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

[Taranakian]

Man - I just wrote a novella and then realised expecting people to read and weigh in was a big ask.

Here's the short(er) version. We were land poor for awhile after buying our property 3 years ago but still had needs that had to be met so, as a first timer, I cobbled together whatever systems I could afford that would meet our basic needs. We didn't have the luxury of spending once.

Our current Frankensteinian system consists of:

- 1x string of 6x 240W panels (22V/11A) - connected to...
- 1x Midnite Classic 200
- 1x string of 4x 240W panels (30V/8A) - (not currently connected as they were a great deal but we don't need them in summer.)
- 2x supercaps/supercap banks in parallel, one with panels, one with batteries
- 1x 2000W PowerTech inverter (Jaycar Electronics special, so far the longest lasting inverter I've bought)
- 2x 220Ah AGMs (hybrid system with below)
- 2x 200Ah drop in LiFePO4s (hybrid system with above, added less than a month ago - great deal on secondhand, unused batteries)
- 1x 100W Ampair wind turbine (not currently connected, just bought recently)
- 1x Enerdrive ePower 12v 60A battery charger
- Cheap briefcase style 2000W Generator
- Various fuses, bus bars, etc.,

I reckon that's it.

Finally, for the last three years, with very few exceptions, we use 1.5kWh/day. The biggest day of usage that I remember was 2.2kWh.

Once we got the LiFePO4 batteries and got them hooked up two things happened:

1 - It became clear that I needed more visibility and more granular details to monitor the SOC of the batteries and I've decided to go with Victron - I needed another charge controller anyways for the second bank of used panels that I bought so that's fine, plus I can then relegate the Midnite Classic to run the wind turbine when I get around to hooking it up.

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...

Now here's where I need opinions...

We already know I need two new charge controllers and with all the new appliances we're buying I'm going to need inverter capacity greater than the 2000W I have available right now, which really means the underlying DC system doesn't much matter - if 240VAC is no longer just for the fridge we should just go heavy AC and skip out on DC for everything but lighting and the water pump. I could go to the store tomorrow and buy another of the same 12V 2000W inverter to parallel and then order a couple Victron SmartSolar charge controllers some time before the winter overcast sets in. I'm just actually a little anxious about whether the short-term-ism of buying components to solve my immediate problem/match my budget has become ingrained and now that I have some more budget (or at least increased ability to rapidly pay off debt) I should be looking at spending more and getting to a point where I don't need to spend again for a real long time. Conversely, it's really addicting to be spending money again, and I'm clear I could be totally wrapped up in the thrill of the spend.

If I'm already spending on big system upgrades, are there intrinsic benefits to going 24V even if we're already well wired up for 12V and use as little electricity as we do? Worth noting, I've only considered going 24V because I hadn't really thought about buying even more batteries, but that's not a line in the sand I guess...I just don't think we use enough power to really get the benefits of 48V but really, actually, what do I know?

Finally, I should also mention that I've just taken a contract that pays very well, but will likely only last four of five months so there's no guarantee I will have the opportunity to upgrade next year or the year after the way I do now. I'm semi-retired and don't often look for work, I'm just tired of nickel-and-diming it (and buying 3 inverters, and 4 fridges, and 3 charge controllers) so I took this contract specifically to upgrade our quality of life.

So, if it were you, would you buy:

A - 1x matching 12V 2000W inverter to parallel with current inverter, 2x 12V Victron SmartSolar options to match two existing solar arrays
B - 1x Victron Phoenix 12/3000 inverter, 2x 12V Victron SmartSolar options to match two existing solar arrays - sell current inverter
C - 1x Victron EasySolar 24/1600 (inverter/charger/mppt), 24V Victron SmartSolar to match remaining solar array, 1x 24v->12v buck converter - sell current inverter and battery charger
D - 1x Victron EasySolar 24/3000 (inverter/charger/mppt), 24V Victron SmartSolar to match remaining solar array, 1x 24v->12v buck converter - sell current inverter and battery charger
E - Some entirely different set up that you'll expand on below?

