Pro's and Con's of each battery type?

Rednecktek

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Con's: Expensive per Amp Hour, requires Battery Management System to roll your own, does not charge below freezing temperatures,
I'd say the cost is about the same over the life of the battery....

True, maybe that needs to be changes to Up-Front cost, but it does mention in the Pro's that the lifespan is much greater.

So far I'm not finding any reason to spend extra on Gel batteries unless I wanted to install them sideways or hang them from the roof. Why do they even sell those things?
 

12VoltInstalls

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Why do they even sell those things?
1) For harsh, high-vibe environments where dependable battery service is required
2) Where minimal battery maintenance is less acceptable and higher expense is more acceptable
3) certain applications like alarm backups where a sealed battery in an enclosure is needed
4) to separate people from their money when they believe that more money offers ‘better’ or is esteemed as a status symbol

I can see it in a low-drain, low cycle, yet long term service application
 

Texas-Mark

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For me, I also consider other things other than long term costs. If I need a new FLA, I can run down to Walmart and grab one any day of the week. No need to wait weeks or months on a slow boat. Since my battery box is outside and space is not an issue, I just can not justify changing until the price of Lifepo4 comes down more, and more importantly becomes more readily available (i.e. on the shelf at a B&M)

 

Supervstech

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For me, I also consider other things other than long term costs. If I need a new FLA, I can run down to Walmart and grab one any day of the week. No need to wait weeks or months on a slow boat. Since my battery box is outside and space is not an issue, I just can not justify changing until the price of Lifepo4 comes down more, and more importantly becomes more readily available (i.e. on the shelf at a B&M)

Costco has some in stock from Li lion energy.

What sold me on lithium is the charge efficiency. Lead has a lot of solar waste involved.
 

Wellbuilt

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Lith look real good , it’s the price they want for them and the fact that they don’t like the cold that turn me off
 

wholybee

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FLA are much more forgiving than AGM with respect to partial states of charging. Both need to be fully charged to prevent sulfating, but FLA you can go a few weeks without doing that, then perform an equalization to make up for it. AGM will die. AGM charges much faster, so if you have the power available it is easier to charge them to 100% every day. (Firefly and lead carbon are a specials case, as are Rolls, each of which offer amazing performance for lead batteries.)

LPF are not new, not at all. There are many DIY installations over 10 years old that still perform to spec. Given that you would need a smaller battery, and that if properly installed and maintained will last so long, they are not expensive at all. Depending on specifics they are about the same cost more or less than FLA.

LFP charge faster than LFA or AGM, do not have issues with not charging to 100%, are *MUCH* easier to determine _accurate_ SOC by counting Ah(no need to account for temperature or peurkurt) , and require much less maintenance than Lead batteries. When you get right to it, lead batteries are damaged by over discharging and overcharging as well, just not as quickly. So even the "need" for a BMS is not unique. Lead batteries would be better off with a BMS as well, and some people successfully use LFP without a BMS.
 

ken morgan

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My take on it is that FLA and LFP batteries require more attention to detail but in different areas in comparison to AGM batteries. (I have no experience other than the three.)

Lead acid requires constant attention to water levels, charge percentages and the required EQ charge.
LFP needs a lot of attention initially in the commission of the pack as well as the BMS setup.
AGM is the easiest for a beginner. (I think)

Most lead acids die in the first year due to sulphation in one form or another. Most users kill their first pack and after that learning experience have great experiences having learned what to avoid.

LFP's if you buy actual good cells to begin with seem to have BMS issues initially but after you get past that you are generally good to go. Most folks seem to have the biggest issue with user mistakes in wiring, or pack location.

AGM's are the easiest to deal with initially but are more expensive then FLA and do not last as long generally speaking (though I had a set last 10 years.)

just my thoughts... I recently swapped to LFP and am learning that the biggest issues most of us have area getting good cells, everyone wants to save a buck and are losing thousands as a result.

YMMV
 

wattmatters

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AGM is the easiest for a beginner. (I think)
This is my beginner pack:

IMG_3121.jpeg

Orange is the new black.

This bank is for outage backup and a bit of ballast so the solar PV can run the pool pump and a few sundry items. They are not for regular cycling. Did a test "outage" night before last and no issues at all. 7.5 hours overnight and I was down to 84% SOC.

It's definitely been a good learning experience. I'll eventually look to progress to LiFePO4 one day if/when I want to move to daily cycling for house loads. But that's a different financial equation. They need to come down in price by quite a bit (at least half).

From my perspective these pre-loved SLA units from a data centre significantly lowered the cost of entry to doing a project like this. Same for my solar PV and rails, picked up pre-loved stuff. I would never have bothered with such a project using LiFePO4 at the moment (not much in the way of pre-loved LFPs about).

Pre-loved comes with extra risks of course, especially when it comes to batteries, but this particular brand/model of paperweights seem to be very tradable items, and at worst they can go to a lead recycler.
 

