Deere Mack Posted April 8, 2014 Share Posted April 8, 2014 Hello everyone! Working on the 79 RD and I have a battery question. I bought the truck with two batterys in it and one is going bad. I want to replace both and add the other two if it's neccessary. Question is, do I need the four batterys? Evidently a Mack engineer somewhere down the line thought so, but what do you guys think? Quote Link to comment Share on other sites More sharing options...
Bigdogtrucker Posted April 8, 2014 Share Posted April 8, 2014 Not in Alabama Quote Link to comment Share on other sites More sharing options...
Popular Post 2stacksuperdog Posted April 8, 2014 Popular Post Share Posted April 8, 2014 If its got 2 then it must be 2 12s so you should be fine. You only need 4 if you got 4 6s 3 Quote Matt Link to comment Share on other sites More sharing options...
Bobby j Posted April 8, 2014 Share Posted April 8, 2014 The "r" models we ran at Overnite come from factory with three, two on left and one on the right. Three carried tractor and set of doubles just fine year round......I have a 64"b" and it does just fine on two it's just a dump truck Quote Link to comment Share on other sites More sharing options...
blackdog2 Posted April 8, 2014 Share Posted April 8, 2014 Two high cranking amps batt will do just fine . There just like apples one goes they all will go .And you will save on maint. weight . Quote Ed Link to comment Share on other sites More sharing options...
Deere Mack Posted April 8, 2014 Author Share Posted April 8, 2014 Well, my dozer & excavator have two but my CH has three. The wiring diagram for the RD was showing four, even for 12v, but I just couldn't accept it. Two it is! Thanks for everyones input! Quote Link to comment Share on other sites More sharing options...
storkmack Posted April 9, 2014 Share Posted April 9, 2014 We run 2 12's in all the bulldogs here in northern Illinois. We don't plug block heaters in until it goes under 20 degrees. Quote Link to comment Share on other sites More sharing options...
BAD DOG Posted April 9, 2014 Share Posted April 9, 2014 Two is all you need. 4 is only needed in extreme conditions. I had just 2 to start my dad's E9 around the yard and it had 2 in it when the guy came and picked it up and it started when it was only 10 degrees out on 2. Quote Link to comment Share on other sites More sharing options...
Lmackattack Posted April 9, 2014 Share Posted April 9, 2014 I run 2 in my truck....as long as its not very cold out and the charging system is in good shape. 2 is all you need? I use the passenger side batt box for storage now... Quote Link to comment Share on other sites More sharing options...
randyp Posted April 9, 2014 Share Posted April 9, 2014 ahem,,only 2 needed. Now, you can get by with no batterys ifn you just hook one of them old crank handles out the front connected to the crankshaft, but you best be a muscled up feller to start it. randyp Quote Link to comment Share on other sites More sharing options...
Deere Mack Posted April 9, 2014 Author Share Posted April 9, 2014 ahem,,only 2 needed. Now, you can get by with no batterys ifn you just hook one of them old crank handles out the front connected to the crankshaft, but you best be a muscled up feller to start it. randypI hear ya! I tried using the boat rope method and wrapping a rope around the balancer, but I couldn't get a big enough knot to hold my pull handle on.. So I've decided to go ahead and buy two batterys.... 1 Quote Link to comment Share on other sites More sharing options...
mrsmackpaul Posted April 9, 2014 Share Posted April 9, 2014 lads I only use one and have air start to start with works a treat can even start with no battery just need a pen to push the air soliniod Paul Quote Link to comment Share on other sites More sharing options...
Vladislav Posted April 9, 2014 Share Posted April 9, 2014 lads I only use one and have air start to start with works a treat can even start with no battery just need a pen to push the air soliniod PaulWhat the air tank do you have for that starter?Wich size and where on the chassis?How many starts can you do from its charge?My R-model with E6-350 fires up well with just one middle size battery when not cold.Vlad Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment Share on other sites More sharing options...
turckster Posted April 13, 2014 Share Posted April 13, 2014 Two 12v batteries should be plenty for a '79 model RD. Some reasons for more batteries is if there are a lot of electrical components, if you have an automated type trans of some sort or all batteries(4) are 6 volt. Quote Link to comment Share on other sites More sharing options...
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