Tulex
Solar Wizard
What's around the hot box is the concern. We can contain the fire inside the box, but if it's glowing red near flammable material, the outcome isn't good.
House burned down
- Thread starter Jejochen
- Start date
robbob2112
Doing more research, mosty harmless
Line the outside with fluffy rockwool panels to act as a heat shield. Make sure any nearby walls are firerock panels. add a vent to the outside using double walled water heater vent pipe and the appropriate surrounding space so it doesn't smolder the wall like we have seen.
Batteries…
Modern vs Old
Why I considered these:
Cavet from Watts 24/7
“‘’’’’’
Through experience, we find that ANY battery chemistry, when cycled 100% every day with high charge and discharge currents has a limited lifespan, some LiFEPo4 batteries make it to about 3 months when worked hard
‘’’’’’’’
Quoted From link. 3 months hard use DAMAGED
Modern vs Old
Why I considered these:
Cavet from Watts 24/7
“‘’’’’’
Through experience, we find that ANY battery chemistry, when cycled 100% every day with high charge and discharge currents has a limited lifespan, some LiFEPo4 batteries make it to about 3 months when worked hard
‘’’’’’’’
Quoted From link. 3 months hard use DAMAGED
Hedges
I See Electromagnetic Fields!
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- Mar 28, 2020
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- 21,204
Quoted from an ad for a competing chemistry.
What is "Hard"? Well in excess of spec?
We expect LiFePO4 to tolerate 0.5C charge, 1C discharge, while kept at comfortable temperature. Isn't that the rate at which 6000 cycle life has been tested?
That would be 3 hours per cycle, 8 cycles per day, 2 calendar years to hit 6000 cycles (equivalent to 16 years cycled once per day.)
Others here do have a number of years use of their batteries, more likely charged around 1/8C and discharged 1/16C on average (daily use), with peaks well above that.
What is "Hard"? Well in excess of spec?
We expect LiFePO4 to tolerate 0.5C charge, 1C discharge, while kept at comfortable temperature. Isn't that the rate at which 6000 cycle life has been tested?
That would be 3 hours per cycle, 8 cycles per day, 2 calendar years to hit 6000 cycles (equivalent to 16 years cycled once per day.)
Others here do have a number of years use of their batteries, more likely charged around 1/8C and discharged 1/16C on average (daily use), with peaks well above that.
Brucey
Solar Wizard
What's considered "high charge and discharge" currents?Batteries…
Modern vs Old
Why I considered these:
Cavet from Watts 24/7
“‘’’’’’
Through experience, we find that ANY battery chemistry, when cycled 100% every day with high charge and discharge currents has a limited lifespan, some LiFEPo4 batteries make it to about 3 months when worked hard
‘’’’’’’’
Quoted From link. 3 months hard use DAMAGED
He says 100% discharge. The guy at Watts 24/7 seems like smart guy to me - and is offering his experiences. He sells all kinds of batteries and equipment.
My past experiences are with aviation and than diesel electric freight locomotive power generation. We used lot of systems and subsystems to get it done. All sorts of variations.
We used 64vdc lead acid on diesel electric freight locomotives.
Knife switch to cut them in and out.
robbob2112
Doing more research, mosty harmless
In the UK you can use the square NH series of fuses as an alternative. They are pretty cheap even if you have to buy holders for them. They have ceramic square bodies and about the same AIC and response times. They look like this - NH style - similar to the link below. The holder is also ceramic and all exposed so you need to have a box to put it in.
One note - lookup and read the data sheet on whatever you land on to verify the current vs time is 0.1 or less with 6x current to be equivalent to the class T
Last edited:
_voltmeter_
New Member
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- Apr 24, 2022
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you can keep them if you have a bms for each battery.
The only logical reason to get more and more batteries is increased capacity. Unless person is on an ego trip with money to Burn.
My assumption is So we hit that sweet spot of not going way up and down with discharge and charge. I have total 6 cycles on my batteries the cycle count goes way up if do deep discharges. Just tapping it 20% or so from 100% makes big difference for my system. I like blue tooth bms. I’d love batrium. I like info.
Think the OP had 100kWh setup to charge that Tesla ….so depending on that use he not only wanted but needed that big of a bank…48v.. 7 strings for their capacity. Think his other use was used for “induction cooker.” Not sure where that was stated….but read it.
