LifePO4 GBS Amp Hour Testing 2.5v to 3.6v per cell

[SunEagle]

One thing that's been nagging me (and my ignorance of lithium batteries from a chemical standpoint) is -- isn't the main degradation with lithium-based batteries connected to dendrite growth from charge/discharge cycles? If that's the case, how does micro-cycling batteries affect that?

Not sure. Lithium based still has a lot of roads to travel hopefully someone will find a great combination of stability, long life and charging technique.

It seems the "deep pockets" have got the DOE interested in "flow" batteries with a big infusion of money to build and test these liquid batteries for Utility type settings. My guess is that they are way out there in cost and may never come down to anything a homeowner could claim as being cost justified.

[smily03]

One thing that's been nagging me (and my ignorance of lithium batteries from a chemical standpoint) is -- isn't the main degradation with lithium-based batteries connected to dendrite growth from charge/discharge cycles? If that's the case, how does micro-cycling batteries affect that?

[smily03]

There's a really fragile connection between jumping the gun and letting the "amazing new technology" cat out of the bag too soon, versus running out of funding trying to develop it. Sometimes I wonder if that's what happened with things like the Aquion AHI batteries and their capacity/cycle deratings? It's too bad...

[J.P.M.]

I, for one, would love to see something better than lead-acid batteries for applications like this. But, I don't want to get suckered, so when things like this happen, it makes me question the credibility of the other things they've been saying. Which is a shame :/

We'd all like to see progress on the energy storage front. Who/Whatever cracks the energy storage nut will be the next Bill Gates, Sam Walton, or Warren Buffett.

From a business standpoint, the destroyed credibility when caught in a fraud is probably the worst part. I've seen profitable business relationships it took 10 years to build go completely sour in 10 seconds when half/un truth or B.S. was discovered. Trust is a very fragile thing. It's also what con men try to build and then use as a tool.

[smily03]

The weird thing, to me at least, is that things like chassis wiring methods shouldn't reveal the keys to the kingdom? I could totally see not wanting to release the nitty gritty about balancing methods, system architecture, charging algorithms, etc. But stuff like wiring? How "special" could wiring be, unless you're doing something unsafe? I was kind of surprised at how hostile he got when Mike asked about that...

I, for one, would love to see something better than lead-acid batteries for applications like this. But, I don't want to get suckered, so when things like this happen, it makes me question the credibility of the other things they've been saying. Which is a shame :/

[J.P.M.]

I just wanted more information concerning his design but also understood maybe why he did not want to give up the "keys to the kingdom" by answering my questions.

Looks like Dax put himself in a box with a Hobson's choice. He can keep his proprietary information to himself and risk looking like a charlatan, or share some of it with the intention of establishing or restoring credibility which may cost him some money or lost business when word of his secrets gets out. Some of us may face the same situation and choose to keep out mouth shut on proprietary stuff rather than play "I've got a secret" and look like a jerk or worse. That's one of those things you can't have both ways. Better to not go down that path and simply smile and shut up.

There is of course a third possibility. Not saying it's so, but there is always the possibility of someone inventing secret scenarios to cover their tracks. Happens all the time.

[SunEagle]

I totally agree with you. There are the same considerations here in Australia.

As far as I can see Dax is just stating what equipment they use in their system. I would be surprised if the equipment he sells is unsafe and doesn't comply with the regulations.

If Dax was recommending using long lengths of cable that were only capable of carrying 100A to the inverter without any fuses and using a vice to crimp the crimp lugs onto the cable then yes you have every right to criticise him.

Simon

The problem is that while Dax is probably using safe circuit design and equipment he has been very secretive in what his systems are comprised of which leaves some of us guessing which requires some of us to be completely trustful in what he says he can supply.

Since I am an Electrical Engineer that type of thing raises red flags and brings up questions that Dax did not want to answer.

I am not mad at him. I just wanted more information concerning his design but also understood maybe why he did not want to give up the "keys to the kingdom" by answering my questions.

[karrak]

The problem is not that the "system works" 99 times out of 100. It has to be safe and has to meet code. Which means it has to be designed with the proper wire size and OCPD to protect that wire.

Things may cost more over here in the US but our insurance companies would quickly make a decision to blame a home owner for not following safe practices should a fire start due to their handiwork where the end resulted in not getting any compensation from the insurance company for the damages that occurred by using an unsafe electrical device. This is something we tress here on the forum about not using unlisted UL solar devices because they are both illegal and dangerous.

I totally agree with you. There are the same considerations here in Australia.

As far as I can see Dax is just stating what equipment they use in their system. I would be surprised if the equipment he sells is unsafe and doesn't comply with the regulations.

If Dax was recommending using long lengths of cable that were only capable of carrying 100A to the inverter without any fuses and using a vice to crimp the crimp lugs onto the cable then yes you have every right to criticise him.

Simon

[SunEagle]

How do we know the 3kW is not the peak rating, allot of the Chinese manufacturers quote the peak rating rather than the continuous rating?

