SiO2 Battery -UPDATE 5 (Two Batts)

[BFL13]

Updates 22 Oct, 8 Nov, 10 Nov (photo), 14 Nov, 15 Dec

http://azimuthsolar.ca/product/12v-100ah-sio2-battery/

Mostly PT has given info on these over several posts in several threads, but I have lost track where.

What are the main pros and cons for this battery again? I might actually have a use for one! What amps draw can a single 100 stand for how long--5 minutes of MW at 100 amps? Left in a hard to access place and no worries? Can float voltage be too high or too low?

(AGMs do not stand up for what I am wanting to do--BTDT 😞 )

Thanks

[MEXICOWANDERER]

C.E.F. Charge Efficiency Factor is a scientific performance ratio as given to storage batteries.

"X" ampere hours discharged

"X" ampere hours needed to replace above

It is a ratio with a decimal in this case a 1. used to express quantities 1.0 being 100%

The highest CEF batteries used to be gelled electrolyte followed by absorbed glass mat. The lower the second number the more efficient the battery.

This should be an easy question to answer using numbers and not rhetoric.

[BFL13]

So here it is (for now) in the outside OEM battery box of the camper.

A. SiO2 on end (as allowed)

B. Inverter with yellow extension cord that goes around to where the shore power cord is where it can be plugged into either the yellow cord or else a shore power source (but never both at once!)

C. The inverter also acts as the voltmeter for the SiO2. 13.0 v showing here (full SiO2). Chart of voltage vs SOC is there on top of the battery

D. Vector charger (clamped on at the back out of sight) that operator sets to 20 amps (not 35!) to be under the 0.25C charging rate, easy to plug into that outside receptacle as shown

The rest of the camper electric stuff is inside as usual with a 55 amp converter on a pair of 6s (under the closet floor-removable to get at the 6s- but vented to outside). So that is my "split bank" arrangement.

[BFL13]

The whole thing does take some logical thinking for sure.

If you are one of those who is already getting the job done, using as much as you want daily and recharging by solar/gen with Flooded or AGM "fast enough" , why spend a ton of money for the latest shiny object just to keep up with the latest fashion?

You need to calculate what good it would do you to have those very expensive batteries instead of what you have now. To do that you need good information on just what those expensive batteries can and cannot do.

Lots of info out there on Li, but very little on SiO2. Some of that "information" is by salesmen ( "drummers" ) making clever claims (smoke and mirrors). It is up to the RVer to do his own math for his own scenario(s).

Even then, you might find that DW will move the goalposts on you! So now you have to figure out Plan B 🙂

[StirCrazy]

I think the thing is if you are going LifPo4 you are building for it, so for instance with your batter in my camper my solar is maxed out as it will only handle what was it 25 amps. my 45 am converter is to much for it so I would have to figure out how to dial that down or get two batteries. My solar will put out 22 amps on a nice day so that almost maxes out one batter for aceptance. If I did LifPO4 I would install a second solar pannel then I could have up to 50amps depending where I am which would recover before noon anything I used the previous night. you dont have to worry about heat so much in the LIFPO4 batteries as a decident BMS will limit curent if the temp gets to hot and there is no three phase its just maximum charge till 100% and done. oh and you can store them at 100% no problemm from everything I have seen. biggest down fall is price and cold weather charging. if they are inside the rv then the cold weather charging isnt an issue and the only way to get the pricce afordable is to build them your selves but not everyone is up to this.


Steve

[BFL13]

pianotuna wrote:
BFL13,

This link doesn't appear to work?



https://energsoft.com/blog/f/c-rate-of-batteries-and-fast-charging

It works for me when I click on that earlier post with the blue link version. I like his opening quote:

"In 1908 Thomas Edison said about batteries: "When a man gets on to accumulators or rechargeable batteries his inherent capacity for lying comes out."

I will try it again on edit here

https://energsoft.com/blog/f/c-rate-of-batteries-and-fast-charging

[pianotuna]

BFL13,

This link doesn't appear to work?



https://energsoft.com/blog/f/c-rate-of-batteries-and-fast-charging

[BFL13]

MEXICOWANDERER wrote:
I'm satisfied with what I ended up with. One thing you lithos haven't mentioned

The charge Efficiency factor

You forgot my post on 22 Oct, page 5 of this thread. 🙂

"I forgot to say that I did not correct for charging efficiency AH count on recharge that the Trimetric uses for heat loss. I don't know what the diff is in heat loss for the SiO2 vs the flooded 27Dc type. IMO this would not be enough of a factor to skew the results of this test."

