Lithium batteries on an AGM budget?

RobOfYork · 03-22-2021, 11:51 PM

I really want to go with lithium but my budget can only afford AGM. Is it even possible to go lithium on a budget?

I want 200Ah of usable batteries. I did notice I can get 200Ah lithium cheaper than 2 100Ah but it scares me not to have redundancy in case of a battery failure.

My total budget is $800 for batteries but I could skimp on other areas of the build and go $1000 for batteries.

Any suggestions?

Ronnie · 03-23-2021, 06:08 AM

Look up DIY solar guy on youtube. Will is his name.

Build you own battery, you can buy the cells for less then a $100 each(need 4) and a bms is around a $100. The cells I looked at are 280 ah, so you would have a 280 ah battery

~Pat~ · 03-23-2021, 06:09 AM

I'm sure someone with more knowledge will respond, what about disassembled hybrid car batteries.? Nissan Leaf, Chevy Volt, etc

Ronnie · 03-23-2021, 06:14 AM

I have heard of trouble from hybrid car batteries, I know of a bus that caught fire from them. They are lithium ion. The lithium batteries generally used for solar are lithium IRON phosphate. Much lower fire risk.

joeblack5 · 03-23-2021, 06:50 AM

Hi Ronnie, is there an article or pictures if the bus that caught on fire?

OP, not understand your worries about redundancy around batteries. Your other thread around charge controllers to our like to go with one large charge controller.. that being an active electronic component has a relative high chance on failure.

We use multiple small charge controllers for several reasons...redundancy one of them.

Back to lithium.. 280 or 272 lithium shipped to your door is about 450 ( 4 cells) to your door from china.
We rune now three strings of these batteries at 24 volt in parallel.

I likely will be going with the electrodacus bms because of the high reliability design/ philosophy.

Vehicle lithium works fine to. Those. Batteries are of a much higher quality. They are good, we use them in our diy electric vehicles..but you want to be sure that stay away from the min and max voltages.

Good luck, johan

kazetsukai · 03-23-2021, 10:18 AM

Quote:

Originally Posted by RobOfYork

I want 200Ah of usable batteries.

Assuming 12V from our previous conversations, that's 2400Wh. Keep in mind with AGM even if you get 2x 100Ah batteries, only around 50% of their capacity is usable (100Ah). You would need 4x 100Ah batteries.

Quote:

Originally Posted by RobOfYork

My total budget is $800 for batteries but I could skimp on other areas of the build and go $1000 for batteries.

280Ah EVE Cells are fairly budget friendly:
https://www.alibaba.com/product-deta...517113167.html

$479 for four cells delivered, 3584Wh usable capacity. Double the bank to eight cells in 2P4S configuration, $936, 7268Wh usable capacity.

You will be waiting around a month at least for these to arrive.

Quote:

Originally Posted by RobOfYork

it scares me not to have redundancy in case of a battery failure.

If you do at least eight cells, you have some built in redundancy. If you do 4 cells, you could always order one or two extra cells to have on hand in case you need to replace a cell (better than replacing a whole battery, don't you think?)

Since this is DIY lithium, you will need a BMS like I described in another thread. This should be designed for use with LiFePo4 / LFP cells, and since you want a 12V bank, it should be a 4S BMS. Let me know if you want some options there.

s2mikon · 03-23-2021, 12:38 PM

Has anybody purchaced from Alibaba? What was your experiance?

kazetsukai · 03-23-2021, 12:44 PM

Quote:

Originally Posted by s2mikon

Has anybody purchaced from Alibaba? What was your experiance?

Waiting on two shipments from them currently, will update my build thread when they arrive for sure. First one shipped in 7 days or so. I have a whole system overhaul in the works, not just batteries. New inverter, doubling up on solar, shore connection refactor, electrical cabinet reorg, etc.

Lots of people over on youtube and the diy solar forums are talking about these 280Ah EVE cells. Basen is considered a known good supplier.

Will Prowse and Off Grid Garage are two YT channels featuring these cells.
https://www.youtube.com/user/errolprowse

https://www.youtube.com/channel/UCSv...dSghKQ9gXDT7pQ

cadillackid · 03-23-2021, 01:09 PM

Quote:

Originally Posted by s2mikon

Has anybody purchaced from Alibaba? What was your experiance?

