diy solar

diy solar

SiO2 Silicon Dioxide Batteries

@Azimuth Shari

Gosh, I've seen these for more than a decade and also wonder why they aren't more popular.

I think poor marketing and dumbing down their tech explanations is what chases the curious away, at least in North America. The constant comparisons to "lead acid" in marketing are tiring. Those of us interested tend to want to know in comparison to WHAT? The average consumer couldn't care less. Us battery-nerds as prospective buyers want to know more details.

So when making comparisons to lead-acid, what type are you comparing to - is it:

Flooded Lead Acid ?
Sealed MF maintenance free (aka sealed FLOODED with extra electrolyte added) ?
Gel ?
AGM (conventional recycled or pure-lead) ?

So when looking at it, their biggest direct comparison is to an AGM battery. The charge / float voltages are very similar. The maximum of 0.25C charge rate is very similar. Their internal impedance is similar (except not to pure-lead!)

Ok. In marketing materials, the "near solid-state electrolyte" is very interesting and possibly key to some advantages. What exactly is this near-solid-state electrolyte tech, and how is it different from Gel's solidified electrolyte, or agm's absorbed glass mat?

Advantages I see:

Ability to discharge down to 0 volts without apparent \immediate\ harm.

Ok, that's good to know in case there is a catastrophic discharge that low, or perhaps a long parasitic drain. Very cool. But it's not something one does operationally. AC inverters will cut off at typically 10.7 to 11.7v, so that's not a huge advantage. Direct DC operations with most 12v nominal devices start to get funky, displays blank, and generally stop at say 10v and give up. But it implies with normal care, the lead-crystal should hold up well.

So again, the biggest advantage here would be being able to recover from an accidental catastrophic discharge, and not really anything operationally advantageous in normal operation. But that's cool nonetheless.

Not having to "top off" or maintain for up to 2 years according to marketing:

WOW! What this implies is that for some reason this battery resists sulfation. Is that true? Do you get full capacity after charging to full, and ignoring it for 2 years? Not suggesting anyone should, but if true, that would be a big plus if they are sitting in retail, or otherwise unused for a season or two and not hard sulfating.

Getting back to it's nearest competitor, AGM. They are notoriously UNDERcharged, especially in solar - simply because there is not enough time to do so in a cyclic situation, where an 8-16 hour float \after\ absorb is actually finished is ideal. So most owners tend to "walk down" their agm's capacity by never getting that last 1% of charge in cycle over cycle and it just hard sulfates.

If lead-crystal is resistant to sulfation, (based upon the topping-off claim) then that would be a great advantage to agm's which are usually under-charged especially in solar. Is this true? Is there data?

So we come back to the major question of WHY aren't these more popular in North America? Is it because nobody knows what the near solid-state electrolyte is? Is it a licensing or dealership issue? Any word on resistance to sulfation as compared to a competing agm?

More technical details like these, exposed in public would go a LONG way. No need to compare to pesky "lead acid". That's a turn off. Nobody cares about that. I think people would want to see something in public, rather than being told hypothetically to just trust them over the phone.
 
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I suspect these "lead crystal" or "silicon dioxide" batteries are lead-acid gel cell.
Besides the voltages, self-discharge rate, internal resistance, I also note 0.1C float charge rate, 0.2C cyclical (it's in a graph, but not listed as a parameter.) Maybe that approaches AGM rates, a bit higher than Gel?

It requires 10 to 12 hours for 100% charge from zero %. 5 hour bulk, followed by 5 to 7 hours absorption. My AGM need 2 to 4 hours absorption. They prefer at least 0.2C (no more than 5 hours bulk) and can accept much higher charge rate.

"Getting back to it's nearest competitor, AGM. They are notoriously UNDERcharged, especially in solar - simply because there is not enough time to do so in a cyclic situation, where an 8-16 hour float \after\ absorb is actually finished is ideal. So most owners tend to "walk down" their agm's capacity by never getting that last 1% of charge in cycle over cycle and it just hard sulfates."

But this new battery type requires exactly that long float, according to graph shown below. At 13.5V to 13.8V, a bit higher than my float.

I wasn't aware that a long Float was required as part of the AGM charge cycle, rather simply dropping voltage to where charge is no longer happening as described in the manual for my battery. It does call for 13.2V to 13.4V Float, while 100% SoC at rest is 12.78V. That 0.4V to 0.6V difference could provide some small charge rate.

I would think the usual problem is where PV production isn't enough to do the required bulk plus absorption. PV used to be expensive but now costs less than the battery, so it is practical to install excess PV, enough to supply all loads while charging at exactly 0.2C for 3 to 4 hours, then absorb for 2, followed by several hours of float.


