48V vs 12V - PART 2: Is a Rack Battery the BEST choice? Vatrer Power 51.2V 100Ah LiFePO4
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- Опубліковано 3 лип 2024
- #48v #lifepo4battery #backuppower #offgrid #solar #vatrerpower
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12V vs 48V Systems video: • 12V vs 48V Part 1: WH...
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![Why a 48V System is Better than a 12V? [Vatrer Power]](http://i.ytimg.com/vi/8ukQ9wQfMIY/mqdefault.jpg)
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Four of the 100AH 12v batteries do tend to cost a little less than one of the 48v batteries. You can also buy them as funds are available, versus having to pay a larger lump sum. The major advantage of using four 12v, 100AH batteries instead of a single 48v battery, is you can always disconnect the four individual batteries and use them for other purposes, when needed. The 48v battery is less portable and more or less dedicated to one use case. You could use four of the 100AH, 12v batteries, in series, for your home solution, then take two of those batteries, in parallel, to run the 12v system in your RV...can't easily do that with a 48v battery.
I have found a similar uses for my old 12V and 24V batteries, but .... mmm. I don't think that's a good reason to actually go-out and buy a 12V battery, even if incremental expansion is the goal.
You can buy 25Ah 48V batteries (The 48V (51.2V nominal) Lithova)... that's about the smallest increment possible for 48V and it is equivalent to a 100Ah 12V battery. I personally think that 2.56 kWh (50Ah @ 48V, 100Ah @ 24V, or 200Ah @ 12V, all LiFePO4 of course) capacities are the best compromise for weight and portability. Easily lifted and carried around.
-Matt
when you buy all the cables and breakers you may find the server rack cheaper, and more durable.
@@davidparker7156 Absolutely correct. BMSs fail all the time too..
some people looking to change from 12v to 48v probably already have 12v batteries so it is generally cheaper to just buy 1 or 2 more 12v batteries then buy a 48v battery
It is, but it is not ideal because you are losing out on redundancy (parallel connections) and robustness (balancing is never perfect) when you do that. And its a lot of cabling and takes up more space. But still perfectly doable if no other configurations are economically feasible.
@junkerzn7312 if you already have 2 * 12v 60ah agm batteries to swap to 48v you only need 2 more which is about $130 and an all in one (like a vevor for about $260) so for less then $400 you can swap your agm 12v system to a 48v system then in a few years get a lifepo4 battery or something
@hy1 It doesn't make a whole lot of sense to try to scale-up an old 12V lead-acid system that small, particularly if it would mean mixing batteries of different ages. Better to save up your money and do a complete replacement with LiFePO4 down the road.
The voltage you go with really depends on just how big a system you expect you might ever want. If the system is expected to remain small (i.e. less than 1000W of solar, less than 5 kWh of usable storage), it is totally reasonable to go with 24V for your upgrade project instead of 48V.
A 24V system can be comfortably built with 50Ah or 100Ah 25.6V LiFePO4 batteries. So roughly storage between 1.28kWh and 5.12 kWh, inverting power up to roughly 2.5 kW, and up to 1000W of solar using 2 AWG main battery cabling and typical bus bars and other low-cost components.
If the expectation is that the system would grow more than that in the future, then I'd go with 48V from the beginning.
-Matt
Looks to be a well built battery system your testing today. Plus the LCD screen is nice.
Just stumbled onto your channel and subscribed. I like the way you explain things.
Awesome, thank you!
Thanks for your review.
What are your thoughts on the build quality of the internals? Like wire sizing and type, welded connections etc.?
I just bought (4) 12v 100a batteries for a grand total of $600. Not near as fancy but for less than half the price it fits my budget. As far a balancing goes according to Will Prowse and David Poz if wired with the leads at opposite ends of your pack they will balance themselves but best to just make sure to fully charge prior to hookup. I have heard that when building a battery from scratch you may have voltage issues so always use a BMS with built in balances.
one advantage i see in the seperate 12 volt batteries connected in Parallel is you can disconnect them and charge them seperately with a low amparage charger like a 20 amp charger.This would work for me in my type of set up, i dont have any high amprage chargers.Prob not an advanatge but this is how ive been charging my 36 volt set up.I do see the advanages with an all in one 48 volt system.
