pianotuna wrote:
SiO2 are much better than regular AGM, which are better than flooded. They have little or none of the monkey business needed for Li chemistries.
yes they are much better than AGM, agm is the worst in my opinion and anything is better than that. they just fit a nich market of anti spill
pianotuna wrote:
There is only one Li chemistry (Lithium Titinate) that would meet my weather needs (not wishes), but it is $1800 per 100 amp-hours, and many would be required because the recommended discharge rate is rather low. SiO2 can do 4C continuously.
and how long are you going to discharge one battery at -40 at 1C? you arnt. you're getting 7 100AH batteries so now are you going to dischage them at 4C? nope I believe you will be under 1C as your trying to ballance the load over a period of time. at 0.5 C that would give you what a 350A draw ( thats more than a 3000watt inverter) and you will only have 420AH available to draw. . well if you bought 7 280AH LFP you would have @1C 1960amps availble on a constant draw, but you would also at -40 have a total of 1960AH availble because they are in the heated space and cold won't affect them. iven if you bought 100 amp battle borns and droped them into the same space you would have twice the amprage capability and capacity at that temp. I don't know why you insist on comparing irelavant numbers. if you looking at 7 batteries compare 7 batteries. oh ya the LFP even at 2.8 times the power size will be about 1/3 to 1/2 the weight and 1/2 the size so depending how your trays are set up you could probably fit more.
pianotuna wrote:
Li are not well suited to cold except for the aforementioned above.
well thats not entirly true, they use Li batteries in skidoos, and quads and they seam to work fine in the cold. but thats another issue and not as relivent in this situation. yes that is the one downfall you need to be above 0 for the battery to charge but it is easily acheavible
pianotuna wrote:
I fail to see how I could warm li batteries up to where they could be charged without using shore power, or a generator. Physical space will only allow 7 group 29 jars. Li are not that much smaller in dimension, and for MAXIMUM cycle life really only have 50% usable (40% to 90%).
three things here there are several ways to heat them up, two you mentioned the third is solar amd you only have to heat the little area where the batteries are but you won't mount them inside so its a mute point I don;t even know why your going on if your not willing to even discuss the ways to do it.
actualy they are about 1/3 to 1/2 the size. the comercial dropins are a lot of waisted space just to make the container the size to drop in. if you want to realize the space savings you have to get some one who puts 280AH in that same size container or build your own. for example a 280 ah home built is 6" x 8' x 11" add say 1/2" to the 6" demention for your BMS heck add a full inch lets live a little.
as for your 50% thats just bull mularky and you know it as we have showed you before. to get rated life of up to 4500 cycles it is 100% then at the end of the life they still have 80% of the original capacity and may live on that for another 20 years. there life is defined as when they hit 90% of there original capacity. if you use a 80% discharge that life can increase to about 7000 cycles depending on the manufacture and configuration. but if I start off with a 280 or 300AH battery, I think I saw 320AH cells the other day now , and lets say I totaly cycle it 40 weekends a year and its rating is only 3000 cycles well after 37.5 years I will only have 224 AH im ok with that. and studies show the first 20% drop is the fastest. its like the output curve of a LED they lose brightness fast to about 80% then they last forever at that level.
pianotuna wrote:
Li do not love to be float charged. That means adding complications to the solar charging system for storage. SiO2 don't mind float at all.
lets rephrase this again. they do not like to be stored at a float charge if your float it set right, for the average person it won't be an issue, the only issue it will add is turning off your batteries when you get home from camping like most people do.
like I said in the last post if they won't work for you because you won't reloacate them or insulate around them and put heaters on them thats fine, but don't claim SIO2 is a far more advanced battery as it isn't true. they are heavy bulky, more expensive than LFP now and have the same limitations of lead asid with a few failsafes built in.
