LiFe PO4 batteries - cheaper replacement for lead acid

[fizzy]

I am no fan of lithium ion batteries. Farr too dangerous and too expensive.
These lithium iron phosphate batteries seem the perfect compromise.
Prices have fallen dramatically.
I am considering replacing the knackered 12v 100amp agm batteries in my wife's mobility scooter witheither 2 12v ones or 1x 24v version. Price is now the same.
They also make great sense for solar backup. I could buil;d a nice big array for my place in Portugal for the same price as a forklift battery. £3500 v £12,000 for lithium ion!

Great test of one on Youtube - bloke really knows his stuff! And no it isn't a scam - he is amazed by the price. Can't find the same seller here but the details and pictures used on Ebay make it look identical.

Some Ebay links below

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[m_c]

Prices have dropped recently.

They're ideal for deep cycle applications, where a suitable charging system is used, and the temperature doesn't get too cold.
Key issues are they don't like over voltage, or the cold.
The built in BMS will likely disconnect the battery if the charging voltage goes too high (means they're not a good choice for applications where charging will be directly from a vehicle alternator).
Capacity drops off quite noticeably in the cold, and you risk damaging the battery if you try pulling/pushing too much current when below freezing. Some BMS systems will simply disconnect the battery below freezing to protect the battery. Batteries are available with built in heating to avoid the problem, or you can sit them on a heat mat.

I fitted two 100Ah LiFePo4 to a mates van who does mobile valeting a few months ago, and they replaced 4 100Ah AGM batteries.
He's getting better run times out of them than when the AGM batteries were new, and they should in theory last longer. He was typically only getting a couple years out a set of AGM batteries, so it'll be interesting to see how they perform longer term.
Being fitted next to a several hundred litre water tank with a frost protection heater fitted, also seems to keep them just warm enough to avoid the cold temperature protection kicking.

 

[fizzy]

How cold is too cold for them?

 

[fizzy]

I just read they work fine in cold weather. Just don't like being charged below 0C.

 

[Kayos]

Lithium is now so cheap DIY is not worth the hassle

I've just completed a job, 23.2kw of batteries and a 3 phase inverter (replaced 2 single phase inverters) cost to customer was £10k

 

[fizzy]

Lithium is now so cheap DIY is not worth the hassle

I've just completed a job, 23.2kw of batteries and a 3 phase inverter (replaced 2 single phase inverters) cost to customer was £10k

Lithium ion still seems expensive. Lithium Iron much better. Which did you fit?

 

[Kayos]

Ion, we are close to the $50 dollar per kW (input cost) that Bloomberg predicted would be 2030, that is the tipping point

We only install PV with batteries these days, extends the usefulness for not much extra cost

 

[fizzy]

Ion, we are close to the $50 dollar per kW (input cost) that Bloomberg predicted would be 2030, that is the tipping point

We only install PV with batteries these days, extends the usefulness for not much extra cost

You should look into LiFe much cheaper. Only £2500 for around 22kw.
Will one of the fancy new 3 phase inverters automatically switch between solar, battery and mains? I assume they must do.

 

[Kayos]

You should look into LiFe much cheaper. Only £2500 for around 22kw.
Will one of the fancy new 3 phase inverters automatically switch between solar, battery and mains? I assume they must do.

We use what the manufacturer specs, yes the inverter controls it all

Currently developing an AI model to learn the use profile and alter the settings dynamically

Big consumers are easy, it's the home users that will benefit from fine grain control

 

[rcx132]

It's the longevity concerns me. I have a pro charger and I curiously like to measure the capacity of lithium batteries that come with various equipment. Most of them are just pure junk after even moderate use.

 

[Gareth J]

I assume all the talk of "kw" above are referring to kWh?

We use what the manufacturer specs, yes the inverter controls it all

Currently developing an AI model to learn the use profile and alter the settings dynamically

Big consumers are easy, it's the home users that will benefit from fine grain control

Last time I looked into adding batteries to my two hybrid inverters, despite us using more than the annual generation from our 40kWp array, I couldn't make the numbers work. The option of selling back electric companies via SEG made a big difference.

That was a year or so ago now though...time to revisit?

 

[Kayos]

I assume all the talk of "kw" above are referring to kWh?


Last time I looked into adding batteries to my two hybrid inverters, despite us using more than the annual generation from our 40kWp array, I couldn't make the numbers work. The option of selling back electric companies via SEG made a big difference.

That was a year or so ago now though...time to revisit?

To be honest we just say KW but know when we mean kw or kWh

Anything bigger than a domestic system is modelled to determine size and number of batteries as it's not just a case of stick some in and see what happens

We always size for self consumption unless the export tariff is worth it

 

[Kayos]

It's the longevity concerns me. I have a pro charger and I curiously like to measure the capacity of lithium batteries that come with various equipment. Most of them are just pure junk after even moderate use.

Given the way they are sized and used it isn't a concern

 

[Gareth J]

Anything bigger than a domestic system is modelled to determine size and number of batteries as it's not just a case of stick some in and see what happens

We always size for self consumption unless the export tariff is worth it

Clearly self consumption is most valuable. I don't have access to modelling gear but a back of the envelope best and worst case guess is easy enough so will have another look. If you/your company are at all interested, I'd be happy for you to quote, pm me if so but no worries if not.