Correct way of attaching battery maintainer quick connect?

[AnnieWaits]

I sometimes use a Battery Tender to top off or maintain my vehicles' batteries when I am not using them. I have a quick connect for the Maverick and have seen mixed opinions as to where to mount it. Presently, I have it mounted to the battery posts, but I've seen people on the F-150 boards say you should connect the negative terminal on what I would call the "car side" of the battery (which, so far as I can tell, is anywhere other than the negative post), because of what appears to be some sort of battery monitor attached between the negative battery post and the main body ground. Which is correct?

Edited to add: Mine is an EcoBoost with the battery under the hood, I understand the hybrid has jump terminals under the hood, which should make connecting a 12V battery maintainer simpler.

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[Gpp]

Not saying this is right or wrong but if you hook the postive to positive and negative to negative post how can it hurt anything.been doing it like this for 50+ years with no problems

 

[Redneck Garage]

Not saying this is right or wrong but if you hook the postive to positive and negative to negative post how can it hurt anything.been doing it like this for 50+ years with no problems

Ahhh yes - I remember 50 years ago too my first 1970 Maverick. I would get up in the morning grab my coffee, get on the 1970 Maverick Forum on my Packard Bell computer, use my cell phone to check my email , plug in the OBD code reader to check for any problems , get on my Ford app to do a remote start and make sure the hybrid system is 100% ........... possibly technology indeed has advanced a bit since 1970 so there may be some sort of sensor that could be affected by the placement of an external 12v source - hahahahahaha

 

[MakinDoForNow]

Not saying this is right or wrong but if you hook the postive to positive and negative to negative post how can it hurt anything.been doing it like this for 50+ years with no problems

The bms attached to neg post could possibly misread the battery soc depending on what is added to the negative post. The bms changes it's rate of charge as well as the fully charged voltage which varies with of the battery type installed and the age/condition of the battery and most likely also dependent on ambient temp. bms considerations is most likely why the power points and 12v circuits are automatically switched off. Do not blow off the manuals recommendation to not connect anything to negative post directly.

 

[AnnieWaits]

The bms attached to neg post could possibly misread the battery soc depending on what is added to the negative post. The bms changes it's rate of charge as well as the fully charged voltage which varies with of the battery type installed and the age/condition of the battery and most likely also dependent on ambient temp. bms considerations is most likely why the power points and 12v circuits are automatically switched off. Do not blow off the manuals recommendation to not connect anything to negative post directly.

This appears to be correct. I did not check the Maverick's owner's manual before installing the pigtail , but did find a thread on the F-150 boards which linked to a couple of documents that seem to be on point:
https://www.f150forum.com/f118/battery-charger-maintainer-connection-502157/

From the QMV bulletin:
"The 2015MY F-150 battery charge state is determined with a Hall Effect sensor on the negative battery lead. All negative current must pass through this sensor. Failure to do so will result in malfunction of the vehicle charging system and shortened battery life. Do not make direct to battery connections at the negative battery post."

From the 12V battery charging & testing quick reference guide:
"To charge or jump start the vehicle, connect the positive cable to the battery positive post and then connect the negative cable to a vehicle ground and not the battery negative post... Connecting directly to the negative battery post can have an adverse effect on the Electrical Energy Management system..."

Given that, I'm planning to relocate the negative terminal of my quick connect to a body ground.

 

[SLINGSHOT]

Could it be connected to the underhood jump posts? Is there a downside to this?

My RAV4, Yamaha bike and Polaris Slingshot are all on Battery Tenders whenever they are in the garage.

 

[AnnieWaits]

Could it be connected to the underhood jump posts?

Yes, on the hybrid--I did the same on my Prius. The EcoBoost doesn't have jump posts since the battery is under the hood, and I probably should have been clearer in my original post that I was referring to the EB's battery configuration. I'll go back and edit it if it will let me.

 

[MakinDoForNow]

This appears to be correct. I did not check the Maverick's owner's manual before installing the pigtail , but did find a thread on the F-150 boards which linked to a couple of documents that seem to be on point:
https://www.f150forum.com/f118/battery-charger-maintainer-connection-502157/

From the QMV bulletin:
"The 2015MY F-150 battery charge state is determined with a Hall Effect sensor on the negative battery lead. All negative current must pass through this sensor. Failure to do so will result in malfunction of the vehicle charging system and shortened battery life. Do not make direct to battery connections at the negative battery post."

From the 12V battery charging & testing quick reference guide:
"To charge or jump start the vehicle, connect the positive cable to the battery positive post and then connect the negative cable to a vehicle ground and not the battery negative post... Connecting directly to the negative battery post can have an adverse effect on the Electrical Energy Management system..."

Given that, I'm planning to relocate the negative terminal of my quick connect to a body ground.

. I am thinking I read somewhere that after charging battery with a charger other than the onboard charger the BMS reset procedure should be done so the BMS can determine the true SOC of the 12v battery and not what may have been stored in memory the last time the truck was powered down. I am thinking I will install a noco genius5 charger in my hybrid although the noco genius10 has more features and if the battery SOC will allow a higher charge rate at the current temperature. Do not remember but maybe the genius 10 can charge battery over a wider temperature range. In central Texas the 5 will handle the maverick 12v battery but I have a much larger battery on the diesel tractor and the 10 would be better for it. I would prefer to hook the noco to the hood jump posts but am concerned about a voltage drop that could cause the Noco to misread the SOC of the battery? So IF the drop was 0.1 volts would the charger then over charge the battery by that voltage. Some batteries are very sensitive to any overcharging. Maybe the extra $$ cost to have Ford install charger would be worth it just to insure it was done "by the book"?

 

[AnnieWaits]

. I am thinking I read somewhere that after charging battery with a charger other than the onboard charger the BMS reset procedure should be done...

The info I read said the BMS reset should only be done when installing a new battery--I think the Maverick counts discharge cycles or something, which obviously shouldn't be reset if you're keeping the same battery.

As to your other questions, I have had a Battery Tender Plus for 10+ years now, and I think I've had three warranty replacements during that time (the 10 year warranty is now expired). IIRC, two just died with no charging and no lights, and one blew a capacitor or something in such a way that the electrolyte stunk up my garage for at least a week. For that reason, I don't really recommend that brand, and may not buy another one in the future, but I do have a lot of their compatible hardware in terms of quick connects, extension cables, and clamps, so would probably buy or make an adapter if I went with a different brand of maintainer in the future.

 

[desmobob]

I have always had a couple of the large wall-wart size Battery Tenders around the shop with several sets of quick-connects for the lawn tractor, motorcycle, snowmobile, and boat. I find that they are reliable UNTIL you drop them; even just a foot or two... that seems to either kill them or make them malfunction.

Anyway, I would definitely attach the positive to the battery and the negative to a good ground. There is just too much sensitive electronic stuff onboard these days to risk doing anything other than what the manual or tech folks recommend.

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