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Thoughts on a mineral oil bath?

Warpspeed said:
Might be even better !
What is the water temperature ?
It will always cool a bit at night, and evaporative cooling during the day should keep it well below peak mid day air temperatures.
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It's not de-ionised water, might be good for temps but pretty sure if my bath isn't placed at least 12inches above ground level there will be sparks. I'll get the cooling from stainless coils dropped down if I decide to go ahead (more I look at battery prices, more likely I will).

Once monsoon stops water will quickly run out and temps will get to silly levels I think around 54°c/130°f is highest I've ever recorded here and that's always in shade.

I mentioned the whole thing to my sister in law and her husband yesterday and they just laughed but didn't seem to have any problems with me building it, I think they will be happy just getting a structure they can build from so the whole thing is becoming more and more likely.
I started pricing most of the materials up and how much my wife's credit card has climbed too so if I take care of it all in one fell swoop it's very likely I should start some time around Christmas.
 
dig a hole, dig a hole, dig a hole. (about 2 meters down) put your stainless coils in the hole back fill with slurry to fully surround the coils. put a small pump for the cooling fluid.
Use stainless sheets as panels for clamping with the cooling loops brazed to the panels.

this is the exact opposite of what most of us do to heat the cells for cold climate, you can run the coolant through the ground loop and then up to the panels that act as your fixture for the cells. create a insulated enclosure using XPS and seal it tight. the batteries themselves in a low draw app like a renewable power system do not create enough heat to really worry about, its the ambient temps you need to deal with. below is one of my battery packs. instead of cooling loops i use heating pads, but its the same premise, just in reverse.

IMG_1910[1].JPG


the battery pack next to it is already closed up. not the prettiest work, but it works well.

i would think that 15 or 20 meters of stainless steel 1/2" tubing in a 300 mm coil would give you about 20 coils. another 4 meters for mounting on each side plate and then however much to reach the battery pack form the ground loop.

a small pump to pump the fluid and you are set.

you could also use copper but its system life would only be about 8-10 years buried directly due to corrosion concerns though it would be quite a bit cheaper. is you use copper then you could use steel plates as your fixture and solder them in place and it would be quite a bit cheaper. the flip side is you would need to dig up and replace the copper tubing about once a decade.
 
Daddy Tanuki said:
dig a hole, dig a hole, dig a hole. (about 2 meters down) put your stainless coils in the hole back fill with slurry to fully surround the coils. put a small pump for the cooling fluid.
Use stainless sheets as panels for clamping with the cooling loops brazed to the panels.

this is the exact opposite of what most of us do to heat the cells for cold climate, you can run the coolant through the ground loop and then up to the panels that act as your fixture for the cells. create a insulated enclosure using XPS and seal it tight. the batteries themselves in a low draw app like a renewable power system do not create enough heat to really worry about, its the ambient temps you need to deal with. below is one of my battery packs. instead of cooling loops i use heating pads, but its the same premise, just in reverse.

View attachment 220984


the battery pack next to it is already closed up. not the prettiest work, but it works well.

i would think that 15 or 20 meters of stainless steel 1/2" tubing in a 300 mm coil would give you about 20 coils. another 4 meters for mounting on each side plate and then however much to reach the battery pack form the ground loop.

a small pump to pump the fluid and you are set.

you could also use copper but its system life would only be about 8-10 years buried directly due to corrosion concerns though it would be quite a bit cheaper. is you use copper then you could use steel plates as your fixture and solder them in place and it would be quite a bit cheaper. the flip side is you would need to dig up and replace the copper tubing about once a decade.
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I was thinking less about brazing more about bath to dissipate the heat more evenly but yes this is the general idea I've looked at thanks for showing.
304 stainless here still seems to rust so it might be a trip to old blighty or take a holiday and come visit you to get a decent roll of stainless other than that pumps and the like are readily available.