I buy all kinds of stuff from them.. its like anywhere.. some suppliers are great others are sell it and forget you exist..

alibaba seems a lot like amazon in that you'll often find the exact same item from multiple suppliers.. each one stating they are the manufacturer so dont just buy the first listing you see.. you may find exact same item for less from another supplier..

I use a credit card wit ha relatively low limit and its set so every transaction blings my phone.. just because the possibility of fraud is much higher when dealing internationally, not from the supplier but from hackers who may be in the mix..

shipping charges can be hefty depending on how things are shipped.. buying multiples often saves.. so ofr instance if 5 or 6 people want to buy a diesel heater the shipping to send 5 of them may only be double what it costs to send 1. many suppliers start offering quantity discounts at as low as 5 pieces..

the timezones are anywhewre from 10-13 hours difference from the US timezones so be aware when emailing back and forth that responses may only be sent / received in the middle of the night

RobOfYork · 03-23-2021, 01:54 PM

Quote:

Originally Posted by kazetsukai

If you do at least eight cells, you have some built in redundancy. If you do 4 cells, you could always order one or two extra cells to have on hand in case you need to replace a cell (better than replacing a whole battery, don't you think?)

Thank you. Now that's a great idea!

RobOfYork · 03-23-2021, 02:00 PM

Quote:

Originally Posted by kazetsukai

280Ah EVE Cells are fairly budget friendly:
https://www.alibaba.com/product-deta...517113167.html

So if I order 5 cells so I have 1 spare + a BMS that would cost me about $700. That is within my budget and I get 280Ah instead of 200Ah.

Hmmm....

Rucker · 03-23-2021, 03:06 PM

I'm also looking at this option seriously. When I started my build ('99 6 window Shuttle) I wanted to pass with a D-, just enough power for a simple system with a little fridge. For me, that was 200 AGM amps and a 1200 Watt pure sine inverter, no solar. It's designed for weekend trips.

But I've been doing more research, and I realize I probably am underestimating the power needs, especially 4-5 years down the road. I didn't specifically define the lifetime of the conversion other than to say 'minimal maintenance', but I don't want to be doing a major electrical overhaul because I didn't plan for changes in use, like maybe taking it off grid for a few weeks every year.

New plan: going the DIY LiFePo4 route with a 3K inverter and 400 watts of solar. For our use, it will be essentially endless power and no need to watch the AGMs. I'll inadvertently kill those AGMs for sure, knowing me.

The DIY math: battery plus BMS should come in under a thousand, but might be a bit more. 4 cells will cost from 500-800 with shipping (lots of price variation between alibaba and amazon, depending on how fast you want them); BMS about $160. Cables, shunt, etc. aren't cheap either.

Not trying to hijack the thread, but perhaps others have experience in this space that bears on your decision to go LiFePo4.

RobOfYork · 03-23-2021, 03:49 PM

Quote:

Originally Posted by kazetsukai

Since this is DIY lithium, you will need a BMS like I described in another thread. This should be designed for use with LiFePo4 / LFP cells, and since you want a 12V bank, it should be a 4S BMS. Let me know if you want some options there.

Would love some recommendations on the BMS to use with 4 cells. I am leaning toward building my on LiFePo4 battery instead of going the AGM route.

kazetsukai · 03-23-2021, 03:55 PM

Quote:

Originally Posted by RobOfYork

Would love some recommendations on the BMS to use with 4 cells. I am leaning toward building my on LiFePo4 battery instead of going the AGM route.

I use https://electrodacus.com/ SBMS0 for my Tesla packs, no complaints there although I'd have to use two of them in the new bank.

I'm considering getting a 16S BMS from DALY for the new bank. They come in a variety of amperages.

100A
https://www.amazon.com/DALY-LiFePO4-.../dp/B08794B2G8
250A
https://www.amazon.com/DALY-LiFePO4-.../dp/B08KD66M54

Make sure you get a BMS designed for LiFePo4 or "LFP". "Lithium" or "Lipo" tends to mean a different Lithium chemistry with different voltage ranges. Electrodacus is configurable for any kind of chemistry.

Ronnie · 03-23-2021, 05:25 PM

Quote:

Originally Posted by joeblack5

Hi Ronnie, is there an article or pictures if the bus that caught on fire?

