battery drain?

[JWBFX4]

Yes it does pull current with the truck off. I can't find the thread around here right now that talks about it but I remember "Jack" had measured the current it draws and its in a thread around here somewhere.

[JWBFX4]

http://dygytalworld.ehost-services13...read.php?t=327

This thread talks about it pretty good. Post #6

[Jackpine]

Originally Posted by JWBFX4

http://dygytalworld.ehost-services13...read.php?t=327

This thread talks about it pretty good. Post #6

And, that thread is accurate for my truck. I have not had a single problem since using the battery tender whenever the truck is sitting in my garage.

Interestingly, I always find I have to run the battery tender (max charging current 1.25 A) about 8-10 hours after driving the truck to bring the battery to a full charge. And, my alternator supplies around 13.9-14.1 Volts when I'm driving. So, even after a full day of driving, the battery seems to be (according to the way the "tender" works, at about an 80% charge level.

I cannot explain this, and it doesn't make any sense to me. It's just the way things are.

- Jack

[Longshot270]

Jack, I bet that the numbers your getting have something to do with the Voltage=Amps/Resistance formula. If the battery tender uses clamps to connect to the battery then it will read more resistance than the vehicle(because the vehicle has been bolted in since day 1). More resistance is going to make the voltage look lower without any higher amps. Could be wrong but it sounded good when it ran through my head.

[RGSMDNR]

ahh ok, thats good to know. Would it matter if the PCM was programmed or stock mode? can someone explain why it draws current while the truck is off?

[Longshot270]

Im not sure having the PCM progarammed would make a difference on the electrical draw. As far as I know the small amount of draw is what lets the computer remember what the latest amounts of data there are. You know when you unplug the battery that you usually lose the radio presets and stuff?(my truck doesn't do it but my dad's does) I think one of the things it remembers is the last driving conditions, I've noticed that some vehicles will throw P1000(?) codes after being reprogrammed or having the battery unplugged. I also think its the same on the gryphon, that small amount of draw lets the programmer remember stuff like your averge MPG and top speeds, that kind of stuff. This part Im not so sure about

[88Racing]

Oh let's see here?
Some examples of current draw while vehicle is off.

KAM. Keep Alive Memory
Security. PATS system.
Remote Start.
Radio memory including clock.
Shut down sequencing procedures when vehicle is turned off.

A battery tender directly bolted to the post clamps may be the best way to combat losses while the truck is sitting. Especially like my garage queen. But if your truck is a daily driver I wouldn't worry about it.

Lars

[Jackpine]

Originally Posted by longshot270

Jack, I bet that the numbers your getting have something to do with the Voltage=Amps/Resistance formula. If the battery tender uses clamps to connect to the battery then it will read more resistance than the vehicle(because the vehicle has been bolted in since day 1). More resistance is going to make the voltage look lower without any higher amps. Could be wrong but it sounded good when it ran through my head.

Longshot - we MAY be talking about two different things. The voltage and amperage numbers I quoted in the other post are with a good digital multimeter. The parasitic draw in my truck is definitely 0.05 amps (50 ma) after the truck has been sitting in a "quiet" state - doors closed, everything shutdown for at least one hour. To this list of what Lars posted for current draw, I also have memory for the pedals and seats and memory for the climate control temperature. The King Ranch also has the door open keypad that has to be alive to accept key input and all our trucks probably have a powered receiver to accept signals from the key fob for remote door unlock.

In this post, the 13.9-14.1 volts are being displayed on the Gryphon with the engine running and this seems a pretty normal regulated charging voltage from the alternator.

What I found puzzling, is the state of the battery after driving. I expected it to be at or near a full charge state. But, I think I just figured out why that may not be so. My headlights have the "auto-on" feature, so when I drive into the garage, they come on. They stay on for about 20 seconds after I shutdown too, as do the interior lights after I get out an close the doors. There seems to be some other, less obvious circuits that are alive too, for about 5 minutes, until the battery saver relay opens. This puts a fairly heavy draw on the battery.

