A few cons of 48V systems.

Riley

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I want to share my experience with the cons of the 48v system that I did not know first.

1. We are almost certainly stuck with Growatt if going 48V, 48V MPP inverter are taking $1400+, and there are no other options. If we want to go with Victron, the issue is the biggest 48V AC-DC charger we can get in the market is a 48V 25A 120V Battery Charger by EG4, which is very inefficient for a 4KW RV generator because it only puts about 50% of the load.
2. There is no cheap Bluetooth battery monitor for a 48v system.
3. For some random reason, 12v batteries in a series could lose balance by themselves; it needs to be balanced every now and then.
4. If you go 24V batteries, 24V 100AH is often more expensive than 12V 200AH
5. Biggest issue: if you have a bunch of small areas that are not at the same angle, you will want more than one MPPT charger for each region. There is no dirt cheap MPPT for a 48v system! 48v MPPT is almost always for big arrays! The cheapest I can find is Victron 100 | 20 MPPT, which supports 48V, but is still $170+.
 

wattmatters

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Compromises no matter the voltage you choose to work with.

As far as inverters go, I'd have thought there was quite a range of 48V systems to choose from.
 

jamiko

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1. Both the Growatt at MPP 48v units are ~$700 for 3kW output and ~$1400 for 6kW output. The Renogy 48v 3500A is on sale for $765 now. So pricing is similar.
2. There is a Renogy bluetooth shunt for $75 or a Victron for $130. You could also use a bluetooth BMS if you have a DIY battery
3. I would rather have a true 48V and not four 12v in series
4. Again I would go with 48V battery and not two 24V in series. Will says there are more rack mount 48V coming so maybe it will get more competitive on pricing.
5. I saw a MakeSkyblue 48V 30A MPPT for $85 on Amazon. I don't know the quality but several people on the forum have one.
 

offgriddave

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I the biggest 48V AC-DC charger we can get in the market is a 48V 25A 120V Battery Charger by EG4, which is very

we're finding out it's only 900w if that

There currently is no commercial solution to charge 48v

here's what I tried

1. MPP LV5048 40A? from generator-- won't accept my generator, rejects with error code. Solution, just buy a $1200 inverter generator.... may or may not work. previous solution didn't work so didn't try
2. Ryden RD6018 - terminals, melted after 6 weeks. Solution buy RD6024 with "1600w" power supply... but terminals still underspec, will probably melt again. may or may not work. previous solution worked, but broken after daily use
3. Ahh finally Signature Solar 24A, this should work. Nope, maxing out at 900w this thread:


Things I didn't try

$2000 Telcom rack mount charger, unknown
$200 HP Blade Server, "not regulated", unknown

About to give up
 

HRTKD

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Apr 24, 2020
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Somewhere South of Denver
I want to share my experience with the cons of the 48v system that I did not know first.

1. We are almost certainly stuck with Growatt if going 48V, 48V MPP inverter are taking $1400+, and there are no other options. If we want to go with Victron, the issue is the biggest 48V AC-DC charger we can get in the market is a 48V 25A 120V Battery Charger by EG4, which is very inefficient for a 4KW RV generator because it only puts about 50% of the load.
2. There is no cheap Bluetooth battery monitor for a 48v system.
3. For some random reason, 12v batteries in a series could lose balance by themselves; it needs to be balanced every now and then.
4. If you go 24V batteries, 24V 100AH is often more expensive than 12V 200AH
5. Biggest issue: if you have a bunch of small areas that are not at the same angle, you will want more than one MPPT charger for each region. There is no dirt cheap MPPT for a 48v system! 48v MPPT is almost always for big arrays! The cheapest I can find is Victron 100 | 20 MPPT, which supports 48V, but is still $170+.

While I'm usually not a fan of 48 volt systems for an RV, I will address the items in your post.

