Battery tender leads thru charge port cover

[Big guy]

I want to route my battery tender leads thru the area of the charge door. I will hard wire the leads to the correct battery connection points. I can't see what's behind that area so I'm a little concerned about where to drill the hole so I don't cause any damage. Any chance someone has a picture of that area from the inside to show where NOT to drill?

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[Robert1380]

I want to route my battery tender leads thru the area of the charge door. I will hard wire the leads to the correct battery connection points. I can't see what's behind that area so I'm a little concerned about where to drill the hole so I don't cause any damage. Any chance someone has a picture of that area from the inside to show where NOT to drill?

One of the guys here (think it was Chi) just showed his done but not sure how he did it. I’ll be watching for this as well.

 

[Steely]

Curious what the need is for the battery tender? If the truck is on the charger will it wake up to charge the 12v as needed if it is not actively charging?

If you set your charge limit to 50% and plug it into the EVSE and leave it like that for a year, shouldn't the truck wake up to charge the 12V as needed and keep the HV battery temperature controlled and healthy?

 

[flabrent]

Curious what the need is for the battery tender? If the truck is on the charger will it wake up to charge the 12v as needed if it is not actively charging?

If you set your charge limit to 50% and plug it into the EVSE and leave it like that for a year, shouldn't the truck wake up to charge the 12V as needed and keep the HV battery temperature controlled and healthy?

From what I've read on this forum there are several "gremlins" that appear from a low charge 12v battery. One of the main issues seems to be missing software updates.

 

[bmwhitetx]

I want to route my battery tender leads thru the area of the charge door. I will hard wire the leads to the correct battery connection points. I can't see what's behind that area so I'm a little concerned about where to drill the hole so I don't cause any damage. Any chance someone has a picture of that area from the inside to show where NOT to drill?

If your 12V battery is regularly draining to the point that you have to put it on a battery tender then something else is wrong and you should solve that issue. I drive and charge very little (13K miles in 3+ years, average 10 days between charging sessions) and my 12V gives me no trouble.

I considered this mod two years ago when my truck was having trouble installing updates. But the BMS fix in Jan '24 helped a lot and I haven't had issues since.

 

[chl]

One of the guys here (think it was Chi) just showed his done but not sure how he did it. I’ll be watching for this as well.

Yes. well, I opend the Frunk and looked down next to the charge port area from the side, used a flash light, also stuck my arm in there and could feel the hinge area and the charge port enclosure (inside of which is the HVB charging wiring) and I could feel that there was a good sized area next to the hinge that could be safely drilled through.

Also I saw someone did this before, so felt very confident about it.

I routed the wire so as to avoid and chance the Frunk mechanism would harm it - there are other line in there to follow. The found an empty space through which to pass the wire into the battery compartment - looking from the battery compartment towards the charge port and you can see it.

The wired it to the correct 6mm screw posts - for the negative connected downstream from the BMS (blue circles not red x's):

Use a fused wire between the battery positive and the connection for the trickle charger just to be safe - need about a 5ft one:

See also this guy's install:

https://www.f150lightningforum.com/forum/threads/charging-12v-battery.16979/

 

[chl]

You should update your Account details - Vehicles to include you own a Lighting - and the year and trim, e.g. 2022 Lariat.

If your 12V battery is regularly draining to the point that you have to put it on a battery tender then something else is wrong and you should solve that issue. I drive and charge very little (13K miles in 3+ years, average 10 days between charging sessions) and my 12V gives me no trouble.

I considered this mod two years ago when my truck was having trouble installing updates. But the BMS fix in Jan '24 helped a lot and I haven't had issues since.

Yes the fixes (hardware and software) helped, but every lead acid battery lasts longer on a trickle charger, and batteries are not cheap anymore.

I have my 2012 Nissan Leaf 12v on a trickle charger (bought the Leaf Dec 2011) and the 12v batery is still going strong - they love to be at 100%.

Just be sure to use one with an AGM setting - AGMs are a bit different from regular 'wet' lead-acid batteries.

 

[chl]

All 12V lead-acid batteries prefer to be kept at a high state of charge, ideally 100%
to prolong their lifespan. Deep discharges cause sulfation on the plates, which can permanently reduce the battery's capacity over time.

How to maintain a high state of charge

• Avoid deep discharges: Discharging a lead-acid battery deeply and for a prolonged period can lead to the formation of hard sulfate crystals on the plates, which are difficult to dissolve.
• Use a proper charger: A proper charger will automatically bring the battery to a full charge and can be left connected to the battery to maintain a full charge without damaging it.
• Monitor voltage: A fully charged 12V lead-acid battery should have a resting voltage of around 12.6V to 12.8V. If it's lower, it's a good idea to charge it.
• Consider trickle charging: For batteries in storage, a trickle charger can be used to continuously keep the battery at 100% charge, preventing self-discharge from reducing its life.

