Lipo vs lifepo4

[john61ct]

Originally Posted by senormechanico

I'm with John61ct on this one. The obvious clue is 3s to get 12 volts.
Take a look at the innards of a 12 volt computer LiPo battery.
It's 3S / xP where X is whatever amp hour battery you select.

Edit: After reading the whole thread, I'm glad to read the 4S. Still skeptical though.

He says that was a typo, actually 4S.

But with a sealed powerpak if that's what it is, market niche full of scammers even in the US, there's no way to tell.

I would not buy such a unit unless it had replaceable internal cells and I can get both detailed spec sheets and links to the cells at reasonably prices from a variety of vendors.

[travellerw]

Originally Posted by john61ct

Just curious, in what sense of "should"?

I consider $5 per 12V-AH to be suspiciously cheap for bare prismatic cells from a reputable vendor, market these days is more like $7-10.

Most "systems" vendors including a quality BMS, come out to 5-7x lead bank prices.

And that's before shipping, last set of bare cells I had delivered from CA cost $250, would have been $300+, but a friend let me use his loading dock and forklift.

Again we are going to disagree. There are a bunch or reputable venders selling bare prismatic cells for $5-$5.50 per 12V-AH (before shipping and BMS). Here are some links (google produces more).
https://www.ev-power.eu/Winston-40Ah...00Ah.html#tab2

Batteries, EV West - Electric Vehicle Parts, Components, EVSE Charging Stations, Electric Car Conversion Kits

Not to mention the tons of venders on AliExpress selling Winston, GBS, CALB or Voltronix cells. Actually, I have 3 vendors I'm working with for delivery down here in the Caribbean and all are aroudn $5 per 12V-AH.

What I think we will agree on is it is very suspect for a vender to be selling cells that cheap.

[john61ct]

Originally Posted by travellerw

Again we are going to disagree.
...
What I think we will agree on is it is very suspect for a vender to be selling cells that cheap.

I don't think we disagree at all, and I certainly don't use "suspicious" to mean "should ignore"

When I say a price makes me feel suspicious, obviously as soon as I see a trustworthy seller, or a detail that accounts for the savings, then I know it's worth investigating further.

I very often buy deals that initially raised red flags.

But a NQAMB guarantee I trust goes a long way to making up the difference, as long as I have the knowledge and equipment to run a thorough set of tests upon receipt.

And yes, that was the high end of suspect price range, bottom end of normal.

See Battleborn for a drop-in as opposed to EWT.

[newhaul]

Originally Posted by john61ct

Why would you think LFP would *ever* come down to lead's pricing?

Raw materials alone are much more scarce.

Demand will be growing much faster than supply capacity for many decades.

They are already cheaper than lead taking longevity into account

if you have the knowledge and infrastructure to coddle them.

Are you sure this isn't actually a "portable powerpak" type unit, with USB ports? Those are usually quoting their AH capacity at the voltage of the internal cells (e.g. 3.2 or 3.7V) to get a grossly inflated spec.

https://vimeo.com/160186774



Ask DMD for a wH rating instead, should come out the same ÷12.

Also, what is the per-unit net weight? not total shipping weight

See if you can get a spec sheet like this http://evwest.com/support/Voltronix%...ry%20Cell2.pdf and post a link here.

They seem to be mostly in the inverter biz

Guangzhou Demuda Optoelectronics Technology Co, Ltd
No. 18, Industrial Zone, Xiaomao 19 Club, Baiyun District, Guangzhou, Guangdong

+86 20 61185082 Ext 808 (Jimmy Lei)
FAX +86 20 61185081

info@dmdpower.com

Solar*PowerInverter_Inverters*Wholesale_DCACInvert er_PhotovoltaicInverter_InverterFactory

Ok wh is 1,260 and weight is 6.5 kg so seems a bit light states 1500 cycles at 70% DoD

[john61ct]

never seen a reputable LiFePO4 that wasn't rated much longer lifecycles.

The whole point of spending more is getting crazy longevity

and that's like **half** the required weight!

so IMO wH is a lie, avoid like the plague, see my above more general notes on safe sourcing

I'm happy to let others be the Ali pioneers

[john61ct]

Winston/Voltronix, CALB, GBS, A123 & Sinopoly

are AFAIK the only trusted makers whose prismatic cells are sold bare, direct to consumers

Additions to the list would be most welcome

[newhaul]

Originally Posted by john61ct

never seen a reputable LiFePO4 that wasn't rated much longer lifecycles.

The whole point of spending more is getting crazy longevity

and that's like **half** the required weight!

so IMO wH is a lie, avoid like the plague, see my above more general notes on safe sourcing

I'm happy to let others be the Ali pioneers

even if it doesn't have a 3000 70% DoD life I doubt ever discharging more than about 50% anyway. I am going to get 2 batteries to run testing on ( even if they are only half the rated ah. Still good price to run testing on )

[john61ct]

My meaning was I have no trust in the vendor and believe nothing they say about the battery specs.

