diy solar

diy solar

House burned down

robbob2112 said:
Link for the contactor?

The MRBF is probably OK, but I get them from Mouser for eaton brand.
Click to expand...
batteryhookup.com

TE Connectivity EV200AAANA 500a 0-900vdc Tyco 12/24v

These were recovered from EV battery modules. These are VERY EXPENSIVE online. If you have any project that needs a high current relay this is your chance to save some money. Make a cheap 30a BMS into a 500a BMS. This will work for batteries in the 9-36v range so perfect for Lifepo4 and Lithium...
batteryhookup.com batteryhookup.com

PotusGobbleBottom said:
Do you think this is excessive?
Click to expand...

Kind of over board but I tend to build things with a fuse and breakers with fuse slightly higher amp rating than breaker to protect. Got them on inverter and 4 bms The breaker can be reset after fault is cleared. The fuse is back up to breaker.

He made a whole lot of extra connections that can get loose and cause problems.
I mrbf per battery , 2 system anl 300amp, and a t class. I’d chuck the 300amp anl fuses.

He has 1 inverter T class fuse and 6 battery mrfb fuses. Plus 6 bms. He shakes worse then I do - he could be a natural welder. I’d lay money he had a fire. 👍

Friends with trolling motors use them on batteries … they work…..according to friends. The inverter fuse is a must. The battery fuses are parallel.

He could easily run a battery hook up type contactor on each of his bank strings and do away with the cut out switches and 300amp anl fuses. Be my advice. Less connections. I think he is running 12vdc inverter system …. His cables look thin to me.
 
robbob2112 said:
This is what I ordered, it has shipped.

View attachment 213105
Click to expand...
These arrived today. I won't be able to fiddle until tomorrow until then. But, they are hefty and a very heavy duty built.

The casing on the fuses are ceramic and the end caps are nickle plated. The holders are also heavy duty built. When it is inserted it takes a flat screwdriver to remove them from the holder. There are tabs on the front which probably match up to an extractor which I will hunt for if I use them.

The AIC is considerably higher than for class T but I didn't look for time vs current curves yet. But unless they are crazy I think this might be a very low cost alternative to class T.

When I test I'll hook up meters and check resistance as they heat up then see is they blow close to the rating. It looks promising though.

And when I blow them I'll cut them open to see what is inside and how they were constructed.

Will make a video of the actual test when it blows so I can review and get the time things.

Will post that to youtube so it is accessible, I don't have a channel or want one so not sure how to do that anonymously. Any pointers?


This is the link

This is the removal handle
 
Last edited:
robbob2112 said:
Will post that to youtube so it is accessible, I don't have a channel or want one so not sure how to do that anonymously. Any pointers?
Click to expand...
I'd use a different service but I don't have any to suggest.

Thank you for taking the time to test something different for the community.
 
D71 said:
batteryhookup.com

TE Connectivity EV200AAANA 500a 0-900vdc Tyco 12/24v

These were recovered from EV battery modules. These are VERY EXPENSIVE online. If you have any project that needs a high current relay this is your chance to save some money. Make a cheap 30a BMS into a 500a BMS. This will work for batteries in the 9-36v range so perfect for Lifepo4 and Lithium...
batteryhookup.com batteryhookup.com



Kind of over board but I tend to build things with a fuse and breakers with fuse slightly higher amp rating than breaker to protect. Got them on inverter and 4 bms The breaker can be reset after fault is cleared. The fuse is back up to breaker.

He made a whole lot of extra connections that can get loose and cause problems.
I mrbf per battery , 2 system anl 300amp, and a t class. I’d chuck the 300amp anl fuses.

He has 1 inverter T class fuse and 6 battery mrfb fuses. Plus 6 bms. He shakes worse then I do - he could be a natural welder. I’d lay money he had a fire. 👍

Friends with trolling motors use them on batteries … they work…..according to friends. The inverter fuse is a must. The battery fuses are parallel.

He could easily run a battery hook up type contactor on each of his bank strings and do away with the cut out switches and 300amp anl fuses. Be my advice. Less connections. I think he is running 12vdc inverter system …. His cables look thin to me.
Click to expand...

Ordered 2 of them to play with. More fun in the sun.
 
Does anyone have recommendations on Class T fuses and holders to use? I have two 48V 5kW batteries right now, but will eventually expand to six (30kW total).

I'm assuming I want 300A Class T fuses? I'm using the mega fuses right now from victron which don't seem to be a good idea from what I've gathered in the thread so far.
 
Travis55 said:
Does anyone have recommendations on Class T fuses and holders to use? I have two 48V 5kW batteries right now, but will eventually expand to six (30kW total).

