Upgrading: Input and thoughts please!!

[ChrisSwolls]

Ok, I could really use some input lol. Right when I think I know what direction I want to go, I second guess it haha.

I’m looking at jumping up from a 24v system to a 48v system. Here’s a quick rundown of the current system:

Victron 250/70 MPPT
1,100Ah worth of AGM batteries
Outback 3500w inverter
Victron BMV712/ shunt
2500w worth of panels
Breaker panel, DC disconnect and all the other usual odds and ends.


I use the system primarily as a backup but would like to slowly upgrade to 48v LiFePo server rack batteries and run off the system more and more to reduce needs. Primary function will always be for power outages from storms and well, the state of the world as we know it lol.

Here’s where I’m at now:

I love Victron products and the ease of use and monitoring. I’ve been doing a lot of research over the past few days and it’s changed my thoughts a lot. I was originally sold on the Multiplus II but since I’ve been looking, I’m seeing a lot more bang for my buck out of the AIO units. I’m trying to do this as budget friendly as possible, but not wanting to skimp either. I’m honestly leaning more towards:

EG4 6000xp
Sungold 8KW split phase
LV6048

I’d like to go split phase since I’m upgrading, so far the 3.5kw has run everything in my home with no issues (gas range, gas furnace, gas dryer).

I’m really liking the AIO units and the massive PV potential, even with my 250/70 I’m limited to around 4kw input.

What’s your thoughts and experiences? How’s the Bluetooth monitoring capabilities?

I have (2) backup 12v setups, I’ll just repurpose the unneeded parts and make one backup setup a 24v. I have another 1.5kw worth of panels on the backup setup as well. I

 

[MisterSandals]

1,100Ah worth of AGM batteries

Looks like 2S8P. Are the main battery connections on the right end of the battery bank? If so, the cells on the left will get increasingly less current and become out of balance and you'd be using a fraction of the capacity.

but would like to slowly upgrade to 48v LiFePo server rack batteries and run off the system more and more to reduce needs.

Is your battery bank failing or why the interest in upgrading to lithium iron polonium?

1100Ah x 12.8V = 14080Wh thats a decent sized battery.

even with my 250/70 I’m limited to around 4kw input

Is this the main the reason to switch from 24V to 48V system?

28V x 70A = 1960W processing limit

If your array is 4000W, you could better use it by pointing half southeast to start charging earlier and half southwest to charge later. You would increase solar production by making the charge times longer. Maybe 1000W eastish, 2000W south and 1000W westish. Lots of range to make this more productive at 24V battery.

 

[ChrisSwolls]

Looks like 2S8P. Are the main battery connections on the right end of the battery bank? If so, the cells on the left will get increasingly less current and become out of balance and you'd be using a fraction of the capacity.

Is your battery bank failing or why the interest in upgrading to lithium iron polonium?

1100Ah x 12.8V = 14080Wh thats a decent sized battery.

Is this the main the reason to switch from 24V to 48V system?

28V x 70A = 1960W processing limit

If your array is 4000W, you could better use it by pointing half southeast to start charging earlier and half southwest to charge later. You would increase solar production by making the charge times longer. Maybe 1000W eastish, 2000W south and 1000W westish. Lots of range to make this more productive at 24V battery.

Correct! 2S8P, they are UPS 12-600MR @ 148Ah. The negative lead connects to the far right, front, #2 batt and the positive connects to the rear left, #15 batt pulling across the whole bank.

Battery bank does great! I’d just like to eventually upgrade for longevity sake, these have done me well though!

The WH potential of the bank is pretty good, as with most I’m always wanting to upgrade lol. With 3 server rack 50XX WH batteries I’d be above what I have now, and can run them lower if I needed to.

As far as the array goes, I only “feed it” 2.5kw now as we all know there’s a lot of variables and usually don’t get full PV input. It’s setup on wheeled stands now so I can turn them to face more easterly for the AM sun and track it during the day. I’m also looking at getting 2-3 of the tamarack ground mount track setups.

I think the split phase option is appealing as well as the 8KW max PV input. For the price, it seems like a decent idea, I’d then add more static panels as you mentioned, facing south and west to capture more.

So far the system does great, it was the first one I put together and I’ve been quite happy with it. Running completely off grid I usually see around a 1-1.2kw draw and the setup easily keeps me in a surplus during the day.

 

[OffGridForGood]

Sounds lnteresting,

I use the system primarily as a backup but would like to slowly upgrade to 48v LiFePo server rack batteries and run off the system more and more to reduce needs. Primary function will always be for power outages from storms and well, the state of the world as we know it lol.

The LFP batteries are not a great choice to sit at full 100% SOC for long periods waiting for an outage etc. Your existing L-A batteries are a better choice for this situation.
If the change you have in mind is actually to use the system daily to run loads, and provide the batteries with some opportunity to run up and down their SOC, then LFP may make sense.
In this case you could just switch to 24v LFP and keep everything else you have, if the concern is the cycle-count you can expect to get from the ESS. However you would need to do something to either cycle the LFP on a regular basis, or keep them from sitting at 100% SOC for long periods of time.
A few members have talked about two battery bank systems, with a selector switch that allows them to choose between L-A or LFP battery banks. Keep the LFP as the reserve back up to the back up - stored at 60-70% SOC and the main bank L-A stored at 100% SOC where these are happy.
Just a few ideas to consider.

 

[ChrisSwolls]

Sounds lnteresting,

The LFP batteries are not a great choice to sit at full 100% SOC for long periods waiting for an outage etc. Your existing L-A batteries are a better choice for this situation.
If the change you have in mind is actually to use the system daily to run loads, and provide the batteries with some opportunity to run up and down their SOC, then LFP may make sense.
In this case you could just switch to 24v LFP and keep everything else you have, if the concern is the cycle-count you can expect to get from the ESS. However you would need to do something to either cycle the LFP on a regular basis, or keep them from sitting at 100% SOC for long periods of time.
A few members have talked about two battery bank systems, with a selector switch that allows them to choose between L-A or LFP battery banks. Keep the LFP as the reserve back up to the back up - stored at 60-70% SOC and the main bank L-A stored at 100% SOC where these are happy.
Just a few ideas to consider.

That sounds like a great idea. I may look into that route, it’d be pretty easy to set up! Thanks for the input, much appreciated!

 

[ChrisSwolls]

Update:

I ordered the EG4 6000XP. I’m also working on a pallet of ZNShine 370w panels. Looks like a killer price, I’m most likely going to split it with a buddy and drive out to pick them up.

I just did some load tests on 240v stuff I couldn’t run on my single phase Outback.

AC Unit: it pulled about 9 amps on startup, continuous was around 7 amps per leg. That puts me well below the 3Kw/25A load rating for the unit. Mathed out, I’m seeing around 880-ish watts per leg, 1600 total.

Furnace: furnace runs 120v, it pulled around 7 amps startup and dropped to around 5 amps running.


Any input?

 

[MisterSandals]

AC Unit: it pulled about 9 amps on startup, continuous was around 7 amps per leg.

9A startup on a unit that pulls 7A continuously sounds wildly inaccurate. How are you measuring the 9A?

 

[ChrisSwolls]

JK lol, I didn’t move fast enough last time and didn’t do a peak hold. It pulled 30.52A for about a second, then dropped to 9.39 and was running steadily at 8.5ish.

Based on those numbers and seeing the testing done the EG4 6000XP will be just fine!

My bad lol