For more information on charging lead-acid batteries, you can read Battery University's article "BU-403: Charging Lead Acid".

You can also watch this YouTube video for a visual guide on the charging process. For a detailed explanation of how to check your battery's health, you can watch this YouTube video .
-----
12V AGM lead-acid batteries prefer to be at 100% charge to maximize their lifespan and prevent sulfation. While they can be discharged, it's crucial to recharge them to 100% as soon as possible after use, as prolonged periods at a lower state of charge can cause irreversible damage.

Why full charge is important

• Prevents sulfation: Leaving an AGM battery partially discharged for too long allows a process called sulfation to begin, which forms hard sulfate crystals on the plates that reduce the battery's ability to hold a charge and decrease its overall performance.
• Maintains capacity: Consistently failing to fully charge an AGM battery will lead to a permanent loss of its charge capacity over time.
• Optimizes performance: A fully charged battery operates at its peak efficiency and performance level, so regularly reaching 100% is best for its health.

Best practices for charging and use

• Keep it topped up: If the battery is in regular use, aim to keep it fully charged as much as possible.
• Charge promptly: If you discharge the battery, recharge it to 100% as soon as you can.
• Don't over-discharge: While AGM batteries are often deep-cycle batteries, it is best not to discharge them below 50% to extend their life. Never discharge below 20%.
• Store properly: When storing the battery, keep it in a cool, dry place and disconnect it from any equipment. It should also be fully charged before storage and checked periodically.

For more detailed information on charging strategies for different applications, you can explore guides from Battery University and Crown Battery (at links above I think).

 

[Big guy]

Yes. well, I opend the Frunk and looked down next to the charge port area from the side, used a flash light, also stuck my arm in there and could feel the hinge area and the charge port enclosure (inside of which is the HVB charging wiring) and I could feel that there was a good sized area next to the hinge that could be safely drilled through.

Also I saw someone did this before, so felt very confident about it.

I routed the wire so as to avoid and chance the Frunk mechanism would harm it - there are other line in there to follow. The found an empty space through which to pass the wire into the battery compartment - looking from the battery compartment towards the charge port and you can see it.

The wired it to the correct 6mm screw posts - for the negative connected downstream from the BMS (blue circles not red x's):

Use a fused wire between the battery positive and the connection for the trickle charger just to be safe - need about a 5ft one:

See also this guy's install:

https://www.f150lightningforum.com/forum/threads/charging-12v-battery.16979/

 

[Big guy]

Thanks Chi. I think we all know the best thing for long term storage on a normal 12volt battery is something like a Battery Tender. We sometimes go away in the Winter and leave the truck plugged in inside the garage. After hearing stories on this site about sometimes OA updates might not go thru if 12v battery is too low or if 12V battery is stone dead you can't get in the truck and have to get to the battery thru the Frunk to charge it. No need if I keep a battery tender on it when we are out of town. Putting the leads inside the charge door looks and works the best in my mind. Thanks again.

 

[Maquis]

Thanks Chi. I think we all know the best thing for long term storage on a normal 12volt battery is something like a Battery Tender. We sometimes go away in the Winter and leave the truck plugged in inside the garage. After hearing stories on this site about sometimes OA updates might not go thru if 12v battery is too low or if 12V battery is stone dead you can't get in the truck and have to get to the battery thru the Frunk to charge it. No need if I keep a battery tender on it when we are out of town. Putting the leads inside the charge door looks and works the best in my mind. Thanks again.

The owners manual has instructions for long-term storage. The use of a battery tender is not mentioned in there.

 

[chl]

The owners manual has instructions for long-term storage. The use of a battery tender is not mentioned in there.

Right I think it says to completely disconnect the 12v battery if it is for a long time.
And to put the HV battery at around 40-50%.

If you completely disconnect the 12v, when you reconnect there is a procedure you have to go through to recalibrate the battery control system - it is described on this forum somewhere if you plan to do that.

When I first got the truck I did not have an AGM trickler and had a trip planned so my truck sat for several weeks in the winter - I did make sure the HV was 40%.

When I came back started right up, but it may have run the 12v down a bit low because later that year I had trouble getting an OTA due to low SOC.

I used the long charge method I had read about on the forum and that worked. Then I got the trickle charger.

There are several ways to solve the OTA problem due to 12v battery that were post on the mach- forum:

https://www.macheforum.com/site/threads/how-to-get-failed-otas-to-install.29749/

 

[Big guy]

If I use a battery tender the 12v will always be charged and I wont have to worry about it. If the battery goes dead/bad and I follow Ford instructions I have to get the frunk open,crawl into the frunk to pull the battery cover to connect a charger. Or release multiple retainers to remove the access panel on the right side to access jump points.

Or just leave a battery tender on it and not have to worry about it.

Thanks for your feedback.

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