Another battery question

[astrocamper]

If you want to track battery state of charge use a monitor with a shunt. Much better than interpreting SOC from resting voltage.

I like the VE BMV-712 with the built in bluetooth and phone app.

[Sweetbriar]

Originally Posted by Tacouser

I should know the answer to this but I think I am having a senior moment.
I have 2-6volt 300ah batteries wired in series making the 12 volts. But my question is do you add the total of the two batteries ah making it 600ah usable total ah , or because they are in series do I have 300ah usable ah ?

Simple way to remember - you can't double both volts and amps with only two identical batteries. It's one of the other and in this example it would be 12VDC and 300Ah.

[Gammel]

astrocamper,
I am a n00b but your 1440 w of solar seems like overkill for a 22' trailer.
Are you doing fusion research while boondocking? A friend wants to know.

[Brad Wilf]

Originally Posted by astrocamper

If you want to track battery state of charge use a monitor with a shunt. Much better than interpreting SOC from resting voltage.

I like the VE BMV-712 with the built in bluetooth and phone app.

Absolutely, I have one coming from Amazon right now, we'll see how it works.

Besides, when your camping there's no resting voltage. Either pulling down and adding in.

[MJClark]

Originally Posted by Tacouser

I should know the answer to this but I think I am having a senior moment.
I have 2-6volt 300ah batteries wired in series making the 12 volts. But my question is do you add the total of the two batteries ah making it 600ah usable total ah , or because they are in series do I have 300ah usable ah ?

...unless you're talking Lithium batteries... various sources put their usable Ah at 90%, so 540 Ah is usable - AND, you won't damage or shorten the life of your batteries. AGM's you can probably use up to 60%, perhaps 70%, but any other type, I believe, would recommend no more than 50% SOC before recharging.

[Mark_K5LXP]

Originally Posted by MJClark

...unless you're talking Lithium batteries... you won't damage or shorten the life of your batteries.

Deeper discharges of lithium batteries does shorten their life as with lead acid. The difference is with lithium there may be inherently 10x the cycles to begin with but there will be a cycle life impact with greater DOD nonetheless.

Mark B.
Albuquerque, NM

[DAN L]

Sorry to hijack this thread,
I need a picture of the starting battery hookup on a ford chassis 1991-1992 Fleetwood bounder.
It has 5 wires. I know where 2 go. Ground and positive are obvious. The other 3 ?
Dan L