The bore hole guys generally dig 4 inch holes so my coils would be a fair bit smaller diameter but I'm leaning towards that as the soil is mainly terracotta clay or some other form of clay so a greater depth may be required, I have some copper so I could always get the post hole digger out and do a test pit and see what the numbers are.
 
Copper should be fine, just a vertical flow and coaxial return should be all you need if you are going down reasonably deep.
Best stainless is 316, but it ain't cheap.
 
Sourcing copper above 12mm diameter might be an issue, where stainless is readily available in any size for mainly manufacturing gates.
 
this needs to be pumped as convection will attempt to bring the hot liquid up. good thing is once it starts cooling it will drop faster in the coils assisting the pump. like I said, copper will last for probably 10 years. will the batteries last that long? the CALB 200 have not been produced for about 5 years now, I know I have 68 of them myself. it took buying that many to assemble 3 good 16s packs. i would guess if you get 10 years out of them you are lucky, so if you need to dig a hole for a new cooling coil in 10 years, no big deal I would guess.
 
Daddy Tanuki said:
this needs to be pumped as convection will attempt to bring the hot liquid up. good thing is once it starts cooling it will drop faster in the coils assisting the pump. like I said, copper will last for probably 10 years. will the batteries last that long? the CALB 200 have not been produced for about 5 years now, I know I have 68 of them myself. it took buying that many to assemble 3 good 16s packs. i would guess if you get 10 years out of them you are lucky, so if you need to dig a hole for a new cooling coil in 10 years, no big deal I would guess.
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The CALB 200 second edition are still widely available here online so I'm wondering if they aren't being produced why so many? There's alot of available cells to choose from il be sure to do a ton of research and post here to get everyone input before buying.
 
These are the CALB cells widely available here
Screenshot_20240610-175522.png

Though the advertised cycles kinda worry me. I'd likely go for the 280ah which are almost a 50% increase to the price but advertise 9000 cycles
 
Daddy Tanuki said:
this needs to be pumped as convection will attempt to bring the hot liquid up. good thing is once it starts cooling it will drop faster in the coils assisting the pump. like I said, copper will last for probably 10 years. will the batteries last that long? the CALB 200 have not been produced for about 5 years now, I know I have 68 of them myself. it took buying that many to assemble 3 good 16s packs. i would guess if you get 10 years out of them you are lucky, so if you need to dig a hole for a new cooling coil in 10 years, no big deal I would guess.
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From my earlier life in the beer industry, party boxes or “jockey boxes” are mobile tab set ups sampling.

Warm keg next to the table, tap lines to cooler filled with ice, 100-200 feet of galvanized copper lines/or stainless steel coiled in the cooler will bring an ambiance temp keg down to 34f as long as you keep ice in the coolers. Not a cheap set up but damn handy for when you want to set up a party ASAP.

Jockey Box Stainless Steel Cooling Coil | Right Hand | BeverageFactory.com

Stainless Steel coils are available in lengths from 50' to 120', and are used in an ice-water bath to chill beer down to the ideal dispense temperature of 36-38° F. 120' right hand.
www.beveragefactory.com www.beveragefactory.com


Bingo.
 
740GLE said:
From my earlier life in the beer industry, party boxes or “jockey boxes” are mobile tab set ups sampling.

Warm keg next to the table, tap lines to cooler filled with ice, 100-200 feet of galvanized copper lines/or stainless steel coiled in the cooler will bring an ambiance temp keg down to 34f as long as you keep ice in the coolers. Not a cheap set up but damn handy for when you want to set up a party ASAP.

Jockey Box Stainless Steel Cooling Coil | Right Hand | BeverageFactory.com

Stainless Steel coils are available in lengths from 50' to 120', and are used in an ice-water bath to chill beer down to the ideal dispense temperature of 36-38° F. 120' right hand.
www.beveragefactory.com www.beveragefactory.com


Bingo.
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Not that expensive whatever the option of cooling is tbh.

