Dual Battery Management

[blupaddler]

Chris

Jack is running just the single Odyssey in his 80. I know he got the BIG one so he can run the fridge and other accessories. He wasn't planning on running a dual battery b/c of added complications and the massive amp hours he got from just the Odyssey.

 

[Desertdude]

I have found that if you run the vehicle at least once a day - there is almost no need for a second battery - no matter what brand - but if you sit for a couple days you will eventually need to re charge it somehow. This is where two solar panels can come in very handy - nice quiet recharging if there is enough sun...

The Engel is very efficiant in energy draw - my music is a fairly low draw - the inverter needs power and uses it :yikes:

Knowing the feeling that the only way I can get moving again is from a jump start from another vehicle (and being all alone)- leads me to always back up the back up

 

[Scott Brady]

I am going to research converting to Oddyssy's and more solar. I will advise of the progress.

I believe it is critical for me to be able to camp for 2-3 days without having to run the motor for extended periods (or at all)

 

[BajaTaco]

Chris

Jack is running just the single Odyssey in his 80. I know he got the BIG one so he can run the fridge and other accessories. He wasn't planning on running a dual battery b/c of added complications and the massive amp hours he got from just the Odyssey.

Thanks Robb, I would only get as large as the group 31, which for Odyssey is at 105AH. (My Optima is 75AH). So that is a 40% increase, which would be nice.

Scott, definitely let us know what you find out. I can't afford to get solar (would rather get new seats first), but I am interested nonetheless.

 

[blupaddler]

I believe it is critical for me to be able to camp for 2-3 days without having to run the motor for extended periods (or at all)

Scott,

I am right there with you, for that exact reason. Which is actually why I have waited so long to do a dual battery.
So, based on your current power draws...fridge, radio, daily photo downloading ; ), and hot water heater...you couldn't stay for two-three days?

 

[Scott Brady]

Unfortunately no, and for a few reasons.

Mainly, the fridge I have is the older unit, and pulls nearly 5 amps

Second, the solar panels are not getting full sun on the tent, I am seeing a max of 2.4 amps at high noon. That is close to their rated output, but not enough. So, I need to add more solar and a charge controller.

Third, just like a fuel tank, my reserve battery is too small. Only 55 amp hours from the blue top. It is not enough, and I already killed it. The Chaser has a 105 amp hour lifeline. I am doing some testing with it to compare performance.

So, I believe my solution is three fold.

1. Larger AH truck battery (at least 70 amp hours)
2. More solar (probably two more panels for 80 watts total)
3. A big daddy aux. battery of 105 amp hours.

This set-up should give me unlimited camping with the exception of showering. To heat the water I need to run the truck. The heater pulls 60 amps. This is not an issue for most trips as we camp and then drive and then camp, etc. That allows me to heat the water while on the trail.

 

[BajaTaco]

Scott,

I am right there with you, for that exact reason. Which is actually why I have waited so long to do a dual battery.
So, based on your current power draws...fridge, radio, daily photo downloading ; ), and hot water heater...you couldn't stay for two-three days?

Robb, I think if you follows Scott's method for calculating your loads for a 24 hour period, like this ...

and then use my calculations in this post to determine how much battery and solar capacity you need, you will be able to figure it out.

Scott, I think since you already have a nice bracket and space for the group 34 battery, you should explore the idea of just adding another group 34 in parallel (provided your brand of choice could utilize the space/bracket where your Optima now resides). This would potentially give you even more AH than a single group 31.

 

[asteffes]

I think the real answer to your problem is:

 

[asteffes]

In all seriousness, when you suggest using two Group 34s in parallel, Chris, are you suggesting running them without an isolator? I know people do it, but it seems that might lead to problems with uneven charge/discharge levels and possible damage to the batteries. It's also more stuff to break, connections to come loose, etc.

 

[Scott Brady]

I think the real answer to your problem is:

:xxrotflma :jump:

 

[BajaTaco]

In all seriousness, when you suggest using two Group 34s in parallel, Chris, are you suggesting running them without an isolator? I know people do it, but it seems that might lead to problems with uneven charge/discharge levels and possible damage to the batteries. It's also more stuff to break, connections to come loose, etc.

Yes, just connecting the two together for 12VDC but twice the AH. Any reason not to do that with the AGM type batteries we are talking about (Lifeline, Odyssey)?

 

[Scott Brady]

Yeah, it is pretty typical to run those batteries in parallel without a separator.

 

[bigreen505]

I think the real answer to your problem is:

Not really. With this homeland security nonsense stockpiling plutonium is getting harder to do, and not everyone generates enough trash on trips for the other way. :shakin:

 

[Mlachica]

In all seriousness, when you suggest using two Group 34s in parallel, Chris, are you suggesting running them without an isolator? I know people do it, but it seems that might lead to problems with uneven charge/discharge levels and possible damage to the batteries. It's also more stuff to break, connections to come loose, etc.

given you use the same battery models or at least batteries with the same internal resistance then there shouldn't be any problems with uneven charging/discharging.

Quality crimps/lugs and using loctite can last 50+ years :ylsmoke: In the electric utility industry we have equipment that's been in service this long and show no signs of letting go. The wiring goes through many vibrations from trains and CB operating mechanisms as well as extreme heat

 

[Desertdude]

I measured the battery area in the Tacoma yesterday and think I can get a group 31 in that same spot - may have to juggle some wires a bit - if I can get one of these battery trays in there I might make a go of it...
I have a dual Optima battery tray( for an FJ40) from the same folks in the link above and it is a superbly crafted product - I wonder if he could make ones for the Tacoma ?