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Cell monitor
"Pulling leg" ??
The Ultimate DIY Solar and build place
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(03-08-2019, 08:08 PM)daromer Wrote: "Pulling leg" ??

10 s was the second time i asked, the other one was the BMS, remember ? ( i bought that btw).
So, i asked the same, with a twinkle in the eyes, and you didnt fall prey.

Invincible, really. I raise my hat.
1 kWp in Test
4 kWh battery target - plus Mobile Home battery
Ultra low cost
Electronics ? No clue. Am machinery engineer.
Sorry, dont follow at all.
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 |  66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
(03-08-2019, 09:32 PM)daromer Wrote: Sorry, dont follow at all.

It's a turn of phrase that likely doesnt translate well
(03-08-2019, 05:41 AM)Dallski Wrote: Did you spot weld first and then solder the fuses on the bent nickel strips? Or did you leave nickel strips on from cell recovery? I'm talking about the positive side. Just curious as that's pretty ingenious and I wish I thought of that.

Im not really sure i could recommend the way i did it, it was kinda labor intensive:

1. bend nickel strip using a form
2. holding the bus copper and nickel strip over the cell spacers, line everything up, and temporarily tie the strip to the bus using copper strand. 
3. solder nickel to bus (for positives), then remove tie wire (where it isnt soldered in too much).
4. weld positives, alignment was really really good. so far so good.
5. cable tie both grids together (not too tight)

6. cut nickel strip for the negatives in 15mm lengths, punch a small hole in one end to house the fuse wire. Bend to 90 degrees
7. weld negatives
8. bend negative strips back on themselves, using a small wood slither (maybe 2mm x 8mm x 20mm),
9. cut fuse wire to length, and make a small hook on one end. Insert hook into nickel tab, make another hook on the other end, and using the springiness of the fuse wire allow both hooks to hold the fuse wire in place. Then solder the two ends, which goes super easy and fast.
10. lastly solder the fuse wire to the bus. I used a combination of locking tweezers to dissipate heat, and small wooden wedges to lift the bus of the cell spacers. Worked ok once i got the hang of it.

At step 2 dont try to solder one at a time, the alignment becomes almost impossible. Also soldering one, melts the adjoining one, so the tie wire helps with this and or locking tweezers to shed heat. At step 5 i realised some cell spacer intersections dont cable tie too nicely. Bodge required here and there. At step 8 i realized the protruding fuse wire might take an alternative path to the cell and i so added the red insulator offcuts to prevent this. God i was glad when it was finished. Gotta be an easier way.

Thanks for the ideas guys.
Wow, that's a lot more complicated than I thought it would be. I was thinking that you could use the nickel strips that are already on the batteries you reclaim and fold them for soldering. Would eliminate gassing (holes caused by removing particularly stubborn nickel strips, like from e-bike packs), as well as keeping the heat away from the cell during soldering, while also saving the time it takes to remove nickel strips.
chargery bms16 (cost 100) monitors all those parameters and also triggers relays to stop charging. All the parameters are programmable.

If you just want over/under alarms the Tenergy Intelligent Cell Meter Alarm Digital Battery (cost 11 dollars) you need 2 of them because they are 6s. I use these and they work good.

Tenergy Compact Cell Meter 
can display total voltage. For 1S-6S LiPo/LiFePO4/Li-ion  battery pack, it can display: total
battery voltage, individual cell voltage and  the difference between the highest and the 
lowest individual cell voltage.
Battery Alarm For lithium-based batteries, Tenergy Compact Cell Meter can be  used as an 
over-charging / over-discharging alarm. It emits a loud beeping sound  and its LED flashes 
brightly when the battery’s voltage rises above 4.22V, or  drops below an adjustable 
threshold between 3.0V and 4.0V.
Flight Time Tracker With Tenergy Compact Cell Meter’s lightweight and compact  design, you 
can mount the unit on your RC helicopter/plane, and during its  flight the alarm can inform 
you when the battery is in need of charging.
Easy To Use Tenergy Compact Cell Meter can read the status of your battery  automatically as 
soon as they are connected. Its simple control makes it  suitable for users at all levels.
LCD screen Easy-to-read LCD screen lets you view your battery’s status at a  glance.   

another one I used is the isdt bc-8s (cost 20 dollars), but this one has a lighted led screen it uses more power then the tenergy

"The BC-8S is also equipped with a number of alarms that activate a beeper as well as flashing 
red lights when triggered. A high voltage alarm, a low voltage alarm, a voltage difference 
alarm (voltage difference between cells) and finally a location beeper alarm for finding lost 
aircraft. All of the aforementioned alarms have user definable parameters."


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