désolé pas parler anglais 
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Yea I thought something was funky when you were only charging at 420W. How loud of a fan we talking about? If it’s negligible, I’d personally go with 10A. I think the 15A would require way too much re-design at this point…but 15A would also be nice…
I think when it comes to a professional product factor, sacrificing some amperage for a more controlled and quieter machine would probably be best.
Whichever you choose, I’m in for one.
2 Likes
I ordered one to test.
That’s the point : sacrifying a feature for satisfying another one.
To choose, both features need to be compared and prioritized.
Regarding the initial specifications of the product, I think I’ll go for 10A@12S over the “quietness”. 
2 Likes
@Pimousse I think this is awesome!! Pitty I’m going high ( on voltage 
) is there a way to reach 16s or even 20s?? I would like to use it for the FOCer vesc
A 19S version could be possible but only at 5A.
But as I said,
1 Like
I will patiently waiting, well that’s not true, but I will wait :).
Sorry I was too excited and I didn’t read the whole tread.
Thanks
Why not go with a larger fan so you can lower the rpm to keep it quiet and still get adequate airflow?
The fan is integrated into the PSU casing. That would require a lot of modification.
Actually, it’s not that loud ! I’d say it’s even quieter than my regular CCCV chargers.
Whaoww Whaoww Whaoww Whaoww Whaoww from the great mister P. Bravo and especially thank you Clem. You’re a pioneer in the field…thank you.
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ShartCmarger?
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Just call it the PimCharger
2 Likes
and 12v too… charge off your car battery
This one is planned.
2 Likes
UPDATE
I work almost daily on this project. Here are some updates.
Electronics
I designed a PCB on which I could fit the tiny MH-ET LIVE module based on ESP32
I received a couple of them and started testing them.
I encountered LOT of issues ! Which is quite weird since it’s the same module used by @janpom in his Davega X… working flawlessly.
I tried almost everything to fix the power issues, but nothing was satisfying enough.
The 5V- 3.3V buck converter is definitely to weak to handle the load when wifi is initializing.
I never had a single power issue with my current module (but it doesn’t have the right footprint and is a bit expensive).
So after tearing out last hairs remaining on my head, I decided to go with my own module.
Yes. MY OWN.
I found some reference designs and other schematics.
This took some time. Meanwhile, I talked a lot with eriders friends + read the forum.
I ended with integrating CANbus (even if I’ve no single idea how to implement it in the code 
).
Here we are :
(easyEDA misses some models to complete the 3D view)
This is the first time I go that far into PCB designing.
I hope I won’t need to do too many rework.
As you can see, I omitted the USB port for saving room and money.
The FW updated is OTA so no need of it in a daily use.
Hopefully, this module will fit 3/4 of the product range.
Product Range
In order to clear my mind, I built a product range :
12S@10A will be able to output true 10A @ 50V (thus more at lower voltage).
For the moment, I focus on the 12S@10A but the 12S20A is quite the same (only adjusting the casing).
Power supplies
I received 600W and 1200W power supplies for respectively 12S@10A and 12S@20A.
I checked the noise level of the 600W (with fan always running).
It’s bearable. I’d say that it’s even quieter than all my chargers.
I measured it with my phone (and a dB meter app), I’ll posted them if you ask for it (I don’t have my notes presently 
).
USB charger and safety
I also decided to change the way of powering my module. Instead of powering it with from USB charger, I’ll use a 90V to 5V DC-DC converter.
Why ?
Simply for adding a new safety feature.
In case of power cut (or user switch off), the main power supply has an inertia (voltage decrease) that doesn’t have the USB charger.
In other words, the module switch off immediately without having the time to tell the DPS to switch the charge off.
The inertia will be for both now, thus allowing the module to put everything in safety before powercut.
Still have to check it out under heavy load.
The downside is that I need to design another PCB for embedding the DC-DC converter and the USB outlet.
Safety first !
Thanks for reading !
13 Likes
I’m very curious about the custom ESP32 PCB. We’re working on a very similar concept with @linsus for the next iteration of DAVEGA X. Or, more precisely, @linsus is working on it. I just keep bugging him.
I’m looking forward to more updates!
2 Likes
Why have you chosen to only go to 12s? 13s would be awesome for the low voltage charger…
I didn’t choose it 
It’s a limitation of the converter module (DPS 50xx = 50V max).
1 Like
UPDATE
Hardware
Main PCB and Power PCB have been ordered.
As mentioned earlier, the plan is to produce 2-3 pre-production units batch.
I cross my fingers that my HW design will be not that bad (I know I can’t avoid at least minor changes).
I did back and forth changes because of the lack of components of JLCPCB SMT assembly service.
So I went back to some THT components which add me some work for the assembly process. 
Software
Power limiting is up and running.
This allows to put higher amp at the beginning of the charge (as the voltage is low) and is decreased slowly to keep the power at its limit.
An animation is displayed on the screen to warn the user about this state.
Values auto-refresh on Web app is now working.
Only values are refreshed (through lite JSON packet), not the whole page. 
But still it crashes randomly because of web server memory over flow.
Working on it.
Testing
I’m hesitating to invest into an electronic load and oscilloscope to perform more advanced tests.
That’s very expensive altough it may save me lot’s of time and money by identifying issues that would lead to replacement or refunds if not fixed before going into production.
Stay tuned !
22 Likes
Thank you so much for building this!
If I may add a wish: Could it be possible charge up to 20s LiPo/Liion instead of 19s? This would make this charger also useful for 72V ebike batteries.
TBH, that would be a deciding factor for me.