltage to keep them fully charged. There may also be a problem with resistance between the Supacat's batteries and the starting socket, either in the earth line or possibly even the positive one. The only real way to check for this is to use the starter lead whilst simultaneously monitoring the voltage at the Supacat's batteries and the Stormer's. Any appreciable difference between the two suggests a poor connection somewhere. Andy Quote Link to comment Share on other sites More sharing options...
Tony B Posted May 31, 2011 Share Posted May 31, 2011 Tony, no it is 1" square hollow structural steel clad in aluminium sheeting. Were you thinking of an Argo perhaps? R Yes I was. :blush: Fibre glass vehicles and electrics are a miserable combination. Quote Link to comment Share on other sites More sharing options...
robin craig Posted May 31, 2011 Author Share Posted May 31, 2011 Andy, all good points, I will report back after maintenance night next tuesday, bit busy on other things this week, Im thinking you are right as from memory the Supacat batteries are physically smaller. R Quote Link to comment Share on other sites More sharing options...
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