From "silicon dioxide" or "lead crystal" data sheet:

1621005397059.png
 
Hey, in regards to Si02 I think I found something more substantial (although there is that aggravating marketing comparison to "lead-acid" without being specific):


If we can sweep away all the marketing droids and just get down to it:

Overall, it looks to be a better choice than a conventional agm/gel in a solar environment! Resistance to sulfation from under-charge, or unintended PSOC. Either from lack or solar insolation, adequate time to charge, or general end-user neglect (within reason).

So kind of what I surmised above, and lends further hints about sulfation resistance.

Had I known this before going LFP, I would have gladly studied it further, cycled and operated it to destruction to learn more.

BUT - I think this is the catch: Upfront cost for entry. Unless one is a battery nerd like me, the average consumer will be just as satisfied with purchasing a conventional agm twice as they undercharge and abuse it.

It was / is the same with LFP when I was starting out and the FLA-forever guys jumped all over that.

I think they really do a dis-service with all those comparisons to pesky "lead-acid" - that was a total turn-off to me as a red-flag since I know how to keep them healthy. :)

Even though I'm for the most part LiFeP04 these days, maybe I'll pick up a smaller Si02 just to test on and make it prove itself.
 
@Hedges
I wasn't aware that a long Float was required as part of the AGM charge cycle, rather simply dropping voltage to where charge is no longer happening as described in the manual for my battery. It does call for 13.2V to 13.4V Float, while 100% SoC at rest is 12.78V. That 0.4V to 0.6V difference could provide some small charge rate.

Most aren't aware. Mostly because simply finishing absorb works (if you actually measure tail-current for a stall) with a NEW battery, but like taking a new car off-the-lot, things change rapidly. :)

This all goes way back to the "float voltage war" days, back when a famous battery maintainer and pure-lead agm makers got into an acrimonious situation about it - so much so, that the maintainer maker stopped publishing specifications and charge graphs. Most other manufacturers followed suit. Back when agm was vying in competition to NiMh for EV's that needed rapid turnaround. Daily cycling. And a float voltage that was too low - basically a "leave it on forever" voltage, resulted in walk-down's in capacity never getting that last 1% in.

CV / Absorb: while a battery is new, it is relatively efficient in the recombination stage. But as the battery ages recombination becomes less efficient at recharge. Usually in the form of heat, although you may not actually "feel" it to the touch. This is where one monitors tail current for a stall - and it changes depending on the aging / internal resistance of the battery over time - or wings it with a timer at this stage.

Float \finishes\ the charge:
Because absorb is not entirely efficient, you still need to get that last 1% in, or you'll walk the capacity down due to that 1% hard sulfating. Cycle by cycle.

So, in order to actually finish, the float voltage needs to be high-enough to get that last 1% in on a REASONABLE timeframe. 8-12 hours at 13.6v typical. THEN you can drop down to the "forever" maintain voltage like 13.2-13.4v. But if you start out at the lower float, then you'll never get that 1% in on time in a cyclic situation!

For many in solar - heck they sometimes never even reach CV/absorb, (sometimes aggravated by premature drop-to-float timers) or if they do, the sun sets before they even get half-way through that, nevermind reaching float! Walk-down time, unless they change their application from cyclic to standby. Or simply let their bank float for a whole day on a weekly / biweekly / or as much as they can to make up for the lack.

SOLAR real-world tweaks:
Some agm manufacturers provide GREAT charge information, such as Concorde, Enersys, Dekka/East Penn and so forth. But many of them assume that one is using an uninterrupted source of power to charge! Or if solar is mentioned, it is almost as if it is intended for those living on the equator, where sun is plentiful. :)

So given the natural inclination to undercharge an agm in an unpredictable solar cyclic application, you'll see tweaks such as these:

BULK=ABSORB=FLOAT

Which means set EVERYTHING for the CV/Absorb of say 14.7v

Simply because someone flips the switch off at the sun every night. So staying in this condition is not harmful, BUT that is ONLY if you are doing daily-cycling!!

Beginner's Tweak for cycling:
Lets say you just barely reach absorb, or your SCC has a quick absorb timer and drops to float prematurely and you only have just one hour left of sunlight? Set your float relatively high, like 13.8v to get in as much as you can until the sun goes away. Daily cyclists only!

If you are standby, or weekend warrior where you have time on your side, then a less agressive normal settings can be used. And that's part of the problem of most agm discussions - daily cycling vs standby application.

If using 2nd-hand batteries with an unknown level of prior abuse or slap-together bank construction - stick to the conservative values.

Sorry man, I even hate seeing my own walls of text....
 
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SiO2 - back on focus
If lead-crystal relieves one from having to play these chess-match end-games to get the most out agm's so that they don't prematurely sulfate, then maybe there IS something to them!