It could be enough of a difference I suppose--I shouldn't have said that without knowing for sure. That Li article said they run into "current density" issues with too much charging current, so that might be equivalent to amps going off to heat in a Flooded or AGM.

[BFL13]

Another way they claim faster charging with Li and in some cases, Si is that they stay in the constant amp bulk stage to a high SOC rather than tapering from the mid-70s SOC range. That is true for Li but I didn't see that as much testing my Si. As reported, amps started to taper at 87.5 %. That is still higher than the usual 75% SOC at that charging rate.

Just how much gen time you save "depends".

Where you can save time with both Si and Li is where you can safely go down to 20% before recharging. With Wets you can do a 50-80 at the high amps zone (more like 45-75 really) so a 30% zone. You start at 50% , normally the low SOC. But here you can do approx 20-90 with Si and a 20-97 with Li at the bulk current limit of the charger, up to a 25% charging rate with Si or 50% with some Li or even 1C with some.

Say you have 200AH of bank. A 20-90 is 70% or 140AH you can do at 50 amps with Si. Takes almost 3 hours. You can't compare with 200AH of AGM doing 45-75 directly. 140AH of 30% zone means the bank would be 467AH. You would need a 120 amp charger to do it in 3 hours instead of a 50 amper, and a Honda 3000 to run it instead of a 2000.

You can "use" the 140 AH with half the battery bank looking at it that way, but then again "use" has to mean "use what?" In my case the microwave can't be used down that low because of voltage drop. Li can do much better with that, so more "usable AH" with Li compared with Si for high draws and you can recharge twice as fast with Li (0.5C vs 0.25C)

So Li wins big there, but then as Itinerant1 said, you have to compare real life set-ups for just how much battery bank, what is the max amps of the charger(s), and what is the "use" -low amp draws for a long time or high amp draws for a short time, or some of each?

IMO, most RVers won't realize much of a "faster charge" than they get now for gen run times doing 50-80s while camping. Depends how limited gen hours are whether say 30 minutes saved matters, or if you are in a hurry to get it done so you can go up to the lake for a swim.

Most of the recharge time is 80-100 SOC which you don't do now anyway, and with Si you would not do the 90-100, but could do the 80-90 a the high rate, so you do save some gen time there ("depends" how much time in minutes)

Unless you can compare an exact scenario, it is not easy to prove a "faster recharge" , but it can be faster in some scenarios for sure, especially with Li.

The dollars it costs (twice as much for Li than with Si if they save the same times in the scenario in question) to save those minutes is another "worth it" nobody else can answer except the individual doing the calculation.

EDIT--I am getting tired of counting bikes and cars and fire hydrants to get on here! 😞

[Itinerant1]

I'm not sure on what you're getting at with the efficiency factor. I've stated it a couple times already that I could practically put a stop watch on the charging. No lllllllooooooonnnnnnngggggg drawnnnnnnnnnn out charging involved.

[MEXICOWANDERER]

I'm satisfied with what I ended up with. One thing you lithos haven't mentioned

The charge Efficiency factor

[Itinerant1]

You're comparing lithium charging in a Electric Vehicle to charging lithium in an rv system.

In the rv world we are working in fractional 'C'. My system is not large by any means and at best if I felt like using the generator while the sun was out producing it's max, the best I could charge at would be 175-200a which would be .35c-.4c on 500ah batteries.
If using just the generator and inverter/ charger that's 100-125a or .2c-.25c, max solar 80a or .16c. None of those rates will harm lfp by any means and at such a fractional 'c'.

I'm sure there is someone out with an rv the have the ability to push higher amounts but imho it's not the norm.


The cell temp increase while charging at the above stated 'c' rates is very minimal. I can see the cell temps on all 20 cells in my batteries.

[BFL13]

I thought the comment from that boat guy on Li was useful. He said they work for full-timers but not for weekend warriors. I will try to cut and paste that here on Edit.

Even if I had unlimited funds, Li would not suit me. Too fussy with all that BMS and what not makes them sound too delicate, but I gather that may not be really how it is. Anyway, that's just me. YMMV.

I remember some years ago running the converter from the Honda, a Vector charger from an inverter strapped to the truck battery while idling, and solar all adding their amps just fine. You just need the various chargers to be at nearly the same voltage and all higher than the battery's voltage, and they add their amps.

