johntelling Report post Posted May 17, 2014 My chassis batteries on my Excursion DP C7 Cat are over seven years old. While the engine starts quickly when I turn the key, I am concerned about their age, and if they will suddenly fail. The existing batteries are Exide HC-31D, which appear to be 700 CCA and 840 CA. Questions - should I replace them now? and what are folks recommending for starting batteries? Thanks, JT Share this post Link to post Share on other sites
wolfe10 Report post Posted May 17, 2014 The "Care and Feeding" a battery receives is a critical part of battery life. If not allowed to deeply discharge, water level is kept above the plates, etc, they can last a long time. I would recommend having them load tested. That will tell you whether they need replacement. Also, on any diesel, it is a good idea to use the boost switch when starting IF the house batteries are fully charged. Hard to supply too many amp-hrs when starting. Procedure is: Engage boost switch Turn key to ignition (intake manifold heater on) When light out, start Disengage boost switch Share this post Link to post Share on other sites
johntelling Report post Posted May 17, 2014 Thanks, that is great advice. I never thought of using the boost switch, and thought it was just for emergencies. However, living in Sacramento where it never gets cold (unless you think 30f is cold!) I have never seen the intake manifold heater come on! JT Share this post Link to post Share on other sites
johntelling Report post Posted May 18, 2014 Thanks, Jim. You may be right, since I have never seen the light come on. JT Share this post Link to post Share on other sites
wolfe10 Report post Posted May 18, 2014 JT, May be a bad light bulb, or bad intake manifold heater relay. Access the top of the engine. Locate the relay by tracing the large-gauge wire back from the intake manifold (driver's side of engine). You should have battery voltage to one large lug all the time. With engine cold, when someone else turns on the key, the other large lug should show battery voltage. If working correctly, with ignition turned on with cold engine, battery voltage will show a significant (more than a volt) drop, as the intake manifold heater is a big load. Share this post Link to post Share on other sites
rsbilledwards Report post Posted June 19, 2014 For what ever it is worth...I have a 2001 Safari Zanzibar with the original chassis batteries...starts just fine good voltage when checked. Just added Battery Lifesaver to increase their life...reduce sulfating. B Share this post Link to post Share on other sites
dickandlois Report post Posted June 19, 2014 When to change out the Chassis and or the Coach batteries for me depends on the Hydrometer reading. A reading of 1250 and below in one cell is a signal to replace them. I change both chassis batteries (pair of Group 31- HD in our case) rated at (925-CCA). One bad cell can discharge both batteries because they are connected in parallel. The Coach batteries are replaced using the same Hydrometer reading, because I change them out in sets of 4. Just last year one of my 6 volt batteries had a cell shot out and it discharged all four. The temporary fix was to get a voltage reading across each battery, to find the bad battery. I removed that pair by disconnecting the ground wire connecting the pair from the remaining good set. This did reduce the total AH by 50 % until a replacement was located for the offending battery. Currently out of sync regarding the replacement cycle. Running one new battery with the best of the set of 4 that was replaced the last time and replaced 2 - 6 volt batteries. One pair of 6 volt batteries, just would not charge above my self imposed change out reading of 1250 on the hydrometer. One battery that was from the previous 4 battery cycle is still reading 1275+ after 1 year and is paired with the on road replacement. Just could not replace one that was still on top of it game, so to speak. Rich. Share this post Link to post Share on other sites
hermanmullins Report post Posted June 19, 2014 What batteries to buy? I have always gone with Interstate. Are they the best, maybe not. However for service you can't beat their response to a problem. On top of that you can't swing a long stick without hitting an Interstate store. (I know it's not a long stick but the correct old saying would not be appropriate for the site). Herman Share this post Link to post Share on other sites
dickandlois Report post Posted June 19, 2014 Herman, Do not think in the long run there is a big difference between Interstate and Exide. Do know that Exide makes the OEM batteries for a number of the auto makers assembling units in the US. I also suspect the Interstate contracts to make some OEM batteries. Rich. Share this post Link to post Share on other sites
hermanmullins Report post Posted June 19, 2014 Rich, I agree but I can always find Interstate but don't remember too may Exide. They are probably out there I just don't remember seeing them. Herman Share this post Link to post Share on other sites
desertdeals69 Report post Posted June 19, 2014 As far a using the boost switch for starting goes on mine that is automatically done when the key is turned on. The solenoid that connects the two banks of batteries to charge while the engine is running is always on when the key is on. The switch in the dash is used only if the engine batteries are too low to start the engine and to low to energize the solenoid. This is the way the factory made it. As far as batteries used in new cars, its a matter of cost and not always the best. I would not select a battery just because a car mfg uses them. A lot of batteries are made in Mexico. Share this post Link to post Share on other sites