OP, not understand your worries about redundancy around batteries. Your other thread around charge controllers to our like to go with one large charge controller.. that being an active electronic component has a relative high chance on failure.

We use multiple small charge controllers for several reasons...redundancy one of them.

Back to lithium.. 280 or 272 lithium shipped to your door is about 450 ( 4 cells) to your door from china.
We rune now three strings of these batteries at 24 volt in parallel.

I likely will be going with the electrodacus bms because of the high reliability design/ philosophy.

Vehicle lithium works fine to. Those. Batteries are of a much higher quality. They are good, we use them in our diy electric vehicles..but you want to be sure that stay away from the min and max voltages.

Good luck, johan

No article or pictures. It was a friend of a friends bus. Our friend also had trouble but no fire just smoke. I do not know the details as to why they caught fire.

kazetsukai · 03-23-2021, 05:48 PM

Quote:

Originally Posted by ~Pat~

I'm sure someone with more knowledge will respond, what about disassembled hybrid car batteries.? Nissan Leaf, Chevy Volt, etc

I currently use two Tesla 24V packs in a 48V configuration and am migrating away from them. Night and day difference to any lead acid battery I've used. I'm moving on to a 16S LFP bank for a few reasons, primarily capacity and voltage range.

You absolutely have to know what you are doing with them and be willing to tinker. At some point I probably should look at my packs with a thermal imager at low and high SoC to see if any cells are self discharging at a high rate. The packs consist of 444 18650-like cylinders in 74P6S configuration, and every cylinder connects to its bus via a fuse. The idea being, the fuse would cut the cylinder from the cell group automatically if it were aggressively discharging.

With the LiFePo4 cells on the market being this low cost, I wouldn't bother with second life EV batteries. If you overcharge or overdischarge any kind of lithium you're still asking for a fire, but LFP is reportedly a safer chemistry than Lipo. The current king of safety is LTO, which is still expensive but will last 50 years. We'll see where that goes.

Quote:

Originally Posted by Ronnie

No article or pictures. It was a friend of a friends bus. Our friend also had trouble but no fire just smoke. I do not know the details as to why they caught fire.

I think ten years from now EV fires might be a lot more well known/common, once the batteries are near their limit and still pushed hard. Only once on video have I seen a pack catch fire outside of a vehicle. Its like a box of fireworks.

BeNimble · 03-23-2021, 06:04 PM

Quote:

Originally Posted by Ronnie

No article or pictures. It was a friend of a friends bus. Our friend also had trouble but no fire just smoke. I do not know the details as to why they caught fire.

The toyota hybrids use NiMH batteries, which can't be connected in parallel. If you do they will overcharge and explode.

So you would need to run the 6.5ah cells in series as they come and then dc-dc the 200 volts up/down to 12 or 24. Interestingly, the Prius are getting their cats stolen the last few years as an epidemic, which makes the car a total, and they still have good batteries. So a 1.5kw pack might be a few hundred bucks.
No aftermarket support that i have heard of, so real diy here.

The LiFePo are much better though and now are quite cheap. If those cheap chinese 280ah cells last, they are a bargain.

teknomad · 03-23-2021, 07:41 PM

https://www.youtube.com/user/jehugarcia

This guy does TONS of stuff with salvaged 18650 batteries, as well as other esoteric formats.

He also buys them from factories and resells them. He's actually the only way to get legitimate panasonic 18650s since panasonic refuses to sell them to consumers, and he's got several crates of them.

Even if you're not buying his batteries he's got a lot of information on how to use them, assemble them, BMS systems, everything. He converted a few classic cars into electric

RobOfYork · 03-23-2021, 10:46 PM

If I buy 5 cells so I have a spare, how would the extra cell need to be stored?

rffffffff · 03-24-2021, 08:07 AM

Quote:

Originally Posted by RobOfYork

If I buy 5 cells so I have a spare, how would the extra cell need to be stored?

I think this gets to the most important difference between lifepo and lead acid.

I’m not sure about storage safety but a lot of people put lead acid batteries in hatches outside. The lifepo batteries need to be kept in a narrow range of temps so either a heated compartment, which seems a little odd to me, or inside the living space, which is a bad plan for lead acid with the off gassing (although I think agm is okay in that regard, are they sealed?)

You definitely have to plan ahead for your chemistry and it’s harder to switch than it may seem at first.

You may also like: