How low can you run the battery voltage?

[Hopeless Diamond]

So lucky me, alternator failed here in Moab. Of course dealer doesn't have one, or the additional one time use parts needed for the replacement. Gonna just have second battery and swap it out as we go home, charging in a friend's truck. It's a Ranger Tremor so it uses the same battery too . Just want to figure out how low to run the battery down before we run into problems.

Sponsored

 

[Jdc]

https://northeastbattery.com/batter...charging your lead,to the memory effect issue.

1. Do I need to completely discharge my lead acid battery before recharging it?

This is a hard and fast NO. By fully discharging your lead acid battery, or even discharging it below 80% of its rated capacity, you could damage the battery.

The belief that a battery needed to be fully discharged before recharging goes back to the memory effect issue. (See question 1.) Since that is no longer an issue (and never was an issue with lead acid batteries) there is not a need to fully discharge.

By discharging a lead acid battery to below the manufacturer’s stated end of life discharge voltage you are allowing the polarity of some of the weaker cells to become reversed. This causes permanent damage to those cells and prevents the battery from ever being recharged.

 

[Jdc]

https://www.powertechsystems.eu/hom...t=Even if you are going,less than 2 years use.
Lead Acid battery downsides
1/ Limited “Useable” Capacity
It is typically considered wise to use just 30% – 50% of the rated capacity of typical lead acid “Deep Cycle” batteries. This means that a 600 amp hour battery bank in practice only provides, at best, 300 amp hours of real capacity.
If you even occasionally drain the batteries more than this their life will be drastically cut short.

 

[rtaylor]

That sucks. If you are planning to make it all the the way back to WA, you would probably need to swap the battery 10-20 times (not practical). Also, there is a high risk of throwing engine fail codes if you start or run with low battery. I think you would be better off renting a tow dolly and pulling it behind the ranger.

You could also check with large dealers in wasatch front (SLC through Ogden) to see of they have part.

 

[Hopeless Diamond]

Yeah, Moab dealer looked at entire region and not everything was local.

Total of seven of us (3 kids) so not viable to tow it back.

We're going to try and run a charger off the Ranger inverter on one battery. Just do a rotation, Bronco gets too low, we swap in the Ranger battery, and then the charger battery goes in to the Ranger. Rinse and repeat as necessary.

If this doesn't work, we leave it at a SLC dealer and fly home.

 

[Lifeliberty]

Damn, that sucks. Good luck. Be safe. Might be better to fly with kids, or rent a car, and have AAA

I was thinking today that the bronco doesn't have a voltmeter for the battery, just the alternator.
I wish you could tell how much juice you had in your battery(like you can a phone).
Is there a way to tell I don't know about?
Otherwise, how are you going to know when to swap batteries?

 

[Hopeless Diamond]

Yes, there are gauges that show voltage, so I'll be watching it the whole way

Obligatory picture...

 

[LockedBronco]

Yeah, Moab dealer looked at entire region and not everything was local.

Total of seven of us (3 kids) so not viable to tow it back.

We're going to try and run a charger off the Ranger inverter on one battery. Just do a rotation, Bronco gets too low, we swap in the Ranger battery, and then the charger battery goes in to the Ranger. Rinse and repeat as necessary.

If this doesn't work, we leave it at a SLC dealer and fly home.

You may end up with a second bad alternator in the Ranger.

 

[LockedBronco]

Picking up 2 or 3 batteries and switching them out as needed MAY work. Once voltage around 11v possible 10.5v , the computer is going to go nuts.

That being said because of all the electronics there is no telling what may happen. All the computers will be fitting for voltage and you may cause more damage then just a bad alternator and battery.

 

[Jazer]

It's been just over 6 months since my alternator stranded me in the middle of an intersection. I was almost to the dealer so I tried to make it there (literally had less than a mile left). Had I known it was the alternator I would have had it towed, but I thought it was a battery issue so didn't think it'd die on me. Once my voltage started dropping I was already committed and didn't have far to go so hoped I'd make it.

My memory is a lil hazy on what happened exactly when.. but it started giving me charging error alerts while still in normal range, obviously the system detected the problem, which you know you have. I'd say I made it a total of 20 miles from the initial error to complete death. Give or take. I started losing systems in the 10-11v range. Media screen, cameras, etc. Then power steering is next. Once you lose that, failure is imminent, in probably a mile or so. I believe it completely died between 8.5-9v.

Personally I would get it towed.

 

[SS Bronco]

There has to be a shop that rebuilds alternators in the greater Salt Lake City area. Good luck on your journey.

 

[kodiakisland]

Last time I had to run a vehicle off the battery, it was at night and had to use the headlights. Got about 25 miles out of a battery. Ruined two batteries, but made it home.

 

[BAUS67]

It's been just over 6 months since my alternator stranded me in the middle of an intersection. I was almost to the dealer so I tried to make it there (literally had less than a mile left). Had I known it was the alternator I would have had it towed, but I thought it was a battery issue so didn't think it'd die on me. Once my voltage started dropping I was already committed and didn't have far to go so hoped I'd make it.

My memory is a lil hazy on what happened exactly when.. but it started giving me charging error alerts while still in normal range, obviously the system detected the problem, which you know you have. I'd say I made it a total of 20 miles from the initial error to complete death. Give or take. I started losing systems in the 10-11v range. Media screen, cameras, etc. Then power steering is next. Once you lose that, failure is imminent, in probably a mile or so. I believe it completely died between 8.5-9v.

Personally I would get it towed.

I'm surprised you made it 20 miles. Most of the new computer controlled vehicles you are lucky to make it 5 miles, too much draw for the battery. In the old carb days you could run for days without an alternator, virtually no draw.


For the record the Bronc used an AGM battery. This is different than your standard lead acid battery. AGM stands for Absorbent Glass Mat. Which means the "acid" is absorbed into a glass mat. No acid to spill out. Similar to an Optima battery. The wife's 22 Explorer Timberline has the same.



2022 Ford Bronco Tech Specs

Ford
https://www.ford.com › suvs › bronco › pdf



Battery group. H7 AGM 80 AH 800 CCA.

 

[Jazer]

I'm surprised you made it 20 miles. Most of the new computer controlled vehicles you are lucky to make it 5 miles, too much draw for the battery. In the old carb days you could run for days without an alternator, virtually no draw.


For the record the Bronc used an AGM battery. AGM stands for Absorbent Glass Mat. Which means the "acid" is absorbed into a glass mat. No acid to spill out. Similar to an Optima battery. The wife's 22 Explorer Timberline has the same.



2022 Ford Bronco Tech Specs

Ford
https://www.ford.com › suvs › bronco › pdf



Battery group. H7 AGM 80 AH 800 CCA.

It's possible it was still providing some charge when I got the initial warning message (low power mode and wanting to preserve power). This was a bad voltage regulator from the factory. Not due to off-roading or mud, etc.

I drove 5 miles home. I did some research that night trying to figure out the best means of troubleshooting and it was holding a charge that was equivalent to one cell being bad in the battery so I ASSumed this was a likely culprit and therefore would be safe to drive it to the dealer in the morning. That didn't work out well, lol. Once I was back on the road I watched the digital display slowly tick down 🫣

Looking at the map now that dealer is 13 miles away, so I made it about 12 more. So about 17 miles from first symptom to sudden death

 

[orion]

Buy a hitch basket, a cheap generator, a battery charger, and an extension cord. I'm sure you can figure out the rest, it may be cheaper than flying home and your Bronco will stay with you. Pretty hillbilly but it should work...

Sponsored