3048LV-MK: "Number of Input Strings = 1"

[caseydelia]

I'm considering buying an MPP 3048LV-MK AIO. I found a spec sheet on Watts247 that says, under the Solar Charger Mode section, "Number of Input Strings = 1". It also says that a 48V battery is required to operate, and that 200Ah is recommended (100Ah minimum). So, to reduce costs, I wanted to have 2 series of (12V 100Ah + 12V 100Ah = 24V 100Ah) in parallel, which would result in 48V 200Ah. But does this violate the Solar Charger mode, "Number of Input Strings = 1" limitation?

 

[Hedges]

I think input strings means PV connections.

PV MPPT inputs care about Voc most of all, Imp next.
If you wire two lower amperage PV strings in parallel, that is no different to the inverter than one higher amperage PV string.

You say 12V 100 Ah, so I think you're referring to batteries.

If you have two of those SERIES connected pairs of batteries joined PARALLEL, you would have 24V 200 Ah, not 48V 200 Ah.

 

[Hedges]

For 48V lithium battery, you're better off with single battery, one BMS. Server rack batteries are popular. Around $1500 or so. SOK from Current Connected might be a good choice.

If lead-acid, then sure, you can connect in series.

 

[Hedges]

It also says that a 48V battery is required to operate

You say 12V 100 Ah, so I think you're referring to batteries.

I don't read too good do I ??

But I think my math and comments otherwise are responsive to your questions.

 

[shampeon]

You are talking about two different things. The solar input and the required battery.

2 24v batteries in parallel is still 24v with double the amps. You would need 4 12v batteries in series to make 48v. Or 2 24v batteries in series.

For the solar input, you will need panels that output more than 48v. The Voc of the panel is what you are looking for. So if your panels are 24v Voc you will need 3 or more in series to get the voltage high enough for your inverter.

 

[Crowz]

I would recommend going with a more expensive unit upfront.
There are several to choose from but I have the sungold tp6048 personally so I'm using it as an example but there are many others at this price point.

Lets say $1300 for the unit at 6000 watts.

1. The reason I recommend going this route is you get split phase power aka 240volts so everything can run off it.

2. Its a true hybrid. This means you connect it up with it being the only thing you have and its "installed". Its not doing anything for you but its there and working. Now you add panels as you can afford them. It takes enough panels in series to make 120volts to get the ball rolling but after that every SINGLE panel you add means your power usage/bill goes down while the suns up. After you get enough panels you can move to buying batteries.

3. If the cheaper one doesn't do hybrid then you will end up spending more on the "required" parts to get it going aka batteries to even be able to use it.

This is the route I went on my 2nd houses solar build and it has been a dream compared to the way I did my last build. It all just works with no headaches.

With a $500 to $700 unit and having to buy 48 volts worth of batteries be it rack or such your looking at $1500 or more.

So now you have a 3k unit and your into it for $2000 to $2200.

The way I'm suggesting your out $1300 for the unit and $700 in solar panels to make your daytime power bill drop big time. So $2000.


Add batteries and a few more panels later to get completely running off solar.

Either routes get you there but I found the more expensive aio purchase upfront left me with tons of options for later and less money actually spent upfront.