How long to idle truck to charge battery?

[fiddypal]

Right now I am doing a cross country road trip and will be driving 90% of the time so not a huge worry at the moment. Alot of the trip will also be 1-2 days camping then 1-2 days in hotels so i should be able to live with the limits of my system. I will also be traveling in the fall so i won't have a fridge that's pulling a ton of power 24/7 trying to fight the summer heat so that's in my favor as well. If i end up totally falling in love with expo on this trip, then i will look into solar and more batteries, maybe even a generator.

Thanks for all the feedback so far!

Are there any other batteries with the same width and length as a group 48 but maybe taller? Looking for a bigger battery that will still fit under the hood in the stock spot where my 2nd battery currently sits.

 

[Ducky's Dad]

Are there any other batteries with the same width and length as a group 48 but maybe taller? Looking for a bigger battery that will still fit under the hood in the stock spot where my 2nd battery currently sits.

You can probably get more capacity in a smaller package by going to a Grp 34. Might be able to fit a Grp 65. Your truck is a V6 gasser, right? Two battery boxes on the front core support, one right and one left? Truck came with a battery on one side and the other box empty? Original battery may have been a Grp 34 or 34/78.

 

[peekay]

my experience with a Tacoma is that the alternator certainly is powerful enough in theory for ANY of these cars, including a small 4 cylinder Civic/Corolla. Remember, the amount of energy that you put into the new battery is watt=amp x voltage. The limitation of your alternator, i.e., amps, is really not coming into play. People tend to assume that the alternator is dumping 30-50 amps constantly into the batteries. I don't believe that happens. In fact, I've almost have never seen my aux battery charge at a rate higher than 15amps. Any alternator can easily handle that amperage.

The problem is that the charge voltage seems to drop once the starting battery is close to topping off, i.e., from 14.2 volts initially, to about 13.3-4, when close to topping off. This means that unless you've discharged the starting battery as well, your charge voltage is not going to be very high for very long. Therefore, the rate of charge into your second battery is going to be very slow. This is compounded if you have kinda thin wires connecting the two batteries, resulting in further voltage drop.

 

[fiddypal]

Ducky - Spot on, its a V6 2014 Silverado 1500 LT Crew Cab. Stock battery is on the pax side, empty bay was on driver side. Pretty sure group 48 is the standard size for this truck, thats what comes up online at all the parts shops when looking for a battery to fit this truck. I know that size fits with the stock mount bracket as that is what i have in there now. I will look into 34 and 65 group battery size to see if they will fit and give me some more juice.

peekay - From what i have been told the charging systems on these trucks are strong. Seeing as they come with an empty bay for 2nd battery out of the factory i have to image that's somewhat true even though i have no evidence to back it up. I have 0/1 gauge wires connecting the batteries and either 4 or 8 (cant remember) gauge running power into the back seats of my cab so i know the wiring setup is strong too.


Lots of good info so far, thanks for all the contributions.

 

[Martinjmpr]

The short answer from me would be this: If you are driving several hours every day, you shouldn't have anything to worry about. Just as a point of reference for the past 3 camping seasons (since 2014) we have used a Truckfridge 41qt (AKA Indel B TB 41) and as long as we are driving every day for a substantial part of the day, battery power has not been an issue.
.
The only time I ever worry about the battery is if I know I'm going to be at a campsite for more than 24 hours without driving anywhere. In that case I either idle the engine for 30 minutes twice a day (typically at breakfast and dinner) or, more recently, I ran a 100w solar panel connected to the deep cycle battery on the trailer and it did OK (see my separate thread about my 'starter' solar kit.

 

[rayra]

I used to have a link to a matrix of battery group sizes, made it much easier to look up what would max-fit, but I can't seem to find it right now.



https://www.batterystuff.com/kb/tools/bci-battery-group-sizes.html

12 Volt Deep Cycle RV & Marine Batteries by BCI Group Number

U1 BCI GROUP NUMBER: U1
LifeLine Battery #: GPL-U1T (AGM)
Universal Battery #: UB12350-D5722 (AGM)
MK Battery #: 8GU1 (GEL)
Universal Battery #: U1Gel-D5870 (GEL)
DIMENSIONS IN INCHES*: 7.71" 5.18" 6.89" LxWxH
Amp Hours (AH): 32

22NF BCI GROUP NUMBER: 22NF
Universal Battery #: UB12550-45825 (AGM)
MK Battery #: 8A22NF (AGM)
MK Battery #: 8G22NF (GEL)
Univesal Battery #: UB22NFGEL (GEL)
DIMENSIONS IN INCHES*: 9.01" 5.43" 9.00" LxWxH
Amp Hours (AH): 55

