Lipo vs lifepo4

[john61ct]

Originally Posted by newhaul

Why disable the temp compensating on the solar?

Because that is required by lead, not LFP. Also

Peukert 1.05
Charge efficiency .99

[john61ct]

$1.5 per AH per 3.xV cell right

$6 per AH in 12V blocks?

$600 per 100AH@12V

If that's the case IMO not worth Alibaba risk, shipping them back for warranty problem not worth it.

[newhaul]

Originally Posted by john61ct

$1.5 per AH per 3.xV cell right

$6 per AH in 12V blocks?

$600 per 100AH@12V

If that's the case IMO not worth Alibaba risk, shipping them back for warranty problem not worth it.

no $1.69per ah for 12 volt 100ah packs. 3s5p configuration. ($169.00 for the 100ah packs ) the 160ah packs are a bit cheaper per ah)

[travellerw]

Originally Posted by john61ct

$1.5 per AH per 3.xV cell right

$6 per AH in 12V blocks?

$600 per 100AH@12V

If that's the case IMO not worth Alibaba risk, shipping them back for warranty problem not worth it.

No the OP is claiming he is getting 1.5ah per 12.xV cell (his supplier is telling him the cells are already 12V).

$150 per 100AH@12V

That is why I commented above.. Very strange that a company could offer cells that much cheaper than the competition.. So we will see.

[newhaul]

Originally Posted by travellerw

Wow, that is almost 4X cheaper than current cells. Personally, I get very nervous when a competing product is that much cheaper. Especially when there are multiple players in the market and they are all priced similarily. Makes me wonder how these guys can go so cheap.

Anyway.. I really hope they work out for you as it would be great for other cruisers. Please report back..

I definitely will report on them after a good testing . ( this is much closer to what they should cost. Ie: about 50% more than Fla per ah)

[newhaul]

Originally Posted by travellerw

No the OP is claiming he is getting 1.5ah per 12.xV cell (his supplier is telling him the cells are already 12V).

$150 per 100AH@12V

That is why I commented above.. Very strange that a company could offer cells that much cheaper than the competition.. So we will see.

and actually I found several different companies that have similar pricing this one was the winner for me. ( they were the first to respond to my questions and queries.)

[john61ct]

3S to get to 12V means these are not LiFePO4.

Can't get away from chemistry, nominal 3.2 is actually at the high end of reality.

I'm betting LiPo, 3 x 4.2 = 12.6V

Not suitable for deep cycling, avoid.

In fact I will say do not self-import from overseas at all unless sources you really trust report hands-on positive experience.

Or via eBay from a high-volume well-rated source, and test thoroughly before NQAMB guarantee period has expired.

Plus the obvious, if it seems too good to be true. . .

[john61ct]

Originally Posted by john61ct

do not self-import from overseas at all unless sources you really trust report hands-on positive experience. . .

Sorry, should have been more specific.

The above applies to China and Russia, other countries where corruption and scamming is the norm.

Wealthier Europe including the Baltic states, Japan, S. Korea, Australia/NZ, where a higher percentage of citizens are honest and their society has strong rule of law and consumer protections, the odds of getting what you pay for are much higher.

[newhaul]

Originally Posted by john61ct

3S to get to 12V means these are not LiFePO4.

Can't get away from chemistry, nominal 3.2 is actually at the high end of reality.

I'm betting LiPo, 3 x 4.2 = 12.6V

Not suitable for deep cycling, avoid.

In fact I will say do not self-import from overseas at all unless sources you really trust report hands-on positive experience.

Or via eBay from a high-volume well-rated source, and test thoroughly before NQAMB guarantee period has expired.

Plus the obvious, if it seems too good to be true. . .

john sorry I wasn't awake yet ( hadn't had morning coffee yet) and hit the wrong number the matrix is actually 4s5p I didn't catch it before it was to late to edit.

[newhaul]

Originally Posted by john61ct

3S to get to 12V means these are not LiFePO4.

Can't get away from chemistry, nominal 3.2 is actually at the high end of reality.

I'm betting LiPo, 3 x 4.2 = 12.6V

Not suitable for deep cycling, avoid.

In fact I will say do not self-import from overseas at all unless sources you really trust report hands-on positive experience.

Or via eBay from a high-volume well-rated source, and test thoroughly before NQAMB guarantee period has expired.

Plus the obvious, if it seems too good to be true. . .

importing thru my trucking company and associated contacts.

[john61ct]

Originally Posted by newhaul

this is much closer to what they should cost. Ie: about 50% more than Fla per ah

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.

[newhaul]

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.

sorry the should part is just my personal opinion . Its not like it is a brand new technology.
Heck they were even talking about lithium as a power source on the original star trek tv series.
Circa 1966.

[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

www.dmdpower.com/indexen.html

[senormechanico]

Originally Posted by john61ct

3S to get to 12V means these are not LiFePO4.

Can't get away from chemistry, nominal 3.2 is actually at the high end of reality.

I'm betting LiPo, 3 x 4.2 = 12.6V

Not suitable for deep cycling, avoid.

In fact I will say do not self-import from overseas at all unless sources you really trust report hands-on positive experience.

Or via eBay from a high-volume well-rated source, and test thoroughly before NQAMB guarantee period has expired.

Plus the obvious, if it seems too good to be true. . .

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.

[newhaul]

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.

I will do extensive testing of them . For now I will order 2 units. Worst case I will have one heck of a big backup battery pack to recharge my tablet and cell phones.