I'm looking at $83 a kWh for Lifepo4 or $125 a kwh for FLA still haven't worked out my total usage (currently at around 20kwh for a whole day but it's not that hot) and how much I need to oversize the battery(any suggestions or just go for a whole day at current rate?). It's around $900 or so dollars saved on buying FLA equivalent which I will happily spend on cooling when given the cycle increase.

I've also been looking more and more about the requirements of grid tie here as the selection of panels is getting less and less and it actually getting more expensive to buy anything other than 550w bifacial (currently same price as a 370w regular mono) 5kw is the max for grid tie here but I can technically double that later as my sister in law builds under the roof i'm fabricating to place the panels on.
 
Stainless is generally a poor conductor of heat. Nickel silver is much better.

I struggled with this problem and was able to solve it with a storm shelter cut into a hill. I know you can't do that directly, but perhaps you could build up a sand hill that will drain well.

I have my panels above the shelter to provide shade to keep the shelter cool.
 

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ThaiTaffy said:
These are the CALB cells widely available here
View attachment 221020

Though the advertised cycles kinda worry me. I'd likely go for the 280ah which are almost a 50% increase to the price but advertise 9000 cycles
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those are exactly the same units I bought 4 years ago and they were out of production then by a couple of years. these are pulloffs from early EV's , busses, and prime movers (forklifts etc. )
you will notice that none of the terminals are flat and are not perpendicular to the cases from where the sellers sand the terminals with a belt sander to clean them up.
its OK, the best ones put out about 90% of the claimed capacity the bad ones.. maybe 50% just letting you know in advance. like I said I bought 68 of them and eventually when I got a capacity tester that worked I could actually test them. in the end I ended up removing the lowest performing 16 cells so that I could match the cells according to capacity and IR to make up a 3p16s pack out of them. that pack should be 600 aH's but it actually load tests out at about 540 aH's.
Thats when I decided to buy the new winston cells that were direct from winston and they test out above capacity, the terminals are flat, have not been sanded and the QR codes are engraved directly into the plastic body, no way to really cheat that one.
the good thing is that the plastic cells seem to have less issues overall then the aluminum cased ones. (just my observations from the last 4-5 years of watching the DIY scene crowds.
 
justgary said:
Stainless is generally a poor conductor of heat. Nickel silver is much better.
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Lol sorry but the chances of me getting any non standard alloys here is like looking for hens teeth
justgary said:
I struggled with this problem and was able to solve it with a storm shelter cut into a hill. I know you can't do that directly, but perhaps you could build up a sand hill that will drain well.
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Flat as a pancake and sadly I can't even find membrane for the roof let alone the garden, a sand hill would wash away in a day with the rainfall here
justgary said:
I have my panels above the shelter to provide shade to keep the shelter cool.
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I'll be building a car showroom or at least the frame of one so it's likely to be a aluminium roof with the panels fitted on top then a control room for the electric gate and my solar stuff will be double skinned, engineering brick internal thermalite external.
 
Daddy Tanuki said:
those are exactly the same units I bought 4 years ago and they were out of production then by a couple of years. these are pulloffs from early EV's , busses, and prime movers (forklifts etc. )
you will notice that none of the terminals are flat and are not perpendicular to the cases from where the sellers sand the terminals with a belt sander to clean them up.
its OK, the best ones put out about 90% of the claimed capacity the bad ones.. maybe 50% just letting you know in advance. like I said I bought 68 of them and eventually when I got a capacity tester that worked I could actually test them. in the end I ended up removing the lowest performing 16 cells so that I could match the cells according to capacity and IR to make up a 3p16s pack out of them. that pack should be 600 aH's but it actually load tests out at about 540 aH's.
Thats when I decided to buy the new winston cells that were direct from winston and they test out above capacity, the terminals are flat, have not been sanded and the QR codes are engraved directly into the plastic body, no way to really cheat that one.
the good thing is that the plastic cells seem to have less issues overall then the aluminum cased ones. (just my observations from the last 4-5 years of watching the DIY scene crowds.
Click to expand...
The issue here is not many people actually have a clue, the more batteries I look at the more I see things like " New" and ">2000 cycles" in the listing.

