diy solar

diy solar

190ah Lifepo4 $590

I bought similar from BLS (aliexpress): 16pcs 130Ah to build a 48v battery. As written above they are shipped in a great package, very well covered, each in a box with foam, and the boxes additional in a foam in the package.
My arrived well balanced, but I did an additional bottom balance (around 2.8/2.9V).
I use them at home with my solar, not sure if I would recommend them for outdoor like marine or RV. They have a alu case with this blue foil, but if you need to pull them in/out I assume the foil does not live long.
I have no capacity meter but comparing the kWh of my charger without a load on an empty battery or vice versa just discharging a full one with constant power without charging they provide roughly the capacity I would expect.
What I like is that the buses are a bit longer as required, so I can arrange the cells in a zigzag with better air flow between each other.
 
I just capacity tested my 190ah.

Bottom balanced at 3.0v, charged at 20A
I achieved 190ah with all cells within 42mv of each other

Final capacity was 193.1ah when cells started to unbalance by 175mv odd with one hitting 3.65

I would like to see how other cells appear once they start getting above 3.5v, as it only takes 1 cell to be out by a fraction to cause large imbalances, the voltage climbs so quickly I would guess even very well matched cells would get unbalanced at the top of the charge cycle.

Anyway, I easily have 190ah usable as I didn't take the bottom voltage down too low, if there's another 5ah there these cells are pretty close to being 200ah

Daly BMS balancing at 3.6v seems to be useless but I am using a 12v wall charger that goes into absorbtion at 10A at this point which is perhaps too high to get them to balance, maybe it will work better under solar.

My thinking now is, use a victron protect to protect the low side, charge to 14v to get 190ah without cells going unbalanced and leave an active balancer connected. These daly bms's seem ok but I did start seeing the voltage creep over 3.65v on the one cell before I stopped the charger, and other people mention they've seen cells hit 2.4v so I don't think they're reliable enough. Plus it's easier to connect big inverters without having to go through the small wires of the bms.
 
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Don't get too excited ,weight seems about a kilo a cell down . 200Ah should be about 5Kilos if full and I see they make and offer a copy of CALB cells ? China Air Lithium Battery Co . So I'd not buy them .lots of frauds going on over there in batteries and there is no warranty worth anything .

Its a punt if you do it and you would only do it because they are cheap. That said I do it often.
They seem legit. As many others have posted. Finishing up tests now
 
I just capacity tested my 190ah.

Bottom balanced at 3.0v, charged at 20A
I achieved 190ah with all cells within 42mv of each other

Final capacity was 193.1ah when cells started to unbalance by 175mv odd with one hitting 3.65

I would like to see how other cells appear once they start getting above 3.5v, as it only takes 1 cell to be out by a fraction to cause large imbalances, the voltage climbs so quickly I would guess even very well matched cells would get unbalanced at the top of the charge cycle.

Anyway, I easily have 190ah usable as I didn't take the bottom voltage down too low, if there's another 5ah there these cells are pretty close to being 200ah

Daly BMS balancing at 3.6v seems to be useless but I am using a 12v wall charger that goes into absorbtion at 10A at this point which is perhaps too high to get them to balance, maybe it will work better under solar.

My thinking now is, use a victron protect to protect the low side, charge to 14v to get 190ah without cells going unbalanced and leave an active balancer connected. These daly bms's seem ok but I did start seeing the voltage creep over 3.65v on the one cell before I stopped the charger, and other people mention they've seen cells hit 2.4v so I don't think they're reliable enough. Plus it's easier to connect big inverters without having to go through the small wires of the bms.
I just got mine in and started testing. Electrodacus sbms default top end cut off is well below 3.65v. I think this could be because of the likely hood of getting unbalanced, as you said. Have you tested further?
 
So a brief update. I've connected and disconnected the battery about 5 times. The other day. One of the terminals came apart. I contacted BLS and they were completely unhelpful.

Anyone know how to fix this.

20200318_140920.jpg20200318_140920.jpg
Dave
 
You should be able to very carefully tap the hole for a larger bolt. Since the hole is so shallow you will need to use a bottoming tap which, you may have to make. If you don't know what it is do a search for it. Use lots of forward/reverse of the tap. Don't try to cut the threads all at once. Make sure you have the right size hole for the tap you use.
 
You should be able to very carefully tap the hole for a larger bolt. Since the hole is so shallow you will need to use a bottoming tap which, you may have to make. If you don't know what it is do a search for it. Use lots of forward/reverse of the tap. Don't try to cut the threads all at once. Make sure you have the right size hole for the tap you use.


Thanks!

now to figure out what to buy and how to do it. family is on isolation lockdown due to severe immunocompromise in my family. could be in this state for a couple of months. Any suggestions for sources on taps, inserts and terminal studs?
 
I saw this style, can't remember brand name, at a truck show and thought they looked like a good product. Better than Heli-coil. Even then in an expensive battery I think I would use a real tap to cut the threads.

Thread insert
 
Thanks!

now to figure out what to buy and how to do it. family is on isolation lockdown due to severe immunocompromise in my family. could be in this state for a couple of months. Any suggestions for sources on taps, inserts and terminal studs?

