How long to charge batteries (running engine)?

Your truck may have a low battery shut off system which would cut all auxillary power when the batteries get down to the point where there's just enough to restart the engine.

I have found idling doesn't charge the batts enough for another full day off the way driving down the road for just 10 miles does.

 

Mechanics told me 4hrs for my 587 Pete to fully recharge.

 

Also, all the blower fans and radio work to siphon off any available 'idle charge' that you may be generating. So if you're not remaining in the truck, at least turn off the cab and bunk climate control systems and this will allow for that much more juice go to the batteries.

 

i dno't have a fridge. but left my cb on while the truck sat 10 days.
i also have a 12v digital clock that never gets unplugged.

4 batteries half dead. almost full day of driving to recharge completely.

last year i was in a t600. it had a fridge. sat 4 days (weekend) waiting for redatior repair. truck had to be jumped. 1 1/2 days driving to fully recharge 4 batteries.

i think the engine has to be above 1000 rpms before the alternator starts throwing a decent charge. i drove a dump truck once. engine had to reach 1200 before the voltmeter jumped off the 12v mark. that only happend upon startup. worked fine all day long.

 

Batteries when they start going dead will run out of juice a lot faster too.

I think hubby ran the truck for at least 3hrs to recharge, but then later on had one go out then 2 more about 2 weeks later. And boy do they stink when they start going bad, like rotten eggs.

If I was cooking, he would bring the rpm's up more also, this may have been due to the batteries having problems though.

Is there anyway you can plug the refrig into an extension cord, or is it at a TS.

 

eventually with this scenario, you will be over working the alternator and shorten it's life. an alternator is only supposed to "top off" the batteries. best to have whatever devices you have running, be unplugged while you are at home. why have something running when it is not needed..???

 

My cooler draws 5 amps. Running for an hour, that's 5amp hours. Times 24, that's 120 amp hours drained from the battery that needs to be replaced.

The trick here is to determine the rate at which your batteries will accept a charge. The higher the charge level, the slower they will accept a charge. The battery manufacturer may publish this data, so check to see if there's a chart that will tell you.

Lead acid batteries typically accept 25% of their rated capacity as a charging rate. If your alternator can support that rate at your set idle speed, then use that rate to calculate time to recharge.

Say the charging rate is 50 Amps. At that rate, it would take about 2.5 hours to fully recharge.

Many variables, very difficult to determine without knowing the particulars of your system.

 

Incorrect, the alternator supports the entire electrical load of the truck while it is running, as well as charging the batteries after the engine is started.

Running an alternator at its rated load will not shorten its life appreciably.

 

When I'm on hometime, I bring my cooler inside the house and run it on the 110v adapter that came with it.

I also had problems recently with the batteries discharging overnight to the point that the truck wouldn't start, and my inverter alarmed on low voltage. What I found was corroded battery terminals on bank B (2 batteries in parallel) that had high enough resistance (8 ohms) that the batteries were not charging at all. Bank A (one battery) was fully charged, and that was the only battery that was supporting the truck. So corroded cable lugs had sapped 66% of my battery capacity. And the corrosion wasn't externally visible; the lugs had to be removed from the batteries before it could be seen. Once they were cleaned with a wire brush and emery cloth and the batteries recharged, the system was restored to full capacity.