"Fast charging" seems to have several meanings for folks. It does not mean way high amps as such. You have to know the acceptance rate curve along the SOC range. You can get the way high amps for the first ten minutes and then they might be the same after that, so all you did was save 10 minutes of gen time. It depends! Then as PT said, you still need a way to achieve those high amps wrt the battery bank size in AH. A big bank can mean your generator can only run so much of a charger in amps, and that's that, which miight only be a normal level of charging rate anyway, so even if the battery bank could take more, you don't have it. 🙂 anyway, off to find that boat guy's quote---(link on back on page 6 of this thread (trawler one) page 2 of that at the bottom)

"The weak point of LFP at this time is the care and feeding needed: they want to be stored in a partial state of charge, and that is not so easily done. With LA batteries in intermittent use (like most boats) you just return to the marina, plug them in, a proper charger brings them to a float state while you walk away. LFP on the other hand, should be run down to 40 - 60% before leaving them. Then when you return next month you are starting the weekend with partially discharged batteries. Currently, that makes LFP a better fit for live aboard on the hook use where they have many advantages, vs. weekend use stored in a marina, or marina live aboard.

The carbon foam batteries seem to have nearly the same life kept in float or partial state of charge - that's why people are paying more for them. No one seems to know on SiO2."

EDIT--here is something on Li fast charging where it says you can over do it and wreck the battery from overheating. There is another one about why charging is slower than discharging C rate if I can find it again

https://energsoft.com/blog/f/c-rate-of-batteries-and-fast-charging

EDIT- " Normally high discharge rate batteries can be fast charged. However, since lithium ions are embedded in the negative electrode graphite during charging, the process of inserting lithium ions into the positive electrode during the discharge process is difficult, so the fast charge ratio is generally lower than the discharge rate"

https://www.grepow.com/page/high-discharge-battery.html?gclid=EAIaIQobChMIsNOZxqr27AIVLiCtBh3YoAphEA...

Note--I find that last one might have a typo or something? Says discharging difficult, so charging is slower?

[noteven]

I am thinking spend number 1 will be on a modern DC-DC charger for my truck camper rig.

Ya I am that guy that would rather listen to the quiet rumbling idle of a 6.2 gas V8 doing a 'mergency charge of batteries vs the lawn mower rpm drone of my Honda "quiet generator"...

Ray at Love Your RV channel just did a couple vids on DC-DC charging from the vehicle alternator, and how running solar, plus DC-DC charger, plus generator AC-converter charging at the same time works. Yes they have Li batteries.

But yes, 1 x 100ah battery for 1 night seems to be the rule in the Dark Season.

I am kind of leaning to Lithium arn batteries, install inside the warm envelope, under a seat where it would be simple to pick them up and move them to heated storage if ever such an emergency were to arise.

Now on the other hand I can own and wreck quite a few good quality FLA batteries for the spend Li and SiO2's need.

But Li lend themselves very well to fast mechanical charging methods....

[BFL13]

I still don't understand the high discharge rate allowed vs the lower charging rate allowed. I read about "C-rates" wrt Li but got bewildered. Something about how Li electrons mate ISTR?

The explanations for SiO2 linked earlier are less than clear too (to me) having to do with various voltages when you stop at different rates and seemed to allow for "ratio" of charge rate vs discharge rates being sometimes 1 to 1 but not clear when that is, and so when you can use the mystery 3C charging for how long instead of "standard" charging rate of 0.3C.

Beats me. Luckily I don't have to worry about faster charging, doing the recharge at home.

I thought my old 156 amps on a 458AH bank was pretty fast for acceptable gen time on the Honda 3000, and that was 0.34C, so 0.3 seems ok to me. But they claim SiO2 can be done faster (less time for a 50-90 is what I would mean by that) but I don't dare try it with my very expensive battery!

EDIT--forgot again that their 0.3C is at the 10hr rate according to a couple of blurbs, so that is really about 0.27 at the 20 hr rate for SiO2 batts. (Note that the 27 for 20 and 30 for 10 is for SiO2 and would be different for other types of battery)

Have to wait for PT to buy one and try out 3C charging and find out what happens! 🙂

[pianotuna]

BFL13,

Thanks for the informative real life testing.

My greatest need is for generator starting. I've killed off 2 AGM by forgetting to turn off the remote electric start.

My hope is that SiO2 will tolerate that kind of abuse (very definitely mea culpa).