When to replace the aux batt and how to know?

[Davexxxx]

I

I constantly forget that it wakes the truck up when I and fartsing around in the garage and get too close to the truck in the driveway with my keys in my pocket. After the 4-5 time of it lighting up when I walk past that I remember to take the keys out and set them on the beer fridge.

I'm pretty good at home. If I see it trigger the lights, I put the fob away but it completely slipped my mind the other night. Out of sight, out of mind.

Cheers.

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[Davexxxx]

Update,

Wish I'd taken a voltage reading just before plugging the thing in but it started Fri morn with resting voltage of 12.5, had been run to do the fan speed 5 test and run to town to get the charger so, it shouldn't have strayed too far from there and according to the SOC chart, 12.5 = 90%

We've all seen batteries with good voltages but weak available amps and I did not load test these batts. The SOC chart is all we have and it is lacking.

Enter the Genius 2D, plugged in some time around 4:00 p.m. on Fri.

Started off flashing red. Instructions say, charging a bat with SOC below 75% and it was pretty warm to the touch. Not scary, melting paint, or making smells hot but pretty warm. Voltage reading at the batt was 13.25 ish.

Checked several times throughout the eve. and it was still flashing red and not near so warm.

By Sat. morn. it was flashing green = either, charging at above 75% SOC, OR, automatically in desulfation mode. It would be better if the latter had it's own code, so a fella could know. The instructions say it is normal for it to go into this mode but doesn't give any time info. My other charger uses a 24 hr. desulfation mode and it didn't call for it the other day so ... ??? So, if you don't catch it while solid green (fully charged) and the whole point of installing an on board charger, is to not have to open the hood, absent some other monitoring tool, you'll never know. Cool to the touch.

Minutes ago, still flashing green, batt voltage at 14.38, cool to the touch.

I don't have anything planned for the truck until at least tomorrow and that could be put off. I'm gonna try to hang with it until it turns solid green, at least this first time, if I can.

Other than the desulfation mode not having its own code and no documentation of that time, I've no complaints. Its small and light but sturdily built. A built in bluetooth monitor would be nice.

 

[Ricksc]

I would not go by those charts. Get yourself a tester

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[Snakebitten]

I love the Bluetooth voltometer.
I have them on everything.
But it's SOC value can be a bit all over the place too.

12.9V for an AGM is 86%??

I could swear it's given me a higher SOC at a lower voltage at times.

All I really care about is the voltage though

 

[Davexxxx]

I love the Bluetooth voltometer.
I have them on everything.
But it's SOC value can be a bit all over the place too.

12.9V for an AGM is 86%??

I could swear it's given me a higher SOC at a lower voltage at times.

All I really care about is the voltage though

I know you're a data nerd (absolutely not a pejorative ) ... If you wanted to get an idea of that, since you have an LFP in the mix, a shunt based monitor, properly synched to it, would tell you.

 

[Ricksc]

Unfortunately voltage does not stop my truck from sleep mode. That happens with SOC. Will be setting up my OBD mx+ to see what that says on battery

 

[Davexxxx]

Some time in the last few hrs. it turned solid green. Batt voltage = 13.05

 

[Davexxxx]

Just realized that the original question in the title, was never answered.

Every time I checked both batteries, they didn't vary by even a hundredth of a volt so, without some variance to give a clue, the only way I'd know to focus on either battery, would be disconnect them from the truck and load test them, which I didn't do.

I think ultimately what happened this time, was I over taxed the batteries, by unknowingly triggering the truck with the fob, repeatedly, over hours.

I've gotten a couple PMs about my charging strategy. Yes, it really is that simple. Yes, it really worked that well. No, there were no ill effects (that I know of) BUT, it is against Ford's instructions and every safety warning re in vehicle charging. So, enter at your own risk. If you want to get around all that, remove them from the truck, bench charge, re-install and then reset the BMS. No rules broken then.

The new strategy? Let the Genius 2D do it's job, unless and until it fails. The negative wire is connected to the body ground, so the BMS is incorporated into the charge circuit and should count what happens and supposedly, reset itself, over time. We shall see.

 

[Davexxxx]

Update to the update.

At ~1:00 p.m. yesterday, unplugged the Genius 2D (It had been solid green, since the previous afternoon) and did my typical errand run to town and back (16 miles, round trip).

As soon as I got back, popped the hood and the truck has been undisturbed since.

Just now checked and batt V = 12.72.

Double checked for scuff marks on the hood and the unit, finding none. It will fit where I've shown it, mounted as I've done.

I'll be checking things similarly for a while, trying to get a handle on battery depletion to try to time when the truck needs supplemental charging. But if I were to suppose how I'll be doing this once this observation period is over, I'd guess that anytime I don't have plans to drive the truck in the coming days, with the plug routed to the grill, its easy enough to just plug it in, as a preventative measure.

As mentioned before, the only short comings I see of this unit, is the desulfation mode, should have a unique light code and or, a built in bluetooth monitor would be a very useful feature.

 

[flixden]

Did you also turn off the welcome lighting that turns on whenever the key is close?
I just did that on mine. Hoping that every little bit helps!

 

[Davexxxx]

Did you also turn off the welcome lighting that turns on whenever the key is close?
I just did that on mine. Hoping that every little bit helps!

Nope. I want the truck to function as designed.

 

[flixden]

Nope. I want the truck to function as designed.

Well, the welcome lighting is an option, I would look at it as being designed to be turned on or off. I haven't gone camping with the truck yet, but I could imagine the lights to be an issue on a campground in the evening.
But that's a little off topic. Not sure how much it really helps with preserving charge, especially if the keys aren't close to the truck at any time.

 

[Davexxxx]

Well, the welcome lighting is an option, I would look at it as being designed to be turned on or off. I haven't gone camping with the truck yet, but I could imagine the lights to be an issue on a campground in the evening.
But that's a little off topic. Not sure how much it really helps with preserving charge, especially if the keys aren't close to the truck at any time.

Fair enough. I'm not sure turning off the welcome lighting, turns off the other key fob power sucks though.

You can test that easily enough. Since you've turned them off, let the truck sit for a while (30 mins?) with the fob away from the truck, 10-20'. Then move the fob to the truck. If you hear any clicks etc. I don't think you've accomplished much by turning off the lights.

 

[Ricksc]

I turned off the welcome lighting. Waiting to see how it does. Wouldn’t think it would draw that much but every bit counts on these trucks.

 

[Davexxxx]

I turned off the welcome lighting. Waiting to see how it does. Wouldn’t think it would draw that much but every bit counts on these trucks.

Since you park on the street ... Has anyone figured out how to keep the power port live beyond the timer limit?

I have a small, 5W solar panel I used to use to keep the house battery on my Class B charged. Just sitting it in the window was enough.

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