Always enjoy your videos. I've been thinking of building a diy portable hand truck 48V system using a server rack battery to use for my shed for lighting and running a small window 6000 BTU a/c and lights for a couple of hours a day. My question is will the 30 amp MPPT be enough to do solar charging (400W) or should I buy a larger amp MPPT in case I decide to expand.
Excellent presentation. Thank you. 48v is king in a home or fixed location where space/weight/form factors are not an issue and 12v needs are not required. In a van/car/truck where there is already a base of 12v devices and needs and space/weight/form factor are critical, 12v setups are far more flexible. Heck, in a car/van/truck, you can literally directly use a 12v battery, such as with a frig, with no watt sucking/wasting convertors/inverters. You can even use them to jump start the vehicle in a pinch. The term "better/best" is answered once you know the use case.
The only time you'd want to stick with a 12V system is if it is a really, really tiny system, like literally if you just needed 20Ah or something, or if the entire system is just running one piece of equipment, or if you simply have too much high-powered 12V legacy gear that upgrading is too expensive for you.
Those are all good reasons to stick with 12V, but that's about it. Most people blow past the system size where one really ought to have considered going to 24V or 48V and many people wind up stuck with huge 12V systems and lots of problems due to that, especially thermal issues.
Often, someone will "start small" and not even realize where that will take them in the future. They select 12V, and wind up stuck with it.
Space, weight ... all of that is the same for a 48V system as for a 12V system. 48V systems are actually lighter, in fact, because you can use much thinner cabling. Now of course, the whole point of going with 48V is that the large-load items (inverter, A/C, space heaters, etc)... those run off the 48V system (or run off the AC inverter).
That represents the economic hit... the "upgrading" that you might have to do.
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Remaining bursty/low/medium-load 12V legacy gear is easily dealt with. Fridge, lights, toilet macerator, run-outs, levelers, etc. For those you use a 12V down-buffer. Basically a DC-to-DC charger and a 12V battery sized for the loads. No inverter (inverter hangs off the 48V system).
It's utterly trivial and the flexibility is immense. And buck converters are like 95% efficient too... no power is being wasted. Some people even just use a 48-to-12V DC-to-DC directly without a down-buffer battery, but I prefer the DC-to-DC charger + battery solution for the 12V legacy gear for multiple reasons.
It can be tiny... literally fuse + Victron 75/15 charge controller + 20Ah 12.8V LiFePO4 battery. Or more substantial depending on the remaining legacy loads... A 100Ah 12.8V LiFepO4 battery is usually plenty. Or really beefy with a Victron DC-to-DC Orion charger (in a big RV for example). That might seem complex, but it's actually not... it is completely trivial.
One can ask... why go with 48V if there is still 12V gear that needs to be powered? One goes with it because the thermals are low, the cabling is far easier, and you can scale down the road incrementally without having to upgrade other components. Think about the solar for example. On a 48V system, ONE little 20A charge controller can handle 1000W of solar without even breaking a sweat.
There's a lot to love her.
-Matt
The advantages of 12.8 volt batteries are price, portability, and weight. I have been discouraged for a long time from a 48 volt hybrid system with server rack batteries because of communication and software errors that I see on UA-cam videos.
There are 48V "auto battery" form factor batteries. I use tons of them myself... no comms. Works just fine.
You don't need communication, nor do you even need a hybrid solar inverter. You can build a 48V system with discrete components the same way you build a 12V system. Unless the 12V system is really tiny, like 20Ah, the 48V system won't weigh any more or be any less portable or cost any more than the 12V system.
The hybrid solar inverter solutions are really meant for larger systems. They can be useful in that regard... an EG4 6000XP, for example, integrates breakers and removes an immense amount of wiring work from the build. But you don't have to spend the money if you are slapping together something small.
12V systems shine only in very tiny setups... less than 200Ah of storage. Once you hit 200Ah @ 12V of storage, 48V @ 50Ah is better, everything is better, cabling is thinner and lighter. Battery weighs the same capacity-wise.
I don't really understand why so many people seem to think that 48V is hard, or more expensive, or takes up more space. It just doesn't.
