12V Vs Inverter

[neilv]

Not totally a Tvan wiring question.
In my prado I have a second battery. The second battery is used primarily form recharging photographic batteries, drone and camera. I have a dedicated 12v cable running to a charging station with cig and usb ports in the back of the car. Just recently my wife bought a Mac notebook which cannot be charged from a 12v outlet it must have 240v so I ran a new cable to a 600w inverter.
I have both 240v and 12v chargers for my drone and camera batteries. Electrically which is more efficient in charging those batteries, using the 12v or through the inverter up to 240v then back down to the battery charging voltage?
Thanks for any assistance.

[luke]

How big is the second battery, and do you ever have any issues with it getting low ?

If you've got plenty of power, then I'd say use whatever's easiest for you, however the direct 12 volt option is definitely more efficient.

For the inverter:

• Inverter's aren't 100% efficient, and you'll also loose more power the bigger they are.
  i.e. If you only need 50 watts, then a 100/200 watt inverter will be more efficient than a 600 watt inverter simply because they wouldn't be wasting as much.
• The inverter needs to increase the voltage from 12 to 240, and also convert DC to AC.
  Your charger then needs to decrease the voltage and also convert AC to DC (so a bit of waste both ways)
• Phones, cameras, and similar will be charging at less than 12 volts, so 12 VDC is already more than enough.

For me, the best reason is simplicity.  A lot of our electronic gear is now USB chargeable, simply because it's easy and common.  Much easier to have a usb in the car, tvan, etc then multiple inverters (which will be more problematic when they fail, and also more expensive to replace)

[neilv]

Thanks Luke that was how I was thinking. Second battery is 100ah so never has run low. But when off the grid for long periods without driving it is good to have knowledge before rather than after.

[MarkA]

Having done the research. My wife's laptop also required a 240v charger but a Targus  stepup unit allows it to charge the 19v laptop straight from 12v   Jaycar also sell a version of this charger for well under $100.

[Cruiser 105Tvan]

I'm with Mark on this.
If you use an inverter to go 12V. up to 240V. there is a big draw at the 12V. side of things.
Far better and safer to keep voltages as low as practical.
I have to use a CPAP machine while sleeping. 
The batteries in the trailer and car last longer at 12V power than using an inverter to power it.
I believe you could use an Inverter while driving around in the tow vehicle for cameras and things, but you'd need to be careful with ventilation/cooling of the Inverter.

Good luck, like to know how you work it out finally.

[robstevens]

This sort of thing?



https://www.ebay.com.au/itm/Car-charger-for-apple-85w-magsafe1-adapter-Macbook-pro-13-15-17-Laptop/181929521916?hash=item2a5bd832fc:g:Lo8AAOSwRbtaMj1v