I'm assuming I want 300A Class T fuses? I'm using the mega fuses right now from victron which don't seem to be a good idea from what I've gathered in the thread so far.
Click to expand...
Blue Sea are usually what’s recommended and what boaters (who have even a greater fear of fire) usually use. Not sure on your amperage needs. I used 300A breakers (along with 250 A MidNite breakers), with amp ratings base off a bit of discussion here but mostly base on the folks that sold me my BMS units. But that was figured for 8x 230A 48v batteries (will be adding four more) with a max continuous draw of 24 kw. I suspect the size of the fuse would be dependent on inverter capability and number of batteries. But I am not 100% sure on this and someone that’s much smarter than me should and will chime in (not sure why I am even giving my two cents lol).
 
People used to recommend that each battery should be set up to handle the max your system can charge/discharge. My Solark max charge discharge is 185 amps so I used 200 amp class T fuses for each battery.
But now I am reading some people recommend using smaller class T fuses for systems with multiple parallel batteries. My system has 5 batteries so each battery might see 50 or 75 amps max when they are all up. I'm wondering if it would be safer to use smaller fuses like 100 amps or even smaller since it would be very unlikely that each battery would ever see more than 100 amps even if a couple batteries went offline.
Are there new recommended class T fuse sizes for multiple battery systems? I would really like to find more info about this idea.
 
fuses are not for battery protection, they are for protecting the wiring

use a bms on each paralel bank and a fuse with rated voltage above 60v (16s) for the wiring
mega or t class fuses can be used
 
_voltmeter_ said:
50/50 chance if a fuse can save the paralel bank, it is the job of the bms. the bms save the paralel bank with a chance of 99%

so mr murphy would go for that 1% and the 50% of no chance for the fuse to trip

it is nothing wrong to use class t fuses but rely only on them to protect the battery is not a good solution.
Click to expand...
I was thinking if the current burnt out the BMS components and caused an arc within the BMS. Then the fuse would blow shortly after.
 
robbob2112 said:
These arrived today. I won't be able to fiddle until tomorrow until then. But, they are hefty and a very heavy duty built.

The casing on the fuses are ceramic and the end caps are nickle plated. The holders are also heavy duty built. When it is inserted it takes a flat screwdriver to remove them from the holder. There are tabs on the front which probably match up to an extractor which I will hunt for if I use them.

The AIC is considerably higher than for class T but I didn't look for time vs current curves yet. But unless they are crazy I think this might be a very low cost alternative to class T.
When I test I'll hook up meters and check resistance as they heat up then see is they blow close to the rating. It looks promising though.

And when I blow them I'll cut them open to see what is inside and how they were constructed.
Will make a video of the actual test when it blows so I can review and get the time things.

Will post that to youtube so it is accessible, I don't have a channel or want one so not sure how to do that anonymously. Any pointers?


This is the link

This is the removal handle
Click to expand...


Fiddle time limited - only time for pictures and a couple of measurements with the 1035

fuses.jpg


fuse2.jpg

Turns out I do have a Mega fuse.


The Chints are HUGE compared to the Class T fuses but they have much higher AIC.
This is the link


This is the removal handle


Resistances in order

200a Chint - 0.35 mohm
300a Class T - 0.22 mohm
200a Class T - 0.88 mohm
125a Chint - 0.20 mohm
100a Mega - 0.50 mohm
200a Breaker - 1.48 mohm - brand is "Red Wolf" off amazon


All measurements taken with 4 wire leads on the ends of the actual fuse. I did measure some of the resistance on the mounts end to end with the fuse but didn't record the reading.

My plan is to run as many amps as I can put through them with a clamp meter to monitor and the 1035+ meter to measure the resistance and how it changes over time.

And if I can find a 3rd set of hands I'll also use the trusty Fluke to measure voltage drop across the fuses.


The 1035 is a mico-ohm meter that measures resistance with a 1kh sine wave verse the standard straight DC current measured by a voltage divider network.


I won't blow the Class T fuses, they are just to spendy, but I will blow the anl, mega, and chints to see how they work out.

I'll use a ceramic heater with fan and a heat gun as loads to blowthe fuses. I have a 2000w inverter and a 1200va victron and will probably have to put both on a bus bar to make it work. I do also have the victron smart shunt to measure the current as well and it should retain the graph as I turn things on.


Will draw up a diagram of what I am doing and post.


Also, I think after this post I will either put the results in a Resource or a separate post by itself.
 
Last edited:
robbob2112 said:
Fiddle time limited - only time for pictures and a couple of measurements with the 1035

View attachment 214918


View attachment 214919

Turns out I do have a Mega fuse.


