I am looking at specs for lithium AA battery capacity vs D cell alkaline battery capacity. My electronics training in high school is getting a bit weak.

The application is a a dual band 40 watt ham radio amplifier with a 12 volt cigaratte lighter power input. At 1 and 2 amp current draw, how long would eight D alkaline cell batteries last compared to eight AA lithium batteries (wired in series to get 12 volts).

(Raises hand) “will this be on the test?”

quote:

Originally posted by arfmel:
(Raises hand) “will this be on the test?”

I wouldn't put it on a test unless I knew the answer. But if I knew the answer, I wouldn't have to ask the question.

Are these charts of any help?

http://www.allaboutbatteries.com/Energy-tables.html

quote:

Originally posted by arfmel:
Are these charts of any help?

http://www.allaboutbatteries.com/Energy-tables.html

The AA lithium there are 3.6 volt, not 1.5 volts, and it seems the power capacity/drain is not linear. If you double the power drain, the battery life goes down by four (or something like that).

The 1 to 2 amp draw will reduce the available amp hour rating of the cells. Look at constant 1500/2000 ma chart
duracell alkiline d cell pdf

Battery University: good info

Serial/parallel battery connections


A 12v portable power pack with 2amp draw might work, not sure what connections you need.
Another DIY solution could be to re-purpose a 12v power tool battery pack?

Looking at the chart, one alkaline long life D cell has more Joules than 4 lithium 3.6volt AA cells. But maybe Joules isn’t the measurement you’re needing.

I’m not much of an expert on Joules and all that. They didn’t even have those when I was matriculating.

I would look into 3s lipo hobby battery’s. They can handle high amps, come in many capacities, and many recharge cycles.

quote:

Originally posted by arfmel:
They didn’t even have those when I was matriculating.

Be careful. Too much of that and you'll go blind.

quote:

Originally posted by Scoutmaster:

The application is a a dual band 40 watt ham radio amplifier with a 12 volt cigaratte lighter power input. At 1 and 2 amp current draw, .......

Series question.... How do you get 40 watts out from 12V @ "1 and 2 amps?"


At 12 V @ 2 A, you could get a max of 24 watts output if the amp was 100% efficient, which it is not.

I am not an Electronics Engineer nor do I play one on TV . However I did take electronics 1, 2, and 3 in High school.

According to Wikipedia Alkaline cells have a capacity of 12,000mah to 18,000mah.

Lithium AA cells like Energizers have 2700mah to 3400mah.

Capacity in series is NOT additive. So even D cells @ 12Volts will be 12,000mah to 18,000mah

AA cells @ 12volts will be 2700mah to 3400mah.

Let us use the lowest figures:

1 amp current draw using AA cells 2.7 / 1 = 2.7 hours

1 amp current draw using D cells 12 / 1 = 12 hours

I hope this helps. God Bless