amp hours

[trouthound]

Hey guys,

a longtime camper, new RV'r here. I recently bought a '99 5er what came factory equipped with a solo 12v battery. I opted to replace the singe 12v with 4 6v GC batteries(Starting Lighting & Ignition | Battery Direct). I'm trying to figure out my load versus battery storage.

Based on the manufactures specs of 240 AH am I correct to assume 960AH out of my 4 6v's?

I can't give a specific usage that I am requiring or that sort of thing. I plan on boondocking a fair bit and with two wee-ones under three I just want to make sure I am sized right for hot baths, and the occasional movie ( on a 12v tv/dvd combo), with minimal lighting. We're not ones for microwaves and a percolator works just fine for morning coffee!

Looking on picking up a voltage meter for the batteries so I can monitor charges a bit closer. If I can't find one for cheap I'll be buying unit for manually testing them.

thanks for reading this,
mike

[Mr_D]

With true 6 volt deep cycle batteries you should drain them no more than 50% of capacity, so 240 AH since you don't take the amps times 4 on six volt batteries in a 12 volt system. With four batteries, when you wire them up you double the voltage and double the AH's of a single battery.
You actually have 480 amps @ 12 volts total available, if they were to be drawn down to empty and at 50% you have 240 AH to use.

[wa8yxm]

With the SIX VOLT you have 480 (Assuming 240 per battery) here is why.

When you add batteries like this:

{Battery}
{Battery}
{Battery}
{Battery}

You add all the amp hours together.

But with six volt pairs each pair is one battery They are added like this (4 six volt)
{Bat}{ery}
{Bat}{ery}

And as you can see that is but TWO batteries.

NOTE: That is also ONE 12 volt battery, though you may think of it as two.

Think of each pair, exactly as you would one 12 volt (4-D size) battery.

So long as you remember there are no six volt batteries once INSTALLED, just 12's that come in two halves for ease of handling, Many questions simply go "POOF".

[RJay]

Wa8yxm is correct.


Four 6 volt batteries have to be connected in a series-parallel configuration to become a 12 volt battery bank. A good rule-of-thumb is when batteries are connected in series the voltage adds and the current stays the same and when they're connected in parallel the current adds and the voltage stays the same.

[trouthound]

That all makes sense, when its put that way. Thanks for the response guys.


mike

[JimM68]

any kind of electric heating device uses a TON of power.

Once last week, I glanced at my inverter panel (2000 watt magnum inverter) while I had the coffee machine going and my wife was using the hair dryer.
the system was pulling TWO HUNDRED THIRTY AMPS out of the Batterys!

After nearly soiling my drawers, I hit the genny start button.
That load would have had my battery's toasted in a couple minutes.

Percolator on the stove is good. Electric one is not. Boiling water on the stove and using a french press for coffee is better.

Leave the hair dryer at home.

Consider putting in a generator. One big enough to run the A/C is nice. a 2000 watt honda or yamaho is simple, easy, quiet, and fairly cheap.

[historyljc]

Mike if you mean by "hot baths" running the hot water heater I don't think that will work. The hot water heater is usually not in an inverter circuit and will only work on shore power or generator.

[Mr_D]

Quote:

Originally Posted by RJay Wa8yxm is correct.

And so was I, you forgot to mention that!

[Quig]

Quote:

Originally Posted by historyljc Mike if you mean by "hot baths" running the hot water heater I don't think that will work. The hot water heater is usually not in an inverter circuit and will only work on shore power or generator.

Hot water heater in mine is gas, only takes 12v to lite it,, sorry if I'm butting in,, or wrong,,

[NomadBD]

I have a travel trailer with two house batteries and a third, solo, group 27 battery I coupled with a 600 watt pure sine wave power inverter. The house batterries power all the normal 12v stuff. The battery/inverter combo powers our tv, electronics, and 5-cup coffee maker.

Take Care,
NomadBD

[wa8yxm]

Quote:

Originally Posted by JimM68 Percolator on the stove is good. Electric one is not. Boiling water on the stove and using a french press for coffee is better.

Not all that thrilled with French Press units.

I use an electric.. but it's a one cup, not so hard on the batteries.

(Sunbeam as I recall,, Takes #2 Cone filters, "Forever filter" or coffee pods (senso type) very nice)

[Shadowcatche]

There is no substitute for carefully monitoring your loads and usage a TriMetric Battery System | Bogart Engineering or similar is recommended.