1. The Victron inverter/charger already has the charger onboard, so you don't need an external charger. The Victron Multiplus 48/300/35/50 charges at 35 amps, which is more than the 25 amps you wrote. That's not huge, but it will draw 15 amps from the generator.
2. The Victron BMV-712 will run about $200. The Victron Smart Shunt does the same, but without the display and costs about $70 less.
3. If you need 48 volts, build a 48 volt battery.
4. Meh.
5. You'll have to wire in series to ensure you have battery voltage + 5 volts to start charging.
6. Cost. 48 volt systems are likely to cost more and you have less selection. Suck it up buttercup.
 

JoeHam

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There are dozens of companies selling 48V inverters. You must not be looking very hard.

I have three different 48V inverters, all made by different companies. None of them the ones you mentioned.

You are welcome to your opinion but much of what you are complaining about is opinion or untrue. I would hate to have others accept these as 48V deficiencies.

It’s not for everyone but 48V has many advantages for non mobile, larger capacity systems.
 

coolbz

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There are dozens of companies selling 48V inverters. You must not be looking very hard.

I have three different 48V inverters, all made by different companies. None of them the ones you mentioned.

You are welcome to your opinion but much of what you are complaining about is opinion or untrue. I would hate to have others accept these as 48V deficiencies.

It’s not for everyone but 48V has many advantages for non mobile, larger capacity systems.
Yes there are many 48 v inverters. No, there are not many AIO 48 v systems.
I think OP is complaining more about AIO selections.
 

JoeHam

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I think OP is complaining more about AIO selections.

That might be.

For AIO only I would note that Midnite Solar, AIMS, Sungold Power, Renogy and Phocos are a few I am aware of without searching for them specifically.

I'm just not a fan of a post on the forum stating as fact that there are no other options, when a bit of searching would show otherwise.

"Almost certainly stuck with Growatt" can be misleading to others looking at making the 12V vs 48V decision.

Opinions expressed, as such, are great and I agree that 48V systems are certainly not for everyone.
 

Riley

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There are dozens of companies selling 48V inverters. You must not be looking very hard.

I have three different 48V inverters, all made by different companies. None of them the ones you mentioned.

You are welcome to your opinion but much of what you are complaining about is opinion or untrue. I would hate to have others accept these as 48V deficiencies.

It’s not for everyone but 48V has many advantages for non mobile, larger capacity systems.
If your system is about 2000w to ~3400w, I don't think there is any other 48VDC 120VAC AIO under $1000?
The only thing is Growatt, newer MPP PIP 3048LV-MK(coming Feb 22), and PowMr(Poor reviews, faker brand).

And for non-AIO, there is not a single AC-DC charger that can pull 70% load of a 4000 watts RV generator and does not costing > $400.
So the whole 48v thing other than Growatt won't save you money. They cost a ton.

this is according to my knowledge, correct me.
 
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toms

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I’ve found that for RV’s, multiple 12V systems is a good compromise.
 

eabyrd

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we're finding out it's only 900w if that

There currently is no commercial solution to charge 48v

here's what I tried

1. MPP LV5048 40A? from generator-- won't accept my generator, rejects with error code. Solution, just buy a $1200 inverter generator.... may or may not work. previous solution didn't work so didn't try
Try changing the AC input on the LV from UPS to APL when using your genset as the input. It worked for me on my LV 6548.
 

offgriddave

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Try changing the AC input on the LV from UPS to APL when using your genset as the input. It worked for me on my LV 6548.

If this works, you're a genius. I thought there was some kind of way to get around it. I'll give it a try. The other idea was using the L1 L2 jumper.

Its packed up it'll take me a week to setup the bench

another thing I am trying is the 220v AC HP 3000w server power supply. however I don't know if it is CC/CV based
 

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JoeHam

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If your system is about 2000w to ~3400w, I don't think there is any other 48VDC 120VAC AIO under $1000?

The majority of the ones I mentioned in post 8 are 3500W and under $1000 last I looked.

One example:


But I have nothing further to add to this discussion I’m afraid.

Again, whatever choice anybody makes is their own prerogative. But choices do exist.
 
