RV and Home Backup Installs

MisterSandals

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I have been reading everything and learning quite a bit from everybody here, many thanks!

I have completed a couple solar installs including 400 watts on the RV with existing lead acid batteries and a 3kw grid tie system on the house. Now venturing into LiFePO4 for the RV and a stand alone emergency system for the house.

Starting with pictures of the parts. I ordered 12 206AH blue cells ($1550 shipped) in November from Alibaba and quite a few bits and pieces from Aliexpress of which most have arrived. Recently ordered most of the rest from Amazon as my system started to gel from reading what others have done and recommend.

I expect to have 206AH @ 12v in the RV and 412AH @12v at the ready in my garage. By "at the ready", i mean extension cord to the refrigerator and chest freezer ready. Keeping the fridge and freezer alive for an indefinite timeframe is the main goal though with the RV in the driveway I will have that available and be fairly solar rich as long as the sun continues to shine regularly.

Modest goals with modest expense I believe.

I am excited to learn some new skills with new tools. Hydraulic crimper, JST crimper, heat gun are new to me though i think i have every other tool one can think of. Hoping for a Cadillac install - having the right tools and parts makes that easier for sure.

I hope to post more info and pictures as I progress and as pieces (2x Daly BMS units) arrive.
 

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BoloMKXXVIII

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I wonder why the house system is being kept at 12 volts. You could easily run 24 or even 48 volts and reduce your cost of heavy gauge wire. Inverters for these voltages are readily available.
 

MisterSandals

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Hi BoloMKXXVIII
I sometimes wonder too. But, I have a LOT of 12v stuff, including a new Giandell 12v 1200w pure sine wave inverter. Buying that again, I "may" have purchased the 24v version.

I have 2 other 12v sine wave inverters in the RV. Those will always need to be 12v.

I can always switch to 24v in the house and I will make that decision when i have to (if/when the 1200v 12v inverter dies). But having both systems 12v is inherently providing redundancy where if i had one 12v system, and one 24v system, I would need to specifically purchase more (expensive!) 12v and 24v backup items.

But at this point, I'm content with my solution and past any product return dates!

Thanks for your thoughts, I appreciate it!
 

MisterSandals

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First connection and balance. All cells tested within .01 with multimeter out of the box. With ISDT balance function (just started in photo), cell 1 fluctuates a bit. Overnight they settled to identical 3.26.
Hopefully i will tire from posting the baby steps (sorry for now!).

Hoping that at 19% charge, which is my intended bottom voltage in use, this will serve as a meaningful bottom balance (i have seen folks recommending 2.5v).

When the clouds get out of the way of my power supply, I will see how they charge!
 

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MisterSandals

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Silicon Valley
Its been a while since i updated my show and tell.
I purchased quite a few little meters and balancers to learn and determine my cells capabilities and differences.
The BattGo has been the most used for a quick glance at 4s cell voltage checking. Way to slow to balance 200ah cells.
The Tenergy 5 in 1 is extremely disappointing. Got it for internal resistance testing but the results are FAR more dependent on cell order that what might be internal resistance. Junk.
I ran a couple discharge cycles thru a 300 amp shunt and i seem to be getting full capacity (just over 200ah) from the first 4s battery - mostly a sanity check.
The HobbyMate Duo Pro charger has been a workhorse since i got it a few days ago.
I have been using solar to charge a battery which in turn powers the HobbyMate to charge cells in parallel at 3.65v for a top balance.
See attached, 4s powering charge of 8p for top balance.

Nearing the point of building 3 4s batteries to test internal resistance (with HobbyMate) and capacity of cells. My plan is to rearrange “like” cells together into 4s batteries, thru a few iterations,544EE0B5-DDE4-4557-A1D9-2249654BDA74.jpeg until they charge and discharge uniformly.
 
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