By the time I get my battery tender hooked up, it takes about 6-8 hours to reach the fully charged state (since it uses a very low charging current to keep from "boiling" the battery - about 0.2 Amps) when the battery is above an 80% charge state. If I simply unplug the battery tender and then plug it back in again, its operation indicates a full charge within a very short time, since there was no big drain while it was disconnected.

The 0.05 Amp draw from the Gryphon (when it's plugged in) was confirmed with Bill. I know I have a total parasitic draw of 0.1 amps when the Gryphon is installed.

Finally, as Lars said, the Battery Tender comes with a "permanent" plug in connection you can attach to the screw terminals of the battery posts. This makes it simple to use.

- Jack

[Longshot270]

Oh oops, I meant the battery charger was reading low, your older post about parasitic draw sounds good to me. I bought the base model XL with no bells or wistles so I was thinking in terms of my truck. But I'm not so sure the extra bells and whistles would draw 80% if your battery in a short amount of time. I've run my truck's stereo plus a pair of 12 inch subwoofers for over 4 hours at full power and only got knocked down to about 9-10 volts. How many CCA (Cold Cranking Amps) is your battery? If I go with my 540 CCA down to 80%, that would be a loss of 108 amps and drop your battery down to something like 10 or 11 volts. Did I mess up on my math somewhere or use wrong numbers? If you left your lights on for a good while I'd expect to see something like that but it sounds like you hook the battery tender fairly soon after parking. I am pretty sure a single 55 watt bulb is usually around 4-5 amps. We must be arguing somewhere but I'm not sure over what. :nerd:

Question: What is the final voltage after the charger considers the battery to be at 100%?

[Jackpine]

Originally Posted by longshot270

Oh oops, I meant the battery charger was reading low, your older post about parasitic draw sounds good to me. I bought the base model XL with no bells or wistles so I was thinking in terms of my truck. But I'm not so sure the extra bells and whistles would draw 80% if your battery in a short amount of time. I've run my truck's stereo plus a pair of 12 inch subwoofers for over 4 hours at full power and only got knocked down to about 9-10 volts. How many CCA (Cold Cranking Amps) is your battery? If I go with my 540 CCA down to 80%, that would be a loss of 108 amps and drop your battery down to something like 10 or 11 volts. Did I mess up on my math somewhere or use wrong numbers? If you left your lights on for a good while I'd expect to see something like that but it sounds like you hook the battery tender fairly soon after parking. I am pretty sure a single 55 watt bulb is usually around 4-5 amps. We must be arguing somewhere but I'm not sure over what. :nerd:

Question: What is the final voltage after the charger considers the battery to be at 100%?

We're not arguing at all, Longshot! We're having an adult discussion that often doesn't happen in other forums. But, I suspect we may be referring to different things, so there's a bit of misunderstanding.

Let's go back to my total "parasitic" draw of 0.1 amps. This can drain my Costco battery (I can't give you the CCA on it because it's covered by the battery holder cover in the truck and I don't want to disconnect the battery to read the numbers - but I know it's at least 50 CCA above OEM) in about 21 days.

According to the manual that came with my Battery Tender: A battery that is 100% charged should read about 12.9 V in a "resting", no-load state (which is several hours after being disconnected from any kind of charger). If it is fully discharged, the resting voltage will be about 11.4 V. If the output voltage is less than 9 V, it is probably defective.

I have another maintainer I use on my trailer batteries called the BatteryMinder Plus, and it says it only goes into the "maintenance/desulphation" mode when the charging voltage reaches 14 V. (It has to get this high during charging, indicating a lot of "back emf" or "charging resistance" to be at a full charge state).

Now, CCA can be a bit misleading. It refers to cranking ability. It's the number of amps a battery can support for 30 seconds at a temperature of 0 degrees F until the battery voltage drops to unusable levels. It's not the same thing as "cranking amps", which is what you get at 32 degrees F and it's not the same as "reserve capacity", which is more a measure of total power stored.

Here's a good link: http://www.carquest.com/partsBatteryFAQMyths.html#6 It covers many battery facts and myths.

And, back to your point about drain in your post. If I have a 0.1 amp parasitic draw, my Battery Tender, with it's potential 0.2 amp output at an 80%+ charge state is really only delivering 0.1 amps. Pretty puny charging current - but it won't boil the battery, either.

- Jack