Truck has an HDD to store CDs and DVDs. I started to download a bunch of CDs for the trip later this month. Battery Tender connected so should be ok, right?

Apparently, playing CDs and saving to disk consumes battery faster than the Tender charges resulting in a dead battery.

I stopped saving CDs. Hoping the Tender completely recharges the battery. 2-3 days?

From completely dead? Probably will not fully charge the battery in 3 days with a battery tender. Enough to start the vehicle probably. Are you sure the battery tender is charging? I would check and see if you don't have another issue like a bad battery.

The Tender was on and green before all this. I noticed that the Tender was red and so I turned on the car to accessory mode and the battery seemed to read around 10v. I didn’t try starting the car.

I might try starting the car tomorrow and drive it around for an hour. It charges faster via alternator, right?

quote:

Originally posted by konata88:
The Tender was on and green before all this. I noticed that the Tender was red and so I turned on the car to accessory mode and the battery seemed to read around 10v. I didn’t try starting the car.

I might try starting the car tomorrow and drive it around for an hour. It charges faster via alternator, right?

Yes, most battery tenders only put out around 750 MAH (MILLIamp an hour). Your alternator should put out 100-150x that amount. I don't know exactly on your vehicle but the alternator probably puts out around 100amps an hour.

Thx. Yea, I think my car is 100A alternator and 80 A-Hr battery.

Do you have AAA? Most AAA service trucks can check your battery condition as well as alternator charging, and of course perform jump starts. You might even have dirty corroded battery terminals, and they can help with that too.

I have found AAA to be quite good for these sort of issues.

Good luck to you.

Don’t have a battery charger?
Your vehicle has all the HVAC settings and controller in the entertainment unit if memory serves correctly. That is going to suck batteries like crazy if not running. Tender won’t keep up for sure nor will it likely fully charge in any quick amount of time.
I got a nice Shumaker charger and quick jump unit at Lowe’s last year near Father’s Day for a great price.
You are wanting to go off road and kayak trips I highly suggest to have a jump box as well.
The jump boxes are worth their weight in gold.
If you are still using a Toyota battery I would dump it as well. I had terrible luck with ours.
Upgraded to higher cold cranking amp and capacity AGM batteries.

quote:

It charges faster via alternator, right?

If you're making a habit of running your battery down, the alternator alone won't fully charge the battery, or if it does, would have to run a very long time, and its life will be shortened. To put a good charge on the battery, get a real charger, preferably an automatic one, and leave it on a low level (not more than ~20 amps) for several hours. In my work I use this one a lot, to keep batteries up. I have had to charge a run-down battery over six hours to bring it up. Then find a different power supply for your accessories.

The HDD and CD player use maybe 20 watts. 20w/12v=1.66a, so a 1 amp battery tender won't keep up. However; an 80 amp hour battery with a .66 amp load should last, 80/.66=121 hours. If the vehicle had a parasitic load equal to the battery tender's output, the battery should still last 48 hours running the HDD and CD player. Assuming it takes 10 minutes to rip a CD, that's 480 CDs worth of power.

^This is my long winded way if saying there may be a problem with your charging system and you should get it checked out. Many auto parts places will check your battery and alternator for free.

A battery tender is designed to keep a battery charged, not to charge a battery that is significantly discharged. It is just a trickle charger, and typically puts out less than 1 amp of current, or just enough to keep up with the natural rate of discharge of the battery while in your automobile.

A car, with everything turned off, will normally pull less than 1/2 amp of current. But in addition, the battery will naturally discharge, even if not hooked up to anything. So the trickle charger works pretty well to keep it where it needs to be.

When you turn your car on, even to "accessory", the BCM wakes up, and it may start pulling an amp or more of current. More than that if the interior lights are on. The radio/entertainment system is typically fused at 10-15 amps, and if it is a premium system with a factory amplifier, that amplifier may be fused separately at another 20 amps. So if you're playing your stereo loudly, you can easily draw 10-20 amps of current. If you have the volume down, but still operating the CD/DVD and HDD, I would guess that your battery would be seeing a load of 5-10 amps.

