Provience
Kill!
I need a place to keep pictures and thoughts and talk through ideas and such, need to start a thread over here anyways
A couple of notes and hopefully lessons learned from the previous Basic Home Battery Questions thread
after much-ado about pellets vs wood vs heat pump, this really seems to be the 'ideal' option, just requires dry wood
https://www.caleffi.com/sites/defaul...dronics_10.pdf
and i've also downloaded several of the Caleffi Idronics .pdf publications, they are awesome. using the outside wood furnace to heat a large water storage tank, to then pump the hot water around the ground to use as livestock trough keep-from-freezing and home in-floor heating and on-demand water pre-heating, caleffi sells/makes the controls to do all that stuff and puts out really good and detailed information on how to maximize efficiency with their stuff.
The thread these exceprts are from is roughly 60 pages in PDF format, if your information or post isn't quoted above, know that i'm reading and considering all of it, just wanted to tag this handful as kind of "general idea" things
A couple of notes and hopefully lessons learned from the previous Basic Home Battery Questions thread
well those questions are right where I started this thread, so topical more than stupid. at least I've learned some things and can, slightly, quantify them. Diesel makes a certain amount of KW based on BTU and, generally, that doesn't change. internal pumping losses, system sizes and whatnot do make some difference, leading to the following things obvious to everybody who already knows:
A 5kw gen will make 3kw of power more efficiently than a 12kw gen, but only slightly.
A 12kw gen will make 8kw of power more efficiently than it will make 3kw of power, but only slightly.
A 12kw gen making 8kw of power will make 20kw of power more efficiently than a 5kw gen making 3kw, but only slightly.
A constant 2kw draw will be more efficient directly off a 5kw gen, rather than a 5kw gen making 3kw or a 12kw gen making 8kw charging a battery bank, more than slightly.
A variable load up to 2kw with more low draw at or near idle is more efficient to use a battery bank and a gen set, how much depends on the amount of time at or near idle, either very little or a bunch.
I was correctly pointed earlier in the thread to start with the charger side, because they can only handle up to a certain charge rate. Pairing the charger up to the generator that is the most efficient at that rate makes for a good match. Running the charger at the max charge rate is the most ideal way to keep the charger operating at it's highest level of efficiency.
Batteries can only accept a charge at a certain rate, so then the battery bank needs to be large enough that it can handle that rate, anything below is missed opportunity, again slightly. Going larger than that doesn't incur a penalty, so long as you don't go so large that a larger controller and gen would be a better fit.
Supporting a 2kw constant load with just a generator would be about $7-10k/year in diesel Anything that you can do to supply electricity that does not rely on fuel, then, can rather quickly pay foritself, though that requires batteries to store the surplus and rest the gen. <- this concept is a big part of why regenerative braking increases the miles/gallon on hybrid cars. I'm just more familiar with cars, so i'm a bit ignorant on how it crosses over to non-mobile applications. ultimately it leads back to heating as that is a massive use of most folks energy.
I have a personal bias towards ground source heat pump supporting hydronic heat: fuel is noncommodity and passive, ground source doesn't suffer the efficiency loss air source does below 40* ambient air, it is only trying to heat water to 85-100* rather than whatever forced air goes up to, a recirculating system should gain efficiency as it recirculates, as the in/out temp delta narrows with time, it allows for cooling and heating, it also allows the option to spin off a leg to use as livestock water trough heater. frozen water sucks to deal with and electric resistance heaters are prohibitive. hauling hot water a few times a day also sucks.
so can an electric system be supported at 'reasonable' cost compared to a propane/pellet/wood/diesel boiler? maybe would it be more ideal to supplement the ~4 months when PV could fall short by using fuel in a generator to charge batteries, or would it be better to supplement with a wood stove or pellet stove for home heat, or, if it needs to be supplemented, would it be better to simply rely on a commodity for primary heat. I dunno, but at least now I have a handy chart that I can take notes on to see some goals. In talking with various people on their current energy uses, propane used for cooking, on demand hot water and laundry (can't air dry in freezing temps ) seems to amount to maybe a couple hundred gallons a year to under 100 gallons a year. even an efficient home would use more than double that if adding in a propane furnace.