I was skeptical for years, but now, maybe I'll give a small learner-batt a shot.

But man, getting past the marketing speak - electrolyte is distributed in a non-hierarchical manner with no gradient concentration in the upper and lower electrode.

Um, you mean no stratification, which is natural to agm or gel as well. Geez, give me a break. That's the kind of stuff that turns me off.

Still might get one to hammer on.
 
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Yikes: re-read my post and want to offer my apologies to my Canadian neighbors and remarks about North American popularity. Seems I need a geography lesson first. :)
 
Well, these are promoted as an off-the-shelf (dealership) drop-in replacement, requiring minimal to no change to existing architecture.

CONFIRMED MY SUSPICIONS (in a good way):

So I went to the source at Soneil Electronics, and found this pdf:


The ATB, or Advance Technology Battery in their own words, is a "New Generation AGM Battery"

So instead of gel or an absorbed glass matt, they use a powdered electrolyte. And a proprietary separator. Ok - fine.

OK, finally!!! Just trying to get through various home-grown dealership marketing brochures and online Q&A to get down to it is a real chore. And even here, with graphs comparing against lead-acid and even NICAD - give me a break. Stuck in the 70's much? :)

Between home-grown marketing and online Q/A questions, it is much as I surmised and I think tackles real-world issues when compared to normal conventional AGM's:

1) Can recover from accidental catastrophic discharge to 0 volts. Yep, that happens.

2) The powdered electrolyte helps it to become sulfation resistant. Helps tackle under-charge capacity walkdown, especially for solar users. And of course utility vehicles that need rapid turnaround and may not have enough time for a truly full charge.

3) This sulfation resistance lengthens shelf-life, particularly important during shipping, transportation, and dealership shelf time delays before reaching the end user. Ie, you don't start out totally sulfated already. Hopefully dealerships will hold true, and return or recycle old stock. I'd like to see a burned-in manufacturing date on the case if there isn't one already.

4) Q&A online reveals that despite being able to be discharged down to 0 volts and recover (assuming it isn't left that way forever), one should not discharge beyond 80% DOD, as that severely affects cycle life. Even less is better. OK, pretty much sop for any vrla.

5) In accordance with the above, it is not entirely clear that the rated capacity is based upon discharge to 0 volts, or if it is rated to an 80% DOD value. Thus a rated 100ah may for all practical purposes be an 80ah. So I am not totally sure if one should de-rate the stated capacity by 20% or not. I do not know. But their rated cycle life is based on no more than 80% DOD, not discharge to zero.

THIS is what I think they should be concentrating on - being a better conventional AGM for most folks and situations where under-charge and casual usage is present. Looks like you will get more from these, than from a standard conventional agm which is not treated properly. Resilient to the neglect or unskilled use that normal agm's are subject to.

But much of the marketing is concentrating on pointing out the faults of other chemistries, rather than heavily promoting these real-world benefits over conventional agm. And of course this SIO2 battery is in itself a variation of the lead-acid, but I digress ...

The problem is as usual like when I first encountered LFP, upfront cost is an issue. If all one is going to go by is by touting cycle-life vs upfront cost, well not sure how much being a "new generation of agm battery" is going to convince people to switch from the lower-cost conventionals - and of course the appearance of LFP which doesn't sulfate at all!

Tough market. Trying to fend off two fronts of old-school tech, vs modern LFP must be hard. I'm not a business major, but my inclination would be to make SI02 more readily available for instant-gratification online purchase (pair of socks and a battery in your cart outlets) at lower prices to attract attention. Otherwise, it was like me buying LFP only from EV vendors back in the day where only the hardcore nerds shopped. :)
 
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its a bit worse than that regarding next gen batteries having to compete against other technologies.
Hydrogen fuel cells have finally got to the "real" commercially viable level!! they have started to deploy big 18wheeler trucks with fuel cells, they have an 800mile range per fill.

while hydrogen has been around for ages there has not been the infrastructure support. Now they are deploying hundreds of hydrogen stations. The next step is also to have the infrastructure to produce "green hydrogen"; much of todays hydrogen is actually produced from..yep.. you guessed it, fossil fuels hehe
Several new technologies are coming online to produce hydrogen from water efficiently.
 
That's always the thing - what is technologically an advance in comparison to real-world practicality.

I remember when the "Zebra" Sodium Nickel Chloride battery was a hot item. :)

In my mind the SiO2's practical advantages over a standard conventional agm are quite inviting for those not wanting to be wedded to proper conventional agm maintenance, and gives some real "headroom" for non-perfection in storage or charge and getting more out of them in the long run.

I'll give them some first hand experience when I can put a small test version in my cart along with a pair of socks. :)
 
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