Hey, I know this has been a long read full of silly anxiousness and I certainly won't be terribly unique in looking for someone smarter, wiser, more practiced than me to just tell me what to do and relieve my entirely-self-inflicted analysis paralysis. Thank you, really, for taking the time to read and for those who take the time to respond.

 

[Tomthumb62]

Why not 48v system since you're upgrading?

 

[Taranakian]

Why not 48v system since you're upgrading?

It's a fine question.

Initially I hadn't really thought about 48V because I'd prefer to skip the expense of buying new batteries and I could rearrange my current bank into 24V easily. I also have given myself the idea that 48V is really for people who make and use lots of electricity and we just don't - I'm not saying that's a factual statement, just something I picked up from somewhere along the way.

Upgrading to 48V will double my expenditure for having to buy new batteries, but I do like an argument about future-proofing and arguably it'll halve the expense of upgrading to 24V and then one day realising I should have gone 48V.

 

[Tomthumb62]

It's a fine question.

Initially I hadn't really thought about 48V because I'd prefer to skip the expense of buying new batteries and I could rearrange my current bank into 24V easily. I also have given myself the idea that 48V is really for people who make and use lots of electricity and we just don't - I'm not saying that's a factual statement, just something I picked up from somewhere along the way.

Upgrading to 48V will double my expenditure for having to buy new batteries, but I do like an argument about future-proofing and arguably it'll halve the expense of upgrading to 24V and then one day realising I should have gone 48V.

You can still use your batteries on a 48v system. You just need two more to make a 48v bank. And get an equalizer device, too. I’m assuming your 2x200Ah batteries are 12v.

 

[Taranakian]

You can still use your batteries on a 48v system. You just need two more to make a 48v bank. And get an equalizer device, too. I’m assuming your 2x200Ah batteries are 12v.

We're building a couple of outbuildings this summer, so it would make sense to me to split our current battery bank between those buildings - put the LiFePO4s in my workshop and the AGMs in my husband's office - and get some LiFePO4s intentionally chosen for our designed setup instead of batteries that we bought because we they were cheap.

You've largely got me convinced. Not gonna lie though, I'm still hoping someone comes around with a compelling argument about 48V being overkill in our situation that also makes a solid case for 24V - only just for the expense of it all.

 

[Tomthumb62]

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.

 

[Tomthumb62]

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.

if your wire runs are short, the extra cost of 24v wiring might not be bad, but since pure copper (or tinned copper) is so dang expensive, that hidden cost adds up FAST with longer runs.

 

[Rocketman]

Take the long-term view…

Plan your ideal system Victron system as if money was not an issue. Then replan your system you can afford - you may find they are not too far apart. (Or there is an upgrade path to go from one to the other).

In a house I would go 48v. Also you can buy much smaller mppt’s w/48v. Go with the Multiplus inverters because then you have the transfer switch and charger built in. Maybe the Multiplus 48/5000?

Good luck with your project.

 

[Taranakian]

if your wire runs are short, the extra cost of 24v wiring might not be bad, but since pure copper (or tinned copper) is so dang expensive, that hidden cost adds up FAST with longer runs.

With the new appliances we're buying, it makes sense to me to embrace AC and only keep DC for our LED lighting, water pump (until it dies or I move the freshwater tank out from under the bus), and UV filter. Given that solar is going into the solar cabinet at 150V for one bank and the second will be 120V, the work of transferring 12/24/48V into 240V is currently being done in the solar cabinet, and there is no single run in there greater than about .5m, and after that it's all 240VAC anyway, well, it seems to me like I don't have much cause for concern around wire runs, but am I missing something?