Originally Posted by Crisbee1 (Post 44749832)
Mountain home has forced air heating, air handler with 2 heat strips each on it's own 60 amp breaker in a stand up 12x12 attic space. Ground mount a/c compressor (not heat pump) and a roof mount mastercool swamper. The heat strips flat get with it, I have one of them shut off, just one can keep 1200 sq ft toasty warm, 2x6, on a slab, lots of insulation. We have been without power for 4 days at a time, Honda 3000w generator runs everything I need. pellet stove noworky without electricity, I have a basic Osburn wood stove. Wood is a pain in the ass. I burn 3-4 cords a year, I cut 2 and buy 1 or 2 depending on the deal, typically $250 a cord for split juniper delivered, not stacked. I cut by myself and usually it takes me all day to get half a cord so 4 days of cutting. $20 for a permit from the FS for 2 cords, set up with a tag system down to the time and date of harvest, get caught cheating it's a federal ticket, if you are not a Dick LEO might tell you to drop your load behind the FS office and don't let me catch you again. By the time you actually put that piece of wood into the wood stove you have picked it up 10 fucking times. Fill woodstove before bed, set heat at 66*, heat will come on 2 or 3 in the wee hours of the morning, get up bump heat to 68*, empty stove ash, build fire, modulate fire to maintain 72*, repeat. This morning
Realsquash
There's some (a lot) of incorrect information here, or maybe just misunderstanding some of the numbers. I read through most of it but there's too much to comment on everything directly. How DIY-ish do you want to get? Your best option $ and efficiency-wise is to set up a Tesla/Leaf/Volt battery at 48v and use a 48v inverter. If you could get a higher voltage inverter that would be more efficient, but there aren't many at a reasonable price. Lead acids are less efficient due to their weird charging requirements. Lower voltages are less efficient. Even an MPPT is more efficient when you run a higher panel/string voltage and a higher battery voltage (to a point). For charging you could use some Telco rectifiers like I do. They are massively parallel, redundant, smart, programmable, compact, run on single or 3 phase, and are 97% efficient at 100% load. They are regularly under $100 on ebay and each one will do 3000w. Eltek is the manufacturer. I have 4 of these set up for charging my Volt bank that's set up for 48v. I also have 1600w of solar panels, but wish I had more. I also have a 12.5kw diesel generator. This is in my motorhome, and this is a very DIY setup. Also know that you're only going to be able to use 50% of the capacity of a lead acid deep cycle, and 80% of a lithium. The Tesla numbers and most of the other stuff you see quoted on the internet are incorrect interpretations of things. Tesla supercharges to 80% for only one reason - the cars and chargers aren't equipped to cool the battery well enough for any more charging power. They will pound in the amps from 20-80% as fast as they can and just stop charging. This is one of the big advantages of lithiums. They don't need to top it off to 100% to get max battery life, so they don't have to spend the time topping off at lower amps to get max capacity, either. If you had to fill a glass with a water hose you'd be much quicker if you didn't have to slow down the water flow to top off the glass right to the rim.