My one brother in law works as a government environmental inspector so it might be a better shout to ask him if he deals with any factories here, now Thailand has started producing for EV's( great idea but the grid can't even cope with everyone's AC units let alone EV charging).
 
ThaiTaffy said:
The issue here is not many people actually have a clue, the more batteries I look at the more I see things like " New" and ">2000 cycles" in the listing.

My one brother in law works as a government environmental inspector so it might be a better shout to ask him if he deals with any factories here, now Thailand has started producing for EV's( great idea but the grid can't even cope with everyone's AC units let alone EV charging).
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Don't get me wrong for the price here in Japan it was worth it. They are still plugging along. I would not let the cell count worry yourself that much. Unless you are cranking on them and your bank is small your cycle count will be pretty low. in three years I think I have a couple of hundred cycles as I built my system so that the batteries can run my house for a couple of days with no input from solar at all. in reality i barely cycle them down about 10% with my current 72 kWh bank (1300 aH) so cycle count is not that big of a deal. now if you regulary run them down to 10% then youa re going to cycle them and they will probably last about 7-8 years.

what are they offering per cell? i was buying them delivered to Japan for about 110/cell back when i initially bought mine.
 
justgary said:
Stainless is generally a poor conductor of heat. Nickel silver is much better.

I struggled with this problem and was able to solve it with a storm shelter cut into a hill. I know you can't do that directly, but perhaps you could build up a sand hill that will drain well.

I have my panels above the shelter to provide shade to keep the shelter cool.
Click to expand...
i remember reading your thread and thinking what a great idea for your bunker/solar (i call it a bunker not sure what you call it), but cool nonetheless.
 
Daddy Tanuki said:
Don't get me wrong for the price here in Japan it was worth it. They are still plugging along. I would not let the cell count worry yourself that much. Unless you are cranking on them and your bank is small your cycle count will be pretty low. in three years I think I have a couple of hundred cycles as I built my system so that the batteries can run my house for a couple of days with no input from solar at all. in reality i barely cycle them down about 10% with my current 72 kWh bank (1300 aH) so cycle count is not that big of a deal. now if you regulary run them down to 10% then youa re going to cycle them and they will probably last about 7-8 years.

what are they offering per cell? i was buying them delivered to Japan for about 110/cell back when i initially bought mine.
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$110 per cell? How do I say this without you feeling sick? Give a bigger number? ¢3000 per cell including delivery.
I looked at the 280ah cells ¢5000 per cell but those are in aluminium housing and your earlier post suggested against this. I've also looked at the sinopoly cells they are generally lower amperage but seems to have an higher cycle rate advertised and are still in plastic enclosures.
 
ThaiTaffy said:
$110 per cell? How do I say this without you feeling sick? Give a bigger number? ¢3000 per cell including delivery.
I looked at the 280ah cells ¢5000 per cell but those are in aluminium housing and your earlier post suggested against this. I've also looked at the sinopoly cells they are generally lower amperage but seems to have an higher cycle rate advertised and are still in plastic enclosures.
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not sick at all, this was delivered over 4 years ago door to door to japan with all customs etc. handled by the seller. the prices have dropped on all cells may as much as by 50% so sometimes you pay to jump in early.

If you think that is expensive, you should know that 32 brand new 400 aH cells from Winston with a warranty were $12,000 cells delivered just last fall, but they are brand new with a warranty from a reputable company with a proven history and track record.

