Ideas needed for 12v systems if I do 24v

[Unyalli]

I want to do a 24 volt system so I can use the Magnum MSH4024M Hybrid inverter instead of the MSH3012M. The question is how to power the existing 12 volt stuff.

1) Use an MPPT solar controller to keep my existing group 27 Interstate battery charged off my GC2's?

2) Use a Samlex SDC-30 24VDC to 12VDC converter?

Other ideas?

Jeff

[MrWizard]

i think buying a 3kw inverter generator makes more sense

i have 505w of solar and almost 1000Ahr of battery capacity, and i would not waste my time straining my battery bank to run a 13k btu A/C

powers our fridge and our lighting plus TV PC, 'OCCASIONALLY' even the coffee maker or microwave,
A/C forgetabout it

[2oldman]

Unyalli wrote:
I see the Orion 25 amp is similar in price to the Samlex 30 amp. Now on the DC to DC converter subject I'm leaning towards the Victron. How long have you used this little dude?

Almost a year. Its output voltage never varies.

This is where I bought it

[BoonHauler]

I was just wondering if the genset power needs to be pure signwave or if it could be a modified signwave?

I have not done any research into these new 'Hybrid' inverters so I have no idea of how that would work.

I'd have to think the genset would have to be an inverter and not an alternator type.

Hey Don, thanks for doing those calc's for me.. 🙂 ..that would be great if it was the only load I have but the Refrig & Freezer (12 VDC) will most likely run about 150 A/H's a day....

[Unyalli]

2oldman wrote:



That's a Victron DC/DC converter with rheostat controlled variable output from 10-15vdc. I keep it at 12.5-12.6 all the time. I can find the model number if you need it. I believe it's rated 25a. I read the specs on your Samlex, and I don't think I saw that the output was configurable. I'd rather see you do that.

I'm really happy with this system, and, the smaller wire is so much easier to work with.

I see the Orion 25 amp is similar in price to the Samlex 30 amp. Now on the DC to DC converter subject I'm leaning towards the Victron. How long have you used this little dude?

[mrekim]

tahiti16 wrote:

When the generator is running you don't use the invertr.

The cool thing about that inverter (12 and 24v versions) is that it will parallel with the generator. You can tell the inverter that the AC supply can only handle 13 amps. If the inverter senses demand greater than 13 amps it will supply additional power from the batteries. If you're running the AC and drawing 12 amps and then turn on the microwave for 60 seconds drawing another 10 amps, the gen will supply 13 and the inverter the other 9.

tahiti16 wrote:

rAlso remember if you areset up for 24 volts you will only have 1 battery rating of amps and if 12 2 batteries of rating. I.e. at 24 wthbatteries rated at 200 amps each you will have 200 amps. At 12 volts with same batteries you will hav 400 amps available.

24V*200A/H = 4800Watt/H

12V*400A/H = 4800Watt/H

So both battery configurations result in supporting the same load.

[Unyalli]

Page 32 of the Magnum MSH Hybrid manual talks about the unique feature of these inverters the "Load Support" feature.



If I limited the "Shore" input to 1000 watts and the inverter loads were 1500 watts this Hybrid inverter would use the existing 1000 watts of shore power and combine in 500 watts of battery to output the full 1500 watts. If this extra 500 watts is provided by solar you have not used your batteries.

Load support VDC on the same page is also interesting. If I added another 200 watts of solar this inverter would back off on it's shore power draw possibly allowing the generator in eco mode to throttle down.

Jeff

[tahiti16]

Jeff
I see where we went a stray. I should have stated I have no intention of running 30 amps off batteries. I intend to run 30 amps off the inverter which will have 1200-1400 watts A/C provided by my generator and 500 watts DC provided by solar.

Jeff
When the generator is running you don't use the invertr. rAlso remember if you areset up for 24 volts you will only have 1 battery rating of amps and if 12 2 batteries of rating. I.e. at 24 wthbatteries rated at 200 amps each you will have 200 amps. At 12 volts with same batteries you will hav 400 amps available.