Dax has said that the 12 volt inverter is part of the module and is connected to the battery via 30cm of cable. Where is the safety issue if he has used the correct size cable, the correct fuses and the cable terminations have been done correctly?

I agree that from a technical point of view it is better to run higher voltages and lower currents but as Dax has said the system he has works. How many times do we see commercial considerations overriding technical considerations?

Simon

The problem is not that the "system works" 99 times out of 100. It has to be safe and has to meet code. Which means it has to be designed with the proper wire size and OCPD to protect that wire.

Things may cost more over here in the US but our insurance companies would quickly make a decision to blame a home owner for not following safe practices should a fire start due to their handiwork where the end resulted in not getting any compensation from the insurance company for the damages that occurred by using an unsafe electrical device. This is something we tress here on the forum about not using unlisted UL solar devices because they are both illegal and dangerous.

[karrak]

If it never draws 275 amps it's not being used as a 3kW inverter. If you install a 3kW inverter and downrate it to 1.6kW, great - but in that case might as well just install a good 1.6kW inverter.

No, that doesn't mean that. 120V and 240V inverters are readily available with a wide variety of mounting options.

The more you post, the more it sounds like your success has been due to luck rather than technical competence and an understanding of the issues involved.. I hope for the sake of your customers that your luck doesn't run out.

How do we know the 3kW is not the peak rating, allot of the Chinese manufacturers quote the peak rating rather than the continuous rating?

Dax has said that the 12 volt inverter is part of the module and is connected to the battery via 30cm of cable. Where is the safety issue if he has used the correct size cable, the correct fuses and the cable terminations have been done correctly?

I agree that from a technical point of view it is better to run higher voltages and lower currents but as Dax has said the system he has works. How many times do we see commercial considerations overriding technical considerations?

Simon

[SunEagle]

Banning users:
I generally let things run, but when bad advice is given, corrected and then attempts to justify bad advice, it's time for a ban. As someone else said,

I agree. While dax may have had some knowledge concerning LFP batteries he continued to show he had no knowledge concerning electrical safety or even the understanding why the currents would get so high on 12volt system making them dangerous regardless of what the battery chemistry used to fed the inverter.

While Math may not be important for some people and for every trade when it comes to designing electrical wiring circuits it is a must.

[Mike90250]

Banning users:
I generally let things run, but when bad advice is given, corrected and then attempts to justify bad advice, it's time for a ban. As someone else said,

success has been due to luck rather than technical competence and an understanding of the issues involved.

[Mike90250]

Now what can anyone say to something so infantile, ludicrious and stupid as what you've posted. Or is it you have no real life experience outside an office or school room and no clue of what or how a real off grid lifepo4 system works. It's plain to see you've not read my posts, just jump on the band wagon in a childish attempt to beat your sagging chest.

However just to amuse you, a 3kw inverter, would never draw 275amp at once or constantly. In an off gird system it would be lucky to get over 1.6Kw at any one time and that would be a large appliance starting draw. I've posted many times, our installations are 240v wired and for the ignorant, that means inverters are situated in the module, connected within 10-20cm of the controller above the pack, or bank. They then connect to each 240v circuit in the house, if you can understand that complicated explanation, or is plain simple understandable language beyond you.

Vacation time for DAX. Take a chill pill.
In your zeal for something, you are now posting seriously dangerous practices, and are unable to comprehend why it is bad.
Many lurking neophytes read these posts and with no knowledge of electricity, they are likely to follow the easy way you describe.

WTF does any style of battery have to do with what I said? Zero..

If you build a system with a 3Kw inverter, you ABSOLUTELY have to plan on that inverter providing 3Kw, and nearly all inverters will provide more till they reach thermal limits and shut down.
So you HAVE to design wiring to safely provide 3Kw - does not matter what sort of battery sources the power, or how far the wires run.

[jflorey2]

However just to amuse you, a 3kw inverter, would never draw 275amp at once or constantly.

If it never draws 275 amps it's not being used as a 3kW inverter. If you install a 3kW inverter and downrate it to 1.6kW, great - but in that case might as well just install a good 1.6kW inverter.

In an off gird system it would be lucky to get over 1.6Kw at any one time and that would be a large appliance starting draw. I've posted many times, our installations are 240v wired and for the ignorant, that means inverters are situated in the module

No, that doesn't mean that. 120V and 240V inverters are readily available with a wide variety of mounting options.

The more you post, the more it sounds like your success has been due to luck rather than technical competence and an understanding of the issues involved.. I hope for the sake of your customers that your luck doesn't run out.

[smily03]

Dude...chill. We're just concerned, because what you posted sounds really dangerous without some further explanation...

3000 / 13.6 = 220, and 220 * 1.2 = 264. Unless you're seriously undersizing your OCPD, you'd have to be running some serious wiring, otherwise you're risking fire. Even if loads are only really ever 1kw, but the inverter is capable of doing more, you have to size the wiring for what the inverter is capable of drawing unless you're going to size your OCPD for the size of the wire you're running. Because something could always short out or act up and make the inverter pull its maximum load, and if your inverter to battery wiring is undersized...oops.