Is a diy battery build still cost effective?
I was pricing some Molicel 21700 P45B 4500mAh 45A cells for 8.15$ a cells (is is cheaper somewhere else?) – coming to $2151.00 to build a pack like these OpenPPG sells at 2199.00. And that was the Bats only, no case and BMS?
Cheers
Set up a patreon to purchase your cells…
Well that is an interesting idea – but I am not a charity case and I dont mean that in a negative way.
Cheers
Yeah I was initially excited about the Molicel P45B, but haven’t been as interest seeing the price of the cells just doesn’t justify the slightly improved performance and reduced internal resistance. I’ll just keep waiting for the next battery tech to hit the market. I’d pay 8.15 $ a cell if it had 6000+ mah and similar discharge performance to the P45B.
If you’re interested I’m selling my setup here:
Available for infos
Batteries have jumped down, the aforementioned P45B example now at $4.85. Recently new kid on the block Tabless AmpAce JP40
Long vid but worth the watch if you’re thinking of DIYing a pack.
The cells are 1200usd with shipping, then you need bms, about 100bucks, then you need nickel, thats bout 80-100bucks. Then you need a GOOD welder with a battery for it thats about 500USD
Thats 1900 dollares and you will need a case, wires, connectors, a good soldering iron and so on. Not worth it. The price of Pauls battery is really good imo.
Absolutely, especially if a one off pack build.
I would love to see the build quality of OpenPPG 4.8 pack. Good value on the surface, what’s inside, seeing is believing.
Cheers
I dont know now – relooking based on lower battery prices
I need 2 4.8packs for my Delta wing to get resonable time up with multiple take offs and landings
So 7k$ Cnd with dutie and tax
Using you additions for a 1 time build with extras
I dont know how many cells needed so I estimated
500 x Ampace JP40 at 4.75 usd — with building extras + duties and taxes , around 5550 canadian
Getting our Asses kicked up here on Exchange so maybe have to weight.
Best wishes to all in the coming new year
In the last two weeks I’ve built two 14s8p batteries with BAK N21700-45D and Molicel P45B.
I’ve paid approx. 400 € (BAK) and 490 € (Molicel) for cells, copper, nickel, wires and plugs.
Only the case is missing. Balancing is done during charging, so I don’t need a BMS inside. The max. current is limited to 200 A by the motor controller.
Nice 
What is the yellow material ?
Cheers
Kapton tape. And below it copper-nickel-sandwich.
That pack is a piece of art! Very nice, good job! 
I also balance charge so no bms, works great.
Hi Stefan, great work! I’m currently building some new batteries. I’m interested in how the pack behaves in relation to the temperature in a case when the battery has discharged 80%. With my cells (15 S/8 P for the competition range), there is no worrying heat development up to around 60%, but then the heat increases considerably up to 80% discharge. It’s not a problem, but I’ve noticed that the higher the cells can handle, the higher the temperature rise, especially towards the end of the discharge. This is different to what happened with Sony 18650 cells in the past.
looks good, have a detail build pics? might have to upgrade my spot welder to do the sandwich methodology.
These pictures are taken after discharging another 7S battery to 39 V (2.8 V per cell, Samsung 50S, which get warmer than the BAK and Molicel cells):
Excellent
Can you share supply links
I found this interesting cooling build. Definately could use some refinement. I would have cap ends with solder copper and used a none conductive cooling just to be on the safe side.
Or go all out and get some fancy dancy cooling tubes, probably not cost effective:
Cheers
Love the large bus bars - assuming diy on those.
The red wires?
Cheers