[2oldman]

Unyalli wrote:
How did you guys talk your selves into thinking I had any intention of running an AC off batteries?

Unyalli wrote:

CA Traveler wrote:
Also make sure the inverter will handle the AC start up surge.

This is precisely the reason for the new Magnum Hybrid's. The 3kw will handle a 15k ac but there's not much left.The Coleman 13.5 PS series use two thirds the power of normal 13.5's and would fit the 3kw Magnum much nicer but 4kw Magnum would not have to work as hard.

That ^^

[Unyalli]

smkettner wrote:
Victron 2000w (12 volt) is just $1500 and will combine power to have the full 3600 watts available to run the microwave while the air is running from the generator.

http://www.jamestowndistributors.com/userportal/show_product.do?pid=61576

I can't imagine needing more than 2000w continuous when the generator and air conditioner are off.

Agreed and I looked in depth at the Victron and liked what I saw. Very nice equipment. Then I found the new Magnum Hybrids and being a yank who believes in my founding fathers vision I'd rather buy American if possible.

Jeff

[Unyalli]

Unyalli wrote:

Argosy24 wrote:
What are you running off of batteries that will need 30 amps @ 120v?

Possibly a Coleman Mach III PS, microwave, coffee pot, TV, Laptop who knows what else.

I'd rather pop a 30 amp breaker than over load the inverter.

Jeff

I see where we went a stray. I should have stated I have no intention of running 30 amps off batteries. I intend to run 30 amps off the inverter which will have 1200-1400 watts A/C provided by my generator and 500 watts DC provided by solar.

Jeff

[time2roll]

Victron 2000w (12 volt) is just $1500 and will combine power to have the full 3600 watts available to run the microwave while the air is running from the generator.

http://www.jamestowndistributors.com/userportal/show_product.do?pid=61576

I can't imagine needing more than 2000w continuous when the generator and air conditioner are off.

[Unyalli]

Well looky how far off topic we have ventured. How did you guys talk your selves into thinking I had any intention of running an AC off batteries?

IF I run the AC it will be with the generator via the inverter so the inverter can handle the start up surge. I will attempt to keep this surge as small as possible by installing a 5-2-1 compressor saver like I did in my previous RV's AC.

Thanks for responding fellas, I'm glad I was not dumped into the ignore bucket (all though I may be now).

Jeff

[pianotuna]

Hi Jeff,

Realistically you are not going to run an air conditioner on that size and voltage battery bank for long (perhaps less than 1 hour to 50% state of charge). If using the bank with a Victron or Magnum inverter only to provide start up surge--then it will work.

I'd favor the 24 volt--but remember each cell has to provide the full amperage of the string. That will be in the 60 amp range for six volt jars--or twice what is recommended. Using 12 volt jars (4) will drop that to 30 amps per cell.

Using four 6 volt for a 12 volt system bumps the amps per cell up to 120. The battery bank will not be happy.

If you have room for six 2 volt agm units you would have a much better chance of powering high draw items for long periods of time.

A cheaper (and better) solution may be to add a larger "hard start" capacitor for the air conditioner.

If you plan on running air conditioning for long periods of time, the cheapest thing you can do is find an inexpensive campground.

Unyalli wrote:
I will have 4 GC2's either in series for 24 volts or two parallel strings of two ea in series for 12 volts.

To start I'll have a realistic 500 watts of solar and my little Champion 2000i inverter generator. I can tell the MSH to only draw 1200-1400 watts from the generator so I don't ever overload it. I'll have to experiment to see how much this will be. I'm certain I'll have to add more solar and that will come after some real life use of the existing stuff.

Jeff

[time2roll]

If you are just using the inverter to boost the generator power to run the air etc you do not need 4000 watts, 6000+ surge + 2000w generator.

My Prosine 1800 will easily start my air conditioner all alone.

Get a smaller boost inverter. Magnum is probably fine but I would have a Victron if spending money. 1800/2400 rated watts is way plenty.

4x GC2 is a bit light for 4000 watts running. May need 8x GC2 or go L16.
Just for short surge might be fine.

Running the air on inverter alone will use over 1200 watts of solar.