Sinopoly and CALB are good companies too, it is just that the market is flooded with old pull offs from EV's that the resellers are claiming are new when they are not. for whatever reason the aluminum cased cells are cheaper then the nylon cased cells, but if you search the forums you will come across many, many cases of issues with clamping vice no clamping, chafing on the aluminum cells with holes being eaten through the cases via galvanic corrosion, (marine and land based) or simple wear (rubbing back and forth in mobile apps). theser are not issues that plague the plastic cased cells. the aluminum makes have their fair share of 2nd hand/reject sellers as well, thats why i chose to spend the coin directly with Winston and avoid these concerns...only time will tell.

YMMV

Cheers.
 
Daddy Tanuki said:
not sick at all, this was delivered over 4 years ago door to door to japan with all customs etc. handled by the seller. the prices have dropped on all cells may as much as by 50% so sometimes you pay to jump in early.

If you think that is expensive, you should know that 32 brand new 400 aH cells from Winston with a warranty were $12,000 cells delivered just last fall, but they are brand new with a warranty from a reputable company with a proven history and track record.
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Yikes that's 12 years of no electricity bills for a payback
Daddy Tanuki said:
Sinopoly and CALB are good companies too, it is just that the market is flooded with old pull offs from EV's that the resellers are claiming are new when they are not. for whatever reason the aluminum cased cells are cheaper then the nylon cased cells, but if you search the forums you will come across many, many cases of issues with clamping vice no clamping, chafing on the aluminum cells with holes being eaten through the cases via galvanic corrosion, (marine and land based) or simple wear (rubbing back and forth in mobile apps). theser are not issues that plague the plastic cased cells. the aluminum makes have their fair share of 2nd hand/reject sellers as well, thats why i chose to spend the coin directly with Winston and avoid these concerns...only time will tell.

YMMV

Cheers.
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All the aluminium case batteries have pretty newly applied shrink wrap so no idea of the mechanical damage although they would be more thermally conductive for my intended use, but is it really worth the risk?
I priced up 64 sinopoly 100ah cells and Daly BMS's to match and it seemed very reasonable but I would rather have something around the 200ah mark but then I would need to order the BMS's directly from Daly as the ones sold here are obviously counterfeit.
 
So I've managed to find a readily available source for stainless steel coils, but they only come in 3/8" 6m lengths and I'm not all that happy about making non accessable connections underground especially with oil. so I'm likely to go with your 2m depth Tanuki that gives me about 6 coils at 4inch diameter, I can order a coil now and see how likely it is I can bend said coil without any kinks and do a test pit.
 
ThaiTaffy said:
Yikes that's 12 years of no electricity bills for a payback
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Not for me, that’s about
ThaiTaffy said:
So I've managed to find a readily available source for stainless steel coils, but they only come in 3/8" 6m lengths and I'm not all that happy about making non accessable connections underground especially with oil. so I'm likely to go with your 2m depth Tanuki that gives me about 6 coils at 4inch diameter, I can order a coil now and see how likely it is I can bend said coil without any kinks and do a test pit.
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i ordered 120 meters of 1/2" stainless pipe from china off of alibaba and it was reasonably priced. Much cheaper then i would have paid here in japan from a local distributor.

I need it for a water boiler heat exchanger I am building to heat my house. they had compression fittings and everything I need and they even pre formed it for me in 1 meter coils and 500 mm coils.
 
Daddy Tanuki said:
Not for me, that’s about

i ordered 120 meters of 1/2" stainless pipe from china off of alibaba and it was reasonably priced. Much cheaper then i would have paid here in japan from a local distributor.

I need it for a water boiler heat exchanger I am building to heat my house. they had compression fittings and everything I need and they even pre formed it for me in 1 meter coils and 500 mm coils.
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I always kinda forget Ali I'll take a look tomorrow when it's not midnight.

Ive been reading the local electricity regulations and requirement so just got round to pricing up the system and starting a list of components, it's currently half the cost of my wife's credit card bill I have to pay at the end of the year so not feeling too bad.

Think I'm going with:
Sinopoly 200ah cells
250ah Daly smart BMS's
Deye 5kw hybrid on grid AiO
Sunpow 380w 120 cell panels
 
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