I guess the crux of my paralysis is, if I go 48V I'll future-proof to the best that is available here in NZ. That's the Victron EasySolar II 48/5000/70-50 MPPT 250/100 GX at $3,842 not including the additional components or batteries (obvi). But if I don't need to worry about the cost of beefy wiring or components because they're pre-existing, and that after the addition of these upgrades we're not likely to ever use significantly more electricity, might 48V be overkill and the EasySolar II 24/3000 at $3,195 be sufficient? While the cost difference between the two inverter/chargers isn't enough by itself to think twice about, the second part of the equation is, if 3000VA/2400W turns out not to be enough in future, it would cost me approximately the same to add another EasySolar II 24/3000 (and significantly less to plug the output of a Phoenix inverter into the AC input of the EasySolar II) as it would to buy the additional batteries required for a 48V system now and with all the components in the solar shed any wiring around that will still be minimal. Also worth noting is the discharge current of our batteries will support up to 4x 2400W inverters at 24V.

I totally get that it sounds like I'm digging in my heels here, and that's cause I'm unintentionally digging in my heels here. But I am taking in what you're saying and chewing on it, and largely trying to get some insight into and test my assumptions. I've got no doubt in my mind that 48V gets me where I need to go, and makes sure that I will absolutely never have to consider switching components to a higher voltage yet again - 48V4Lyfe. I just guess I'm just bumping up against a feeling that 24V vs 48V for our usage is "6 one way, half-dozen the other" and if, for our usage, they're both much-over-muchness then I'm really struggling against my sense of value.

I appreciate you taking the time to help me feel it out.

 

[Taranakian]

Take the long-term view…

Plan your ideal system Victron system as if money was not an issue. Then replan your system you can afford - you may find they are not too far apart. (Or there is an upgrade path to go from one to the other).

In a house I would go 48v. Also you can buy much smaller mppt’s w/48v. Go with the Multiplus inverters because then you have the transfer switch and charger built in. Maybe the Multiplus 48/5000?

Good luck with your project.

Man, I am oscillating on this...

I don't mind spending for the right system, and I don't mind taking on debt to pay for the right system if need be - we'll pay it off, we always do. I guess my blockage is around understanding that 48V is significantly better than 24V - at least enough to justify the expense if all of our wire runs are quite short anyways and I've already got beefy wires and components for having been 12V for the last 3 years. I don't mind taking on the expense for the right setup - I'd much rather spend and be done - but I'm not entirely convinced that going 48V isn't spending for the sake of it based on our actual real world usage.

The upgrade path is a fine point, too. We are building a couple of outbuildings this year, one of which is going to be my workshop/shed which will have battery powered tools but nothing grunty/pugged in so 24V won't go amiss in there if it's insufficient for the housebus. Which totally contradicts one of my initial statements - not being clear we'll have the opportunity this time next year to throw at another high dollar upgrade in the near future so making the most out of this one...but it seems I can't have it all (or at least won't let myself).

I'll get the EasySolar II which has an embedded Multiplus II and an MPPT charge controller which means.

 

[hwy17]

my blockage is around understanding that 48V is significantly better than 24V

It's not for electrical characteristics or wire size. It's for components price and availability.

The 48v ecosystem is so much larger than 24v now. 24v really restricts your choices.

 

[Taranakian]

It's not for electrical characteristics or wire size. It's for components price and availability.

The 48v ecosystem is so much larger than 24v now. 24v really restricts your choices.

THAT is worth a think about. I guess I haven't really thought about components besides what's strictly necessary to take electricity from our solar panels, safely put it into batteries, then safely deliver that battery power to 240V at our appliances. I should defo give peripherals a noodle.

Thanks for the insight.

 

[hwy17]

THAT is worth a think about. I guess I haven't really thought about components besides what's strictly necessary to take electricity from our solar panels, safely put it into batteries, then safely deliver that battery power to 240V at our appliances. I should defo give peripherals a noodle.

Thanks for the insight.

Yeah and I do mean the major components too. Even if you don't end up needing a larger inverter, most of the competition in batteries is in the 48v market.

 

[Supervstech]

Define "induction coooktop"

I have installed 8400W 240V cooktops...

