Hybrid Battery Rundown Solution - Battery Tender ($55 total) w/Installation Photos

[mwbaumannmo]

My Maverick is only 4 months old, but I've read quite a bit on the primary battery getting run down. Even though a 2025 model with a U.S. made FoMoCo battery, I didn't want to start down the whole battery replacement road.

Bought a battery monitor set that has a remote BT monitoring panel. Easy attachment to the battery in 2 minutes. Monitor panel can go anywhere within 30'.
https://www.amazon.com/dp/B0DGQH5S1H?ref=ppx_yo2ov_dt_b_fed_asin_title

Also got a battery tender as the truck may sit for 5-7 days.
I can plug in the tender and it charges up the battery up to ~14.0 volts, then shuts off. It will kick back on around 12.8-9 volts and refresh the battery.
https://www.amazon.com/dp/B074KK8RCW?ref=ppx_yo2ov_dt_b_fed_asin_title

Photos are below on complete easy installation which took 20 minutes to figure out best way to install. I used the plug-in connector and attached to the primary battery terminal under the hood. Was also able to route the connector out the left front fender well for charging when needed. There is also a little pocket in the fender well around 10 o'clock that allows the cord to be perfectly tucked in for storage.

Still learning more about the simple battery tender and the charging routine. Peak current is 1.5Amps.

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[HeyBales]

So you can have the Monitor outside the truck, to see about watching when usage drops, or spikes, after turnoff? (so no door open that resets the clock)
Does it log thru time, that you can get the logs if needed?

 

[mwbaumannmo]

1. Yes,I keep the display on the tonneau back corner so I can view the voltage before opening doors or the key getting triggered. When driving I put in the console to monitor the battery. Will continue to keep external until I know the trending and behavior of the truck charging/rundown. My thoughts are to eventually just put the remote battery display on the garage wall by the driver's door to check before getting in, and after getting out and all lights go out. That will let me know if I need to plug in the battery tender.

2. The primary battery starts getting charged after 3 seconds from turning on the truck and still in Electric mode. Even with no gas engine sound, the EV battery starts charging the primary while driving away from home slowly in Electric mode. The voltage goes up to ~14.5V right away after vehicle is turned on.

3. This monitor does NO LOGGING, only realtime. There may be more expensive units to chart the variances.

4. The ultimate goal is to only plug in the battery tender when I expect the truck to sit for 2+ days.

Note - The CRANKING VOLTAGE on the display still reads Zero after driving 6 times, probably because the voltage level doesn't drop enough yet with a new battery to be recognized as a start event. Also, the truck always goes into electric mode after turning on (and starts charging the primary battery). The gas engine rarely runs initially after vehicle turn-on.

 

[icegradner]

You seem to have the positive on the wrong post under the hood. The correct one is under the red cover.

 

[mwbaumannmo]

You seem to have the positive on the wrong post under the hood. The correct one is under the red cover.

The positive is essentially on the main battery cable under a small black flip cover. The black cover post I used is a hard connection to the red jumper post. I didn't want to have the ring terminal in the way of the other jumper post (Red flap) for jump starting. I left the factory nut on the cable torqued down, and added an addtional washer/nut to go over the primary nut. Purchased charger cable also has an inline fuse with a 3 amp.

 

[EffNo50]

CRANKING VOLTAGE will not show as the 12v battery is not used to crank the engine, it uses the HVB for that. Also the ICE charges the HVB, not the 12v. The HVB charges the 12v via a DC-DC inverter.

 

[Prickly Pear]

I went to hook up my battery tender the other day but my 20" cable really didn't reach far enough for me to poke out somewhere in the front of the truck. I like your no drill solution!
Can you take a better shot of where the charging cable exits into the wheel well from the wheel side? I can likely poke around and find it but a picture is worth many words. You have a shot from the inside where the cable goes under some insulation - was there just a hole there you used?
I recently bought a tube of dielectric grease that I'll use on my connector as the wheel well is a pretty wet area.

 

[MakinDoForNow]

My Maverick is only 4 months old, but I've read quite a bit on the primary battery getting run down. Even though a 2025 model with a U.S. made FoMoCo battery, I didn't want to start down the whole battery replacement road.