If you've already decided, then you deserve our gratitude for being willing to take arrows in the back

and of course I'll be curious about its characteristics and performance, especially what a 20-hour load test shows about true capacity.

[newhaul]

Originally Posted by john61ct

My meaning was I have no trust in the vendor and believe nothing they say about the battery specs.

If you've already decided, then you deserve our gratitude for being willing to take arrows in the back

and of course I'll be curious about its characteristics and performance, especially what a 20-hour load test shows about true capacity.

they have yet to tell me the shipping costs.

I am intending on using my thermoelectric cooler as the load source . It draws 5.12amps.
I know not scientific but will get us in the ballpark between the foul lines

Besides even if it won't work as a house bank. Would make one heck of an aux power source for my nav tablet.

[GTom]

Originally Posted by newhaul

yes it might at that if you intentionally drive a nail through the entire battery shorting all of the plates bet you would have disastrous results with an agm or Fla if you intentionally cause a dead short in them to.
They would be in individual 100ah batteries spread out in my engine room . I can get the lifepo4. In the same format. Wonder what they would do if you drive a nail through it.

Any kind of packaging failure has the same effect, LiPo doesn't need a nail it needs just a little air... Haven't heard about phone battery failures? Samsung had to call back its entire Note7 line because of faulty LiPo fires.

If a single ~3Ah cell is capable to do this, I don't think you can "smartly distribute 100Ah units" on a boat. A single one of them is capable to take your vessel apart.

Anyway, if you do it, just let us know, which marinas are you using

In lithium country Winston LiFeYPO4's are interesting to look at.

[newhaul]

Originally Posted by GTom

Any kind of packaging failure has the same effect, LiPo doesn't need a nail it needs just a little air... Haven't heard about phone battery failures? Samsung had to call back its entire Note7 line because of faulty LiPo fires.

If a single ~3Ah cell is capable to do this, I don't think you can "smartly distribute 100Ah units" on a boat. A single one of them is capable to take your vessel apart.

Anyway, if you do it, just let us know, which marinas are you using

In lithium country Winston LiFeYPO4's are interesting to look at.

in case you didn't catch it . These have turned out to be lifepo4 units. Now the biggest issue is the weight of the bank. It is low for lifepo4 at 100ah. I will post test results after I have had a couple months to fully test them.

[hellosailor]

LiFePO4 is the only "lithium" chemistry that does not use a flammable petroleum-based electrolyte. So it has an inherent advantage of NOT being flammable and explosive in the same manner as all the other chemistries.

It also is probably the least powerful, in terms of kilograms-per-watt, but that's not a huge difference.

Considering that none of the lithium battery makers, especially the big Chinese ones, seem to be sure of how to properly charge and use their products, and that even the biggest names (Panasonic, backed by Boeing engineers, or the international aviation consortiums and the UN air safety people) aren't sure why their batteries just like to start huge fires at times...

Who would even consider a more flammable battery type on a boat? Unless you're a diehard racer who really is trying to shave off pounds.

IIRC three commercial aircraft were lost to lithium fires last year.

[newhaul]

Originally Posted by hellosailor

LiFePO4 is the only "lithium" chemistry that does not use a flammable petroleum-based electrolyte. So it has an inherent advantage of NOT being flammable and explosive in the same manner as all the other chemistries.

It also is probably the least powerful, in terms of kilograms-per-watt, but that's not a huge difference.

Considering that none of the lithium battery makers, especially the big Chinese ones, seem to be sure of how to properly charge and use their products, and that even the biggest names (Panasonic, backed by Boeing engineers, or the international aviation consortiums and the UN air safety people) aren't sure why their batteries just like to start huge fires at times...

Who would even consider a more flammable battery type on a boat? Unless you're a diehard racer who really is trying to shave off pounds.

IIRC three commercial aircraft were lost to lithium fires last year.

yes there were 3 or 4 aircraft lost due to battery failures . ( batteries overheating and smoking) likely due to improper charging of the specific matrix. ( lithium cobalt oxide(LiCoO2) )

[GTom]

Originally Posted by newhaul

in case you didn't catch it . These have turned out to be lifepo4 units. Now the biggest issue is the weight of the bank. It is low for lifepo4 at 100ah. I will post test results after I have had a couple months to fully test them.

Thx, I have to admit, didn't read all the posts after your reply

[newhaul]

Originally Posted by GTom

Thx, I have to admit, didn't read all the posts after your reply

ok no problem ( reread the post of mine you quoted especially the 3rd to last sentence.