Jack Posted December 5, 2008 Share Posted December 5, 2008 One of the problems with my GMC is that I think that the batteries that I have put on there aren't man enough for the job. But that doesn't make any sense to me. Surely as long as the amps are being replaced and the battery starts the truck then what does it matter what amperage the battery is?? Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted December 5, 2008 Share Posted December 5, 2008 Can you start again and tell us exactly what battery you have put on please? Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted December 5, 2008 Share Posted December 5, 2008 P.S./ Have they have got AAA or AA on them? Quote Link to comment Share on other sites More sharing options...
Jack Posted December 5, 2008 Author Share Posted December 5, 2008 Can you start again and tell us exactly what battery you have put on please? Sure, it is a 60amp battery that I bought from an agri merchant - this is the second battery that I have put on in the last 20 months.....:??? Quote Link to comment Share on other sites More sharing options...
Jack Posted December 5, 2008 Author Share Posted December 5, 2008 P.S./ Have they have got AAA or AA on them? Not sure - I will have to check tonight. Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted December 5, 2008 Share Posted December 5, 2008 6V or 12V? Quote Link to comment Share on other sites More sharing options...
Stormin Posted December 5, 2008 Share Posted December 5, 2008 Think you mean 60amp hours. That is the total theoretical power in the battery. Will deliver 60 amps for one hour or 1 amp for 60 hours in theory. Doesn't sound particularly large capacity for starting a truck to me. Of more real concern is the CCA or Cold Cranking Amps. This is a better measure of the power the battery can deliver in a short burst for starting. If the battery is not upto the job extra heat and resistance will occur in starter cables and the starter motor. Eventually the wires or windings can burn out. The battery I recently installed on my Ward La France is rated at 1100CCA. http://cgi.ebay.co.uk/12V-TRUCK-BUS-BATTERY-TYPE-629-3-YR-GTEE-NEW_W0QQitemZ110285579538QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CommercialVehicleParts_SM?hash=item110285579538&_trksid=p3286.c0.m14&_trkparms=72%3A1301%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318 Quote Link to comment Share on other sites More sharing options...
pop larkin Posted December 5, 2008 Share Posted December 5, 2008 60 amp hour should be plenty to get it going. I'll have a look and see what battery I put on the Chevy tomorrow when I go over to the yard. I bought mine from our local motor factors and bought one that fitted in the battery box rather than on amperage rating so I don't actaully have a clue what rating it is!! I still have the original 6v starter on the Chevy (which I assume you do on the GMC too?), and have no problems with getting it going. Usually 1-2 cranks and it will fire (well would fire up, I have the head off it at the moment). Does it crank the engine fairly fast or is it a bit sluggish? May be a carb/fuel problem or timing/ignition problem if it is cranking but not firing up? Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted December 5, 2008 Share Posted December 5, 2008 (edited) Jack, I really don't think the battery is your problem. The battery you have should be fine if it is not sulphated up. This 6V battery I use on the jimmy and jeep is 50Ah, 815CCA. It is half the size of a typical jimmy battery. Norman, unless your starter motor is the limiting factor this 12V battery, 56Ah, 830CCA will spin your Cummins over quicker than that big slab of lead and plastic you just bought :cool2: It is the same size as most car batteries. They are even more impressive when used as a pair on a 24V starter system. There are course other reasons for using batteries with a bigger Ah rating, and where these batteries may not be appropriate. You can take the p!$$ out of me, but you can't take the p!$$ out of these babies. Don't worry, I won't ever mention them again :-D p.s. the black battery in pics is an old jimmy one. Edited December 5, 2008 by N.O.S. Quote Link to comment Share on other sites More sharing options...
Jack Posted December 5, 2008 Author Share Posted December 5, 2008 There has to be an issue with something with my electrical system - alternator may be? Why go through 2 x 12v batteries in under a month Quote Link to comment Share on other sites More sharing options...
Chrisg Posted December 5, 2008 Share Posted December 5, 2008 There has to be an issue with something with my electrical system - alternator may be? Why go through 2 x 12v batteries in under a month Have you had the batteries checked out that they are indeed u/s Quote Link to comment Share on other sites More sharing options...
