Battery Capacity

Fred Mc · October 02, 2018, 10:51:33 AM

I'm looking at buying a couple of 6v deep cycle batteries that have 225 Amp Hours (AH)@20 Hr.
Does this translate into 450 Amp hours when you connect them in series for 12 volts.

thanks

Fred

buswarrior · October 02, 2018, 11:11:55 AM

Nope, still 225 ah, when you build 2 to 12 volts, but you did double the available WATTAGE.

You can't double the proportions twice!

Using watts is a popular "apples and oranges" solver

Happy coaching!
Buswarrior

richard5933 · October 02, 2018, 11:20:06 AM

In parallel batteries will increase amperage with the same voltage. Two 6v batteries with 225 Ah connected in parallel will provide 6v with 450 Ah. This is how 12v batteries are usually connected to make a 12v battery bank.

In series batteries will increase voltage with the same amperage. Two 6v batteries with 225 Ah connected in series will provide 12v with 225 Ah. This is how 6v batteries are usually connected to make a 12v battery bank.

We've got two pairs of 6v batteries connected in a combination of parallel & series, which double both the voltage and the amperage. Each pair is connected in series to make 12v, and the two pairs are connected in parallel to double the amperage.

Lots of ways to skin this particular cat.

Fred Mc · October 02, 2018, 12:30:11 PM

Why is it generally accepted that 2x6 v batteries is better than 1 12v?

windtrader · October 02, 2018, 01:00:25 PM

Better in what way? Never heard of that. Maybe two batteries cost more than a single of same spec.

buswarrior · October 02, 2018, 01:14:52 PM

Apples and oranges.

It is mostly about the lead.

Equal weight and style of internal construction will yield equal results.

Too many variables to make a blanket statement like that regarding 6 volt or 12 volt.

Uninformed vs educated?

Happy coaching!
Buswarrior

Fred Mc · October 02, 2018, 01:34:00 PM

"Better in what way? Never heard of that."
The implication seems to be that you get more power from 2 6v batteries than one 12 v. When it comes to fork lifts, golf carts ans similar machines they almost always advertise 6 volt batteries.

richard5933 · October 02, 2018, 01:46:15 PM

Quote from: Fred Mc on October 02, 2018, 12:30:11 PM
Why is it generally accepted that 2x6 v batteries is better than 1 12v?

Can't speak for anyone but myself on this one. I went with two pairs of 6v (Trojan L16) because that combination allowed me to get the maximum Ah capacity in the physical space I had available and still be able to lift the individual components by myself.

Was that the best way? Don't know. But it worked for me.

sledhead · October 02, 2018, 03:06:22 PM

a buddy of mine has a tag trailer and had 2 x 12 volt batteries at 12 volts . I told him he would do better with 2 x 6 v batteries at 12 volts

his words not mine way way better !

dave

TomC · October 03, 2018, 07:05:44 AM

To answer the 6v or 12v battery question-is weight of each battery! A Trojan T-105 220amp/hr battery weighs 62lbs. My 8D 12v Lifeline AGM battery with a bit more power at 255amp/hr weighs 165lbs and is a bear to lift.
I'm going to use the 6PL-6CT Lifeline batteries that are 6v and 300amp/hr ea. They are about 3.1" taller with the same foot print as the T105 and weighs 90lbs. A lot easier than the 165lb 8D beasts. Good Luck, TomC

chessie4905 · October 03, 2018, 07:09:02 AM

I use 4 of these.

https://www.interstatebatteries.com/products/srm-4d

richard5933 · October 03, 2018, 07:19:18 AM

Quote from: TomC on October 03, 2018, 07:05:44 AM
To answer the 6v or 12v battery question-is weight of each battery! A Trojan T-105 220amp/hr battery weighs 62lbs. My 8D 12v Lifeline AGM battery with a bit more power at 255amp/hr weighs 165lbs and is a bear to lift.
I'm going to use the 6PL-6CT Lifeline batteries that are 6v and 300amp/hr ea. They are about 3.1" taller with the same foot print as the T105 and weighs 90lbs. A lot easier than the 165lb 8D beasts. Good Luck, TomC

This is part of why we went with the L16. Provides 390 Ah and weighs 115lbs. That was the limit of my desire to lift a battery.

Fred Mc · October 03, 2018, 09:25:58 AM

"I use 4 of these."
So what are they rated in amp hours?

chessie4905 · October 03, 2018, 10:57:02 AM

Their description says 390@ 25 amps

Gary Hatt - Publisher BCM · October 03, 2018, 11:30:51 AM

My bus came with (6) 4D 12V batteries. That are quite a few amp hours. I switched over to (

6V Trojans and am much happier with the results. The 4Ds were not truly deep cycle so they just did not work as well. The 6V batteries seem to be holding longer charges. Besides, the 8Ds seemed to get heavier every time I had to replace them.