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ken morgan

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This is my beginner pack:

View attachment 65764

Orange is the new black.

This bank is for outage backup and a bit of ballast so the solar PV can run the pool pump and a few sundry items. They are not for regular cycling. Did a test "outage" night before last and no issues at all. 7.5 hours overnight and I was down to 84% SOC.

It's definitely been a good learning experience. I'll eventually look to progress to LiFePO4 one day if/when I want to move to daily cycling for house loads. But that's a different financial equation. They need to come down in price by quite a bit (at least half).

From my perspective these pre-loved SLA units from a data centre significantly lowered the cost of entry to doing a project like this. Same for my solar PV and rails, picked up pre-loved stuff. I would never have bothered with such a project using LiFePO4 at the moment (not much in the way of pre-loved LFPs about).

Pre-loved comes with extra risks of course, especially when it comes to batteries, but this particular brand/model of paperweights seem to be very tradable items, and at worst they can go to a lead recycler.
I have nothing bad to say about AGM's. (other than cost) I ran with AGM's in both my camper (9+ years) and my cabin (3+ years) but my cabin ones died at the 3+ year mark as they were not getting fully recharged each day and got "walked down" till I had to replace them. with the price of LFP I decided to make the jump as well as increase my PV array to make up for the walking down effect.

Which remind me folks... do not trust the % charged functions on any of the shunt based capacity meters unless you manually set the percentage of efficiency...I had mine set to auto efficiency and it kept reporting that they were getting fully charged, but they were not, and thats what "walked down" my AGM bank. Death by a thousand cuts.
 

wattmatters

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I expect mine to get cycled perhaps 20-30 times over the next couple of years.
 

ken morgan

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I expect mine to get cycled perhaps 20-30 times over the next couple of years.
when you say cycled are you talking 50-70% of capacity or less? My biggest concern is micro cycling...is it a concern? I leave my A/C on a timer so that I will draw down at least to 75% on a daily basis to avoid this...is it even a concern? I do not know but wish I had more info in regards to this.
 

wattmatters

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when you say cycled are you talking 50-70% of capacity or less?
Here's my SOC plot over the last month. Note the battery capacity was doubled inside the last week.

Screen Shot 2021-09-22 at 2.47.03 pm.png

You can see the small daily dips in SOC when the battery was half the current size at 190Ah (48V). Mostly due to idle load consumption overnight (inverter, pool pump controller, Raspberry Pi). From here on those minor dips will be half as deep as the battery now has twice the capacity.

During the day the draw is minimal to zero. Battery acts as ballast while solar PV (2.2kW) meets the (320W) demand. If the day is particularly cloudy/rainy then the PV will still supply most of the pump's energy while the battery supplements. And when the pump's duty cycle ends the battery gets whatever solar capacity is left to aid a recharge during the rest of the afternoon. For reference, August is Winter here. We're just moving into Spring.

At far right of the plot the deeper dip is a simulated grid outage I performed the other night after I had doubled the battery bank capacity. 8 hours overnight (10pm-6am). It was a test run to check everything. The next day wasn't exactly brilliant solar conditions but recharging was no issue (along with running the pump).

So it's only one month of data, and mostly with a battery of half the capacity I now have, but I think that's plenty to know that for the most part cycling is going to be between a SOC of 95-100%. A deep discharge day might get down to a SOC of 80%. I'll know better after a full year of course.

And if things get really bad and we are talking a multi-day outage, in Spring/Summer/early Autumn I may not even need to supplement with generator. But I have that too if needed.
 

ken morgan

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Why does it concern you?
I had read somewhere, either here or on the NAWS forum that micro-cycling was not good for LFP's from what i remember the gist of the discussion was that LFP's do not like being stored at full charge and that it was better to more fully cycle them but keep it between 40-80% as much as possible. currently with full sun if i did not use the A/C i would be at full charge by 1100 with m current PV array vs usage. I am heavily over paneled for he summer months but just about right I think for the winter months.

thats why I am looking into possible diversion schemes for the summer months... IE no charge for two or three days and instead diversion dumping that into a massive insulated water tank, and then bringing battery pack to full charge in one day or close to full charge so letting the pack drop to 40 or 50% and then recharge to say 80-90% and then repeat cycle.

its that I just do not know enough about this battery chemistry.
 

wattmatters

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I had read somewhere, either here or on the NAWS forum that micro-cycling was not good for LFP's from what i remember the gist of the discussion was that LFP's do not like being stored at full charge and that it was better to more fully cycle them but keep it between 40-80% as much as possible. currently with full sun if i did not use the A/C i would be at full charge by 1100 with m current PV array vs usage. I am heavily over paneled for he summer months but just about right I think for the winter months.
Ah, OK. I thought you were talking about lead acid.
 
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