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Discussion Starter #1
Came across this on Ali Express: 12.6V 200AH Lithium ion Battery and that comes to about $340/100ah. That seems like a pretty good price point for LiFePO4. Anyone tried these yet? Any opinions on if this is worth a shot?

I haven't posted much yet about our build plans, but we will be fairly heavy electric users, induction cook top, low power microwave (600w), dorm fridge (extra insulation), and maybe a 5000 btu window unit (only for short usage when we have to leave our little dog for a short while). Maybe 600 watts or so of solar.

I am thinking about buying a couple of these batteries -- bad idea?
 

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You know there are only two response to this: 1. Sure, why not? What's the worst that could happen? and 2. Are you mad? Evil demons lurk inside batteries that are just waiting to jump out and burn your van (and garage and house and town) to the ground.


A friend used to joke that bicycle lights (output measured in lumens) from China were never as bright as the advertised rating. He decided they were measuring in chumens. Like lumens, but much smaller. I bet those AHs are also smaller than expected.


FWIW, I'm in camp #2 . Lithium batteries are not to be trifled with.
 

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For consistency with rest of industry/world, probably best to compare cost on a per kWh (kilowatt-hour) basis, not Amp-hour.

Prices are heading down, but $270/kWh seems very low for retail. On the other hand manufacturers like Tesla are reportedly below that now. A big cost difference may be the battery management system.
 

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Discussion Starter #4
Are you mad? Evil demons lurk inside batteries that are just waiting to jump out and burn your van (and garage and house and town) to the ground.
I'm an old solder jockey and we claimed that all electronic components are filled with smoke; one wrong move (or for no reason at all) and PHFFFT! out comes all that smoke! I'll try and not let the smoke out of the evil demons! >:D
 

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I'd stay away from this. This is a 12.6V li-ion (NOT LiFePO4) 18650 battery. Nominal voltage is 10.8V so most inverters and DC appliances will not operate that low.

EDIT: I reread your first post and will upgrade what I said. I'd 100% NOT buy this. induction cook top, low power microwave (600w), dorm fridge (extra insulation), and maybe a 5000 btu window unit (only for short usage when we have to leave our little dog for a short while) will all be running from your inverter and 10.8V isn't going to cut it. You are also dealing with a more sensitive battery when it comes to overcharge/discharge. Lifepo4 is a safe chemistry compared to other lithium batteries. These are they type that can catch fire when shorted or overcharged or over discharged.
 

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Discussion Starter #6
I'd stay away from this. This is a 12.6V li-ion (NOT LiFePO4) 18650 battery. Nominal voltage is 10.8V so most inverters and DC appliances will not operate that low.
Poorly written Chinese ads -- read a little closer, even on the picture of the battery, is shows it as LiFePO4.
Who knows if it is true. Where did you see the bit about 10.8v? Or is that a characteristic of an 18650? I actually don't see that in the ad either... maybe you need to teach me how to read between the lines on these types of ad!!!
 

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I'm an old solder jockey and we claimed that all electronic components are filled with smoke; one wrong move (or for no reason at all) and PHFFFT! out comes all that smoke! I'll try and not let the smoke out of the evil demons! >:D
I prefer AvE's nomenclature calling them angry pixies. Since pixies when treated with respect are neutral or even helpful. And let's face it when the smoke comes out, it's usually someone's fault-- an assembler's or manufacturer's error or somebody else's fault, but never our own ;)

My favorite story of releasing the smoke is watching a technician power up a board to test it and a component catches fire and rains molten material on his crotch, catching his chair and pants on fire :eek: He was a juvenile prostate cancer survivor, so nothing much phased him. He kept that chair with burn hole and all for years afterward.

Per the LiFePO4 batteries, I'd say they are likely relatively safe as far the the pixies are concerned if applied properly. Not sure about their longevity or value, as there's only a 30 day warranty and they quote 1000-1200 charge cycles whereas many other manufacturers quote 2000 cycles. I'd say that's your biggest risk. Could be that they're just being more realistic than others, however.
 

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Poorly written Chinese ads -- read a little closer, even on the picture of the battery, is shows it as LiFePO4.
Who knows if it is true. Where did you see the bit about 10.8v? Or is that a characteristic of an 18650?
A 18650 is about 4.2 VDC fully charged, so 3 cells is their rated 12.6 VDC. They nominally droop down to 3.7 - 3.6 VDC which is 11.1 - 10.8 VDC.
 

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Discussion Starter #9
So are nebulight and Ziggy trying to tell me that running an inverter off batteries with 18650 cells is always a bad idea? Should one (if inclined to lithium) instead choose batteries with 26650 cells, or what?

Sorry to be so dense...
 

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18650 is the size of the cell (18mm wide by 65mm long). It's not the size, it's the chemistry of the cell that determines the voltage. Most 18650 cells are li-ion (LMO, NMC, LCO chemistry). The problem with those chemistries is the resting voltage of 3.6-3.7v. With that, with 3 in series you get 10.8-11.1V (12.6V fully charged) which is usually too low for 12V appliances and most inverters low voltage cut off. If you put 4 in series you get 14.4-14.8 (16.8v fully charged) which is sometimes too high for most 12v appliances and some inverters.