-Matt
@@junkerzn7312 IMHO it's the marketing of these systems that creates this impression. This is a developing market for the average consumer out there, and as technology has improved, recommendations continue to change to meet what manufacturers want to sell. I bought a Battleborn 100ah 12V LiFePO4 back around 2018 or 2019 for $899. I still have it. Back then it was about all you could buy. Today, you have 48V systems being manufactured, and the vendors are pushing them into the market largely via these kinds of videos. Consumers were sold 12v systems initially because that's what was there, and they are used to the concept of 12v because their car batteries are 12v. Now the shiny new toy is a 48v systems, and the marketing juggernaut is now trying to get consumers to spend more money and upgrade. There's a lot of re-educating going on in the space, and it will take time for the average consumer to come around to 48v. I compare it to the same thing that is happening with American car manufacturers: they only want to sell large luxury vehicles, and so have simply stopped making small sedans and economy cars. The day will come when no manufacturer will make a 12v LiFePO4.
Right on Matt
You’ve convinced me, but a slight overkill for something like a shed or outdoor garden house where lighting is the biggest draw, but I do like the 48v system 👍🏻
I bought 2- 12v 410ah RV batteries from Vrater and can’t get them to take a charge. Brand new out of the box!!
Any ideas would be greatly appreciated here.
Thanks
did your video show that the batter would not discharge when below temp or just that it would not charge?
Install a transfer switch on your house service panel, kill the main breaker and let us know how long a system will operate with solar back up. It did not work for me and I installed a dual fuel Generac system propane/gasoline. I am all for the battery concept but when an ice storm takes out the rural power lines and the sun doesn't shine, it was not enough for me.
I currently have 2* 100a 12v marine lead acid batteries but plan to get LifePo4 eventually. But, i want to put an inverter/charger and was debating on whether or not to use a 24v system because i already have these 2 12v batteries in my rv. Should i get a 24v or should i stick with 12v?
I am testing this setup with a LiTime 48V (51.2V) 30Ah LiFePO4 Lithium Golf Cart Battery, Built-in 60A BMS, Support 2C Discharge, Max. Power 3.07KW, wondering what settings I should use?
Another element for having parallel ... easier weight wise to handle. We are not always "young whipper snappers" :-) ... I think a really important aspect is the ability to monitor ... so each should have a bluetooth or monitor aspect easily attachable.. even if no tooth, have a plug where one can plug or hard wire to each battery (12V)
so a single 48v battery was my original plan but then I came across a deal for 4 12v 150ah ecoworthy batteries for $1000 and even with 4 sets of 1awg cables it's less than $1100 so I scooped that up,now I have 7.6kwh instead of 5.2kwh👊
Have you tested these batteries to see if they actually are 150 ah?
Do yourself a favor and buy the 48v "battery equalizer" right away. Those four batteries will drift apart, giving you less system output and working one or two of the batteries harder than the others.
12v just has so many more options for use.
Cost. I’ve seen several 12v 100ah batteries I can get for $180. I may be wrong but I have yet to see a 100ah 48v battery for under $800.
When the rack mount batteries get down to the equivalent price it becomes a no brainer.
This is a good observation. Even at $250 for a 12v 100ah battery, they cost less than most of the 48v server-rack options. Now, it's not apples-to-apples, because the 48v batteries typically have communication options to integrate with an inverter, but for raw storage capacity, you're right.
$180? That sounds like lead-acid to me though I wouldn't be surprised given the fire-sale prices 12V LiFePO4 batteries are selling at right now.
A 100Ah 48V battery has FOUR TIMES the capacity of a 100Ah 12V battery. The equivalent for a 100Ah 12V battery is a 25Ah 48V battery... so something like a Lithova, which is $260 or so. Definitely not $800.
As you get into the larger capacities, the cost differential drops to basically zero. Price out 50Ah @ 48V vs 200Ah @ 12V, for example. Then look at 100Ah @ 48V vs 400Ah @ 12V. And so forth.
One other thing to consider is that the bigger 12V batteries have smaller BMSs. A 400Ah 12V LiFePO4 typically only has a 250A BMS in it (3.2kW). Whereas a 100Ah 48V LiFePO4 will have a 100A BMS in it (5kW).
