It takes about one week to the point where its on the verge of not turning over fast enough. When I was originally testing and found #14 to be the major leaker, I let it sit over night without the fuse. From 100% at the start of the test they were down to 45% in 24hrs. Im waiting to figure out the drain problem before I install my new Motorcraft batteries. The old is probably only little over 6 months old. While its running its putting out a strong charge. After its started for the first time, no problem restarting it....

 

That sounds like a very large draw down on the order of something I would expect to come from a large load that is not shutting down.

 

While normally I would agree, but I dont think these Optima hold that great of a charge anymore. Ive read that AGM batteries discharged fully is bad on them. This draw will constantly do that to them, down to 10%. This being measured with my Schumacher charger....

 

Disconnect alternator hot wire and see if it goes away

 

Actually one of the chief advantages of absorbed glass mat batteries is they are the most tolerant of all battery designs to deep discharges as opposed to standard batteries. They are used frequently in high-end RVs for this reason.

I would suggest rather than rely on your charger, if you have a multimeter and know how to take an amp reading, you take one as it will give you a much better measure of your rate of discharge. Or take a voltage reading when fully discharged to 12 volts which would be 50% discharged.

 

So I just pulled #14 fuse again (5A) which was my major leaker....didnt turn off the Edge. I guess I have more digging to do. I will try the Alt wire as suggested.

 

No dice on the power cable. Fuse #3 (20A) does shut off the Edge display. #3 is Cigarette lighter, Data link connector. Does not drop power consumption like fuse #14 does.

When #14 is plugged in it spikes to .68A but settles down to .20A

Rv_Tech, I'm not quite sure what you wanted me to do with my multimeter reading voltage instead of using the charger??? Calculated formula maybe???

 

I trust most multi-meters for accuracy. The reason for this is, if I am reading your posts correctly, you are dropping fully charged batteries from about 12.6 - less than 12 volts in a very short period of time. To me, that is a monster drop that can not be accomplished with a .2 amp drain unless the batteries are seriously dead, but you can start your truck, so that would argue against a drop down to less than 12 volts.

One thing you have noted is you feel the batteries may be off their game. I would have them tested or retested, if that has already been done.

I would be thinking of a draw about comparable to leaving the headlights on or something similar in terms of amp draw.

Not doubting what you are saying, just trying to double check. I work on stuff like this all the time and love electricity, so it is an interesting puzzle.

 

I charged both batteries to full capacity ~12.4v within 1/2hr the charger is showing 70%. Im starting to think my passenger battery is killing the driver side. I would think charging the DS battery would charge the PS at the same time...nope. DS can be 90%, switch side and it will be like 5%. I feel like im chasing gremlins....lol.

 

I don't know if this will seem like it makes sense, but the one thing I have discovered is the weirder something seems like it is, the more likely it is to have a very simple solution. My thought would be with that kind of imbalance on the charge rates with two batteries in parallel, you either have a bad cable to one of the batteries, or you have a bad battery.

 

Rv tech.....you read my mind with all your followup tests since my last post. I was kind of leaning towards the lack of draw at .2 amps and possibly bad battery as well. I have not checked amp draw but my truck has sat as long as 3 weeks and not had trouble cranking. Mine is an xl so it has fewer electronics on it too.

 

My brother has a '99.5 his also can sit for 3-4 weeks and fire just fine....also running Optima red tops. This is my second set. My first set I suspect was doing the same thing. They covered them under warranty but I had to eat shipping to send them back since I ordered them off the 'net. These new Motorcraft Max batteries I bought at the local O'rielly's with a 36/100 month warranty so dont have to deal with shipping them again!

 

When you disconnect your batteries what do they read individually?

 

I went threw 2 sets of red tops. I now believe they are junk battery's. they both swelled on me and my alternator was putting out 14.2v. Not to mention they wouldn't hold a charge after a couple months and when I contacted optima and told them my issue they basically told me to GFY. Not great people to deal with in my opinion. I ditched the red tops

 

I've used optima's some on my other boats and had good luck with them. But on my new boat I have verado's Mercury requires agm's and discourages optima's.

In my truck I usually just get the plain batteries with highest cca at advance auto.