6 volts and CPAP

Huntindog wrote:

Sam Spade wrote:

Camsmom wrote:
Wondering what special magic we can get out of these now.

There is no magic.
Your capacity will be slightly less than twice what a single 12 V battery was.

Umm.. If the 6 volts replaced a group 24 (Which seems to be the most commonly used) 12 volt, then he will have slightly MORE than twice what a single 12 volt had.... The sixes are the same dimension except they are taller. That is where the extra capacity comes from.

YEP, Huntin' is correct.

Not to mention though those typical "RV/Marine" group 24 or group 27 batteries are a "combination" battery. In other words they are designed to cater sort of as a "starting" battery but with a slight deeper discharge..

The downside is it does neither function well (as a starting battery or a deep cycle)..

Discharge a RV/marine battery to 50% DOD often and it will be damaged..

Those 6V GC batts are designed to be discharged down to 80% DOD with minimal loss of capacity..

Group 24 RV/marine battery typically has about 70 Ahr capacity and of that you will only want to use 20% for longest life.. That would mean only 14Ahr could be drawn.. TWO 12Vs in group 24 would give you a mere 28Ahr!!

Sure, you could drag them to 50% but you WILL be buying new batteries pretty often.. and you would only get 70Ahr..

On the other hand, a pair a 6V GC batts has about 210A hr capacity and if you use 50% of that you have 105 Ahr of usable capacity..

Don't know about you but 105 Ahr (6V GC batts) IS a lot more usable capacity AND much longer life than two group 24 RV/Marines which at 50% is only 70 Ahr and a much shorter life.