Second Battery & Battery Management System in Trunk

[Markuson]

Come on man a single battery isn't expo enough!!

(I use the Slee bracket with group 31 AGM and hit it with an AGM Odyssey charger once a month and a Noco GB150 in the drawers just in case - no dual battery here)

I actually just yanked my 31 and swapped in an identical type 35 I had on hand (ended up with an extra I thought was bad, but that turned out to be fine). I am liking it so far, and may jest go with two 35’s.

Makes the leeching between batteries improve (so far anyway).

PS. My fridge/freezer stays on 24/7. Most don’t do that. So ya, I’m the oddball.

 

[TeCKis300]

Rr


Re microwave, I often leave it at home.
The only “extreme” part is the thought of a microwave. Fridges are common, and in hot weather especially, it takes a lot of power to keep stuff frozen/cold.

But...the lowest fuss hot food is heating pre-cooked stuff from home. Want hot chocolate? Throw a bottle of chocolate milk in the micro for two minutes and away you go. We do that even in the road. Wife makes a killer breakfast casserole... Heat and done. Leftovers=instant food. It’s great for quick getaways. Other times, it’s just the stove.

But in general, it’s great to have high power as an option. Power tools...other battery chargers...helping other campers run/charge stuff without turning on their trucks just to charge, etc really makes a second battery useful. I have tiny soldering tools, Dremel, etc. and most would be surprised how often those come in handy right out of the truck.

Even at home, I tend to use my truck as a small workshop. The neighbors are used to me using my tailgate as a work bench...and I do the same in the field. Laptop stays powered with a regular 85W charger and no need to run the engine or turn on the the 100W built in inverter in the field.

About the built in inverter:
I have lithium battery chargers plugged into it 24/7 so that batteries are topped off always...but only charge when truck is on. It really works out perfectly for low draw, trickle charging.

For USB devices, my USB ports are always powered and I am constantly using my new external ports while fiddling with things.

Anyway... Just thought I’d share some of my uses. I do use power more than most. But I suspect if others realized how useful it is, I might not seem like such an oddball power extremist. But ya...I’m probably in the top 1%...​

The way you're using your system is not much different than my trailer or an RV. Your RV or recreational vehicle is just in the form of an overlanding vehicle. Much more similarities than differences. Though I still argue that an RV is even heavier on power systems as it's a matter of duty cycle to provide for more "passengers" and the larger infrastructure systems, including microwave. For a vehicle based RV to have a batt installation that rivals an RV, seems questionable.

I'm completely with you on use of microwaves. And coffee makers. And hair dryers. Using batts to drive these high power momentary use devices requires deeper reserves than what may be reasonable when talking SWaP (size, weight, and power). Fortunately for a vehicle based RV, there's a nice big powerplant on the front of it. That IMO, should be your go to when powering these devices. Same big inverter, but rely on your cars motor to supply the amps. Rather than putting on all that weight for big heavy batts. Same with adding solar as that solves the power generation side for the long haul, rather than again SWaP for reserve capacity.

Back to using the motor. On my trailer, I will even use the remote start on my key fob, to momentarily fire my engine to support these high power devices. The 7-pin doesn't provide huge ampacity capability, but any bit helps rather than throwing on more batts on my tongue. Cause even for a large travel trailer, SWaP always matters.

 

[Markuson]

The way you're using your system is not much different than my trailer or an RV. Your RV or recreational vehicle is just in the form of an overlanding vehicle. Much more similarities than differences. Though I still argue that an RV is even heavier on power systems as it's a matter of duty cycle to provide for more "passengers" and the larger infrastructure systems, including microwave. For a vehicle based RV to have a batt installation that rivals an RV, seems questionable.