The owner at Watts 24/7 is not my friend. I have never bought anything from there but did consider it for those linked batteries. They are around 167 pounds each for batteries looked at. With my bad back - probably not for me. Same for lifepo 48v 280ah box contained “Popular Big Battery at ~280 pounds”. Of course once in place they are HOME. Right?
The lifepo and such are not stable without help something to control them. The lead acid and silicate are simple grunt high amp. I cringe when see ppl talk about using 12 volt 100ah Lifepo with bms in high amp draws such as riding lawn mower change over from lead acid - applications. 3 blade motors plus drive motor.
4 total in work modes ….several done….. any reported failures? We will only know if they report in and let everyone learn….. Appreciate you sharing and it is how we all learn.
Will Prowse did a recent video on this battery. I would not want to move it around much. This is latest trend. Boxed batteries. UL approved.
~282 pounds is specs
Brucey
Solar Wizard
The Silicate batteries are interesting to potentially replace lead acid in below freezing conditions, both need to be only used to around 50% discharge for max life. Note in the listing it says "We parallel these with lithium batteries to give maxium surge capability" so maybe not as much current capability as LFP?
Daddy Tanuki
Solar Wizard
yeah I only work on conventional ships but the nukes are crazy anal about everything and with good reason. here at Yokosuka the US government flies in people from pugent sound naval shipyard to oversee and or sometimes perform repairs on the carrier. some of these fools are here for 3 or 4 months living in a hotel sucking up per diem like its koolaid in rural indiana
squowse
Solar Enthusiast
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- Jan 4, 2021
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Well of course I do. But what if the bms fails to interrupt a short circuit?
SilverbackMP
Solar Addict
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If one has or is building a sizeable system, a 20 foot connex would be much much better than those 10 ft variants. My power shed is 12x12 and I wish it were bigger. Granted a garage door takes up one side, and I have two sets of those smaller form factor wall mounted server racks in there too for my main coms room.
To expand, I’d need to get rid of the server racks and a little work bench that’s under them and/or frame in the garage door.
To expand, I’d need to get rid of the server racks and a little work bench that’s under them and/or frame in the garage door.
SilverbackMP
Solar Addict
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Then again, I also have my 7.7 Sunny Boys in there (along with the Sunny Islands) and most folks wouldn’t have big chonkin AC coupled line inverters.
Yeah, you will never complain about too much space when your needs change. If you add 2" rockwool insulation then a container only nets you ~80-84" clear. I'd also suggest a door in the far end. A 20' container would let you put 7xEG4 14.3kWh batteries low and as many inverters above as you wanted, with AC distribution on the opposite wall.
_voltmeter_
New Member
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- Apr 24, 2022
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then you can nothing do.
bms and fuse this is the maximum protection
you can remove all flammabale stuff around the battery and build protection against fire with fibercement board or bricks
i have a smoke exhaust on an ups with an 1000m³/h pipe fan
this is all i can do
i have a sunny island 8.0 and a sunny boy 5.0
Brucey
Solar Wizard
Orion recommends multiple redundant and independent methods of disconnection, and a contactor per string, I see nothing about the design of a Batrium where the dangers of multiple strings without the means to disconnect those strings wouldn't also apply to it.
I guess in theory the contactor shutoff could be considered the primary method of disconnection per string with a class t per string as the redundant backup? Or use two separate BMS and contactors?
I guess in theory the contactor shutoff could be considered the primary method of disconnection per string with a class t per string as the redundant backup? Or use two separate BMS and contactors?
_voltmeter_
New Member
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the fuse is not for disconnetion of the battery. it can be overcharged by current lower the trip current of the fuse.
i would call a redundant backup, a mosfet bms and a contactor controlled by an other bms
in the batrium case contactors and a mosfet bms (like jk) each bank
Daddy Tanuki
Solar Wizard
i don't have the necessary experience at the storage levels the OP had, but for me, If i was using a batrium, or orion I would have a separate BMS that could disconnect each string, just like I do know. i would also have a separate class T fuse for each battery string... just like i do now. the one thing I will add to my system as a takeaway from this is a mechanical relay/contactor whatever you call it for each string and it will be controlled via the current BMS's vice using the BMS to control the current directly. it might burn a little juice but over the last three years everyone of us at one time or another has made the claim you need to de-rate Chinese electronics to be safe... a 100 amp BMS is only good for 60 amps etc. etc. I have always de-rated mine and my current DALY 150 amp units rarely see more than about 15 amps each in discharge and maybe 35 each in charging and i felt that was good enough. now I want a mechanical contactor to take up the strain instead. just feel better with it.
