Round-the-clock battery maintenance- good or bad?

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I have NOCO GENM1 4-Amp on-board charger/maintainer installed under the hood of my Tahoe. It is a part of the offshore 120V power devices grid on the car that are connected to power through wifi timers, so I can control the timing and what devices are on from the house.

The truck is parked outside, and is plugged in through the waterproof AC port plug mounted under the rear bumper.

The charger is on by default when other devices are on (transmission and engine heater pads, interior heater, seat heaters, etc). I also turn it on overnight once a week to run a full cycle.

The truck sits most of the time, and when it is in use, its smart charging system detects that the battery is fully charged and drops the voltage to 12.6V while driving.

I was wondering if it would be helpful at all to run the charger like that 24/7? Would it be helpful or detrimental to the battery life? It is a smart maintainer, after all.
What about when the ambient temperature drops to -10C? Or -20C?
I just don't want to do too much of a good deed...
 
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Shouldn't be something to worry about, if anything it will prevent sulfation. I have an OptiMate 7 Select. If a car is not going to be used for a while, I leave it connected for a couple of days or so. In maintenance mode, it continually monitors the battery and adjusts voltage accordingly. Being a smart charger/maintainer, I'm sure the Noco works the same way.
 
personally I dont see an issue, what's the difference between this and keeping the battery on a battery tender outside of the vehicle. If it was stored, the battery would be having the same thing happen.

But a battery tender is charging the battery at room temp (inside). I think at a certain temp even batteries (lead-acid) can freeze and you don't want to charge them then! ouch!
 
Thank you guys! Regarding low-temp conditions, maybe the battery blanket should be the next thing? It can be turned on through thermostatic switch whenever the maintainer is on. What do you say?
 
I should or you can too, look up what the minimum temp for charging a lead acid battery is.

but warm it up isn't a bad idea.
 
Originally Posted By: yugrus
its smart charging system detects that the battery is fully charged and drops the voltage to 12.6V while driving.


That's not right at all.....
 
Well, that's what most of the new owners of this family of trucks say when they see the needle going to the left of the scale. Some begin to panic. But in fact, this is perfectly normal. ECU monitors the charging process very closely, using the voltage AND the current information. There is in fact the current measuring loop on the main wire.
Besides it's intended purpose to be able to claim fuel consumption reduction, the system protects the battery from overcharging. It kicks right back in when the battery charge becomes depleted. The voltage isn't constant and varies according to the charging demands.
On the other hand, our Mazda, with its hi-tech Skyactiv has a very dumb charging system, with 14V+ no matter what the conditions are. Go figure. ..
 
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Sounds brilliant. As an added bonus shore power is 10-15x cheaper than that you generate yourself via gasoline. Just sad that your truck comes to this-- they should sense winter and not pull MPG shenanigans.
 
Originally Posted By: eljefino
Sounds brilliant. As an added bonus shore power is 10-15x cheaper than that you generate yourself via gasoline. Just sad that your truck comes to this-- they should sense winter and not pull MPG shenanigans.


I think you had better review your numbers. Around here, only the off-peak residential electric rate is less expensive than gasoline power and it's a close call for that.

The trade-off will obviously vary with rates and efficiency, but it's certainly not 10x-15x.

Smart chargers vary considerably in their 'smarts'. I would check that your specific model compensates for the temperature and battery chemistry correctly.

Battery charge optimization has been around for at least a quarter century. A basic version was on Japanese alternators that used the brake light circuit to increase output. That would increase engine braking when slowing down, and reduce the engine load when pulling away after stopping. Modern versions are similar, which much more information available. They can target a state-of-charge range that maximizes the battery life, not always pushing to 100% charged.
 
I back into the driveway, and I need to literally trip over the cord to get in the truck, so no concern of driving away with it attached.
The charger does not have temperature compensation. It was intended for marine applications. Does that mean that it will overcharge the battery at the temperature extremes? I already have plans for thermostatic battery blanket, so this mitigates the low-side concern, but still.

Going down to -10C, would un-changed rate of charge be detrimental to the battery life?
 
Not scientific but the battery on my John Deere 4310 the tractor lasts 2 years without a charger and 7 years with a msintenance charger.
 
just a quick question. How cold does it have get to freeze a lead acid battery with a charge in it? It was my understanding that a charged battery , even a low charge, can't freeze. School me please. TIA
 
Originally Posted By: andyd
just a quick question. How cold does it have get to freeze a lead acid battery with a charge in it? It was my understanding that a charged battery , even a low charge, can't freeze. School me please. TIA


There is a good analysis here: http://mathscinotes.com/2013/02/battery-freezing-math/

The freeze point is quite low...and I think only people in very northern climates need to worry.
 
For the past couple years I have had 2 NOCO G3500 chargers hooked up to my E450 and KLR with no issues. One benefit of my NOCO is that it has a cold weather mode (
Since my factory E450 battery was 5 years old I replaced it this fall with a new Interstate and it's been hooked up since new.
 
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Originally Posted By: djb
Originally Posted By: eljefino
Sounds brilliant. As an added bonus shore power is 10-15x cheaper than that you generate yourself via gasoline. Just sad that your truck comes to this-- they should sense winter and not pull MPG shenanigans.


I think you had better review your numbers. Around here, only the off-peak residential electric rate is less expensive than gasoline power and it's a close call for that.


Cool! Let's do it. Say a Honda EU2000 inverter generator on eco-mode goes 8 hours on 1 gallon of gas. Also assume they were getting 1000 watts out of it on average (high!)


8000 watt-hours/ gallon
.8 kWh/ gallon
.8 kWh/ $2.25 price per gallon
1.00 kWh/ $2.50 worth of gas
vs 1.0 kWh/ $.15 on shore power

Now for a car:

1 kWh = 3413 Btu.
115000 btu/ gallon of gas
Engine is 25% thermally efficient
Alternator is 55% electrically efficient
115000 * .25 * .55 / 3413 = 4.63 usable kWh in every gallon of gas
$2.25/ 4.63 = 48.6 cents/ kWh running on gas.
 
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