What is the amp hours on my battery?

[scubieman]

NOTE: I found answer. I jumped the gun.

http://www.interstatebatteries.com/c...o/marine_f.asp


I was wondering how many amp hours my battery has. It is a interstate HD24-DP

This is specs off interstate batteries website:



Reserved capacity on battery says 100. Can someone explain?

[herk7769]

Scoobie, I am not sure of your question.
Are you looking for definitions of the terms?

Cranking amps is how much juice can come out in a short burst.
Cold cranking amps is how much can come out in a short burst when cold.
These two are important for starting you car; not powering your camper.

Reserve Capacity is the number you look at for house batteries. Your battery can deliver 25 amps for 100 minutes and be dead.

[scubieman]

I think the battery is a mix battery not a true deep cycle battery. I wanted to know amp hours but figured it out.

[herk7769]

What formula did you use to figure out your amp-hours?
I would love to know.

I had to call Deka's USA rep to find out the 20 hour rate amp-hour capacity of my DC-24 batteries (75 Amp-Hours) for input into the TM-2025's battery monitor program.

[scubieman]

I used link that is in first post and it told me.

[herk7769]

Reserve Capacity and amp-hours are not the same. I did not see the amp hours stated in the link; just reserve capacity.

RC for your battery is = 25 amps for 100 minutes

Amp-hour capacity is rated over a 5 or 20 hour period (it will be stated in the documentation) and states the maximum number of amps that can possibly be delivered over that period of time. There is a curve that adjusts the amp hour capacity based on dishcarge rate (the higher the draw; the less amp hours possible). That is why you can run the lights and small draw stuff for days; but make one pot of coffee off the inverter and your battery is toast in a few hours.

[scubieman]

I looked at site again. I noticed it said at 5 amps it will last 11.6 hours. So I have 58 amp hours right?

Lou, quick forumla here.

Say I have 100 Ah battery. How many Ah is that if I use a 400 watt power invertor which is 110 volts?

[herk7769]

ok, I think I have this right; so here goes. Again, any EE dudes out there speak up! I am a novice here.

First we need to assume that the Power Factor in a single phase AC inverter is 1.0 Anything else makes the "figurin'" too hard.

So, Power (in Watts) = Amps (I) x Volts (E) for both AC (PF=1.0) and DC

400 watts of Inverter Output requires how many amps of 12 volt input?

400=12xI solve for I and you get 33.3 amps of battery draw to produce 400 watts assuming no loss in the inverter.

So what can I power with 400 watts of AC output?

400 watts = 120 volts (E) x I (amps) Solve for I and you get 3.3 amps.

This is why you never want to power your 1500 watt AC coffee maker from your 2000 watt inverter. To create 1500 watts of AC you need to pump in 1500 watts of DC plus inverter loss; that works out to about 125 amps of 12 volt DC.

You need BIG wires to your inverter to carry that load. In fact the instruction manual for my 2000 watt inverter suggests a 175 amp auto-resetting fuse inline with the battery. Since my battery bank is 150 amp hours (2x75 AH); making coffee eats up nearly all my capacity (dead batteries) in about 30 minutes. I use a percolator or french press for my morning fix.

This is why Thomas Edison's scheme to power the nation with many safe low voltage DC generators; lost out to Bell and his idea of using less power stations but more dangerous high voltage AC.

Oh, and don't get me started about how long you have to run your generator to put those AMPS BACK IN!

[TheSasks]

A 400 watt inverter will easily draw 30+ amps on your 12v source line so at full output don't plan on a 100 amp reserve battery lasting very long, maybe 80 minutes 90 tops. I had a Xantrex 1800watt inverter and 2 Trojan 6 Volt golf cart batteries in our old trailer. The connections had a 250 Amp circut breaker and double 00 guage welding cable 4 ft long to the inverter from the batteries. But I could run the coffee maker or microwave for a very short time with it. And those Trojans were rated for 447 minutes at 25 amps. I say this just to let you know if you want to use an inverter you better get some really good batteries.

[scubieman]

All cause I want to dry camp for a night and run 120v fans and tv. Grrrrrr