Most use Lithium iron phosphate know as lifepo4 or LFP. It has a 3.2v nominal voltage so 4 in series is 12.8v which is perfect for 12v applications. It also is a much safer chemistry and has thousands of cycles in it's lifespan compared to around 500 for most other lithium chemistries. It's weight to storage capacity isn't as great as NMC or other chemistries (thought is still WAY better than lead acid), but it's safety and cycle life have made it the go to for RV/Van conversions. It also has a VERY flat discharge curve which means the voltage doesn't drop until the batteries is almost dead. lifepo4 requires a battery monitor to know the state of charge because of this.
 
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The URL/Site you referenced suffers from poor 'cultural translation' making it virtually impossible to assess what they're selling. It's confusing and contradictory. Like the other commentators here, we're not even certain what the chemistry is. There is one section that (correctly) lauds the benefits of LiFePO4, but everywhere else they scrupulously avoid using the term "LiFePO4" simply calling their product 'lithium' or 'lithium ion'. What further fuels our suspicions are certain of the 'specs'. For example, maximum charging voltage of 12.6 volts!? Four LiFePO4 cells (in series which is absolutely standard) can't be charged at such a low voltage.

Then there's the maximum charge rate spec of 40 amps! Really? Our LiFePO4 back can be charged at a 3C rate (i.e. 3 times its AH capacity) or, 1,500 amperes! A 200 ah battery of this type should be chargeable up to 400 amps. And is this a joke - - supplying a 3 amp charger? What good is that?

On further study of their Site, we did find a 600ah - - said to be LiFePO4 - - for a $2,200+ price tag with ‘specs’ more reminiscent of what we’d expect for a LiFePO4 battery.

Good luck, but please, ‘buyer beware’.
 

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I think this thread underscores that Lithium-based systems are not for novices. You really need to know what you are doing like Winston and other adventurous souls on the forum to successfully build a system.

Lead based FLA and AGM batteries are a safer and cheaper alternative for those who are not at this level and you can always retrofit your system should better options arrive in the future.
 

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Discussion Starter #13
I love this stuff! I think you guys are 100% correct that the AliExpress ad I posted is NOT LiFePO4, so good catch ya'll!! Why the heck do you suppose I posted it here? Is it wrong of me gain knowledge at other members' expense, or is that the entire point of this forum??
 

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I love this stuff! I think you guys are 100% correct that the AliExpress ad I posted is NOT LiFePO4, so good catch ya'll!! Why the heck do you suppose I posted it here? Is it wrong of me gain knowledge at other members' expense, or is that the entire point of this forum??
Don't get me wrong. Ask away! I'd rather you ask than not, and thank you for contributing and bringing this battery to the forums attention.

I've slightly more than a passing familiarity with electronics having designed and programmed embedded controllers for the cellular industry, yet I don't yet feel comfortable investing in a lithium system. Were I programming say an intelligent LiFePO4 charging system for a cellphone, I'd definitely defer to an Electrical Engineer to review every circuit and component. This is a relatively new and fast changing technology and with any bleeding-edge technology comes extra expense and risk.

The trouble with being a novice (and I was counting myself as one here too) is you don't know what you don't know. Lead acid systems are just more tried and true and a road more people have travelled, that's all. If you want to go for a lithium system, then certainly study up and consult experts before investing thousands of dollars.
 

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I love this stuff! I think you guys are 100% correct that the AliExpress ad I posted is NOT LiFePO4, so good catch ya'll!! Why the heck do you suppose I posted it here? Is it wrong of me gain knowledge at other members' expense, or is that the entire point of this forum??
Bring on the questions! I think you asked a fair question and got some useful responses.
 

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The rest of us benefit from these discussions. We will all be using some currently esoteric battery system in the future. Think where LED lights have come from in just a few years!
 

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The scariest part about LiFePO4 for me is the idea of leaving a dog in the camper with the A/C running and hoping it hasn't stopped running while you are away. Someone has posted on this forum about their A/C failing when they did this and the dog died from exposure. I'd try to figure out a way to have a breeze from a fan and fresh water available instead. If the fan stops working at least with open windows the interior temps won't sky rocket.
 

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The scariest part about LiFePO4 for me is the idea of leaving a dog in the camper with the A/C running and hoping it hasn't stopped running while you are away. Someone has posted on this forum about their A/C failing when they did this and the dog died from exposure. I'd try to figure out a way to have a breeze from a fan and fresh water available instead. If the fan stops working at least with open windows the interior temps won't sky rocket.
Well don't leave the dog in the van. Lifepo4, agm or shore, there could be a failure in any AC system. I'd never leave my dog in the van. I travel around any limitations that would require me leaving my dog in the van.

Sent from my Pixel 2 using Tapatalk
 

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Hey Gap, I wasn't addressing you directly, just people in general that leave their pets in a van unattended. Everyone is different, but our dog is part of the family and I wouldn't leave a kid unattended in a van, so I wouldn't leave my dog. This question gets asked A LOT on other forums and facebook groups. I try to remind people that failures happen regardless of what battery you have. While the same could be said about your house AC, a failure at home wouldn't heat up the home fast enough to cause a pet to die. A van or car on the other hand can get hot very quickly. As you said, it's better to have a vent open so it doesn't turn into an oven.
 
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