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SeanWasHere · 08-15-2018, 08:48 PM

I hope the knowledge base here can help me. I'm having trouble with my new yellow-top Optima battery in my tow vehicle. I bought the battery under a year ago, as a replacement for the old and tired red-top Optima. The red battery was 8-10 years old and had served me well. I've already replaced the yellow-top once under warranty because it went flat. I run the truck weekly for 10-15 minutes to keep it charged. Last week, it was having trouble starting the truck, when I tried to start it this week, it was so low, I had to unlock the truck with the key instead of the fob. When I looked at the Curt trailer brake controller, it displayed "LB" (ignition in the off position).

I have a couple questions; should the brake controller be wired so that it's only receiving power with the ignition on, am I draining my battery because of some constant draw from the controller?

I've had Optimas in the truck for the past 10-plus years, never had one go flat, now I've had two fail within a year. Has Optima suffered a loss of quality?

I don't have a multi meter, should I get one to aid in diagnostics?

Open to any suggestions/advice,

-Sean

**DKB_SATX** · 08-15-2018, 09:10 PM

Sounds like 2 things going on. "running the truck" 10-15 minutes a week is probably not enough to keep the battery charged, especially if you're idling. The alternator doesn't put out a lot of amps at idle, the start takes a toll and it sounds like some phantom load is siphoning off charge over time.

My P3 brake controller with the Ford factory harness on my previous truck always had power. It would go to sleep after a while, but even with the ignition off if you pressed the brake it would wake the display and stay on for a while before going back to sleep.

Are you not using the tow vehicle for anything but towing the trailer? Maybe you could get it a "Battery Tender" type smart trickle charger to maintain the battery when the vehicle isn't being used regularly.

SeanWasHere · 08-15-2018, 09:20 PM

Thank you for the quick reply. The truck doesn't see much use other than towing. I'll look into a artery tender and using it for a couple of weekly errands.

-Sean

ITSNO60 · 08-15-2018, 09:21 PM

Is your tow vehicle new enough to have an accessory delay and does it shut off any lights left on after parking it? Even if it does, sometimes everything is not included, for instance I had a Toyota Highlander and the map lights did not auto shut off, if you left one on it would stay on till the battery went dead.

What I am getting at is your glove box light. Sometimes they stay on, especially if it is crammed full of stuff and the door doesn't close tightly. Other than checking for loads that you can actually see, the next step would be checking for loads that you cannot see which will require an amp meter. If the load is fairly large you can see it by placing a 12 volt filament lamp in series with the positive battery connection, you will see a dim glow in the filament, the brighter the glow the greater the suspect load. May need to do this in a dimly lit area.

SeanWasHere · 08-15-2018, 09:44 PM

It's a 2003 F150 that I bought new. I don't think it has any shut-off features. I also installed Firestone 3000 lb bags. They're supposed to be off when the ignition is off, but I need to verify that. Once I get the battery charged, I'll see if the bags will inflate with the ignition off. If so, they could be maintaining minimum inflation using battery power.

I'll get an amp meter later this week. Thanks for the tips.

-Sean

ITSNO60 · 08-15-2018, 09:47 PM

Quote:

Originally Posted by SeanWasHere

It's a 2003 F150 that I bought new. I don't think it has any shut-off features. I also installed Firestone 3000 lb bags. They're supposed to be off when the ignition is off, but I need to verify that. Once I get the battery charged, I'll see if the bags will inflate with the ignition off. If so, they could be maintaining minimum inflation using battery power.

I'll get an amp meter later this week. Thanks for the tips.

-Sean

My Superduty is a year older than yours and has accessory delay and auto shutoff timer, and a number of circuits and relays that draw power for a short period of time after shutdown.

If you get an amp meter keep in mind that on most modern vehicles you need to wait up to 30 min after shutting off and closing the doors for everything to go to sleep.

**DKB_SATX** · 08-15-2018, 10:07 PM

DC clamp ammeter recommendation: Southwire 21050T, about $85 from Lowe's and elsewhere. About 1/3 the price of the Fluke I really wanted but didn't want to pay for. (it's a full-capability multimeter so a handy overall gadget.)

SeanWasHere · 08-15-2018, 10:50 PM

Hi Brian, I've noticed that my engine-bay light will turn off after awhile when I'm working on oil changes and such, it must be simelar to yours.

David, thank you for the recommendation, I'll look into that.

-Sean

Bobbo · 08-16-2018, 08:13 AM

I am another who thinks that starting the truck for 10 to 15 minutes takes out more power than it restores. You are not keeping your battery charged. You are discharging it faster. You need to either get a battery tender, like was already suggested, or drive the truck at relatively high engine rpm's for 45 minutes or so.

I, also, have a truck that is mostly used for towing. What I do is drive it, exclusively, for one week, then drive my daily driver for one week. I alternate the two. You could do the truck for one day every week or so, just be sure to pick a day that you are actually DRIVING somewhere.

ShinyPete · 08-16-2018, 08:31 AM

Put a high quality battery maintainer on your truck. It’ll keep things up to snuff, won’t overcharge it, etc.

LowbedDon · 08-16-2018, 09:36 AM

Get the alternator checked, they're in the electrical line, they go bad at times.

toadster82 · 08-16-2018, 10:12 AM

If you have a bad battery in your Airstream, it will pull a charge from your truck if its plugged in. When I first got my Airstream the batteries from the dealer were shot, and it killed my truck overnight. I awoke to a dead Airstream, and a dead truck.

greenflag · 08-16-2018, 11:45 AM

Another vote for Battery Tender.
Get one on Amazon or your local auto parts store.

WhereStream · 08-17-2018, 12:46 AM

Quote:

Originally Posted by toadster82

If you have a bad battery in your Airstream, it will pull a charge from your truck if its plugged in. When I first got my Airstream the batteries from the dealer were shot, and it killed my truck overnight. I awoke to a dead Airstream, and a dead truck.

This happened to me as well.