Charging issues
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Charging issues
I'm pretty sure I already know my problem but wanna get your guys advise before I jump into it incase there is something I'm missing. When I first start my truck & its sitting at idle the alternator only puts out 11.7 v, it's not until I increase the RPM's that it will jump up to 14v so I'm assuming the alternator is on it's way out?
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I'm pretty sure I already know my problem but wanna get your guys advise before I jump into it incase there is something I'm missing. When I first start my truck & its sitting at idle the alternator only puts out 11.7 v, it's not until I increase the RPM's that it will jump up to 14v so I'm assuming the alternator is on it's way out?
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@Bigtruc Is that 11.7V during GPR ACTIVATION OR AFTER the GPR shuts off? The GPR can stay on for upwards of 2 minutes during that time you’ll never see 14V. I typically see 10.7-11ishV while the GPR is activated when it shuts off the voltage jumps to 13-14V. I have a volt meter in the cab and an LED wired to the GPR so I can see the immediate relationship between the GPR and the charging voltage...
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The only reason this was even brought to my attention is because last night I autostarted my truck to warm up & it sat outside idling for 45 min before the autostarter timed our. Then when I actually went out to leave I tried starting with the key & she almost didnt start cuz batteries were so low. I also got a voltage critical low on my drone app & the gauge on the dash read very low until I started driving. That's when I went out this morning & tested it.......started the truck & put a volt meter on it & was reading 11.7 volts & I left it there for over 5 min to make sure the glow plugs were off & it never changed until I bumped up the RPM's then it went up to 14
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. Belt is only a couple months old & pulley's seemed to be fine when I checked them over while replacing the belt
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You're in Minnesota. It's so cold in Minnesota, my thoughts freeze thinking about it. No wonder I'm typing so slow.
Stock alternators can't put out much current at idle. If the current demand to replenish your batteries is substantial, it could be that the stock alternator can't keep up at idle. The 110A alternator only produces 110A when spinning at over 5,800 RPM, Divide that by a 2.9:1 pulley ratio and that equals 2,000 engine RPM. So even after you elevate your idle to get the alternator to produce enough power to overcome the depleted battery recharging demand in the cold weather and raise system voltage to the set point of regulation, the alternator still isn't producing 110A until driving down the highway.
A couple of folks here have purchased and installed "Idle Pro" alternators. These are 230amp rated brutes that WILL produce enough current AT IDLE to match depleted battery demand without elevating RPM. Although I'm not sure about Minnesota. Brrrr.
Dang it. Even though I only typed 2 paragraphs, somehow 2 additional posts managed to slip through in between time. Frozen thoughts = frozen fingers.
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Key on engine off, GPR on: 11.2V climbing to 11.6V over 10 seconds, as glow plugs warm up and draw less current
Starting 10 seconds after key on, engine idling, GPR on: 11.7V, alternator putting out maybe 40-50A trying to replace starting load and glow plug draw.
Engine idling, GPR off: Voltage slow climb over 30 seconds or so to 14.4V.
It could be that alternator is tired. If your battery terminals and cables are good/clean/tight, you could get that alternator tested or change it out, or just replace the voltage regulator inside it. I replaced the regulator/brush set on my alternator and got it going again. I have dual 110A alternators, but when I disable the second alternator to simulate a single alt truck, my voltage behaves as described above.
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