Obviously a battery tender won't keep up with that, and depending on the size and health of your battery, it could be below starting strength in as little as 30 minutes to an hour. Even a good strong healthy battery could be pooped in an hour or two.

How long were you working with the CDs/DVDs?

Also, why do you have a battery tender? This is a vehicle that you don't drive very often?

The battery tender may get your battery back to starting strength in 2-3 days, depending on how low it is. Make sure all doors (and the hood) are closed, so the vehicle electronics will go to sleep and draw as little current as possible. And don't go try it until you need it, as a failed attempt at starting will put you back to where you started, and even if it starts you'll be worse off, unless you actually drive it for 5-10 minutes.

Thanks for all the great info guys. Especially the technical number crunching.

I woke up to a Fluke reading of 13.x volts (car was on the tender for about 15 hours with car off) and was able to start the car. The car seemed to start fine. I went for a 1 hour drive. Upon coming back, the Fluke was reading about 13.07V; I reconnected the Tender.

I probably saved about 15 CDs to HDD (each CD takes about 15 min). But the actual power on time is longer because the system doesn't start recording the next CD until playback of the first is finished. Sometimes I would I would skip to the next CD but most times I couldn't get to the system so playback would finish before starting to save the next CD. So, the car was probably on for about (0.25 * 15) + (guessing) 5 hours or about 9 hours (maybe more).

Mark Levinson stereo + LCD display: 9 hours * (2 to 5 amps) = 18 to 45 A-Hr. Assuming I have an 80 A-Hr battery, I guess I depleted 25-50%?

Honest -- I have the tender because this is just a vehicle for trips and kayaks. I have a daily driver car.

Based on the car starting and a Fluke reading > 13V, do you guys think the battery is okay. Just drive around (13 hour drive) / keep it on the tender and it'll eventually fully recover? Or should I be thinking about replacing it.

quote:

Originally posted by konata88:


Based on the car starting and a Fluke reading > 13V, do you guys think the battery is okay. Just drive around (13 hour drive) / keep it on the tender and it'll eventually fully recover? Or should I be thinking about replacing it.

At that moment the battery has a surface charge. The only way to fully determine battery condition is to load test it.

Most all auto parts stores will load test your battery for free. It generally takes only a minute for them to load test it.

A load test at this point probably won't be accurate, as the battery probably is not fully charged.

quote:

Originally posted by Some Shot:
A load test at this point probably won't be accurate, as the battery probably is not fully charged.

Indeed.

Clean the battery terminals.
Charge the battery with a proper battery charger at an appropriate rate and time of charge.
Drive for a short time and distance.
Load test battery.

Thanks guys. Amazing all the expertise here.

I’ve got blinking green on the Tender now. That’s a good sign, right?

I’ve got a jump starter albeit untested.

https://www.walmart.com/ip/DBP...t-LEDEmerg/294346852

Blinking green on the Battery Tender is a good sign.
The jump starter you linked is also a good sign.
I've bought a few similar jump starters on Amazon Lightning Deals for the 9 vehicles I'm "sort of, hahaha" in charge of keeping up.

Doesn’t your car have a USB port? Can you not burn CD’s onto a large flash drive and then play that through your audio system? I haven’t tried it, but think the capability should be there.

quote:

Originally posted by trapper189:
The HDD and CD player use maybe 20 watts. 20w/12v=1.66a, so a 1 amp battery tender won't keep up. However; an 80 amp hour battery with a .66 amp load should last, 80/.66=121 hours. If the vehicle had a parasitic load equal to the battery tender's output, the battery should still last 48 hours running the HDD and CD player. Assuming it takes 10 minutes to rip a CD, that's 480 CDs worth of power.

^This is my long winded way if saying there may be a problem with your charging system and you should get it checked out. Many auto parts places will check your battery and alternator for free.

Agreed. I would suspect you have an electrical system problem. Maybe your battery itself is on its last legs.