candurin Posted August 9, 2016 Report Share Posted August 9, 2016 I'm basing this on the voltage readout on my hardwired radar detector (which shows voltage on the main screen). Before, when I had my OEM battery (540 cca) the voltage was always displaying 14.4V while driving. Now, a month ago when I replaced the OEM battery with the 850 CCA interstate battery, my radar detector is always displaying 14.1V while driving. Should I be concerned about the health of my alternator? I have no issues starting the car (remote or otherwise) and everything seems to be normal. Voltages are confirmed with my meter on the battery terminals, while running. Just curious to know why I am losing 0.3V while driving. My car only has 49K miles. Quote Link to comment Share on other sites More sharing options...
macbwt Posted August 9, 2016 Report Share Posted August 9, 2016 Not sure of your Model year etc. The Series of battery? 54 or 65? You did apparently upgrade to a 65 it seems. The reduced voltage may be due to the new battery not requiring as much power to charge it. Thus the alternator is not producing the higher voltage. The engine draws on this also so in essence the system is not having to produce as much power. I would be more concerned with voltage dropping under load below say 13V with fans, ac, lights and other accessories on This would be an indication of a shunting or loss of voltage from the alternator. You can use a Solar BA7 battery and charging system device that will tell you the health of your charging system under load and is a very accurate low cost device for this purpose. 1 Quote Link to comment Share on other sites More sharing options...
WWWPerfA_ZN0W Posted August 9, 2016 Report Share Posted August 9, 2016 Are the terminals tightened down properly? Did you allow for the Battery Management System to learn the characteristics of the new battery? (You can do it on your own, it's just more expedient at a dealership.) If so, you can get a Solar unit as suggested above to load test the battery and alternator condition. Quote Link to comment Share on other sites More sharing options...
candurin Posted August 9, 2016 Author Report Share Posted August 9, 2016 Thanks for the responses, guys. I've had the battery on there for a month and I just haven't posted about it. Terminals are on solid, clean and lubed. The battery is the MTP-65 interstate battery. Not sure how to make the BMS learn it, but it should have done so after a month, no? I've been running AC non-stop for two months now (damn NJ weather!), so I'll go and check if there is any fluctuations and report back. It has never dipped below 14.0V. Quote Link to comment Share on other sites More sharing options...
akirby Posted August 9, 2016 Report Share Posted August 9, 2016 I believe the alternator output is variable and controlled by the PCM so it might be normal. Quote Link to comment Share on other sites More sharing options...
candurin Posted August 9, 2016 Author Report Share Posted August 9, 2016 Glad to hear. After seeing "14.4" for many years, just wanted to make sure my simple battery swap was not headed towards a larger issue. Quote Link to comment Share on other sites More sharing options...
enigma-2 Posted August 9, 2016 Report Share Posted August 9, 2016 Just curious to know why I am losing 0.3V while driving. My car only has 49K miles. Voltage drop occurs for many different reasons, what else is on the circuit (not just the Escort) what is the wire size going to the detector (all the wiring involved, measured from the battety to the detector connection). 0.3 v is nothing Quote Link to comment Share on other sites More sharing options...
candurin Posted August 10, 2016 Author Report Share Posted August 10, 2016 everything is stock wiring. I hardwired the escort detector by using a two pin phone cable with an inline fuse, wired directly into the mirror. At most it is a 6" (yes, inch) cable. Oddly enough, I just put my meter on car battery after using the remote start and it read 13.67V (the lowest reading I have ever taken). Once, I turned the key, it stayed at 14.0. So, getting lower than typical results, but its probably weather related. I'll keep an eye on it for sure. Quote Link to comment Share on other sites More sharing options...
enigma-2 Posted August 10, 2016 Report Share Posted August 10, 2016 everything is stock wiring. I hardwired the escort detector by using a two pin phone cable with an inline fuse, wired directly into the mirror. At most it is a 6" (yes, inch) cable.Sorry, I failed to make it clear. Voltage drop is not occurring over the short 6" connector to the mirror, but rather over the entire harness; from the source (the battery) to the load (the detector). Remember the harness is seveal feet in length, probably 20-30 ft. (guessing). In every electrical circuit, there is voltage drop. Also, other loads connected to the same circuit (the mirror) can influence the loss. If your really concerned, the Solar battery monitor would provide you with a clear picture of your charging system. I have this monitor (-7 version, forget the actual model designation). It's easy to use and does a quick and excellent job of telling you exactly what's going on. It will read out your battery's current state in voltage and CCA's and the state of the charging system during starting and running. Quote Link to comment Share on other sites More sharing options...
omar302 Posted August 10, 2016 Report Share Posted August 10, 2016 The BMS relearn process, if not using a tool, "takes approximately 8 hours for the Body Control Module (BCM) to learn the new battery state of charge. During this 8 hour period, the vehicle must be undisturbed, with no doors opened or keyless entry button presses. If the vehicle is used before the BCM is allowed to learn the new battery state of charge, engine off load shedding can still occur and a message may be displayed." 1 Quote Link to comment Share on other sites More sharing options...
candurin Posted August 10, 2016 Author Report Share Posted August 10, 2016 Thanks Omar. I read that last night. My car sits for up to a week at a time at the airport quite often (which explains why my car only has 49k miles). Today. The voltage was reading 14.3 for the hour drive to airport. Oh well. Seems as though it's working as intended and I was glad to have everyone talk me off the ledge. I may pick up the solar 7 just the same. Would probably work on our kids SLA power wheels batteries! 2 Quote Link to comment Share on other sites More sharing options...
enigma-2 Posted August 10, 2016 Report Share Posted August 10, 2016 I may pick up the solar 7 just the same. Would probably work on our kids SLA power wheels batteries! Only works with the three types of 12 volt batterys. Quote Link to comment Share on other sites More sharing options...
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