Matthew Becker
New Member
Batteries: Twelve 12v200ah Vestwood batteries. 4 on each shelf of shelving rack = 48v * 3 strings.
Each string is connected to a bus bar for connection to the load.
All in one MPP 3048-LV-MK.
The all-in-one says 4 AWG.
The battery skimpy one page product manual says 2 AWG.
I tried a dry run setup using 4 AWG wire and got everything working so far, but there were some hiccups - mostly because I am a 1st time DIY and no matter how many videos you watch to learn, there is a hands-on experience aspect that is needed. I'm now working on re-doing it as a permanent install using cement board as recommended in the MPP3048 manual.
ISSUE #1 - WIRE SIZE
I'm now considering switching to 2AWG wire, even though I actually think the 4 gauge wire might be good enough. Thoughts? Should I switch? The more permanent setup using the cement board for latching everything on to is going to cause me to have to redo some wire lengths anyways, so the difference in cost to upgrade the wires to 2 AWG is only going to be maybe $100. But if y'all think that the 4 AWG is good enough, then I'll go ahead and save that $100.
The load on the all-in-one is going to be about 800w normal with surges no higher than 2kw.
ISSUE #2 - DISCONNECT CAPABILITIES
I want an easy disconnect for the wires at all points so I am not working on anything that has the potential to complete a circuit while I am working. I am looking at Anderson Connectors or a DC Disconnect switch. Thoughts? The Anderson connectors actually sound like an easier approach just because I am in a tight space and it sounds like an easier connect/disconnect than to try to get the ring terminals onto an actual switch. On the other hand, you don't need to actually disconnect both + and - to cause the circuit to be cut and the Anderson connectors seem to want you to put in both the + and - wires.
Thoughts on what to use for being able to easily connect/disconnect the batteries from the system? Yeah, I know that once it is running, I am quite unlikely to need to disconnect again, so permanently connecting everything all at the beginning does make sense, but in my dry run, I did have a few times where I saw sparks flying and being a relative novice at DIY, I would prefer to be working on a disconnected circuit. Just feels safer.
What products do people use for this?
ISSUE #3 - AC CHARGING AMPS LEVEL IN SETTINGS?
Final question - on the MPP device, I attached on the AC in section the ability to plug in to a wall outlet. But I have not tried to do this yet mostly because the settings options are a bit ambiguous. It talks about how many amps. Is this amps on the AC side or amps on the DC side. The wall outlet I am using is on a 15 amp circuit. So am I supposed to put in 15 amps on the AC charging capability? Or do I set that to 30 amps because 48v @ 30 amps is still under what the AC circuit is able to put out?
Eventually, I have 12 panels that are 315w each, so about 3700w that I will be able to bring in from solar. But that is for another day. I am not at that point yet. I want the batteries/all-in-one/AC-charging running first. Then I will add the panels in. One step at a time.
So for this post, I am asking 3 questions:
1) Wire size? Is 4AWG good enough? Or do I need to go with 2AWG as the battery product manual says?
2) How to not be working on a live circuit? Easy connect/disconnect mechanism? Ideally I would like one on each string from the batteries to the bus bar and another between the bus bar and the all-in-one. What products do you recommend?
3) AC Charging Amps level in settings for the MPP 3048?
TIA.
And feel free to rip any of what I am saying to shreds - especially if you have specific advice about anything to go along with it.
Each string is connected to a bus bar for connection to the load.
All in one MPP 3048-LV-MK.
The all-in-one says 4 AWG.
The battery skimpy one page product manual says 2 AWG.
I tried a dry run setup using 4 AWG wire and got everything working so far, but there were some hiccups - mostly because I am a 1st time DIY and no matter how many videos you watch to learn, there is a hands-on experience aspect that is needed. I'm now working on re-doing it as a permanent install using cement board as recommended in the MPP3048 manual.
ISSUE #1 - WIRE SIZE
I'm now considering switching to 2AWG wire, even though I actually think the 4 gauge wire might be good enough. Thoughts? Should I switch? The more permanent setup using the cement board for latching everything on to is going to cause me to have to redo some wire lengths anyways, so the difference in cost to upgrade the wires to 2 AWG is only going to be maybe $100. But if y'all think that the 4 AWG is good enough, then I'll go ahead and save that $100.
The load on the all-in-one is going to be about 800w normal with surges no higher than 2kw.
ISSUE #2 - DISCONNECT CAPABILITIES
I want an easy disconnect for the wires at all points so I am not working on anything that has the potential to complete a circuit while I am working. I am looking at Anderson Connectors or a DC Disconnect switch. Thoughts? The Anderson connectors actually sound like an easier approach just because I am in a tight space and it sounds like an easier connect/disconnect than to try to get the ring terminals onto an actual switch. On the other hand, you don't need to actually disconnect both + and - to cause the circuit to be cut and the Anderson connectors seem to want you to put in both the + and - wires.
Thoughts on what to use for being able to easily connect/disconnect the batteries from the system? Yeah, I know that once it is running, I am quite unlikely to need to disconnect again, so permanently connecting everything all at the beginning does make sense, but in my dry run, I did have a few times where I saw sparks flying and being a relative novice at DIY, I would prefer to be working on a disconnected circuit. Just feels safer.
What products do people use for this?
ISSUE #3 - AC CHARGING AMPS LEVEL IN SETTINGS?
Final question - on the MPP device, I attached on the AC in section the ability to plug in to a wall outlet. But I have not tried to do this yet mostly because the settings options are a bit ambiguous. It talks about how many amps. Is this amps on the AC side or amps on the DC side. The wall outlet I am using is on a 15 amp circuit. So am I supposed to put in 15 amps on the AC charging capability? Or do I set that to 30 amps because 48v @ 30 amps is still under what the AC circuit is able to put out?
Eventually, I have 12 panels that are 315w each, so about 3700w that I will be able to bring in from solar. But that is for another day. I am not at that point yet. I want the batteries/all-in-one/AC-charging running first. Then I will add the panels in. One step at a time.
So for this post, I am asking 3 questions:
1) Wire size? Is 4AWG good enough? Or do I need to go with 2AWG as the battery product manual says?
2) How to not be working on a live circuit? Easy connect/disconnect mechanism? Ideally I would like one on each string from the batteries to the bus bar and another between the bus bar and the all-in-one. What products do you recommend?
3) AC Charging Amps level in settings for the MPP 3048?
TIA.
And feel free to rip any of what I am saying to shreds - especially if you have specific advice about anything to go along with it.
