Electrical/Battery System Questions

[brightond]

Hoping to get some clarification here....

I am planning on a Battery Bank to support our Daily House requirements...

Lights
Fridge (120 on inverter)
Water Pump
Kitchen Appliances (120 on inverter)
Bed Fans

I also want to have the option to use my Dometic AC/Heatpump and MaxxFan roof vent fans while running the generator or hooked up to shore power.

My question is concerning the Invereter/Charger that I should be looking at. The Pure Sine Wave Inverters are all rated by their Watts. What should I consider for Watts with this setup? If I don't intend on using the Roof AC while on Battery then do I need to factor that load into the equation?


I'm also unclear about how this Inverter will act as a charger. Does this happen when it's fed 120? Can this multi stage charger also charge the bus battery bank (used while bus is running?)

Thanks for the feedback. Please forgive my ignorance

James

[john61ct]

What inverter? Separate function from charging. There are combi units but pricey, I prefer separate.

Need to know the actual wattage draw of each appliance. And startup can double or more compared to continuous.

PSW is safest, some device types don 't need it but.

Any running big loads off battery try to go DC native, no inverter needed and lots more efficient.

[brightond]

No Inverter selected yet. Was thinking I'd want a Pure Sine Wave Inverter with 3-4 stages of charging to ensure my batteries are taken care of. Planning on Lead Acid that I have to maintain.

[ol trunt]

Probably simplest and cheapest to use an inverter for 120v and a converter (3 stage) for charging your batteries from either shore or genny power. If you add solar you'll need a charge controller for it.

Automatic switching devices are available to switch source to source but there is nothing wrong with a manual "swap the plug" system as I have done.
Jack

.

[JDOnTheGo]

Morning James,

What you describe is pretty typical in the RV world. The combined inverter/charger is fine and works as you stated. Some of us prefer separate units so they can be repaired/replaced independently. You will end up with what amounts to two electrical distributions. The first comes from/thru the inverter powering the components from battery or shore/generator power (when it exists), the second is separate and powers connected components only when shore/generator power is available.

Sounds like you need to perform an energy audit or budget. That is the process of determining how much power each component consumes and how long you plan to use it each day. From that information, you can begin sizing your battery bank, inverter, solar array, etc. If you do not already have the components, some guess work is often required. A Kill-A-Watt meter is very helpful.

12VDC ceiling fans are available and can be ran directly off the battery/12VDC system. Typical ceiling vent fans also.

Finally, remember that all battery banks are limited in how much power they can provide and how large of an inverter they can support. In other words, just because a 5000 watt inverter exists doesn't mean that it will work well connected to a 100 AH 12VDC lead-acid battery bank.

[PNW_Steve]

I would be cautious when it comes to "kitchen appliances "...

It would take a very significant battery bank and inverter to support electric cooking appliances. Large loads like induction coocktops are more easily supported with your generator.

Or, go propane for cooking.

[brightond]

Thanks for the replies!

I'm fine with keeping things separate. May even prefer it. So, can anyone refer me to a 4-stage charger that would be independent of an inverter? I think I'm leaning towards using the affordable Sam's Club 6V GC2 Batteries for my first battery bank. I'm nervous to invest in expensive batteries without the knowledge experience to maintain/use properly.

So, with perhaps 6 of these batteries (my audit has me planning on roughly 1156 watt hours per day) what is a charger that could charge these fast and efficiently when connected to shore power or running a Honda eu2000 generator (or two connected together.)

The Inverter would really be for the fridge. When running appliances I would plan on shore power/generator Any recs for adequate size/quality inverter?

[JDOnTheGo]

I like the offerings from Progressive Dynamics (such as this - not saying that is the right size for you, just pointing you to the product line) but there are many good options.

Without knowing anything about your refrigerator, I am only guessing but.... I would expect your daily power usage to be higher than listed when using a residential refrigerator. I have a big Samsung and it uses about 1600 Wh/day. Of course, there are hundreds of possibilities/variations...

[brightond]

Here's what I was planning for Fridge...

https://www.bestbuy.com/site/insigni...E&gclsrc=aw.ds

[Mannix]

If you want to know how many watts your fridge is going to draw, buy a watt meter. You can measure the draw while the fridge is running, measure when not running, and get a total draw over time. Then you can plan accordingly. As mentioned before, motor startup can temporarily draw a large load, so plan for that as well.

[PNW_Steve]

I am looking at the Iota IQ line.

For anything beyond a 2kw inverter I would suggest 8 of the GC2's in series.

[brightond]

Just to clarify, with 8 6v batteries, I would only wire two in series at a time right? This way I basically have 4 12V batteries right?

Could anyone chime in on my existing bus battery bank? The bus came with 3 12V automative batteries. I think these will need replacing but wanted to know if I need to do all 3 or if I could get away with 1 or 2? Bus had GPS unit/radios/tuner/school flashing lights before I converted. Could that be why they had so many batteries?

[PNW_Steve]

Originally Posted by brightond

Just to clarify, with 8 6v batteries, I would only wire two in series at a time right? This way I basically have 4 12V batteries right?

Could anyone chime in on my existing bus battery bank? The bus came with 3 12V automative batteries. I think these will need replacing but wanted to know if I need to do all 3 or if I could get away with 1 or 2? Bus had GPS unit/radios/tuner/school flashing lights before I converted. Could that be why they had so many batteries?

If that's what you want to do.

Take a look at the stickies I linked above and it will explain, better than I can, why, if you insist on a 4-5kw inverter that you will be better served with a 48v house battery.

Here is another good read: https://www.solarpaneltalk.com/forum/off-grid-solar/off-grid-solar-panel-systems/5140-solar-off-grid-battery-design

I was looking for this one regarding Peukert Law:https://www.solarpaneltalk.com/forum/off-grid-solar/batteries-energy-storage/11731-peukert-law-batteries-and-you

[PNW_Steve]

Originally Posted by brightond

Just to clarify, with 8 6v batteries, I would only wire two in series at a time right? This way I basically have 4 12V batteries right?

Could anyone chime in on my existing bus battery bank? The bus came with 3 12V automative batteries. I think these will need replacing but wanted to know if I need to do all 3 or if I could get away with 1 or 2? Bus had GPS unit/radios/tuner/school flashing lights before I converted. Could that be why they had so many batteries?

This is for starting/coach batteries? Not house batteries?

If so, then as long as you provide adequate cold cranking amps you should be good.

I have had buses that used two 8D's or three group 31's. When it came time to buy batteries the bus with the three group 31's was cheaper.

[Coolbreezetravels]

the first thing you need to do is find out how many amps and/or watts each item will use, that will tell you how big of an inverter you'll need. I personally went with an Aims 2000 watt continuous 6000 watt peak here's an amazon link on the one i went with https://amzn.to/2WojsZJ

[Doktari]

Iota DLS chargers with IQ4 are good chargers. It is not power factor corrected however so if you run off a 120 volt generator it’s not very efficient. Longer run time. Good inverter charger combinations are power factor corrected. Shorter run time.
I’d like to have a fully adjustable charge. A big 48 volt Iota DLS power supply/charger feeding a big programmable charger controller could be set to charge any battery voltage at any amperage rate. That would be useful as I mess around with different batteries. But expensive!

[john61ct]

Looks like they're limited to only 700W output.

And not adjustable voltages.

Telecom / data center PSUs are worth looking at.

[john61ct]

Iota tech support says no problem paralleling their units for greater current output.

Gives great flexibility powering off multiple AC circuits if needed.