One battery or two

philh wrote:
Are you better off with 2 6v golf cart batteries or 2 12v deep cycle batteries?

SoundGuy wrote:
Forum pundits will automatically say 2 GC-2 6 volt batteries but that ignores inherently higher internal resistance which can cause excessive voltage drop under heavy load from an inverter. A pair of 12 volt G31 batteries, especially AGMs, will offer similar capacity but with much lower internal resistance and therefore suffer less voltage drop under heavy inverter load. Secondly, a pair of GC-2s, while taller, will also have a smaller footprint than a pair of G31s so the space you have available also plays a role. So - the answer is, it depends on your intended use. ;)

time2roll wrote:
Unless you have a large inverter typical max load is less than 10 amps.

Sure, but a 10 amp load @ 12 vdc is just 120 watts - barely sufficient to power anything. With a 1000 watt PSW inverter I'd typically pull ~ 60 amps @ 12 vdc to run just the toaster. Voltage drop under load means the difference between the inverter handling the load OR the inverter alarming and shutting down due to excessively low incoming voltage which in turn is why battery internal resistance is an important consideration and why forum pundits' recommendations for dual 6 volt GC-2s over a pair of 12 volt G31s doesn't tell the whole story.

SoundGuy wrote:

philh wrote:
Are you better off with 2 6v golf cart batteries or 2 12v deep cycle batteries?

Forum pundits will automatically say 2 GC-2 6 volt batteries but that ignores inherently higher internal resistance which can cause excessive voltage drop under heavy load from an inverter. A pair of 12 volt G31 batteries, especially AGMs, will offer similar capacity but with much lower internal resistance and therefore suffer less voltage drop under heavy inverter load. Secondly, a pair of GC-2s, while taller, will also have a smaller footprint than a pair of G31s so the space you have available also plays a role. So - the answer is, it depends on your intended use. ;)

Unless you have a large inverter typical max load is less than 10 amps.

Before I got into the TT world....I would have said one good battery.

Through forum advice based on my primarily boondocking style, I went with 2 - 6V batteries.

I replaced all lights with LED and added a couple of portable 40W solar panels for the longer camp stays.

I don't run out of power. Ever.

And my new Honda generator has ZERO time on it. Probably will stop bringing it.

Water and waste is the issue I keep my eye on.

Atlee wrote:
Can't plug the TV into a Ford and get any juice from the Ford chassis battery, unless you're letting the Ford idle, and that's not a good solution for electricity for the TV.

And even if you didn't idle the Ford, you'd still have to have the switch turned to ON.

When the Ford switch is off, no power can run from the chassis battery to the TV.

I can't speak to GM products, or Rams.

In my previous post I said "light use" - running the truck for a few minutes to supply emergency power to a camper is going to make zero difference to the truck. Yes, with GM products the 7-pin Bargman's charge line is hot all the time whether the truck is running or not. Regardless, I have a 16' 4 gauge booster cable which I can use to connect directly from my Silvy's battery to the trailer battery, resulting in far less voltage drop compared to plugging the trailer into the truck's 7-pin Bargman. This works especially well when my 1000 watt inverter is under heavy load from a toaster - results in far less voltage drop and prevents the inverter from alarming even under full load. Considering we may only dry camp a couple of times each season, just what the OP said is his situation as well, I've eliminated the need for a second trailer battery. It's not complicated. :R

philh wrote:
Are you better off with 2 6v golf cart batteries or 2 12v deep cycle batteries?

Forum pundits will automatically say 2 GC-2 6 volt batteries but that ignores inherently higher internal resistance which can cause excessive voltage drop under heavy load from an inverter. A pair of 12 volt G31 batteries, especially AGMs, will offer similar capacity but with much lower internal resistance and therefore suffer less voltage drop under heavy inverter load. Secondly, a pair of GC-2s, while taller, will also have a smaller footprint than a pair of G31s so the space you have available also plays a role. So - the answer is, it depends on your intended use. ;)

Are you better off with 2 6v golf cart batteries or 2 12v deep cycle batteries?

To the OP. Good choice.

Can't plug the TV into a Ford and get any juice from the Ford chassis battery, unless you're letting the Ford idle, and that's not a good solution for electricity for the TV.

And even if you didn't idle the Ford, you'd still have to have the switch turned to ON.

When the Ford switch is off, no power can run from the chassis battery to the TV.

I can't speak to GM products, or Rams.

SoundGuy wrote:

Lynnmor wrote:
So you may run out of power just a few times a year? That may be trips lacking the fun factor. One battery deeply discharged is worse for battery life than two discharged much less.

An exaggeration considering the OP said - "We don't do a lot of boondocking, maybe a couple times a year for a couple days." In a pinch one can still plug the trailer into the tow vehicle for light use - i.e. powering a couple of LED lights or running the water pump for showering, etc. Even a portable solar panel could restore some of what is used from a single battery. No biggie at all. A dual battery setup for many is overkill, despite claims to the contrary by forum pundits. :R

Easy to add a battery later. I have traveled thousands of miles with many nights unplugged with just one battery. Pretty simple to monitor voltage and keep it above fifty percent charge. Furnace really kills a battery, so I don't travel in really cold weather. Simply upgrading from the usual group 24 to a 27 or larger may handle the OP's needs.

Thank you to everyone for the input.
I think I will go with my gut and have 2, 12 volt
batteries installed.
Tinbender