If you have 2x6s than yes you could charge each pack individually with a 6s hobby charger but you should match always the voltage of the packs.
If you get 2x6s packs than yes you could charge it just like the lipos trampa does.
I assume your battery builder will wire the balance wires and adapters for each pack like it would be on a 6s lipo pack and yes that would than also work with the charger trampa sell or recommend on there website.
That’s how my packs are wired up for charging with a smart bms (smart bms gives you the opportunity to check each p group voltage via app and adjust cut off and other parameters)
Legend, thanks mate you just solved all my problems.
I do like the thought of the smart BMS as the battery builder mentioned he can supply them and they work quite well. I think I might have a mull over going the Graupner charger vs. BMS + brick routes over the next day or two and then get in touch with Trampa.
The smart bms is cheaper and you can get different brick charger but balancing takes longer than with the graupner or ultra charger.
Both ways will work for it, so don’t overthink it
This might be a silly question, but is it possible to pull the entire current from the battery straight throught the nickel strips, or do I need some kind of hub going through to be able to carry all the currrent? I’ll be using 8x0.15mm nickel strips and will probably double up every connection.
Also second question: why not use copper strips with higher conductivity inseted of the nickel plates?
People have found it much more convenient to solder strand wires rated at higher currents rather than having to stack the necessary amount of nickel plate. The nickel plate method is more time consuming and opens up to more possibility of failure in the way of broken welds. It is also my understanding that the difficulty of welding copper strips outweighs the benefits. But this is just what I’ve gathered, open to more insight.
On my pack intended to draw 160A, I doubled up the nickel and soldered 8AWG solid copper across all the P groups, and used 2x 10AWG silicone wire to connect the P groups with 8AWG silicone for the main leads. Soldering the solid copper across the P groups was probably not the best for the cells, but they seem to be fine since voltage drop is super minimal, capacity is great, and everything is in balance.
To answer my own question, so others can learn.
after few emails with Bestech, I made video for them checking voltages on balance wires. voltages were 3.44V except two groups where they were lower. and Bestech’s answer was if I am using LiFePO4 cells?
after that, I have replaced faulty bms with exactly same D140 (same Batch like faulty) and everything is okay, no heating. still have to try charging it.
In conclusion, yes, bms was faulty out of the box and I still have to convince Bestech that I have nothing with it.
Has anybody tried this BMS? Do you think it is possible to bypass the discharge? I ordered the 20a version (maybe a stupid decision) because it’s the cheapest, in hopes of being able bypass it.
Also follow up to my previous question: how many of the 8x0.15mm would i need to handle the full 75a of a 12s5p battery?
There’s a zillion of bypassed diagrams on the forum. Nothing special about this one. Just use the search button. You connect the VESC(s) directly to the battery as if you didn’t have any BMS. You only connect your charger and the battery to the BMS. That’s it.
Thank you for the information @moon, I am not sure if I want a kwelder, I am more interested in a Sunkko, but there are so many different models, what is the difference on them ? 737G or 788H or 737U.
And I couldnt find the malectrics.
There must be a good, reliable and affordable option? As soon as I get started I will definitely make a battery building thread on my process.
Please correct my confusion. I am having some trouble understanding why people use 12awg and higher awg wire for series connections in 4p setups if 12 awg is only rated for around 20 amps. I’ve seen many 4p builds utilizing 2 12 awg wires to bridge series connection, but assuming 80% total retained capacitance, such a set-up will only be rated for 32 amps.
Assuming one uses 20A cells in 4p, shouldnt the series connection be rated for 80A?
The confusion may come from the fact that many amp charts use a minimum wire length of 1 meter or more (i have seen 4m min on some charts)
Since inside a battery pack the runs are very short, you can run more current and still stay cool. Heat is the enemy in this case as heat creates resistance which creates more heat…
