12v or 24v for efficiency

[afarr86]

Hi,

I understand some basics about wattage, volts and amps etc but I am trying to decide what would be the most efficient system

Situation - 2 x 110 amp hour 12 volt batteries wired in parallel. Use these to heat approximately 8 liters of water through a DC water heating element. Which of the two scenarios below would be most efficient concerning pulling the most power from the batteries? If I understand this correctly it is least pull of amps is most efficient - is that correct?

1) Use a DC heating element - 12v 300 watt directly. So 2.5 amps
2) Use a DC heating element - 24v 300 watt via 12v to 24v transformer module. so 1.25 amps

Thanks in advance

 

[davesparks]

Another newish problem is the introduction of a percentage of bio-diesel which does not withstand long storage.

Tell me about it, I've been battling with the diesel bug on my mates nb for ages.


I've sacked off the main tank for now and she's currently running from a re-purposed 25litre smoke fluid bottle with a thoroughly un-BSS bit of pipework.

 

[pc1966]

Tell me about it, I've been battling with the diesel bug on my mates nb for ages.


I've sacked off the main tank for now and she's currently running from a re-purposed 25litre smoke fluid bottle with a thoroughly un-BSS bit of pipework.

When looking in to this for our generator I discovered that HVO fuel is supposed to last 10 years in storage. Just a shame its 20% more expensive!

I think the "Shell GTL" (Gas To Liquid synthetic fuel) is similar, but I never got any prices for that.

 

[brianmoooore]

At least propane doesn't 'go off' in the bottle.

 

[pc1966]

At least propane doesn't 'go off' in the bottle.

We had been looking at LPG for our generator for that reason, also harder to steal (if bulk tank, not bottles) but not a lot of choice and more civil works and safe clearance requirements so last-minute options forced us to a long-run diesel unit.