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48v Victron Lifepo4 build

doubleohwhatever

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Dec 14, 2020
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Hi All,

I'm looking at putting together what will basically be a battery backup for a few circuits in the house. The grid is fairly reliable where we're at but we're at the base of a mountain and a few times a year high winds trying to get over the mountain take out lines in the area. Electricity has always been restored within 24 hours so that's our goal for the backup. 24 hour backup for the fridge, lights in a few rooms (with two 50w ceiling fans), 250w blower fan for gas furnace and the outlet the garage door opener is plugged into.

The system described here is almost exactly what we'd like to do:

The difference being we want to use the following hardware:
Inverter: Victron MULTIPLUS-II 48/3000/35-32 230V GX
Autotransformer: Victron Autotransformer 120/240vac-100a
Batteries: 16 3.2v 280ah LifePo4 batteries from Shenzhen Luyuan

I think I have most of this figured out but I have a few questions I'm hoping someone can answer:

1) Is the BMS offered by Shenzhen Luyuan any good? If not, is there a recommended BMS that can handle 16 batteries?

2) We're in the US and I *think* I can feed the MULTIPLUS-II 48/3000/35-32 from our split phase system via a hot from each phase. Is this correct?

3) The 100a victron autotransformer is only a little more $ than the 32a autotransformer. Would there be any benefit at all in going with the larger unit?

4) Is compression needed for these batteries?

5) What sort of enclosures are available for these batteries?


I've installed several solaredge systems with and without storage in the past. So my questions above are mainly on the items I'm unfamiliar with which are Lifepo4 batteries and the victron hardware.

Any feedback and help is welcome! Thank you!
 
I am doing the exact same thing at the moment. I am not super familiar with Victron gear so I hope this isn't a stupid question. Why do you need an inverter/charger AND an autotransformer? The inverter already seems to have two phase output, which is why I am asking.
 
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I’m doing the same thing with a Schneider CSW 4048.

240v from the main panel to the CSW 4048. Then 240v out to a critical loads panel. The CSW also has an auto transformer inside so I could feed it from a 120v generator if my batteries die.

I will try to summon @the_colorist who does a great job of explaining/understanding the Victron with transformer for the US market.
 
Hmm, that Schneider solution looks interesting. With the AC switchbox that makes for a very tidy install.
 
I'm not aware of any single victron inverter that has native (US spec) split-phase output. My understanding is that you either have to run two 120v inverters in parallel or a single 230v inverter with an autotransformer.
Ah, thanks for the explanation. So the Victrons are set up for 50hz 220 and the transformer converts to 60hz for US operation. Makes sense. I know they make good stuff, but are you in the price range of a SolArk with that setup? I know some like discrete components as well.
 
So the Victrons are set up for 50hz 220
Most can also be configured for 60hz/240


know they make good stuff, but are you in the price range of a SolArk with that setup?
Nah. Going either with Victron or Schneider would be around half the cost of a SolArk box.

Their switchgear was a bit pricey for my taste so I used a $50 Square D panel.

Not nearly as tidy however!
Yeah, as tidy as it would be, standard panels are just sooo cheap.


At the moment I'm comparing the Schneider SW and the Victron Multi-Plus-II. While I don't currently plan on adding solar, I want that to be an option and I can't seem to figure out how Victron handles rapid shutdown. So that might be a snag.
 
Schneider has superior hardware, average software and below average support IMHO.

Victron stuff is quality and just works. Their software and app monitoring are excellent.

The cost of a 48v Quattro put me off that choice but I use their SCC’s, SmartShunt and CerboGX so if I wasn’t so cheap I would probably be all Victron ?. If they had a 48v MultiPlus for the US market I would have done that.
 
Victron stuff is quality and just works. Their software and app monitoring are excellent.
The victron software and overall attention to fit, finish, etc is what caught my eye to begin with.

The cost of a 48v Quattro put me off that choice
I had initially dismissed Victron due to this exact reason. The Quattros are just expensive. Then you have to add a GX controller.

However, due to the small number of circuits I want backed up, I *think* I can get away with this a 48v 3k Multi-Plus GX and an autotransformer. Those two items (with shipping) are $1,886.15. I can't find anything else that competes with that price. That's one of the reasons I posted here. It's so cheap that I feel like I'm missing something.
 
My Schneider CSW4048 and a ComBox were 2-3 hundred bucks less than that for what it’s worth.
 
Is yours a CSW4048 or a SW4048 (or are they the same)?

After some more digging just now, I can indeed get the SW4048 for $1,445 shipped. The ComBox I can find for $275. However, apparently it is being phased out in favor of the Conext Gateway which is $200 more. I'll have to see what benefits there are with the newer unit.
 
Conext SW = CSW

I got mine here:


They are one of the few to do free shipping on this beast. No sales tax on solar stuff in AZ. Also, if you sign up for the email list you get 5% off your first order. At the time it all came to around $1280 shipped. The price must have gone up a little since then.