Dave,

If your going to disassemble and reassemble that battery you might want to go the helicoil route. Aluminum threads will wear far more than the helicoil insert.

If you get a kit you will have to grind the tip off of the supplied tap a bit so it does not go thru the bottom of the terminal while tapping.

Here is a link to a M7 kit at Amazon

M7 Helicoil
 
Looks like you pulled out a helicoil from the battery... I dont like the idea of stainless insert in the aluminum... but it should be ok, if the lugs are clean.
 
Dave,

If your going to disassemble and reassemble that battery you might want to go the helicoil route. Aluminum threads will wear far more than the helicoil insert.

If you get a kit you will have to grind the tip off of the supplied tap a bit so it does not go thru the bottom of the terminal while tapping.

Here is a link to a M7 kit at Amazon

M7 Helicoil


I got an M6 helicoil to stay, but it's not going to hold up for too long. The M7 kit seems like a good idea but I can't find M7 terminal studs. They look like set screws to me and I can only find them even sizes. Maybe I'm looking for the wrong thing. Hard to search for stuff online when you don't already know what it's called. ?

Anyone have guidance? I have no idea how thick these aluminum inserts are. Is M8 going to be a problem?

I agree with the comment about stainless and aluminum. I'm not sure what my other options are though. Interesting dilemma, and my satisfaction with this purchase is not where it used to be.
 
Besides the diameter the big difference between M6 & M8 is the pitch. You will end up with about one less thread for the same depth.

One of the best places for screws of of all types is McMaster Carr. They are a bit more expensive but pretty much have about everything.

https://www.mcmaster.com/grub-screws

Helicoil kit is the way to go with thread inserts. I have had nothing but problems with the Chinese kits Amazon sells. Ended up getting my money back and threw them all out.

A problem you will may have is that the tap is made for going though a hole and not a bottoming tap. To get the tap to cut full threads to the bottom of the hole you may have to grind off the taper.

Helicoil
 
M7 is not common, past M6 only even sizes are common, you'll not find much M7, M9, M11, ... if any.

I would use either a M8 helicoil or an american size helicoil if smaller than M8 but still bigger than your current hole (and as @Opie91 said, use a quality kit from Helicoil or Recoil, not a chinese copy).

Then use a stainless steel stud, hold in place with loctite (that might even be a time to use red instead of blue loctite).

And when you torque the nut don't go past what the manufacturer of the battery recommend or, if you don't have, 5 N.m (normally it would be 6 Nm but I run a simulation with less depth than the standard one as the terminals are very shallow). That's also valid for the other, non damaged terminals.
 
Fwiw. I too bought a set of the 195's 8 of them to be exact delivered to USA/Florida. they have been sitting for about a month now. (project has not yet fully unfolded) the voltages when they arrived were spot on. all the same. even now a month later.? still the same.I also bought 2* 200A Bms's -S Meant to add I would go the Helicoil route too.
 
Fwiw. I too bought a set of the 195's 8 of them to be exact delivered to USA/Florida. they have been sitting for about a month now. (project has not yet fully unfolded) the voltages when they arrived were spot on. all the same. even now a month later.? still the same.I also bought 2* 200A Bms's -S Meant to add I would go the Helicoil route too.
@Dave1 Were you able to repair the threads? Any advice for someone with the same problem?
 
@Dave1 Were you able to repair the threads? Any advice for someone with the same problem?
I have a machining background so perhaps for me the solution was easy. ymmv. But I would consider going to the next closest thread size available no matter what thread that ends up being. Primary reason? you remove the absolute least amount of material from the battery. Use a bottom tap. shoot for the closest size thats popular. then tap the hole. should be super easy as it is lead. take your time. then have also on hand a short stud ready to insert (make sure the bottom of the stud sits flatly on the bottom of the hole you tap). when done 1 of your posts will be larger. but lets face it on these batteries? they are too small imho anyways. -Sam feel free to pm me if you need more details. (FWIW a helicoil is perhaps one of the best solutions but their is more at risk and it will cost more $ as you have to buy the correct kit)
 
I have a machining background so perhaps for me the solution was easy. ymmv. But I would consider going to the next closest thread size available no matter what thread that ends up being. Primary reason? you remove the absolute least amount of material from the battery. Use a bottom tap. shoot for the closest size thats popular. then tap the hole. should be super easy as it is lead. take your time. then have also on hand a short stud ready to insert (make sure the bottom of the stud sits flatly on the bottom of the hole you tap). when done 1 of your posts will be larger. but lets face it on these batteries? they are too small imho anyways. -Sam feel free to pm me if you need more details. (FWIW a helicoil is perhaps one of the best solutions but their is more at risk and it will cost more $ as you have to buy the correct kit)
So you recomend just going up one size and re-tapping for a larger screw? In my case I would go from a M6 to M8.
 
So you recomend just going up one size and re-tapping for a larger screw? In my case I would go from a M6 to M8.
Yes, Or a 5/16 x 24 I'd go to which ever is closer. a #12 is actually closer but not as common. Also you need to see how your hole tear out looks. decide from their.
 
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