Or do you mean coumtertop simgle burner induction cooktop?

 

[Taranakian]

Define "induction coooktop"

I have installed 8400W 240V cooktops...

Or do you mean coumtertop simgle burner induction cooktop?

It's a 2 burner portable cooktop rated at 2400W total.

 

[Tomthumb62]

Yeah and I do mean the major components too. Even if you don't end up needing a larger inverter, most of the competition in batteries is in the 48v market.

Yes, OP you won't be finding any good deals on 24v batteries or components. They are a very niche market. They are marketed to people just like you...stubborn to go to 48v "because 48v 'feels' more expensive than 24v" and so they ding you every step of the way because very few companies sell 24v and those who do can do so at a premium price, because the market will allow for it.

I forgot to mention this very real fact that @hwy17 wisely points out. There is really NO good reason (if you intend to save money) to go 24v unless you've already sunk your cookies into a 24v system. You're at an upgrade point, make it a once and done.

As for exactly how do you do that, sorry I can't help much as my main experience is with a tiny 12v that basically powers a fridge, laptop and two phones and basic RV things (lights, water pump). But I've been a regular on this forum long enough to know the writing on the wall when someone would be wise to go 48v for a home system.

 

[Rocketman]

Because it sounds like you will need 2 systems - you could go 24v on one and 48v on the other. Start on the 24 on the house - then move it to the shop/ outbuilding and get 48 for the house.

Still plan both systems out first - that way you have the capability you need and also so you buy items that work for both - for example don’t buy the mppt 100/50 it only does 12v and 24v buy the mppt 150/45 or 150/60 because it can do 12,24 or 48v.

 

[jeremyee]

I went from 12V to 24 and then to 48. I should of gone straight to 48V and saved a bunch of time and money. go 48 Volt

 

[Taranakian]

Yes, OP you won't be finding any good deals on 24v batteries or components. They are a very niche market. They are marketed to people just like you...stubborn to go to 48v "because 48v 'feels' more expensive than 24v" and so they ding you every step of the way because very few companies sell 24v and those who do can do so at a premium price, because the market will allow for it.

I forgot to mention this very real fact that @hwy17 wisely points out. There is really NO good reason (if you intend to save money) to go 24v unless you've already sunk your cookies into a 24v system. You're at an upgrade point, make it a once and done.

As for exactly how do you do that, sorry I can't help much as my main experience is with a tiny 12v that basically powers a fridge, laptop and two phones and basic RV things (lights, water pump). But I've been a regular on this forum long enough to know the writing on the wall when someone would be wise to go 48v for a home system.

- 48V doesn't just "feel" more expensive - it actually is significantly more expensive in that I am currently in possession of batteries I would use for a 24V 9.6kWh battery bank which will get us by for 3-4 days of no power production. Given the life of LiFePO4s and that I can add more, the rapid development of battery technology, that I'm not running a high-power workshop or industrial site, and that battery prices are coming down this just doesn't land for me.

- Everything in NZ is a premium price. Everything. I won't be finding good deals on 24V batteries, I get that for sure. I also am no more likely to find a good deal on 48V batteries.

- I've been around forums in general long enough to know when conversations come to a head because of a combination of OP stubbornness (totally owning that) and people giving opinions/advice without addressing anything meaningful in the OP's original questions/follow-up responses. I appreciate you having taken the time to respond, and it's great that you "see the writing on the wall when someone should go 48V" but you haven't actually addressed what the tell tale signs are and why 48V is so much better, when 24V looks entirely sufficient especially when you remove the assumption that any gear is significantly cheaper here in NZ than any other gear, or even readily available here in the first place.

 

[Q-Dog]

Do what works best for you. I am very happy with my 24 volt setup and have no plans to change to 48. I just added more 24 volt batteries and would have to build or buy new batteries to go 48 volt. If we do need more capacity we will likely parallel another 24 volt MultiPlus.