Inverter/Charger AND an extra Charger?

[Tikvah]

I've learned that my inverter will either charge or invert, but not both at the same time.  The problem is, when I plug into a simple 15 amp extension cord, I don't have enough power to recharge and run anything in the bus.

So, I got this wild idea.  What if I run my power off the inverter and have much of what I need, and plug in only a 24V charger to maintain the batteries?  The inverter will absorb the short term higher loads ie: coffee pot, or water heater, etc.  The charger will bring the batteries back from the heavier loads.

Am I out to lunch?  Will this work?  Will there be any conflict?

Thanks

[sledhead]

this one is amazing but big bucks !
if you only have 15 amps to plug into it will add more power if needed from your battery bank then as soon as there is power available from your 15 amp post plug it will recharge the batteries  . again and again . I have used my a/c this way and was shocked how often it was recharging the batteries well the a/c was on

https://www.solarwholesaler.ca/product/magnum-msh4024m-24v-hybrid-invertercharger/

dave

[Tikvah]

this one is amazing but big bucks !
if you only have 15 amps to plug into it will add more power if needed from your battery bank then as soon as there is power available from your 15 amp post plug it will recharge the batteries  . again and again . I have used my a/c this way and was shocked how often it was recharging the batteries well the a/c was on

Yup, I know there's some pretty awesome technology out there, but I'm just a poor man working my way through life.  I like my inverter and I don't want to buy another.
But in my little brain, another charger seems appropriate. 

[Tikvah]

Something like this perhaps?
https://www.batterystuff.com/power-supplies/load-bearing-chargers/power-max/power-max-pm3-30-24.html

[Utahclaimjumper]

  You can still only do so much with a 15 amp cord, there is no free lunch.>>>Dan

[Iceni John]

Something like this perhaps?
https://www.batterystuff.com/power-supplies/load-bearing-chargers/power-max/power-max-pm3-30-24.html

One thing to be aware of with the Iota and Power-Max chargers  - they have very high starting surges, and their Power Factor is also quite low (about 0.6-something if I recall for the Iotas).   This means they could trip breakers when first switched on;  their low PF isn't of concern unless you're powering them offgrid from a generator.   The alternative to a low PF charger is one like the Mean Well (what a name!) that has a PF in the high-0.9s, but because it's a multi-stage "smart charger" it won't charge batteries if there's any load on them at the same time  -  that doesn't sound too smart to me.

Do your research first  -  chargers aren't as simple as they seem!

John

[Lin]

Since chargers and inverters often have their own quirks, what might seem like a good idea might not work out the way you want it to.  If you have a particular charger in mind, maybe you could speak to someone in their tech support department to get their blessings.  Same goes for the inverter.

[Tikvah]

Since chargers and inverters often have their own quirks, what might seem like a good idea might not work out the way you want it to.  If you have a particular charger in mind, maybe you could speak to someone in their tech support department to get their blessings.  Same goes for the inverter.

Ya, that's a good idea.  For example, I never thought of the fact that some chargers don't charge if there is a load.  That's specifically why I want it - so it charges during a load.

[bevans6]

I can run everything in my bus except the AC and charge my batteries at their normal rate with a 15 amp circuit.  I think you are trying to fix something that isn't broken.  With most smart inverters you can adjust the charging current, and therefore the current draw on the 15 amp circuit.  Modern smart battery chargers don't really draw all that much current once the initial inrush of bulk charge is done.

[Geom]

Hey Dave, what kind of inverter do you have?

I agree with bevans, a modern "smart" inverter/charger would have a max current setting that controls how much it is allowed to draw from the incoming shore AC (whether from mains or gen).
If I understand your proposed solution, you'd essentially be robbing from Peter to pay Paul anyway, since your storage pool (your batteries) is the same and your input feed source is also the same (15amp input). So unless you plugged your charger into a different 15 amp circuit, you'd risk blowing your single circuit. Plus, regardless, if the standalone charger ever detected a draw (i.e. a significant enough voltage drop that exceeds its output capacity to compensate), it will likely shut down. That would mean that your battery bank doesn't have the capacity to handle that current load and is trying to use the charger as a DC source.

Your inverter should be smart enough to invert (i.e. Draw from batteries) when load requires it (augmenting input AC with inverted DC from batts), and when load settles down and normalizes, it should cease being an inverter and return to being a charger (as max input current allows). Thus indeed never really inverting and charging at the same time.

This is the way Victron and Magnum (among others) do it.

[Tikvah]

This is what I have:  http://www.theinverterstore.com/3000-watt-pure-sine-inverter-charger-24-volt.html

3000W 24V

[Oonrahnjay]

...  Your inverter should be smart enough to invert (i.e. Draw from batteries) when load requires it (augmenting input AC with inverted DC from batts), and when load settles down and normalizes, it should cease being an inverter and return to being a charger (as max input current allows). Thus indeed never really inverting and charging at the same time.

This is the way Victron and Magnum (among others) do it.

      Some sources call that "load sharing".  An Outback (at least some Outbacks) don't do that.  If you exceed the max set on your shore cable, it will shut down draw on the shore power and pull *all* the juice to invert your loads from the batteries.  Then, when your loads drop below the max, it will go back to using some shore power to run your loads and use the rest for recharging the batteries.  It's probably not a big difference, but it seems to me that it's less sophisticated and will draw batteries deeper and more often than the load share system.
      I didn't know enough to ask the right question when I bought the Outback.   

[sledhead]

load sharing yes . as the a/c cycles and the compressor turns off and on that is when the inverter starts charging but if the a/c cant keep up then yes it would be shared with the batteries . the system works great as you will never blow a breaker  ( 15 amp ac )  now if you are a POWER HOG and can,t control the amount of power you use then 15 amps will never work . a little trick I do when I only have 15 or 20 amps available is if you want to turn something else on when the a/c is on just turn up the setting on the thermostat for the a/c then when you can turn off the other item ( say a toaster ) you can turn the a/c down again to cool off with out tripping the breaker . works great

dave   

[sledhead]

forgot to add there are settings that you can use to set the ac amperage that you have say 15 amp ,20 amp 30 amp that is how the inverter knows when to use the battery bank to add to the system + if you set the incoming ac amps on the display you can see how much amps you are using at any time

sorry for the drift

dave

[thomasinnv]

Load sharing will simply switch between inverter power or shore power as the ac load requires. Hybrid inverter will supplement shore power by adding inverter power to it as necessary, combining both sources of power together. Load sharing inverter only provides one or the other source of power, not both at the same time. Important to know the difference if you're shopping so you know you get what you expect it to do.

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