24BCI GROUP NUMBER: 24
Lifeline Battery #: GPL-24T (AGM)
Universal Battery #: UB12750-45821 (AGM)
Trojan Battery #:T24-GEL (GEL)
Universal Battery #:UB24GEL-D5872 (GEL)
DIMENSIONS IN INCHES*: 11.13" 6.60" 9.25" LxWxH
Amp Hours (AH): 80

27BCI GROUP NUMBER: 27
Universal Battery #: UB12900-45826 (AGM)
Lifeline Battery #: GPL-27T (AGM)
Universal Battery #: UB27GEL-D5873 (GEL)
Trojan Batter #: T27-GEL (GEL)
DIMENSIONS IN INCHES*: 12.00" 6.63" 9.06" LxWxH
Amp Hours (AH): 90

31BCI GROUP NUMBER: 30H
BatteryStuff Part #: UB121100-40603
DIMENSIONS IN INCHES*: 13" 6.8" 9.5" LxWxH
Amp Hours (AH): 110

31BCI GROUP NUMBER: 31
Lifeline Battery #: GPL-31XT (AGM)
Lifeline Battery#: GPL-31T (AGM)
MK Battery #: S31SLDG (GEL)
DIMENSIONS IN INCHES*: 12.9" 6.75" 9.27" LxWxH
Amp Hours (AH): 125

4DBCI GROUP NUMBER: 4D
Universal Battery #: UB4DAGM-45965 (AGM)
LifeLine Battery #: GPL-4DL (AGM)
Universal Battery #: UPG4DGEL-40701 (GEL)
MK Battery #: 8G4D (GEL)
DIMENSIONS IN INCHES*: 20.5" 8.13" 10" LxWxH
Amp Hours (AH): 200

8DBCI GROUP NUMBER: 8D
Lifeline Battery #: GPL-8DL (AGM)
Universal Battery #: UB8DAGM-45964 (AGM)
Universal Battery #: UPG8DGEL-40702 (GEL)
MK Battery #: 8G8D (GEL)
DIMENSIONS IN INCHES*: 20.75" 11" 11" LxWxH
Amp Hours (AH): 245
6 Volt Deep Cycle Batteries by BCI Group Number

GC2BCI GROUP NUMBER: GC2
Trojan Battery #: T-105 (WET)
Universal Battery #: UBGC2 (AGM)
Lifeline Battery #: GPL-4CT (AGM)
MK Battery #: 8GGC2 (GEL)
DIMENSIONS IN INCHES*: 10.38" 7.13" 10.88" LxWxH
Amp Hours (AH): 225

8DBCI GROUP NUMBER: L16
Lifeline Battery #: GPL-L16T (AGM)
Trojan Battery #: L16RE-B (WET)
Trojan Battery #: L16RE-A (WET)
DIMENSIONS IN INCHES*: 11.64" 6.95" 15.73" LxWxH
Amp Hours (AH): 400
12 Volt Starting Batteries by BCI Group Number

25BCI GROUP NUMBER: 25
BatteryStuff Part #: OPT-25
DIMENSIONS IN INCHES*: 9.94" 6.81" 7.63" LxWxH
Amp Hours (AH): 44
CCA: 720

34BCI GROUP NUMBER: 34
BatteryStuff Part #: OPT-34
DIMENSIONS IN INCHES*: 10" 6.88" 7.63" LxWxH
Amp Hours (AH): 50
CCA: 800

34MBCI GROUP NUMBER: 34M
BatteryStuff Part #: OPT-34M
DIMENSIONS IN INCHES*: 10" 6.88" 7.94" LxWxH
Amp Hours (AH): 50
CCA: 800

34MBCI GROUP NUMBER: 34R
BatteryStuff Part #: OPT-34R
DIMENSIONS IN INCHES*: 10" 6.88" 7.63" LxWxH
Amp Hours (AH): 50
CCA: 800

34/78BCI GROUP NUMBER: 34/78
BatteryStuff Part #: OPT-34/78
DIMENSIONS IN INCHES*: 10" 6.88" 7.63" LxWxH
Amp Hours (AH): 50
CCA: 800

35BCI GROUP NUMBER: 35
BatteryStuff Part #: OPT-35
DIMENSIONS IN INCHES*: 9.31" 6.82" 7.82" LxWxH
Amp Hours (AH): 44
CCA: 720

75/25BCI GROUP NUMBER: 75/25
BatteryStuff Part #: OPT-75/25
DIMENSIONS IN INCHES*: 9.31" 6.82" 7.82" LxWxH
Amp Hours (AH): 44
CCA: 720
- See more at: https://www.batterystuff.com/kb/tools/bci-battery-group-sizes.html#sthash.TdDksDwo.dpuf

 

[Ducky's Dad]

My old GMC K1500 is happily running two Optima 34/78 Yellows on a factory 105amp alternator. That alt went into the truck in East BFE when the high-amp custom alternator fried itself in the desert. Never felt the need to upgrade the alternator in that truck again after that experience.