Stormin Posted December 5, 2008 Share Posted December 5, 2008 Jack, I really don't think the battery is your problem. The battery you have should be fine if it is not sulphated up. This 6V battery I use on the jimmy and jeep is 50Ah, 815CCA. It is half the size of a typical jimmy battery. Norman, unless your starter motor is the limiting factor this 12V battery, 56Ah, 830CCA will spin your Cummins over quicker than that big slab of lead and plastic you just bought :cool2: It is the same size as most car batteries. They are even more impressive when used as a pair on a 24V starter system. There are course other reasons for using batteries with a bigger Ah rating, and where these batteries may not be appropriate. You can take the p!$$ out of me, but you can't take the p!$$ out of these babies. Don't worry, I won't ever mention them again :-D p.s. the black battery in pics is an old jimmy one. Very nice but it won't build muscle lifting it in and out of the truck! Then how are you going to have the strength to tackle the other heavy jobs? By the way 830CCA is one third less than 1100CCA, and 56ah is only one third the capacity of my 170ah. I bet your little battery was more expensive too and a lot easier for the light fingered to carry away. Quote Link to comment Share on other sites More sharing options...
Adam Elsdon Posted December 6, 2008 Share Posted December 6, 2008 Have you checked the voltage output of the dynamo/alternator at varying revs, it may be the regulating side of the charging system has broken down, and you are running your battery into the ground, or you are cooking the battery by over charging it. Are you using a proper automotive battery or a leisure type battery, there are distinct differences in the construction, leisure batteries dont like fast heavy discharges that a starter motor will take, automotive batteries dont respond well to total discharge states. Test for amp useage when the vehicle is turned off, if there is a continuous leak it could be a faulty earth or wiring problem. 60amp battery sounds about right, military petrol engines dont need massive batteries, due to the low engine compression ratio (unless its a diesel of course)and as standard most vehicles are only running lighting, most military trucks probably have the current use that a basic Austin Mini has, as they dont exactly have all the mod cons! If you have a big amp 1000 cca battery, it just means you will blow a bigger hole in whatever shorts out i.e. your sticking starter motor, dodgy unfused accessory lighting wiring etc! Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted December 6, 2008 Share Posted December 6, 2008 Jack, It is difficult to advise, not seeing your truck, but I think you said once that it had been modified to an alternator. Now an alternator needs to turn faster than a dynamo, hence why they tend to have smaller pulleys, compare to those on dynamos. As the GMC has a wide section belt, wider than modern engines usually, I am wondering if you have a suitably sized, ie. diameter, pulley, perhaps the unit is not running at sufficient speed. This is all guesswork, because none of us have deduced the actual problem with the batteries yet. Have you returned your first battery to the supplier for a warranty claim? There are normally 2-3 years guarantee on them these days. Quote Link to comment Share on other sites More sharing options...
R Cubed Posted December 6, 2008 Share Posted December 6, 2008 Hi Jack, Are you now back trying to sort this out ? did your mate look at it yet ? As in the Help my GMC is Broke or summat like that, have you checked any of the bits suggested or would you like me to come down at some stage and have a look?? Forget about the alternator at the moment, this will not stop the truck starting, get a good 12v battery biggest that will fit in the tray, and go for a reputable make Lucas exide etc, don't skimp on cost it will pay off in the long run, then try to start ? what happens ? (1) starter does nothing ? problem between bat and starter. (2) starter turns slowly ? as above or naff starter. (3) starter and engine spin over quick but will not fire ? ignition problem. Go with this and let us know. Quote Link to comment Share on other sites More sharing options...
pop larkin Posted December 6, 2008 Share Posted December 6, 2008 I have converted the Chevy to 12v alternator using the kit form Jolley engineering (I think the same one as Jacks). I used all the supplied parts including the pulley and have no problems with the rpm of the alternator for charging. The only thing I need to do is give it a quick rev to get the exciter coil going then it charges fine, even down at idle. It could be the regulator playing up. If the alternator is suspect, just whip it off and take it to a good auto-electrician who should have the correct test bench for running up the alternator and checking the output. Quote Link to comment Share on other sites More sharing options...