Bought a battery monitor set that has a remote BT monitoring panel. Easy attachment to the battery in 2 minutes. Monitor panel can go anywhere within 30'.
https://www.amazon.com/dp/B0DGQH5S1H?ref=ppx_yo2ov_dt_b_fed_asin_title

Also got a battery tender as the truck may sit for 5-7 days.
I can plug in the tender and it charges up the battery up to ~14.0 volts, then shuts off. It will kick back on around 12.8-9 volts and refresh the battery.
https://www.amazon.com/dp/B074KK8RCW?ref=ppx_yo2ov_dt_b_fed_asin_title

Photos are below on complete easy installation which took 20 minutes to figure out best way to install. I used the plug-in connector and attached to the primary battery terminal under the hood. Was also able to route the connector out the left front fender well for charging when needed. There is also a little pocket in the fender well around 10 o'clock that allows the cord to be perfectly tucked in for storage.

Still learning more about the simple battery tender and the charging routine. Peak current is 1.5Amps.

From what I have read, the connection you have made to the negative post needs to be moved to the other side of the bms so the bms can measure any current the monitor uses. To prevent the bus from miscalculating. The bms should see all of the current you add while charging but the current used by the monitor will disappear and (possibly be considered internal shorting in 12v?).

 

[mwbaumannmo]

This remote/BT added only uses 2mAh (48mAh per day), so I don't have much concern of current draw from the monitor device tainting the BMS calculation.

If Ford were more precise on their battery usage and charging calculations we wouldn't be dealing with any of these battery replacement concerns.

 

[mwbaumannmo]

1. On my 2025 there was a small 3/16" gap in the inner felt fender well that I could see light through. (See photo). I fished the charging wire through this gap. The end connector tucks quite nicely into the indentation of fender well at that location. If you run your finger along the inner fender well you'll find the indentation when the wire can be routed through.

2. The lead wires on my tender were also short. I spliced in another 5 feet of wire so no extension cord is needed.

 

[MakinDoForNow]

So you can have the Monitor outside the truck, to see about watching when usage drops, or spikes, after turnoff? (so no door open that resets the clock)
Does it log thru time, that you can get the logs if needed?

Hey!!! HeyBales
I found this on electric engineering site.
RE: Recovery of 6/12 volt dead batteries:
How much current needed. Initially could be very high voltage but have to monitor temp and fluid levels. Probably explains why have to take battery out of vehicle for a controlled recharger to run REPAIR MODE! Additional time due to temp control of recharger.

Some years ago I've bought this scooter with a dead 6 V Bat; only started with pedal kick. Placed bat in a controlled recharger: 6V times square root 2, roughly 8.5 V. It was a 4AH, so regulated (tried) charge at 10%, thus 400mA; but as bat was dead, had to increase voltage up to 10 or 12V (can't really remember) untill those 400mA could be achieved. At this point, had to monitor liquid inside cells and charging current; almost every 20 minutes or so, had to decrease voltage to obtain correct charging current. Eventualy reached a point where could have 400mA with corredct charging voltage (8.5 V) and always monitoring electrolite in cells. Then, let it sit charging for 14 hours. It became as new. Guess that excess voltage was needed to "break" bad salts in electrodes. Those collegues of mine (electronic professionals) gave these instructions and from that point, always used those references: Square root 2 times bat voltage, at 10% mA for 14 hours.

 

[Prickly Pear]

1. On my 2025 there was a small 3/16" gap in the inner felt fender well that I could see light through. (See photo). I fished the charging wire through this gap. The end connector tucks quite nicely into the indentation of fender well at that location. If you run your finger along the inner fender well you'll find the indentation when the wire can be routed through.

2. The lead wires on my tender were also short. I spliced in another 5 feet of wire so no extension cord is needed.

Thanks for that - I'll poke around and see if my 24 has a similar opening!

 

[scottjl]

this is the monitor i use, doesn't have a display but connects via bluetooth to a phone app. you can get current charge, cranking test, charging test, and track a trip.

https://www.aliexpress.us/item/3256808142796238.html

 

[rivermaverick]

CRANKING VOLTAGE will not show as the 12v battery is not used to crank the engine, it uses the HVB for that. Also the ICE charges the HVB, not the 12v. The HVB charges the 12v via a DC-DC inverter.

Correct, the 12V battery can be charged, jumped or replaced. The concern is the HVB, it will self discharge. Ford recommend running the engine for 15 minutes every 14 days if the vehicle is not being used. Not practical if you are out of the country for months at a time!

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