I'm completely with you on use of microwaves. And coffee makers. And hair dryers. Using batts to drive these high power momentary use devices requires deeper reserves than what may be reasonable when talking SWaP (size, weight, and power). Fortunately for a vehicle based RV, there's a nice big powerplant on the front of it. That IMO, should be your go to when powering these devices. Same big inverter, but rely on your cars motor to supply the amps. Rather than putting on all that weight for big heavy batts. Same with adding solar as that solves the power generation side for the long haul, rather than again SWaP for reserve capacity.

Back to using the motor. On my trailer, I will even use the remote start on my key fob, to momentarily fire my engine to support these high power devices. The 7-pin doesn't provide huge ampacity capability, but any bit helps rather than throwing on more batts on my tongue. Cause even for a large travel trailer, SWaP always matters.

There is no doubt that my setup is “questionable.” No one I knew of had done it when I decided to try it. And I agree it’s similar to an RV.

And yes about engine use. I run the engine when I run a microwave through my inverter. Even then, the strain is due to voltage drop on DC power’s way to the rear. I just went through the painful process of cramming both positive and negative 1-gauge wire through the door jams. NOT an easy task!! But it made a real difference.

But anyway, ya. Microwaves are used for short bursts of high power. For that, my engine is on. For everything g else though...two batteries are great.

 

[JohnJ7]

Thank you all for the advice.

@fireball I am by no means an expert and this is my first build. My thought process was to isolate power draw of accessories from the main battery. The most I'd be stationary is one to two nights tops. That's the reason I asked the question. I am sure many on here have a lot more experience than I do and wanted to see if the accessories I want to run justify a secondary battery. And if they do, is the trunk a bad location to have the setup. I have thought of the goal zero and will probably go that route for running camp lights and charging devices.

 

[TeCKis300]

There is no doubt that my setup is “questionable.” No one I knew of had done it when I decided to try it. And I agree it’s similar to an RV.

And yes about engine use. I run the engine when I run a microwave through my inverter. Even then, the strain is due to voltage drop on DC power’s way to the rear. I just went through the painful process of cramming both positive and negative 1-gauge wire through the door jams. NOT an easy task!! But it made a real difference.

But anyway, ya. Microwaves are used for short bursts of high power. For that, my engine is on. For everything g else though...two batteries are great.

More enviable than questionable. It's enough to power the whole convoy! I give you credit for pushing the envelop.

Only trying to help others with context as to how much reserves and power is actually needed. Perhaps lighter, cheaper, and easier solutions to power needs.

 

[Markuson]

Expo?
Meh...

I just try stuff that I think might be interesting/helpful to me.
It’s fun to try. They don’t always work out.

When I did my inverter setup, I didn’t even know about those expos.

One impressive diodad I saw at the expo was an automatic-poo-wrapping toilette. But it was $800. I went for a plastic manual-poo-wrapper from REI.

 

[RET2]

OK that's it I draw the line at auto-PWT.

 

[Markuson]

OK that's it I draw the line at auto-PWT.

It was definitely the most entertaining DEMO at Expo.

I told the salesman that I didn’t feel comfortable buying one unless I **personally tested it.** Hehe (I was not gonna but an $800 toilette, but he and I were both smirking.

Was actually a pretty impressive invention.
After...um...use... -It automatically detached the “package...” vacuum sealed it, then melted it shut...then um, “reloaded” it so it was ready for the next...well...load! Haha

Oh, and the device box itself was bright, metallic GREEN.

 

[619TOY]

Poo’d saver...

 

[RET2]

NOPE,NOPE, just plain nope. I don't even want to know where the excess air goes from the vacuum sealing. Too much info for Wednesday. Your dogs laughing sooo hard... green bags poo ?

 

[TheFatMexican]

I dunno... It was great running a fridge/freezer, charging drones and running a microwave while camping in Baja earlier this year. The one truck without a second battery...that had a drone...appreciated charging multiple devices/batteries at once in camp, and I appreciated doing it without concern. 2nd batteries are great.

Thanks Mark! I was that guy with the drone. Zak's friend Carlos. I finally bought my own Land Cruiser. Looking forward to another trip to Baja!