Jack Posted December 6, 2008 Author Share Posted December 6, 2008 . Have you returned your first battery to the supplier for a warranty claim? There are normally 2-3 years guarantee on them these days. Good point Richard - I could do that! Cubed - will be looking at over Christmas when I have some time off and was just working on folks advice and working back from the begining. So starting at the battery as I will have to buy another as the one here will not hold a charge. I need to drive my truck - I am missing it Quote Link to comment Share on other sites More sharing options...
fv1609 Posted December 6, 2008 Share Posted December 6, 2008 Maybe you have something slowly discharging the system? Have you a battery isolator switch fitted so that you can kill battery power when not in use? Put an ammeter in series with a battery lead with everything turned off & see if any current is drawn. Or easier still use a clampmeter like this: http://www.digital-meters.com/Tecpel-DCM-033-Clamp-on-Amp-Meter-p-16509.html Just open the jaws & clamp it over one of the battery leads you can test leakage current, measure current drawn by lights, starter etc & of course measure current going into the battery when charging. Amazingly this is a problem on wife's Hilux Surf. There is a constant leakage of at least 0.1 amps. If the thing isn't used for a few days then in this cold weather starting is a struggle particularly with short trips, lights & heater on. So it never gets charged upo fully. So I have to top up the charge every couple of weeks in the winter. Ah yes could be a new battery. This new battery lasted a year, second new battery only "lasted" a year until I started topping it up in winter now its on its third year. If you go on the owners site you find it is a very common problem. But people "cure" it with a new battery, so it "must" have been the fault of the battery! Nobody seems to think about the discharge, so much for modern technology! Quote Link to comment Share on other sites More sharing options...
croc Posted December 6, 2008 Share Posted December 6, 2008 Jack, I really don't think the battery is your problem. The battery you have should be fine if it is not sulphated up. This 6V battery I use on the jimmy and jeep is 50Ah, 815CCA. It is half the size of a typical jimmy battery. Norman, unless your starter motor is the limiting factor this 12V battery, 56Ah, 830CCA will spin your Cummins over quicker than that big slab of lead and plastic you just bought :cool2: It is the same size as most car batteries. They are even more impressive when used as a pair on a 24V starter system. There are course other reasons for using batteries with a bigger Ah rating, and where these batteries may not be appropriate. You can take the p!$$ out of me, but you can't take the p!$$ out of these babies. Don't worry, I won't ever mention them again :-D p.s. the black battery in pics is an old jimmy one. and here's me working away with batteries filled with acid, do they really work that much better with p!$$ in them? :-D Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted December 6, 2008 Share Posted December 6, 2008 :rofl::rofl::rofl::rofl: My battery man solved a garage proprietor's strange battery dilema - whenever he left a battery outside the workshop on the ground it went duff and woulkdn't hold asny charge. Battery man called round one day and caught proprietor's dog p!$$ing over a battery - problem solved (strong alkaline killed the acid - even just a small amount getting into vented caps) :cool2: Quote Link to comment Share on other sites More sharing options...
pop larkin Posted December 6, 2008 Share Posted December 6, 2008 On my Hilux Surf I had a problem with the battery 'live' occasionally touching against the power steering pump reservoir which would discharge the battery as it went direct to ground, which leads me to the GMC battery box. If like my Chevy box you have the terminals attaching over the cover make sure the live wire/terminal isn't touching against the battery box cover as this will zap all your power away. With original 6v battery which was very tall the terminal was well clear of the cover, but with the 12v battery which was alot shorter the terminal ended up below the cover. I have since choked up the battery to clear the cover, but yours may be earthing out there? Quote Link to comment Share on other sites More sharing options...
Marmite!! Posted December 6, 2008 Share Posted December 6, 2008 (edited) Surely any battery shorting out directly to earth would be immediately obvious by the sparks flying & signs of arcing :confused: Edited December 6, 2008 by Marmite!! Quote Link to comment Share on other sites More sharing options...
ArtistsRifles Posted December 6, 2008 Share Posted December 6, 2008 I think you mean "arcing" Lee - "arching" is what the user does when grabbing hold of a terminal giving off the light display described!!! :rofl: :rofl: Quote Link to comment Share on other sites More sharing options...
Marmite!! Posted December 6, 2008 Share Posted December 6, 2008 I think you mean "arcing" Lee - "arching" is what the user does when grabbing hold of a terminal giving off the light display described!!! :rofl: :rofl: Typo corrected :pfrt: Quote Link to comment Share on other sites More sharing options...
Jack Posted December 6, 2008 Author Share Posted December 6, 2008 Many thanks folks for the advice and will report back at Christmas :coffee: Quote Link to comment Share on other sites More sharing options...
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