I was too cheap to get the Gateway and at the time the ComBox wouldn’t interface with the newer Insight app/website but I got an email yesterday morning that ComBox support was just added!

I think you may give up some remote configuration ability though. Remote monitoring should be complete but I haven’t set it up on the new site yet, still on the old one. The Gateway also has wifi router built in while the ComBox needs a dongle or Ethernet cable. There may be other differences I’m blissfully ignorant of also ?.
 
Thanks for the link! With the 5% off and free shipping, that will definitely be the cheapest.

Btw, do you have a link for information on the battery in the photo you posted?
 
Argh... Just came across this in regards to the SW4048:

"For code-compliant installations in Canada and USA, the DC Switchgear accessory is required"

So if I want a code-compliant Schnieder install I'll have to tack ~$340 on the total price for the DC box. I'm going to assume the DC box is required because the battery terminals stick out the side of the inverter without a protective metal shield/box.

Overall, the Victron solution is what I'd *like* to go with but there is just so little information using the European Multi-Plus-II units in the US. The Schnieder solution is very simple to install in comparison.
 
The battery is from Signature Solar, link in the first post here:


Thanks for the info on the new ComBox but I don’t even use much of the abilities of the old one.

I am comfortable that my system is safe without the switchgear from Schneider. The terminals have shrouds over them and are located where they are safe. Your system your choice though.
 
I ended up going with the 4048 from Schneider and ordered via the link and discount provided above (Thanks!). I *really* wanted to go with Victron and had figured out the wiring, etc. However, the Schneider 4048 will be a cleaner install due to not needing a separate autotransformer and based on everything I've read is a just solid workhorse of an inverter.

A bit of info for anyone who comes across this thread in the future:

I did end up calling Schneider and after about an hour I was able to talk to someone that knows their solar products well. I was told that while they are still selling the ComBox for the moment, it's basically been discontinued and not recommended for new installs. The new InsightHome and InsightFacility are launching in February and will be more comparable replacements than the expensive Conext Gateway.

Since my batteries won't be here for 45-60 days, I figure I'll just wait and see how the InsightHome device is priced and if it's too expensive I'll just grab a cheap(er) ComBox.
 
Apologies I wasn't able to ping back sooner. I hope the 4048 works well for you!

So with the 48/3K from Victron, they only offer it with a single-phase 230V transformer. There is no center-tap so you only have Neutral and Line, with the voltage between them 230V/50HZ by default (EU standard). To achieve split-phase (2x 120V lines 180 degrees out of phase), one needs to adjust the Victron to 240V/60HZ and use an external transformer to create the two 2 legs and a new neutral.

It's easiest to visualize by looking at one of Victron's layouts:

Victron has several advantages over Schnieder but Schnieder does build a solid product for sure.

The top 3 advantanges Victron has as far as I'm concerned are: Cost, Lithium CAN integration & low-wattage efficiency.

Victron is cheaper than almost everyone if you have installer pricing.

In my opinion, efficiency is other place where I feel Victron pulls ahead BUT I haven't ran any tests or even installed a SW4048 so I have to go off the datasheet.

Schnieder hasn't released an efficiency curve chart anywhere that I have seen. The max eff is reported at 94%. I could be wrong but I suspect they are using an E-Type transformer among other things. I also suspect that 94% isn't until around 600W or so. That means if you average 300W or less, you could be operating in the 70% eff range.

Victron's peak eff is 96%. It's my understanding they purposely designed it to be eff at low wattages. Here is thier published chart:

1611819066457.png
1611819093540.png

It can be heard to really feel the difference until a person tried both units on the same bank with the same loads. We had a situation once where we pulled an Outback 3KW inverter and replaced it with an SMA 6048. The improvement in battery life (lead) was palpable. I'm guessing but it seemed like the OB inverter was burning a good 25% more power than the loads were pulling. Possibly more. The SMA was leaps and bounds more efficient.

I believe there a bit of information around the forum about the lithium CAN integration so I won't cover it much here. For me, I'm not hugely comfortable installing systems that don't have integration and BMS charging control, especially banks we build ourselves. I feel its too risky in the long run. When I do have to for one reason or another, I tell the client I have to de-rate the number of cycles that would normally estimate to 80% capacity.
 
Apologies I wasn't able to ping back sooner. I hope the 4048 works well for you!
No worries! I appreciate the reply.

Without having access to Victron installer/dealer prices, the 4048 was the cheaper option and the wiring less complex. Although with the schematic you linked to the wiring for the Victron is now clear. I was uncertain about the wiring between the inverter and the grid 240 but the schematic makes it clear that the second 120v *does* indeed get wired to neutral on the inverter. That just seemed bonkers to me and not having that confirmed made me too uneasy.

Is there a list of BMS units that support 16S and CAN integration with Victron hardware?

The efficiency at lower wattage is a concern for me and I may have to send the 4048 back and re-think my setup. Thanks again for the information.

Edit: Also, with the 48/3K, would there be any advantage to the 100A AT?
 
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