It dropped to -34 (-30 f) here the other day and my truck didnt want to start. Load tested my battery and it was shot. I had killed it a couple times out in the bush in the summer, that and the cold obviously didnt help it.

Now my question is I got a 1100CCA battery to replace it. Starts great and no problems I can see. However I put one of my Edge gauges to the battery voltage and it seems a little high to me. 95% of the time I am sitting around 14.4/14.5. I saw 14.6 once and a couple times it has dropped down to 13.8. I googled ford f150 voltage spec and nothing came up.

Does anyone know what the average voltage output is supposed to be? Or what do you see day to day.

 

What happened before or during the times it read low ?

At what engine state are those readings taken ?

What are they taken with ( just the Edge ? ).

 

- Not really sure honestly. I commute a decent distance so I figured that it was just re-charging the battery from start up

- 2000 rpm highway speeds. Stereo on. HVAC on. In some cases heated seats on and sometimes not. Doesnt seem to matter.

- Yes just with the edge. I just stared to look into it after I lost the last battery. No warnings or anything on the dash and the gauge is normal.

 

I realize Scully needs those answers to give his diagnosis, and they are important. Having said that, as a generality, I think they're pretty decent readings. That's a lot of battery to charge, if it was down a little when you bought it, but batteries are seldom down unless they've set in stock for a while. You shouldn't have seen the 13.8 on a Ford unless you had fully charged the battery and were at idle at a stop and maybe had turned 2 or 3 things on at that time. Probably should be checked at about 17-1800 when sitting. Scully is much more the guru than me so we'll see what he says.

 

Code, I respect your inputs in this forum, but I'm going to take exception to something you said in this last post, because I think it could be confusing.

If you have a FULLY charged battery, the alternator voltage readings will always be higher than if the battery is somewhat depleted. So, the part I've "bolded" is my hangup. Yes, I totally agree that turning on a slew of accessories is going to reduce the charging voltage, and, if the battery is a "high capacity" one and if it is discharged a bit the charging voltage will also be reduced.

But, a FULLY charged battery will tend to register a relatively high charging voltage value (due to its resistance to being further charged). And, maybe a high capacity battery will show an even higher voltage if fully charged. *shrug* ??

Anyway, I agree totally that a voltage reading of 14.6 is not really too high and 13.8 is not too low.

On my truck, I regularly see 14.1-14.2 when I'm driving with a fully charged battery, but if I hook up my trailer, with its two batteries and the DC powered refrigerator, I'll see the charging voltage drop to 13.6 on a long trip, with stops where the batteries are not being charged.

I guess, in the part I bolded, I would have said "partially depleted" instead of "fully charged". Does this make sense, I hope?

- Jack

 

Thanks for the input guys. Driving home from work today saw 14.1/14.2

Didnt know if it was too high. Just happy to hear other people are seeing the same numbers.

 

Nope, at least I believe that's a real good #. Remember that a battery fully charged should be 12.6-12.8V (starting battery, NOT deep cycle). A deep cycle battery should be 13.1-13.2 fully charged if it's in good shape. These are just a general rule. There are a million variables. The additional voltage up to 14.2 or so (roughly 1.5-1.7) is what's running the car and accessories. Actually Amperage, but what we have had for the last 50 years or so is a volt gauge where before that we had an amp. gauge. The car is actually normally running on the alternator once it's started, just feeding the juice through the battery to modulate it.

 

Jack, I fully respect your input also but on this one I'll have to disagree with you. I have charged and tested literally thousands of batteries (both at work and for my own and others vehicles) in a very long career in automotive work. Even more so in the last 8 years of it when I did Code3 outfitting and batteries were often dead on new vehicles for a large variety of reasons.
I have used many different chargers and types of chargers. I currently still have a shop wheeled charger but much prefer to use the 25A "Smart charger" Virtually every charger I've ever used has a tapering circuit in it that senses the amount of charge in the battery and reduces the charge automatically as the charge comes closer and closer to "full". The Smart Charger has circuitry that senses this in a much more technical way than the simple "tapering charger". It shuts it off and turns it on as needed to keep from any overheating of the battery (and it REALLY works), and tapers down to almost nothing before the battery reaches "full charge" and shuts of and shows "full". Which incidentally is 13.02V, but a starting battery won't hold that, only 12.6-12.8V.
I've only said all this to say that all battery chargers drop from their peak to a lower state of charge as the battery is closer to "full". And the electrical system in a car is no different, dropping lower as the battery approaches "full" The difference in a car is that the voltage regulator does the controlling and when the car is being run to charge it, it's also using some of that juice to run the car and any other load. Within a range, determined by the regulator, you will always show higher voltage (or amperage) when a battery is depleted and a lower voltage (or amperage) as the battery is close to charged.
Now that I have you thoroughly confused... That's my story, and I'm stickin' to it.

 

I'm not confused by your explanation, Code, but I still don't buy it. (Of course, this discussion is only of interest to us - everyone else probably is asleep by now).

I agree 100% with your description of the way a "smart charger" works. It senses the voltage across the battery terminals (the "back emf") and limits the charging current inversely proportionally to the rise in that voltage. And yes, 13.02V or thereabouts is the voltage you will see on a fully charged battery that is still connected to a smart charger.

But, a fully charged battery will register its highest voltage state whether or not it is connected to a charger. And, the vehicle voltmeter is measuring the voltage across the battery terminals. IF, you turn lots of high draw accessories on and are sitting at idle, that voltage will drop, just as you said. But if the battery were discharged, the reading with those accessories on would be even lower.

We could test this, of course, with a multimeter on a charged, and then a discharged battery with the engine on and accessories on or off. Trouble is, I don't happen to have any discharged batteries! My "garage queen" (the truck) and my trailer are both on battery minders to maintain their batteries in a fully charged state.

So, that's MY story, and I'm sticking with it too!

- Jack

 

Anything under 15V is OK - it's not gonna hurt the battery.