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Eltek Flatpack2 48/3000 HE - 3kw each. You would have to look for a shelf on ebay like I did, or you can make your own box for them and build your own connections for the rear of them. They normally slide in from the front of a cabinet and they are packed in tight. They can operate on their own or you can buy the controller to program them. There have been some people in the past who have reprogrammed them for others on the DIY electric car sites. I just bought a thing to program them on ebay, I think it was $50. They work by themselves, don't need to stay connected. When all the rectifiers are connected their inputs and outputs are all in parallel. There is a can bus connection between all of them as well. They will load balance, they are hot swappable, etc. You can program them to be a constant current supply up to a specific voltage, where they will taper off in constant voltage. You can set the max current on them, etc. I like them because I can log all of them and what they are doing, temps, etc. On the battery capacity you're off - my pack is a 16.5kw model, so I charge it to 100% and discharge to 20%. That's the 80% of capacity. Going between 20% and 80% is internet hogwash, no electric car on the planet does this because going only to 80% doesn't give you a large number more cycles. Also, I think you misunderstand the charge/discharge thing. If you have the gen running and powering the charger and you turn on the inverter, the power is going to come from the charger, not the battery. All the power will come from the charger and will go into the battery and the inverter. That's basically how it works. On my setup, since I can't use the OEM BMS to do anything, I am just reading the pack sensors and ambient temp outside. I also watch the water temp in the reservoir. The objective is to keep the pack under about 95F in the summer, and above 25F in the winter if I'm doing anything big with it, like charging. Slow discharge in the cold is no issue down to 5 or 10F, but I just keep it warm. Optimum temp is like 75, but depending on the situation it might be wasted energy to bring it up to that temp. It doesn't take a lot to keep the temp up in the winter. I have a 48v hot water heating element in the reservoir and the brushless 12v pump from a Volt (cheap on ebay, basically the same as a ZL1 intercooler pump) that I can run at a very low speed, so it takes almost no power. I run the heating element at a low power level. There is also a small heat exchanger with a small fan on it so I can cool the pack at night when the air cools off, for example. I also built a very small A/C compressor deal to cool the battery below ambient, but I haven't needed it more than a few times in the past couple years so it's out of there at the moment because I never finished the enclosure for it. I used the evaporator/coolant heat exchanger from the volt for that, too. It's a TXV setup, nice and easy. If i ever end up travelling where it's extremely hot I'll finish the enclosure and put it back in. I do not have any cell balancing devices, I do manually check the cells a couple times a year just to be safe, and so far I'm 0.03v different high to low. No kidding. I do need to get a monitor built for it. There are lots of cells to manage here and pretty much all of the aftermarket stuff is junk and causes more dead cells than they save. I'm running a Magnum MS4400PAE, which is a 120/240 split phase 4400w inverter. Here's an in-progress photo I had online showing the battery and main panel:
thanks. i'm going to need to read/look at that a couple more times. Concerning the capacity, there was a GM article talking about how they consider them unsuitable for auto use at 12kw, so that is what I was figuring as an easy to figure worst case capacity. still plenty useable even if it can no longer charge up to the full 16kw. but if it a non-issue, then by all means, the more the merrier. it does seem like I've misunderstood the charge/discharge thing, thank you for clarifying that. makes sense. interesting that there isn't a way to use the OE water pump/heater. it seems like it would be really simple to set that up with a high/low temp switch to keep it happy. in a non-mobile use with a bit more space especially. hell, it could be tied into a home HVAC and treated as a 'zone', wouldn't be much in terms of heat use compared to what the whole rest of the home is sucking up. So just to clarify: Generator->bus bar->rectifiers->batteries for charging and then batteries->bus bar->4400W Inverter- >Load for discharge edit: eye see now, rectifier handles the AC to DC stuff and inverter the DC to AC stuff, so the Eltek flatpack does the charging/managing/loading side https://www.eltek.com/globalassets/i....ds3-1-7- 1.pdf. gosh, that seems much better, and you can run the gen at 220v instead of 115v and the rectifiers are handling the parrallelellding, with the battery cells set up at nominal 48v 3kw banks, and then however many of those 3kw banks/rectifier combos for however much storage you want to add.
after much-ado about pellets vs wood vs heat pump, this really seems to be the 'ideal' option, just requires dry wood
https://smokelessheat.com/product/vedolux-40-ub/ i'm also going to drop this thing here. it is a natural-draft wood gasification boiler. No electric blower, so that is neat I found a whole bunch that wanted ~1500watts just to run the blowers....for that same power(ish), i'll take the heat pump and not have to deal with wood or thermal storage so the idea of a high efficiency boiler that doesn't require electric input pretty well makes wood worthwhile
https://www.caleffi.com/sites/defaul...dronics_10.pdf
and i've also downloaded several of the Caleffi Idronics .pdf publications, they are awesome. using the outside wood furnace to heat a large water storage tank, to then pump the hot water around the ground to use as livestock trough keep-from-freezing and home in-floor heating and on-demand water pre-heating, caleffi sells/makes the controls to do all that stuff and puts out really good and detailed information on how to maximize efficiency with their stuff.
The thread these exceprts are from is roughly 60 pages in PDF format, if your information or post isn't quoted above, know that i'm reading and considering all of it, just wanted to tag this handful as kind of "general idea" things