-Matt
@@junkerzn7312 there are a few different 100ah Lifepo4 on Amazon selling between 180 and 200. I will say I can’t speak to the quality of them so buyer beware.
Yes your spending more. That's said you are generally getting much more from 1 battery vs multiple. For example would take 4 100ah 12 v batteries to even equal one battery.
@@EatingWild Agreed. I think I would like the pricing to be closer though. If I can get 4x12v for under 800, I would say that 1x48v at $1000 would be good enough. It looks like recently in the last week or 2 I'm seeing pricing get closer to that now on the 48v front so it may just take a little more time.
On parallel connections, there is actually no limit. That is, it is solely an issue of safety and the battery's internal interrupt rating, so you can expand in excess of whatever limit is specified simply by adding additional fusing and breakers.
People often use the Victron Lynx Distributor (not the "Power In") to parallel a large number of batteries together. Each distributor cable pair goes to a bank of 4 batteries in parallel and the distributor provides the appropriate fuses.
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For series connections (which is never recommended no matter the count)... there is a common-mode limit related to the overall system voltage that becomes an issue with BMS disconnects on individual batteries in the string. So the typical manufacturer specification must be adhered to.
A whole-battery balancer is mandatory for lithium series configurations, and those generally only come in increments of 12V so you generally have to be in DIY mode if you are going to connect two 24V batteries in series. But this is easy to do too... it's just a normally-open voltage-monitoring relay and a 50W 50 ohm dump resistor with a heat sink on each 24V battery to dump energy above 28.4V (assuming a 56.8V overall charging target for the bank). (also use a small inline glass fuse to power the relay & resistor for safety since it is tapping off each battery directly).
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In terms of initially connecting batteries in parallel, for LiFePO4 since the charge and discharge curves are so flat, the batteries only need to be close in voltage to be connected together. Even if they are at wildly different SOCs. Your first full charge cycle will behave a bit weirdly but will get everything up to the same SOC by the time its done, and the next discharge/charge cycle will deal with any remaining differential.
-Matt
Howdy David,
Very good information as always. One thing I still don't understand is the breaker between the inverter and the battery. There is a breaker on the battery, yes? Is it an AC or DC breaker on the battery? Is that why you need the external breaker between the battery and the inverter? I have also seen these 48v server rack batteries come in different sizes, from 50ah all the way up to 400ah. Who is going to lift a 400ah battery by themselves? LOL.
Thank you as always, Steve.
Fusing and breakers have to match the capabilities of the wiring they are protecting, at a minimum, or be smaller. The breaker on the battery is for the capabilities of the battery and/or expected battery cabling, often inclusive of battery surge capacity. But this breaker is ONLY for the battery cabling to the bus-bar. It isn't for other cabling hanging off the bus-bar.
The cabling for the inverter is typically NOT 2 AWG on a 48V system. So it needs to be fused and often also breaker'd for the smaller of (cabling current capability) and (inverter-size / expected loads). This is usually substantially less current than the battery breaker.
Breakers are also often installed even when there is also a fuse on the same cable. The reason is to make maintenance easier to perform. If I want to mess around with an inverter I can just flip the breaker for its cable off and leave the rest of the system live. Same thing for a solar charge controller or any other cable hanging off the bus bar. Even though fuses are there for protection too, having to unscrew and rescrew fuses all the time just to do minor work is really annoying.
In fact, solar cabling often has a breaker both in the combiner box AND also at the point where it goes into the charge controller, allowing work to be performed in either location with a convenient flip of a nearby breaker.
In solar / battery / inverter systems, nearly all breakers should be 2-pole. Break on both the positive and the negative. Fuses are usually only on the positive. Breakers are generally on both the positive and the negative.
All DC wiring must use DC breakers. The breakers on the battery are DC breakers (they had better be!). They are DC breakers and also generally they should be *unpolarized* DC breakers since power can often flow in both directions (plus people wire polarized DC breakers up incorrectly *all* the time, creating a fire risk instead of adding safety).
