Battery issues

Hey guys and gals! I’m new to the forum and new to tundras also. I came here looking for help.
Truck: new to me 2011 tundra 146,000 crew max, 5.7, 4x4.
Problem: I was driving down the road to get the truck registered, no issues that I noticed other than the wipers were running slow as I was going through some fog, figured my wiper motor was trying to take a dump. About 30miles from home almost to the dmv truck just died. I might have had lights on the dash but didn’t notice was trying to find my way to the new dmv location. When I got it pulled over I didn’t have any power, no hazard lights, nothing. Had it towed home and started some testing. Trying to jump the battery I could only get like 8.5volts to the battery trying to jump it with the Corolla, as soon as I take the cables off .5volts in the battery, got a new Napa agm battery, i get it put in and I had some pulleys not turning, I was smelling rubber burning assumed it was the belt going across a frozen pulley, went to put some paint on some of the pulleys so I could tell for sure they were turning or not and then they all turned so maybe not? truck sounds odd at start up like something is causing a drag on the motor. According to my harbor freight multimeter the battery is holding about 13volts when the truck is running and when I turn the truck off every 30seconds or so the battery loses .1volts.

I think that’s about everything I have found so far, I was going to start by throwing an alternator on it, but maybe I should pull the serpentine belt and spin the pulleys by hand to see if it’s one of them causing the “drag” on the motor. Does anyone else have any ideas I can check? It would be greatly appreciated

Jeff

 

Is it a constant loss of .1v every 30 seconds? That could be a short or some sort of parasitic charge that is draining your battery. I wouldn't replace the alternator until I knew for sure that was the problem. Chasing wires is probably your next task, not fun but maybe the only way to really determine if you have an issue.

 

13V even running is a little low. Should be closer to 14. Put a load on it while running (high beams, blower motor on high, wipers on) and see what the voltage is while loaded. If it goes under 13 you’ve probably got a bad alternator.

 

Ok, some diagnosing this morning-

at first start up no load, the volt meter at the battery terminals started at 13.8volts, dropped .01volt every 5second almost exactly until about the first minute. Now it jumps around between 14volts and 13.73volts. Then after a couple more minutes i don’t make it to 14volts anymore and I get 13.83-13.62volts, still no load

with a/c and high beams on starting 13.51volts, it would slowly drop to about 13.40 and about every 7 seconds the a/c would cycle from off to on the volts dropped about .05volts. At the end of the load test(high beams and a/c) about 5minutes, I slowly dropped to 12.88volts. Then after the motor was turned off the bolts went back up .01 volts every 5seconds. Stopped at 13.10volts

start- no load. 13.88
Start- Load 13.51
End test 12.88
engine off/no load
Back up to. 13.10

 

Call around, have alternator tested

 

Since you got the AGM battery do this to increase the charging power:

https://www.tundras.com/threads/agm-battery-charging.97564/

I'm not saying this will solve your problem but I'm also not sure that you have a problem since you replaced the battery.

 

Drove my Tundra today for the first time in a couple of weeks. (less than year old True Start 27F battery)
My voltages, measured by my Ultra Gauge, are much higher than yours. First start 14.06 - no load, battery had been on maintainer for past 2 weeks. After driving for about 10 miles, voltage 13.86. Idling, lights and AC on, 13.86 - 14.02. Voltage NEVER dropped below 13.86. FWIW
ps, I didn't get a battery voltage reading with just the key on....

 

Sorry for the no response, I finally got the alternator in. After I got it out I wasn’t going to put the 140,000 mile, 11 year old alternator back in. When I got the new alternator you could tell the old bearings were bad. The old alternator still spun but nothing like the new one, put the new alternator in and just at idle, no lights or anything I am over 14v. So that was part of the issue.

next issue(maybe): when I start the truck, It hasn’t been started for almost 3 weeks, it starts and immediately goes to about 1,000rpm(normal idle). Most vehicle I have ever drove start up when cold at about 15-1800rpm and slowly drops to a normal idle as the engine warms up.

EDIT: fixed the 3rd issue
3rd issue: putting my sway bar back on, the bolts that go into the frame go about half way in and get really hard to turn. Doesn’t seem like the threads are boogered up, I don’t think I’m cross threading as they are pretty coarse threads, I have tried cleaning the bolts and threads. It seemed to help but not totally. Should I just crank them down? Or anyone have other ideas


thanks guys I will look into the booster diode