Personal opinions please? If already upgrading gear, should I go from 12v to 24v?

[Kiwi2000]

2 - Suddenly we've been on a big kick of buying appliances that we finally have the oomph to run. We've got a dishwasher being delivered on Monday, we're buying a new induction cooktop, and we've got a benchtop combi-oven on order. The combi-oven and induction cooktop will only be used from mid-Spring - mid-Autumn when we have plenty of excess solar. We bought a fancy woodstove a couple of years ago that's specifically designed for cooking and we have a fire every day in the colder times of the year so already have a hot cooktop and oven. The dishwasher is rated at 560Wh/day, but we'll have it hooked up to the hot water heater directly so it should be less than that...

I think you'll need to work backwards from your loads. Look at what those appliances are going to draw then do the numbers on how you will power them.

Some modern dishwashers heat the water as they run and can draw several kilowatts. Trying to run those off 12v may be next to impossible.

I know what you mean about the availability of 12v batteries and components in New Zealand compared to 24 or 48v batteries.

I run most of my house on a 12v system. All reasonably small loads though. The biggest load is the 2000w hot water cylinder element. And I run that off its own dedicated 3000w inverter.

 

[Daddy Tanuki]

while racing cars it was always a pair and a spare because two is one, and one is none. if you are living offgrid, you need spares or you will be down without power sooner or later.

Factor in the simple fact that as time goes on 24 volts will slowly die away. 12 will not due to RV's and vans and cars. 48 even if it gets replaced by say a higher voltage (say 96 for instance) will be around much longer than 24 as 24 offers no advantages over 48. so when you do blow one up 5 years from now will there still be any tier one makes for 24 volt?

 

[Crowz]

I started out with 24v when I did my first house. Im on 48v now on the newest house. I have a 12v system too that runs misc stuff.

Now to put my experience with it all in perspective I found with 12v I'm worried about what I can run and runtime.

With the 24v equipment I wasn't worried at the time as much about what I could run but the runtime was an issue at times.

With the 48v I don't worry about runtime or what I can run. Even with a single battery I can run 4 to 6 hours running my house and that is with a 800watt to 3kw varying load. The inverter can do 6kw and surge to 18kw.

So for me if I couldn't have but one system and I was doing it all over today it would be all 48v. Not a cost vs whatever choice as much as a worry free and just enjoy it point of view. Also I would make sure it can do hybrid grid usage even if you don't have any connection to the grid now. It really doesn't cost more or very little more and if you ever do use the grid you will kick yourself for not having it.

 

[Whats_per_question]

If I were going to use this system for my home and the cost of 48v was the same as 12/24v, it would be a no brainer. Future proofing. Plus wiring for 48v will be 1/4 the cost of 12v and roughly 1/2 cost of 24v. But greater danger, so make sure you run your system by the smarty pants people here before energizing anything.

Just my 2c worth; I would argue the opposite - that a 12v system built for X watts of power is much much safer on 48v than 12v, because a poor terminal on 48v (at 1/4 the current) is much less likely to melt insulation or copper than the same system running 12v and four times the current. In terms of danger to the installer, I touch both terminals of 48v batteries with bare hands all the time, never had an issue.

 

[WindWizard]

The big issues with 12v, 24v, 48v is the amount of current you are going to be running from the batteries to the Inverter. It is easy to figure it out. If you are going to need a 5kwatt inverter, then the amount of current will be 12v - 416 amps, 24v - 208 amps, 48v - 104 amps. This does not take into consideration the surge current that some motors and refrigerators etc use.

Not only do you need to consider the size of the wire to handle the load but also all of the stray resistance due to connections. If you put your hand on a connection and it is warm or hot, then that is a serious problem.

With a 12v system then the connections should be examined on a periodic basis to avoid a fire hazard. With a 48v system then it does not require the same amount of current, so it is not as much of a fire hazard.

When I started to plan my system, I went through the same thought pattern of 12v, 24v, 48v. I looked at equipment and I wanted something that I could cry once and be done with it. I wanted something that worked and something that I did not have to babysit or have it go up in smoke after a year or two.

Another thing that came to my mind when I was considering which voltage to use was the charge controller. That seems simple enough but with a 12v system a Victron 250/100 charge controller only puts out about 1200 watts or with a 24v system the same charge controller doubles the wattage and puts out about 2400 watts and at 48 volts the very same charge controller puts out about 4800 watts.

And then the solar panels have to be based on the amount of wattage the charge controller can handle. So with a 48 volt system, you can use 4800 watts of solar panels.

After much thought I went with a 48-volt Tier 1 system, and I am glad that I did.

 

[Whats_per_question]

The big issues with 12v, 24v, 48v is the amount of current you are going to be running from the batteries to the Inverter. It is easy to figure it out. If you are going to need a 5kwatt inverter, then the amount of current will be 12v - 416 amps, 24v - 208 amps, 48v - 104 amps. This does not take into consideration the surge current that some motors and refrigerators etc use.

Not only do you need to consider the size of the wire to handle the load but also all of the stray resistance due to connections. If you put your hand on a connection and it is warm or hot, then that is a serious problem.

With a 12v system then the connections should be examined on a periodic basis to avoid a fire hazard. With a 48v system then it does not require the same amount of current, so it is not as much of a fire hazard.

When I started to plan my system, I went through the same thought pattern of 12v, 24v, 48v. I looked at equipment and I wanted something that I could cry once and be done with it. I wanted something that worked and something that I did not have to babysit or have it go up in smoke after a year or two.

Another thing that came to my mind when I was considering which voltage to use was the charge controller. That seems simple enough but with a 12v system a Victron 250/100 charge controller only puts out about 1200 watts or with a 24v system the same charge controller doubles the wattage and puts out about 2400 watts and at 48 volts the very same charge controller puts out about 4800 watts.

And then the solar panels have to be based on the amount of wattage the charge controller can handle. So with a 48 volt system, you can use 4800 watts of solar panels.

After much thought I went with a 48-volt Tier 1 system, and I am glad that I did.

As many people say ... " You will appreciate quality tools long long after you have gotten over the pain of buying them" or something like that.

I read a post on this forum that lamented Victron for being "overpriced eurotrash" or similar wording. There's no point replying to those people, and there's no point saying "i told you so" to the poor sole who has trashed their new battery with an over-charging PWM that is labeled MPPT (i'm looking at you TradeMe!) when you know that they did it (bought the cheap controller) because they didn't know any better.

This forum is great for giving people advice, and i'd like to think that many users have been saved from a disaster by the gentle guidance this forum offers. Thank you to all of you who regularly steer people in the right direction.

Have a great new year everyone!

 

[time2roll]

I will generally recommend 2000 watts (solar or inverter) max on 12v. Maybe a little more with an RV that has many other 12v items.
For a cabin/home/shop etc go right to 48 volts if upgrading beyond 2000 watts.