LifePO4 batteries for use with Midnite Classic 150?

[jflorey2]

Ah, so you are charging your magic batteries with AC . . ..

No; he is referring to a Nyquist impedance plot of a lithium ion battery. This is a method called impedance spectography, and tells you a lot about a battery. For example, pure resistances show up as fixed real impedances across all frequencies; charge transport (a big part of cell resistance) is frequency dependent and shows up at low frequencies.

Ever load a battery and see a sudden voltage drop, followed by a slower one? You are seeing those two different mechanisms in play - one fast (resistance) one slow (charge transport.) Spec'ing resistance misses that effect; spec'ing impedance captures it.

[Mike90250]

Well, I'll admit to being new to measuring battery impedance. I can see DC resistance, and how that can vary and change, but I've always considered impedance as C & L interaction with an AC signal, or DC pulsing fast enough to develop some reactance (almost like AC only slowly)
I totally know about resistance and charge transport effects but never called them impedance.

[Sunking]

No; he is referring to a Nyquist impedance plot of a lithium ion battery.

I know what Nyquist Spectroscopy is, but has nothing to do with the topic of charging, nor is it exclusive to lithium batteries. It boils down to a Randles equivalent circuit so the user can determine battery health and predict how a small form factor battery battery will perform in a high frequency switch load like a cell phone. Non of which applies to charging a battery with DC current. All one really needs to know is AC Impedance will be lower than DC Resistance up to the point where the inductive characteristics coating on the plates. Completely irrelevant to the topic at hand.

Where Impedance can be useful is battery monitor to make a WAG of battery health and SOC which no manufacturer has figured out how to do yet because it is to darn complicated and not fully understood. For solar use charging and discharging is completely meaningless jibber jabber. Yes you will get a slight dip and rise on a heavy discharge. Who cares on a 48 volt battery is less than 1 volt on Pb and less on Lithium. It means nothing to the user or be of any concern.

[karrak]

Ah, so you are charging your magic batteries with AC, and that's where the problem of you vs world comes to a head. Impedance or Impudence ?

No, It is not me vs the world, it is me against the "alternative facts" that Sunking keeps stating. Don't have any problems and my posts are respected on the other forums that I post on...

Simon

Off grid 24V system, 6x190W Solar Panels, 32x90ah Winston LiFeYPO4 batteries installed April 2013
BMS - Homemade Battery logger github.com/simat/BatteryMonitor
Latronics 4kW Inverter, homemade MPPT controller

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[Mike90250]

No, It is not me vs the world, it is me against the "alternative facts" that Sunking keeps stating. Don't have any problems and my posts are respected on the other forums that I post on... Simon

If your posts on other forums are all taken at face value, then, they don't have the sharpest knives in the drawer, When I see your posts, and a couple words are in glowing neon as I skim it, it's like Whoa - Where is this harebrained idea from.

[Sunking]

If your posts on other forums are all taken at face value, then, they don't have the sharpest knives in the drawer,

You got it Mike and 100% correct. Karrak came here for only one reason as he has admitted on this so called other forum. He clearly states he only came here to harass me on Bottom Balance. He asked for war, he got war and lost. If you remember Mike when Karak showed up and got ripped to pieces, Karrak went so far to go to other forums to recruit other people to come here and attack me. Did not work out so well for them.

Mike you know I speak the truth. Given the fact Karrak came here only to attack me, recruited others to come here to attack me, SPAMS the site, has been banned twice already for giving bad/dangerous advice, and lost Link privileges; What more do you need to ban him permanently? He done everything he can to get banned and deserves it. He certainly cannot take a hint he is not welcomed here.

FWIW he did go to a DIY EV forum where the members are very knowledgeable and sharp. Most members are engineers, technicians and scientist. They shredded Karrak to pieces with his hair brained ideas. .

[karrak]

Sunking, are you deluded enough to really believe the garbage that you wrote in the last post or are you just throwing as much mud as possible in the hope that some of it will stick?

I did not come here to harass you, I came here to put a counter viewpoint as someone who actually has an off grid LFP battery based power supply. As soon as it became apparent that I might actually know what I am talking about and couldn't be fobbed off you get nasty. The original discussion starts here solarpaneltalk.com/forum/off-grid-solar/batteries-energy-storage/lithium-ion/18054-lifep04-batteries-for-solar-bms?p=231297#post231297.

I assume your statement "He clearly states he only came here to harass me on Bottom Balance" refers to this statement

Thanks Paul, the only reason I am posting on the other forum is to counter the gospel according to Sunking and some of the things that he is saying that I think could easily lead some poor bastard to make a big mistake and wreck hundreds if not thousands of dollars worth of batteries.

from here http://forums.energymatters.com.au/s...20.html#p46991. I will leave it to others to interpret what I said.

As for recruiting other people, I assume you mean wb9k who happens to be the head of the warranty labs at A123. Here, solarpaneltalk.com/forum/off-grid-solar/batteries-energy-storage/lithium-ion/20597-mechanisms-that-decrease-the-lifespan-of-lithium-ion-batteries-and-how-to-avoid-them?p=247629#post247629, he states why he came to this forum.

I'm not a regular poster here, but after similar encounters with Sunking on two other forums, I was approached by Simon to ask ask if he could quote one of my posts (which can be found on the battery technology forum at endless-sphere in a thread called "lithium balance--is it top, bottom, or middle?"). I said he could post with or without attribution, which is good because the moderators here have apparently forbidden attribution, which I find difficult to understand.

As for the DIY EV forum shredding me, here is a link to the thread diyelectriccar.com/forums/showpost.php?p=713538&postcount=1 that I assume you are talking about, I post under the username simat on that forum.

Simon

Off grid 24V system, 6x190W Solar Panels, 32x90ah Winston LiFeYPO4 batteries installed April 2013
BMS - Homemade Battery logger github.com/simat/BatteryMonitor
Latronics 4kW Inverter, homemade MPPT controller