The Chints are HUGE compared to the Class T fuses but they have much higher AIC.


Resistances in order

200a Chint - 0.35 mohm
300a Class T - 0.22 mohm
200a Class T - 0.88 mohm
125a Chint - 0.20 mohm
100a Mega - 0.50 mohm
200a Breaker - 1.48 mohm - brand is "Red Wolf" off amazon


All measurements taken with 4 wire leads on the ends of the actual fuse. I did measure some of the resistance on the mounts end to end with the fuse but didn't record the reading.

My plan is to run as many amps as I can put through them with a clamp meter to monitor and the 1035+ meter to measure the resistance and how it changes over time.

And if I can find a 3rd set of hands I'll also use the trusty Fluke to measure voltage drop across the fuses.


The 1035 is a mico-ohm meter that measures resistance with a 1kh sine wave verse the standard straight DC current measured by a voltage divider network.


I won't blow the Class T fuses, they are just to spendy, but I will blow the anl, mega, and chints to see how they work out.

I'll use a ceramic heater with fan and a heat gun as loads to blowthe fuses. I have a 2000w inverter and a 1200va victron and will probably have to put both on a bus bar to make it work. I do also have the victron smart shunt to measure the current as well and it should retain the graph as I turn things on.


Will draw up a diagram of what I am doing and post.


Also, I think after this post I will either put the results in a Resource or a separate post by itself.
Click to expand...
How about source web links to those fuses and fuse mounts?

Watch this

~3:30 mark watch Will Prowse test a T class fuse. 🤣

 
OffGridInTheCity said:
Inadequate wall thimble for generator exhaust. The idea was to store/run generators from in the shed for shelter and noise abatement. And in fact, I ran the generators every other month for over a year and all seemed OK. The exhaust didn't seem that hot after 5 feet of exhaust pipe - I could pass my hand thru the exhaust.

On the day of the fire, I did a 40min generator run around noon, finished, and visually checked things - all seemed OK. However, it appears a smoldering fire was started and broke out of the wall 12hrs later ~midnight. By 1am the tanks were torching.

There was a formal fire investigation and I learned a few things from the fire folks. For example, did you know that wood can ignite as low as 200F? My research indicated more like 400-500F. Also, wood can slowly char over time from heat and lower the ignition point.

Yikes - DIY has risks and I feel so bad tarnishing DIY'ing with my mistakes.... e.g. inadequate thimble but even more so, not thinking clearly that the outside of a shed wall is *flammable* and propane must not be stored near anything flammable.

And BTW... the Champion 100297 w/74db specs was still causing 70db 5 feet from outside the shed with 2x6 framing, insulation. siding, and double dry-wall! Noise abatement was a failure. Going forward I'm going to spend $ for a Honda eu7000is with 58db and run in the open for emergency power.
Click to expand...
Fire can be tricky, back when I was an apprentice HVAC guy I got called out to service a zero clearance gas fireplace.

They would start it and a little while later it would make a whooshing sound so they had only used it a few times since new. The gas was leaking back in the wall cavity and igniting in the wall, it would burn up the oxygen and snuff itself out. It was chard black with 1/4” of charcoal.

The original installer had hard piped into a wall fireplace valve ran a flex from there in the wall cavity to a 1/2” nipple going into the fireplace, when they hooked it up they spun the nipple twisting up the gas flex in the wall causing a leak.

It was a miracle the house didn’t burn down, it had been like that for about 12 years when I found it.
 
Just to get beyond the fuses and BMS type in the failure discussion, what do you guys think about spacers, shelf deflection and its potential impacts?

I know cheap utility shelves will deflect at about 1:120 at their rated load, so I did some back-of-napkin math and came up with a worst-case spacer requirement of about 1mm between cells (assuming 50% compressibility) for a single row of 16x280Ah cells on a 48" shelf. A 1,000 pound rated shelf seems to really be the minimum suitable for cells when you factor in some compression and standard 0.5mm spacers.
 
robbob2112 said:
My plan is to run as many amps as I can put through them with a clamp meter to monitor and the 1035+ meter to measure the resistance and how it changes over time.
Click to expand...

The way I make higher AC amps is wire a transformer as either isolation or auto-transformer, use a breaker (fuse in your case) to short out the LV secondary windings, connect primary in series with resistive load.

480V windings in series with 120V windings delivers 5x current through device under test, e.g. 1800W 120V space heater draws 15A, breaker being tested sees 75A at 24V. With low enough resistance load it should be possible to get over 1000A and fast-trip a 200A breaker, with 200A circuit and 25kVA 240/480 to 120/240V transformer.
 
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