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railcon56

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While I'm usually not a fan of 48 volt systems for an RV, I will address the items in your post.
Can I ask you why you are not a fan of this? I have to make a decision very soon. I have a 12v 800ah system now, I was going to go with a 24v EG$ but they aren't in stock... But 48v is. I want 3 eg4's A/C (Wife with MS needs some A/C) ... I'll start off with 2 and add another later in the summer as more money becomes available.
 

HRTKD

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Can I ask you why you are not a fan of this? I have to make a decision very soon. I have a 12v 800ah system now, I was going to go with a 24v EG$ but they aren't in stock... But 48v is. I want 3 eg4's A/C (Wife with MS needs some A/C) ... I'll start off with 2 and add another later in the summer as more money becomes available.

It comes down to high amp 12 volt loads and simplicity. If you're in a fifth wheel you have high amperage 12 volts loads in your landing gear. If you put in a 48 volt system you'll need to spend a fair amount on one or more 48-12 step down converters. On-board generator? Yep, high amp load to start it.

Want to charge the battery bank from the truck's alternator? A 12v-48v DC-DC charger is necessary. It's true that even if you had a 12 volt system a DC-DC charger would be a good idea, but now with a 48 volt system you must have it.

A lot of the ancillary components, like breakers and switches are rated to only 48 volts. Your 48 volt system lives well above that all the time, so the commonly available components aren't suitable and you're going to pay more for components that are rated for higher voltage.

The cost savings in smaller wires due to higher voltage will be exhausted once you add up the cost for the higher voltage components.

That's not to say that a 48 volt system is wrong. It's just going to cost you more than a 12 or 24 volt system would.

There's a threshold that is often suggested here on the forum that if you need to invert more than 3000 watts, a 12 volt system isn't a good match. It would require some very large cabling and fusing to handle the amps, but it can be done.

My dad has MS so I understand some of the needs of an MS patient. My dad moved to El Paso a couple months ago to get away from the bitter cold in Colorado. We'll see how he does when the heat hits down there in Texas.
 

railcon56

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It comes down to high amp 12 volt loads and simplicity. If you're in a fifth wheel you have high amperage 12 volts loads in your landing gear. If you put in a 48 volt system you'll need to spend a fair amount on one or more 48-12 step down converters. On-board generator? Yep, high amp load to start it.

Want to charge the battery bank from the truck's alternator? A 12v-48v DC-DC charger is necessary. It's true that even if you had a 12 volt system a DC-DC charger would be a good idea, but now with a 48 volt system you must have it.

A lot of the ancillary components, like breakers and switches are rated to only 48 volts. Your 48 volt system lives well above that all the time, so the commonly available components aren't suitable and you're going to pay more for components that are rated for higher voltage.

The cost savings in smaller wires due to higher voltage will be exhausted once you add up the cost for the higher voltage components.

That's not to say that a 48 volt system is wrong. It's just going to cost you more than a 12 or 24 volt system would.

There's a threshold that is often suggested here on the forum that if you need to invert more than 3000 watts, a 12 volt system isn't a good match. It would require some very large cabling and fusing to handle the amps, but it can be done.

My dad has MS so I understand some of the needs of an MS patient. My dad moved to El Paso a couple months ago to get away from the bitter cold in Colorado. We'll see how he does when the heat hits down there in Texas.
Thank you for the MS comment... Money always plays a role, and a Major role at that. But isn't 48v safer for even 2500 watts? Safety probably makes up 90% of the decision for me... but I also know 48v is closer to killing you. Eg4 having the built-in circuit breaker can just be turned off I always wear glasses and rubber gloves when I build or work on these things.
 

400bird

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4. If you go 24V batteries, 24V 100AH is often more expensive than 12V 200AH
It should be! The 24v battery is twice the capacity.

12v x 100 ah = 1.2kwh
24v x 100 ah = 2.4kwh

Do you need a separate battery charger?
Why not use the charger part of your inverter/charger?
 
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