two batteries one inverter

[BrianG]

I've never installed an inverter. Got a 1100 watt modified sine wave. Two batteries with a switch. I keep the switch on "Both" for starting and running. Then knock it down to #2 at anchor when shut down to keep one batt fresh. Should I hook the inverter direct to the #2 battery for the same reasons?

 

[DDW]

An 1100W inverter will draw over 100A when running at full load. That is a pretty big ask from a single battery unless it is really big. However since you already have a paralleling switch, you can always switch that to Both if you are running a big load.

Modern thinking is to always leave the switch on Both as it will make the batteries last longer. If these are start and house batteries, it does leave open the possibility of running them down and not being able to start.

 

[Comodave]

If you leave it on both you at sometime run the batteries down and be unable to start the engine. I would carry a jumper pack that is capable of starting your engine and keep it topped up.

 

[BrianG]

If you leave it on both you at sometime run the batteries down and be unable to start the engine. I would carry a jumper pack that is capable of starting your engine and keep it topped up.

I plan to do that. They're super useful for us 12v tinkerers. Btw I have solar to keep the batteries interested at anchor.

 

[BrianG]

An 1100W inverter will draw over 100A when running at full load. That is a pretty big ask from a single battery unless it is really big. However since you already have a paralleling switch, you can always switch that to Both if you are running a big load.

Modern thinking is to always leave the switch on Both as it will make the batteries last longer. If these are start and house batteries, it does leave open the possibility of running them down and not being able to start.

I don't *plan* on a big load... usb ports, 14" monitor, laptop and camera battery chargers.

 

[DavidM]

I don't *plan* on a big load... usb ports, 14" monitor, laptop and camera battery chargers.

I would add some direct 12V to usb ports or at lease use cigarette lighter plugs for charging usb powered devices. That should cover everything but your 14" monitor and laptop. Then turn off the inverter when the latter things are not in use or charged up.

The others will draw little current- a couple of amps when charging tapering down to nothing after they are fully charged. It is more efficient to power them from 12V than a three step conversion: 12V/120VAC/5V. Plus an inverter in standby with low or no load still draws significant standby current.

Here are some panel mounted usb ports powered direct by 12V: https://www.amazon.com/s?k=12v+rv+u...ix=12V+rv+usb+por,aps,377&ref=nb_sb_ss_i_1_14

And here are some cigarette lighter plug in usb ports: https://www.amazon.com/s?k=cigarett...igarette+lighter+,aps,234&ref=nb_sb_ss_i_8_18 I really like the one with the led voltmeter. Gives you another easy voltage measurement any where there is a cigarette lighter outlet.

David

 

[Bacchus]

Many TVs are in fact 12V and can be powered direct vs 120V and transformer. There are combo 12V and USB outlets that are very handy for low power needs.
https://www.satpro.tv/Marinco-SeaLi...QEy2HQFz6ZJzfM6esb6C9s0Nc4iJ_suRoCktgQAvD_BwE
I installed one of these to handle laptop and phone/ tablet charging and it has worked put very well eliminating the need to install or run an inverter for very light loads that dont really need 120V.