Thank you for making this video! If the Vatrer also had RS485 it would be a no brainer vs more expensive vendors! Did it come with cables to link it to the MCCB you have between it and your inverter in the video, or did you have to buy / make those separately?
No, it didn't come with any cables. I just crimped my own. :)
@@ReeWrayOutdoors that's good to know! What awg did you use?
@thedabbler2753 I used 2awg since it can handle up to about 120A which should be a solid 15-20% higher than the 5000W 48V inverter I'm using will ever pull (and my DC breaker is rated for 120A as well).
I think that a lot of home owners don't want to deal with 100 pound packages. 25 pounds is pretty easy for almost anybody to manage.
Yeah but you're wasting a ton of space with the smaller batteries. I would rather deal with 4 batteries vs 12-16
Not sure if this will have any "real" impact, but 48 volts is less than 50volts... which is relevant to the NEC. Whereas, 51.2 is greater than 50v, so more of the NEC applies.
Nevertheless, Its convenient to have 100 AH "packs"... etc, with all the built in meters and switches etc.
Multiple 4s cell batteries will have multiple BMS, so cost, component mtbf, compatibility. I guess those are a plus if you want to break them into individual 12v 🤷♂️
I purchased 4 12volt timeusb for about $820, find a server rack battery for that price.
1:35 I know one reason you might want to put batteries in series is that you need less current going through the wires... was looking into building a smallish DIY Powerwall, which I could barely afford, and found that to deliver enough power to the house for the 5-30 seconds I would need for the rare and brief power outages I would need several hundred amps of 12v... not only would I need to have batteries capable of supplying that, I would need wires and the necessary amenities to safely convert then output the power... increasing to 48v or over 80v lowers the amperage down considerably.
I could be wrong, as I am not rather educated in battery building, and haven't looked further in it after finding most my "design" would require pricy industrial quality parts such as the 1400 dollar DC to 120v AC converter. My biggest mistake was not researching enough before I started making my "designs" so likely I will completely redo everything if I were to go down that rabbit hole again.
Pushing house-sized amounts of power reliably can get expensive, for sure. Regardless of the voltage. Usually you don't try to do that unless you are willing to spend like $50K-$100K on a large battery + solar + whole-home system.
Instead for the moment I just focus on the critical loads in the home... a few lights, furnace fan, and fridge mostly. I've been planning a whole-home system for ages and it keeps changing... haven't pulled the trigger yet but I'm getting closer. I'm already up to 10 kWh of storage and 2 kW of panels "off-grid" (grid is used for low-battery support only). Most of my house is still on the grid, though.
-Matt
@@junkerzn7312 That's what I was thinking a bit back, and even started looking at it again; started looking at a simple UPS for my desktop and the router, as I am in college, and thats how I do my work, but couldn't wrap my head around how it would work and felt I shouldn't mess around with that until I do lol.
@@Suzuki_Hiakura If you want to throw together something really cheap just to play with that is suitable as a desktop UPS, try this for a little project:
30Ah @ 12.8V LiFePO4 battery ($80)
Victron Phoenix 500VA 12V 120V pure sine wave inverter ($148).
Victron Blue Smart IP65 12V 5A battery charger ($85)
An alternatively, you could try a cheap vehicle 12V inverter for around $40 instead of spending $148 on the Phoenix... but make sure it is pure sine wave and don't operate it at more than 50% load (vehicle inverters are poorly built)
Total: $313 w/ the phoenix, $205 w/cheap vehicle inverter, not including wiring or wire splices.
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Wiring... 10 AWG cabling is sufficient
Wire splices, I recommend using WAGOs for splicing wires together. Get a little $25 assortment.
Wire cutters, strippers, etc.
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That's a fun little project to get your feet wet. The Victron charger even has a bluetooth app for playing around with the mode and operation.
-Matt
48v is a whole lot cheaper and safer given a ot less connections points, small gauge wiring, lugs, terminals, busbars etc….
Common March 10th! ;)
I got a 12.8 volt 50amh LifePo4 battery.
I'm using an 54.7 volt ebike charger , will the 54.7 volt do damage to the LifePo4 battery?
Prices on 12V LiFeP04 batteries are tumbling. You might save hundreds of $$ getting 12V batteries.