Newb beginning first build

Re: Newb beginning first build

Welcome to the forum.

You're going to need to define the requirements a little more specifically. For example 1000 to 1500 Watt pure sine inverters: there are lots of good ones. Should it have a built-in AC charger? That changes brands and price points. I'm going to point you to our host's OG inverter section here so you can peruse some of what is available: http://www.solar-electric.com/inverters-controllers-accessories/inverters.html

Battery brands. There are several good ones, but what exactly you get is going to depend on how much capacity you need in Watt hours, how deep the discharge should be limited, how portable it needs to be, et cetera.

I would hazard a guess you are looking for back-up/portable power for a CPAC machine. You'd be amazed at how many people need that! If this is not the application, please tell us what is and we should be able to tailor the help a little more precisely.

Re: Newb beginning first build

Sockpuppet wrote: »

I presume the inverters listed are closer to top of the line quality products, which also translates to a more costly product. I'm not opposed to the additional costs associated with a better quality product, but also don't wish to overspend for a less expensive product that would be adequate for the task.

Well they range from the basic and inexpensive Samlex units (about $380 for 1kW 12V) to the more complex inverter-chargers such as the Outback (about $1700 for a 2kW 12V). In between there are some options like the Exeltech line (about $568 for 1kW 12V). Just to give you some idea of the kind of things that are available and what they may cost.

An inverter charger would be a nice feature, but would it be capable of simultaneously charging multiple batteries on household AC?

The inverter-chargers are designed to recharge their own battery banks, whatever that may be, when solar is not available but an AC source is. The value here is that their chargers are designed to work with many different ranges of deep cycle battery so they can be programmed for 'ideal' Voltage and time. Standard stand-alone AC chargers aren't really up to the job, so some life expectancy is sacrificed. The down side is that they are bigger, heavier, and more expensive. The OB is an inverter-charger, the Samlex and Exeltech are not.

If everything is perfect, I require to be able to potentially operate 700 Watt hours for 4 hours, before the capacity is discharged too low for operation.However life does often happen to present imperfect scenarios, so I wish to have some wiggle room on that number, to perhaps even include some comfort items.

Okay now we're talking real numbers. 700 Watts for 4 hours is a 2800 Watt hours AC. As a minimum requirement, that's actually pretty big. As in shift up to a 24 Volt system, and then you need 275 Amp hours minimum to meet that requirement at 50% DOD (which leaves almost no room for error). It's actually more power than my entire cabin uses in a day, including running a refrigerator and water pumps. This is looking portable only in terms of "do you have a large truck"? Even skipping the inverter-charger and going with the lightweight LiFePo (not all that easy to work with nor cheap) batteries this is substantial. Especially once you add PV (about 850 Watts).

I can always build a system to be able to move it, but again, an apartment doesn't lend itself to a lot of space. As such, I'd prefer to keep it reasonably compact.

See above. Compact is not going to be a major feature when you have to store up that much energy.

CPAC? You must hold the same values I do. LOL.

I wouldn't be amazed at all. I have too many years working public safety and nursing, witnessing a fair amount of people with sleep apnea.

Seriously, I wish it were as simple as a CPAP or BiPAP application at roughly 50 Watts per hour. Without going too far, I potentially require to continuously power a ventilator, humidifier, and pulse oximetry; with intermittent operation of suction, nebulizer, CPT vest, and Gastrostomy pump.

Each has its own internal power supply for a few hours of operation during utility interruption, but as with any device, its potential for failure or subsequent discharge exists.

Okay, a bit beyond the CPAC demands then (some of them have much worse than 50 Watt requirement). Sounds like a whole palliative care ward you're trying to maintain. Well I've done some clinic systems for remote places ... but they didn't have to move about.

I know they probably won't let you run a generator in your apartment but ... It's hard to beat fossil fuels for compact power storage.

I wish there were a better answer here. How's the budget? LiFePo is more compact than standard batteries with a slightly wider usage range and more resistance to partial state of charge conditions, but approximately 3X the price of standard lead-acid batteries and somewhat more complex to set up and run. They are not for the faint of heart or beginners really.