This is an alternative to the xiaoxiang app called Overkill solar.
The xiaoxiang app showed the same data though.
Probably gonna replace it
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It just seems odd that it wasn’t throwing an error or something. All your balance connections are glued or taped in place? Could one of the balance jst connectors have been loose but you didn’t notice ? That’s all i can think of, it does look like everything on one was missing but im not certain. Could test it and silicone or hot glue them down again just to make sure
Edit, nm that’s 12s right? One connector I believe
One, and it’s in perfect condition. All wires measure the correct voltage
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Hopefully someone with more experience can chime in here with the easy solution because I’ve not see this type of issue before. If it was mine I would order a new bms and shit can that one - no second chances from me anymore. I’ve done my fucking around and my tolerance for finding out is low.
If the app doesn’t see the pgroup then id assume the bms doesn’t see it. I would monitor charging very very closely and make sure it’s balancing only when charging so it doesn’t kill a p group to try and balance it to match one of the ghost groups.
I have a spare bms if you’re interested in not waiting for a slow boat but it’s not an exact match - it’s the 10? To 17s llt smart bms. Just whatever I paid and shipping unless you’re in Seattle area.
The fruit is not included, wont make customs inspection for Belgium
My first battery build with a Kweld! 
Any feedback would be appreciated.
This 10s4p pack with cheap BAK cells was a practice battery for my wifes low powered 250w ebike. The battery will sit inside a frame bag with foam cushioning.
- I used 0.2mm nickel plated steel. The wires were overkill for 25a max amps, but oh well.
- I used a 40a daly BMS with on/off switch
- Kweld settings: 25J. Did a test weld, and the nickel ripped leaving dots.
Step 1: Hot glued all the P groups
Step 2: Added fishpaper dots to separate the S groups.
Step 3: Hot glue all the S groups
Step 4: Spot weld!
Step 5: Add BMS leads
Step 6: Add the positive and negative leads
Step 7: Kapton tape, fish paper, heat shrink
It took me 4hrs from start to finish. And I think it turned out really well for a low powered practice battery
link, this battery got it’s own thread:
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Not bad. Here is few alarming things I spotted in your images:
You can see all this sharp edges on the positive side ? I marked them with red. I always use dremel to make them round and smooth and usually fit precisely with positive terminal (no overlaps). It’s probably harder when you use 2 pieces of nickle.
Here I marked in pink your balance wires. They are bending directly on the sharp nickle. Try to wire them to not touch nickel but if you have to put fish paper under it, few layers. You also don’t need such a thick wires.
This is a THICK wire but thin nickle connection 
Your heat will concentrate in the middle where 3 pink arrows touches. You should distribute it. Best way is to solder wire directly to nickle like I painted in green. This solder connection does not look encouraging but maybe it’s not that bad.
This I think is the biggest red flag. You need to put fish paper when green arrow is pointing.
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thanks for the feedback. I’ll keep them in mind for the next build. And I’ll add fishpaper by the positive lead exit area
Oh shit. I didn’t see those sharp nickel corners on the positive cells.
If the deck you’re putting this on is flexy at all you really need to go back in and snip all of those. A quality pair of knippers will make short work of them.
But those will 100% short the pack & likely start a fire if this battery sees a decent amount of usage.
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Thx for the tip. Set my DV4s 45 A per side and the thing is like a rocket on dual 6374 motors
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Hi! Does anyone here use JBD BMS? Why it is “only” charging my battery to 41.5V, instead of 42V? Maybe it is some settings?
What’s your charger voltage at?
I measured 42V.
I’ve seen that happen a lot. I wouldn’t worry about it cause you’re only losing like a single percent of battery capacity and it is a bit healthier for the battery to just keep it like that.
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It might have charged to 42.0V.
Every pack will settle back down in voltage a little after charging stops. This is normal and as @Akbrock47 mentioned it’s only a tiny drop for your setup. Your pack is fully charged. 
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Looks like the battery will be decent, but i’d be watching temps on that xt90 while you weld. Xt90 got way too hot for me to be comfortable with, qs8 was MUCH better
Kinda put together spontaneously so likely ill revisit connection out.
