stormsearch

The battery charging section which tmcolegr provided is from the Ford Workshop Service Manual. This is the manual provided to dealerships and service techs. It is not included in the Owner Manual. Ford doesn't publicize the Service Manuals but many sources provide the info.

Any ground point is good preferably other than battery negative post. Any of the ground strap connections in the engine bay work fine. That is Ford's recommendation.

Also noted, for many years, the outgassing of the battery is normally vented out on the negative side of the battery. If confined and a large amount has accumulated, sparks from a charger or jump start clamp can and will ignite this gas. But with newer battery technology and now AGM this is really unheard of these days but still recommended by Ford. In a severe outgassing event, it will be obvious. Anybody who cannot recognize this, smell it, see it, is the reason why we put the verbage in the Owner Manual for the litigation happy country we live in.

For all who are concerned when I'm not at work, here is what I do on vehicles that need a jump start or re-charge 1 or 2/year. I connect the charger and jump start leads directly to the battery negative and positive posts. Very occasional re-charging and giving the BMS system to update after a few days is no big deal. It won't hurt anything, won't pull a code, won't lessen the life of any component. At worst, if you are receiving the shutdown message it will continue to display until the BMS obtains a good reading by sitting overnight.

Connecting jump cables directly to the battery with the hood open and using logic won't do anything. In my 20+ years at Ford, I've never seen "an issue" by doing this. Realize within Ford there are many non-technical/electrical people who work on cars all over our campus and do the same with no ill effect. These are cars which are notorious for weak/dead batteries after testing, troubleshooting, sitting on lots forever, etc.

The most damage I've seen is when somebody puts a dumb charger on a battery. I've seen one battery incident over these years that would get people excited and was due to over-charging. Generally, an over-charged battery will outgas, possibly leak acid thru seams and cause issues in surrounding areas.

BareBonesXL

I had a friend use a lighter to check the electrolyte level in a battery, way back in high school days. The hydrogen gas ignited and blew battery acid up in to his face. It made for a good story, about throwing him in the car and jumping curbs to get to a gas station with a water hose. It was a Friday night, sitting in the shopping mall parking lot.

And hydrogen has no smell so your nose isn't going to give a warning. Sulphuric acid vapor does, but it doesn't burn.

Connecting a battery maintainer to a charged battery won't generate a bunch of current. Connecting one to a discharged battery, or one that needs desulfating might generate some high current. The smart chargers usually have different settings to choose from. Trying to charge or desulfate an old battery might be where some of the overheating comes from. I had an old battery bubbling away using the old Schauer charger. I knew it was almost dead anyway.

Seems like connecting up a battery is about like determining towing capacity. It depends.

rsylvstr

Good Lord. I know it is based on how far down the battery is discharged, but this is crazy. I have a battery tender Junior connected to my 2013, directly to the battery, and it has been on for 24 hours and is still a solid red line meaning it supposedly has not hit 80% charged. Granted, my truck has been sitting for two weeks without being driven, but I would think it wouldn’t discharge that quickly. I should’ve stuck the voltmeter on it before using the trickle charger.

BareBonesXL

You're in the "depends" zone (no offense). One thing that hasn't been mentioned is the capacity of the battery, CCA, versus charge rate of the charger. You have a tiny "tender" (again, no offense), probably on a high capacity battery. 0.75 amps. Low flow trying to fill a big container. My old Schauer charger is a 4 amp charger. Probably why my old almost dead battery was bubbling. You're probably safe from boiling your battery but have to wait for full charge. Your Tender is not a charger, it's a maintainer.

http://products.batterytender.com/Di...12V-0-75A.html

rsylvstr

12.45v at this time.

rsylvstr

rsylvstr

BareBonesXL

Deltran has a ridiculous number of products. If the chargers/tenders are so smart it seems like they wouldn't need so many options. Some even come with a lunch box. I chose the old style 1.25 amp because my last one worked fine and it had a 10 year warranty.

rsylvstr

tvsjr

It's a battery TENDER, not a battery BULK CHARGER. It's intended to keep up with any parasitic battery drain and keep the battery topped off, not bulk charge the battery from a discharged state.

A Group 65 battery is typically around 65Ah. Assuming even 50% depth of discharge, you would need to put 32.5Ah * 1.2 (no charging process is perfectly efficient) = 39Ah into the battery and it would take 39Ah / 0.75A = 52 hours to do that.

Personally, I wouldn't suggest a 0.75A tender for a 65Ah battery. That size is fine for a motorcycle battery or something similar. My Kussmaul charger is 20A into two battery strings, and I have 170Ah total capacity on board.