diy solar

diy solar

Future of DIY LiFePO4 looks bleak…

Again, DIY being less expensive for a LiFePO4 battery with special requirements is a no-brainer.

Looks like you’ve built 4 105Ah 4S / 12V batteries for $1636 minus the cost of the inverter.

Using the reference I just posted, you could have bought those 4 batteries OTS from Amazon for $680 ($170 each).

So unless you got your BMSs for under $50 and your cells for under $40 each (shipped), your batteries were not less expensive than lowest-cost OTS (again, overlooking that your DIY batteries are 250A and the OTS batteries on Amazon for $170 were only 100A).

Would be interesting to know what you spent on the batteries alone as an end-of-2023 datapoint for DIY ~100Ah 4S / 12V.
I’m looking at building DIY storage for my DIY camper. Comparing my original idea of using EG4 rack batteries (24v or 48v) it is cheaper. We haven’t decided on which voltage we want to use yet. But for most average mobile solar users, 12v prebuilt china batteries are cheaper. Those people also need less storage capacity and use less panels. If I was just power a fridge, a fan or two and some led lighting, sure 12v is great. But we will be powering a mini split, fridge, lights, fans, Xbox, tv, chargers, etc. So higher voltage will be much easier for us. Anyways. I can build diy for almost half the cost of buying the EG4. So to me it’s cheaper. Granted shit is constantly changing in price. So when we finally build our solar system that may change and I may go back to the idea of rack batteries. But either way it’s all in fun because at the end of the day, do whatever makes you feel happy

Also, I’m sure I’ll share our whole set up when we finally get it done next spring
 
I’m looking at building DIY storage for my DIY camper. Comparing my original idea of using EG4 rack batteries (24v or 48v) it is cheaper. We haven’t decided on which voltage we want to use yet. But for most average mobile solar users, 12v prebuilt china batteries are cheaper. Those people also need less storage capacity and use less panels. If I was just power a fridge, a fan or two and some led lighting, sure 12v is great. But we will be powering a mini split, fridge, lights, fans, Xbox, tv, chargers, etc. So higher voltage will be much easier for us. Anyways. I can build diy for almost half the cost of buying the EG4. So to me it’s cheaper. Granted shit is constantly changing in price. So when we finally build our solar system that may change and I may go back to the idea of rack batteries. But either way it’s all in fun because at the end of the day, do whatever makes you feel happy

Also, I’m sure I’ll share our whole set up when we finally get it done next spring
For boats and RVs, 24v makes a lot of sense. Cable sizes are about 1/4 of the cross-sectional area for the same volt drop as 12v.
Lots of kit is already available in 24v due to trucks running 24v. Fans, led lights, fridges etc. The cable runs are not super long in an RV so 24v works pretty well.
I much prefer DIY over cheap retail batteries. I can build a way better specification for less money than a cheap battery with unknown cells, crappy BMS and passive balancer. At a later date I can swap out a BMS if a choose to do so or even a dodgy cell.
 
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Do any of these 100ah budget batteries have BMS with Bluetooth that report each cell voltage?
 
For boats and RVs, 24v makes a lot of sense. Cable sizes are about 1/4 of the cross-sectional area for the same volt drop as 12v.
Lots of kit is already available in 24v due to trucks running 24v. Fans, led lights, fridges etc. The cable runs are not super long in an RV so 24v works pretty well.
I much prefer DIY over cheap retail batteries. I can build a way better specification for less money than a cheap battery with unknown cells, crappy BMS and passive balancer. At a later date I can swap out a BMS if a choose to do so or even a dodgy cell.
The 24v 8S DIY packs I am working with have balanced well. Am adding a portable 24v system and am already considering picking up another batch in the new year. As indicated elsewhere if one decides to move to 48v in the future the existing wiring can more than handle the load.
 
I have swapped out the BMS on one of my DIY packs from the Chargery to the JK BMS .... It's kind of amazing how much better the balancing is working with the JK .... and the Chargery has pretty good balancing compared to some of the others with passive balancing.
I had 4 chargery on my 4 banks. They were very inconsistent with readings and reliable current measurements. The DAY I installed my JK BMS on all 4 banks all batteries came into perfect alignment voltage wise for charging up to my Max of 55V and the batteries have never operated better. The chargery would always be beeping up top and shutting down but they were all false readings checked with multimeter. Something is either too sensitive or the voltage does weird things with it up top. I tried to power externally as well. No deal difference. Just junk for me.

Could have saved alot of wiring headache not having to wire in giant contactors on my setup for the chargery. Love and learn. We all have a box or room full of old solar gear im sure! Add my fried growatt to the pile last week.

JK 200A all the way.
 
Got her down to two for $3000 DDP. I may buy and be the guinea pig…haha.

Having them add a 200A DC breaker and trying to talk them into adding active balancing module for the PACE BMS. But their engineers are telling me no need…

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OK, placed order for two.

$3120 total. Had them add DC breaker, active balance module and wheels.

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On the other hand one could build their own custom dolly with swivel casters with 2x4s which could fit the battery case more exactly.

 
On the other hand one could build their own custom dolly with swivel casters with 2x4s which could fit the battery case more exactly.

I guess. But this looks better. And I didn’t do so well in woodshop.

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