Battery maintainer in vehicles with dual batteries

[GON]

The Ford app sent me a message that my 2919 F350 with dual batteries is turning off its Internet monitoring program due to low battery voltage.

The F350 has been parked for a month. A smart battery maintainer is hooked up to one of the two batteries.

So, I am guessing either the battery maintainer has become unplugged or failed, or that the battery maintainer only charges the battery that the maintainer is connected to,- not both batteries. And the battery that powers the Internet monitoring of the vehicle is not the battery with the maintainer connected.

Am I missing anything in my analysis of the situation?

 

[Jetronic]

just to be clear, it's a 12V system with 2 batteries in parallel, right?

In that case the maintainer isn't maintaining. If it's a 24V system, you need 2 maintainers, or a 24V one hooked up correctly.

 

[GON]

just to be clear, it's a 12V system with 2 batteries in parallel, right?

In that case the maintainer isn't maintaining. If it's a 24V system, you need 2 maintainers, or a 24V one hooked up correctly.

It's two twelve volt batteries, providing 12v output, not 24 volts. I don't know if one battery powers certain items, or if both batteries simple provide double amperage.

 

[LazyDog]

The battery's might also be weak, how many amps on the maintainer?

 

[eljefino]

My RV had a house battery and a starting battery, both underhood, with the house battery isolated with the key off. But if you have, say, a diesel, you'll have them both paralleled, and both will charge off that little wall wart.

I assume the vehicle is some distance from you, and hard to check on?

 

[GON]

The battery's might also be weak, how many amps on the maintainer?

Both batteries were fully charged a month ago. Have a one amp smart charger as the battery maintainer.

 

[ctechbob]

One amp isn't enough for two big diesel batts. Probably need at least a 5 amp charger for that. I know Noco doesn't recommend their 1 amp charger for full sized car batts (Even though it does work).

But yes, those batteries are just connected in parallel. Only need to connect to one of them, although there will be a (very) slight voltage loss across the cables, it should be negligible.

 

[LazyDog]

You might have to switch the maintainer to the other battery. I wonder how many amps is the monitoring system pulling.

 

[GON]

One amp isn't enough for two big diesel batts. Probably need at least a 5 amp charger for that. I know Noco doesn't recommend their 1 amp charger for full sized car batts (Even though it does work).

I didn't know that.... I am using a noco as not to overcharge the battery, my course of action may be flawed.

 

[ctechbob]

I didn't know that.... I am using a noco as not to overcharge the battery, my course of action may be flawed.

The Noco's are pretty good at maintaining, you could use the 5 or 10 even and be just fine.

 

[ctechbob]

The Noco's are pretty good at maintaining, you could use the 5 or 10 even and be just fine.

Also.

When I was babysitting mom's Maverick this past year, it stayed on a Noco1 and the truck would still shut itself off after about 14 days. It would just say something like 'features are disabled to conserve power'. The battery was still perfectly charged, I guess it just works on a timer.

 

[GON]

Also.

When I was babysitting mom's Maverick this past year, it stayed on a Noco1 and the truck would still shut itself off after about 14 days. It would just say something like 'features are disabled to conserve power'. The battery was still perfectly charged, I guess it just works on a timer.

Thanks, that is a super helpful reply and the message you received is a like message I received. Maybe the power down is not monitored by battery voltage, but simply by idle days.

 

[ctechbob]

Thanks, that is a super helpful reply and the message you received is a like message I received. Maybe the power down is not monitored by battery voltage, but simply by idle days.

Just have to check the voltage and see if the Genius1 is keeping up. Still might not hurt to get a 5/10 for it. Especially as the temps go down.

 

[SC Maintenance]

I believe 1A should be enough. Even a typical large car battery is maybe 75-100 Ah. So 1A charger will put out 24Ah per day. No way a healthy battery or healthy system pulls more than 1A. However running a little Noco at 1A continuous likely will kill it over time?

How exactly is it set up? Do you have the batteries paralleled and the truck is connected directly to only one battery? Where is the charger connected? I wonder if one is taking most of the charge due to internal resistance or something then the charger thinks its full and stops. Unsure how that would happen, but the whole thing is odd.

 

[GON]

I believe 1A should be enough. Even a typical large car battery is maybe 75-100 Ah. So 1A charger will put out 24Ah per day. No way a healthy battery or healthy system pulls more than 1A. However running a little Noco at 1A continuous likely will kill it over time?

How exactly is it set up? Do you have the batteries paralleled and the truck is connected directly to only one battery? Where is the charger connected? I wonder if one is taking most of the charge due to internal resistance or something then the charger thinks its full and stops. Unsure how that would happen, but the whole thing is odd.

I am.not sure how Ford configures the batteries. The truck has only one alternator. But I didn't research if the batteries provided double amperage, or power different systems.

 

[Jetronic]

It's two twelve volt batteries, providing 12v output, not 24 volts. I don't know if one battery powers certain items, or if both batteries simple provide double amperage.

It doesn't matter if the 2 positives are connected, which you could always do if it's not. It acts like 1 big battery.

 

[John105]

just to be clear, it's a 12V system with 2 batteries in parallel, right?

In that case the maintainer isn't maintaining. If it's a 24V system, you need 2 maintainers, or a 24V one hooked up correctly.

Never thought about it before when it comes to a vehicle/truck. I remember in the old days, our data center battery backup had 10 batteries connected in series to provide 120V.

 

[SC Maintenance]

It doesn't matter if the 2 positives are connected, which you could always do if it's not. It acts like 1 big battery.

Unless Ford included some sort of isolation so one doesn't drain the other if one goes dead?

 

[ctechbob]

Unless Ford included some sort of isolation so one doesn't drain the other if one goes dead?

The last SuperDuty I looked under the hood of they're just straight up connected in parallel. Nothing goofy between them.

Although.

Ford gonna Ford, but I doubt they would put the money into another big relay in the truck.

 

[ctechbob]

I believe 1A should be enough. Even a typical large car battery is maybe 75-100 Ah. So 1A charger will put out 24Ah per day. No way a healthy battery or healthy system pulls more than 1A. However running a little Noco at 1A continuous likely will kill it over time?

How exactly is it set up? Do you have the batteries paralleled and the truck is connected directly to only one battery? Where is the charger connected? I wonder if one is taking most of the charge due to internal resistance or something then the charger thinks its full and stops. Unsure how that would happen, but the whole thing is odd.

Thing is you have parasitic losses in the cables as well as the batteries. They don't convert 100% of the incoming current to charge. There is loss there as well.

I was incorrect with one thing. I thought I remembered Noco putting a limit on the charger:

Looks like that is just for charging, maintaining they seem to think it would be ok. Still, with temps dropping he's probably better off with a bit bigger unit.

I am also not taking my own advice. I have a Genius1 in the garage on a Marine battery and a backup group 35 in parallel. Although there's nothing hooked to them, the cables are short, etc. Plus they're not mission critical, I'm not depending on them to crank anything.