Dead batteries

[GORILLA BE STROKINNN]

My truck wont start batteries are dead, not a huge problem for me to fix but i do have some questions about it. i have a charger i had my girlfriend put it on the truck (i cant because i deployed) and it isnt wanting to take the charge. she has been starting it about every 2 weeks and letting it run.
One of my chiefs out here told me that his 6.0l alternator doesnt kick in til 1200 rpm.... is this the same for the 7.3? because one of the tunes on my chip is a 1200rpm idle tune. would that be enough to bring the battery back up if a friend of mine was able to get it started? or should i just have my girlfriend drive it to work?

[madpogue]

The alt kicks in at a lower RPM, but since the glow plugs run for 1-2 minutes, it's not gonna do anything until after they cycle off. The alt is a bad way to maintain a charge on a stored vehicle anyway. If the charger isn't trickling a charge into the batteries properly, a new charger would be in order. Ideally, your GF should get two of those little low-amp trickle chargers, disconnect both batteries, and keep each battery on its own trickle charge. Cheaper than replacing the batteries, and ultimately cheaper than starting the truck all the time just to charge the batteries. 'Course, _driving_ the truck every now and then (like, once a month) would be a good thing too, to keep the tires from flat-spotting, etc.

[audiocontr]

Your chief doesnt know what he is talking about. The alternator may not peak until 1200 rpms but it sure as hell functions at idle.

[GORILLA BE STROKINNN]

i bought a set of battery tenders on amazon and they are in the mail im gonna have my girlfriend put them on when they get there and just plug them in for me...

[coot1]

Most battery minders can handle more than one battery. I would only hook up one to your batteries. They might fight each other and not keep your batteries topped off properly as one might fool the other into thinking the battery was up to charge. If you you use two battery tenders you should disconnect the batteries so that they are not connected together in parallel.

[Term3]

Originally Posted by coot1

Most battery minders can handle more than one battery. I would only hook up one to your batteries. They might fight each other and not keep your batteries topped off properly as one might fool the other into thinking the battery was up to charge. If you you use two battery tenders you should disconnect the batteries so that they are not connected together in parallel.

Exactly. Only use two battery tenders if the batteries are disconnected from each other.

[madpogue]

Oh, I just figured that went without saying. I do remember reading somewhere that charging batteries in parallel is not a good idea. 'Course, the alternator does that all day. Maybe that admonition only applied to dry cells.

[coot1]

It's fine to charge batteries in parallel. You can even use multiple chargers to recharge dead batteries but once they get up to charge you should just use one minder when trying to maintain them at full charge.

[Term3]

A shop that sells only batteries and chargers told me both batteries get charged up at the same time with the tender as the batteries are in parallel. They told me if I used a tender on each battery then each tender would see the voltage from the other tender and assume the battery is fully charged or close to it. If the batteries are real low they said it's ok to use two tenders but when the batteries get closer to being fully charged only use one tender.

[madpogue]

I did say "disconnect both batteries".... And if the batteries are "real low", you'd want to use more of a medium-level charger (6A or so) rather than a minder/tender.