Have a float charger too so will hopefully do well. If i end up swapping out to something else later ill get some solar panels for the shed and use it there. Id be pretty happy if i could mostly run my shed off the sun.
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Yep keep the battery fully charged all the time, i leave the charger on even when im welding
The correct float voltage for a lead acid AGM battery is very important to their longevity.
Ideal float voltage is influenced by the battery temperature, state of health, and any loads which might still be on the battery while it is being floated.
Floating too low a voltage will allow slight discharge to occur, even if float voltage is well above resting OCV, and more so if there are still loads on the battery whilst being floated.
When I have floated my AGM’s too low, and then manuLly boost voltage back to absorption voltage, the amperage required to achieve the ~14.4v, and how long it takes that amperage to taper to 0.05c at a constant 14.4v indicates the battery was discharging while being floated, but float 0.15v higher and it nearly instantly tapers back to 0.05c at 14.4v.
Different AGM manufacturers will spec a float voltage, at 25degrees Celsius, from between 13.2 to 13.8v, and lots of maintenance chargers designed for flooded lead acid might only hit 13.1v, and some will be 14v, so double check, and use a dc clampmeter over one of the leads, so you can see how much amperage the battery is accepting at the voltage the charging source provides.
Lead acid batteries are petulant in regards to achieving excellent Longevity from them.
I would have loved to be able to monitor individual cell voltages when living off grid, but with AGMs, one has to rely on voltage, and how much amperage is required to achieve that voltage, and how long it takes amperage to taper to low levels, at absorption(not float) voltages. Judging lead acid performance while discharging is how much voltage it can maintain under the load, and for how long it can do so.
And then, when rechargjng, does it take 106% of the energy it discharged for amperage to taper to 0.05c over 6.6 hours or 125% over 12 hours?
With Lead acid, achieving max longevity, and max performance, requires true 100% recharges, and few ‘smart’ chargers actually can achieve this, but especially so on a deeply cycled hard working lead acid battery.
99% recharges are half as good as 100%, with lead acid, in terms of achieving max longevity.
…
Regarding spot welding, I dont have a Kweld, just a cheapo welder on a cheaPo Zee 3s 5.2ah 80c battery. My first practice welds showed the hottest part of the circuit was the fake looking XT60 on the 12awg leads coming off the cells. I’d replaced that with Xt90s and then shorter millisecond pulses were required to achieve same weld but the hottest part of circuit was the 12awg on battery side of XT90.
Xt90s as the inrush current on these cheaPo welders helps them to smoke their mosfets prematurely. I now use a small 22ah agm just to power the welder’s circuitry through xt90s, and the lipo through xt90s for the weld juice.
I tried one cheapo welder with a black circuit board, it proved barely capable of welding 0.15pure nickel at max duration pulse. I then tried it on my pair of 7 year old but still healthy 6v Deka GC-2 AGMs, with about 900CCA (when new) on kts lowest power setting and a 7ms pulse, and it tried to drill a hole through the battery can, machine gun style, as mosfets shorted closed. Brown underwear, and thankful for eye protection.
There is definitely a goldilocks zone on the weld battery with the cheaPo spot welders.
I’ve been surprised how quickly my LiPo depletes from 12.55 to 11.9v when welding 0.1copper 0.1nickel plated steel sandwiches with 70ms pulses, just doing one row on a 10s2p battery. I have been disconnecting my cell meter from it when welding for fear of smoking it, and try to keep lipo in 12.0 to 12.55v range, as going lower requires increasing pulse duration.
I’d love the consistent reliability of a Kweld, but cant afford it.
AGM batteries have much lower self discharge than flooded lead acid 2-3% per month at 25c vs 12-15% for flooded, but they still dislike being stored undercharged, and the lower they sit there and the longer they sit there, the less energy they can store and the slower they can deliver what they can still store.
Getting a petulant mistreated AGM, and to a lesser degree, flooded lead acid back to its max potential remaining capacity and performance is almost the exact opposite of what everybody who has turned a wrench on an automobile , will authoritatively tell you.
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