It's getting colder and my truck is starting slower and slower like the batteries are run down. Still starts with maybe 2 revs but I'm afraid it's going to leave stranded me on a really cold day. I bought the truck used and assume the batteries are original.

So the question is can the alt recharge the batteries on a short commute, mine is only ~2 miles (I know not good on a diesel but it's what I own) and if not should I charge the batteries maybe once a week, or buy new batteries. I've checked a few places and can get the OEM from Napa for $93 with a 7 year warranty 750 CCA or go to Checker auto $97 3 year 850 CCA.

Advice.

Thanks

 

They will charge some in ten minutes but it depends on how run down they are. Take the truck down to the local auto parts place and ask them to load test the batteries, if they are original,it could be a dead cell and then no matter how much they are charged it will never be complete. Replace them both so there's no further problems down the road

 

The alternator on any vehicle is designed to maintain the batteries not charge them. If you are only driving 2 or 3 miles at a time you are actually using more juice to start the truck than you are putting back with the alternator. I have a caravan that I use for short 3 mile runs and I have to put a battery charger on it every 3 months or so, otherwise the battery will lose enough power that it will not start. Old batteries only make this worse. I would charge the batteries and if you go 3 months between charges then you are fine. If it will only go a couple weeks between charges then you might want to buy some batteries. Drive the truck further would help too.

 

Thanks for the replies

I drive the truck on weekends more but not always, I still average 12,000 + miles a year. This is was bought as a tow rig for our TT and the DD had to go.

I'm thinking batteries now and the NAPA 750 CCA's should do the job right? 7 year warranty sounds good.

 

How cold is cold? I found in my dually that it would be slower to crank in the cold when below freezing. I changed my oil to synthetic 5W40, made a world of difference.

If you are getting new batteries, I'd reccomend getting some group 31 batteries. About 1" bigger in all dimensions (will require cutting up the battery boxes some), is 1200 CA, 950 CCA and 210 min reserve. Much bigger than the stock group 27 batteries. Last winter, my alternator failed on me. I drove for three days (300km) and ran my heater for around 6 hours total on those in -20 to -25 weather. The batteries were getting low, but still had life in them and are still going strong. And they were cheaper than the 27's I was originally gonna buy.

 

As stated above, your commute is not long enough to recharge the batteries. There are a few solutions which do not include driving the truck more. I run a small solar panel on the dash of my truck and intentionally park to face the sun and it does a great job of maintaining the batteries(you need to be parked in the sun though). You could also just hook up a battery charger but that is kind of a pain. Because our racecars have to be jumped/charged so often, we just put anderson connectors on a charger and on a wire coming off the battery so that we can plug in the charger without getting to the battery.

 

you had better take some lessons in automotive charging systems before you make a statment like that

 

right john,it never ceases to amuse me with all the misinfo on these pages,been a diesel mech or as they like to call therselfs now techs for 47 years

 

If an alternater can put 50 amps and 14.5 volts..I would think it will charge you batts no problem
Your problem is you are not allowing enough time for it to do the joib..considering grid heaters and all.

 

This was years ago, so, I don't know how it applies to newer vehicles. Anyways, I had heard from a couple mechanics that about 15 min run time above 1000 rpm. There was a reason for the +1000 rpm, but, I just can't remember what the significance was now. Like I mentioned before, this info was from years ago, probably around 1990 and directed at cars from the time or before. I don't know how far materials technology has made it into the charging systems on newer cars or trucks and suspect not much has really changed from then to now.

 

The only place where you should apply that rule is on vehicles ,airplanes with very small alternators . They will still charge it up..but it is very hard on them.
Say a Porsche 911,the alt is no bigger then you fist and they are about 600 bucks so what ya want to do in that case ? (keep the work of the alt. to a minimum.
( the rason for the small alt. is weight saving)......you folks will not understand.

 

Hi john, nice part of the country you're in over there...

Okay, I'll try...

How fast your alternator will charge your batteries is determined by your charging capacity less your total load. But you must first determine how much charge your batteries need based on the draw from your starter and heater grids. Niether of which I know.

The formula would look like this:

Charged Battery 'a' - Starting load = battery level 'x'
Alternator capacity - total (running) load = charging capacity 'y'
Time = 't'

y * t = a - x

y,a, and x are constants (again, I don't know the numbers) solve for t.

Your charging capacity changes based on whether you're running lights, the grid heaters are cycling, the vent fan is running, etc...

 

I picked up a small trickle charger from Walmart that mounts permanently on the truck. Plugged it and my block heater into a short extension cord that I leave a bit hanging out of the front. Now when I plug the block heater in the batteries get a bit of a charge as well.