I would like to be able to find the gerber file of v4.40 to be able to order the modules from JLCPCB
Thanks
[DIYBMS_Lishen_v1.4_VB.zip|attachment]
not quite sure on the policy, hope Iām not doing anything wrongā¦
thatās @Jau work with two additions:
A. jumper to disconnect board for programming without having to physically remove it (as suggested by @Andrew_Congdon a week ago)
B. added the breakout thermistor that hopefully can be stuck on the side of the prismatic cell
normal disclaimers apply, havenāt built and tried it!
EDIT: found some issues on the PCB, donāt do anything with that!
V.
Just remember that all the current for balancing will be going through the 1 or 2 jumpers. Normally they should be considered to be rated for about 1a at max each.
My thinking wasā¦ if you have a 16s battery and you consider the top cell the positive might be 53V and the negative ~50V. This made me think you only need to disconnect the negative terminal but I guess you really need to disconnect both? Iāve converted the project to kicad and added a jumper. The boards are on their way from JLCPCB so I can test them. As the jumper is only going to see 1A at 3.5V I think it will be adequate but of course can be modified if someone has a better idea.
not an el.engineer, have to admit I lost you thereā¦
I expect the reprogramming will take place on a notebook with a usb connection to the whatever board which will be mounted on the modules. So I assumed voltages will be floating no common ground between the notebook and the module meaning just opening the circuit to the battery terminals should be enough. I expect that both connection cables to the neighbouring modules will be also disconnected.
am I missing something?
anyway easy to add a couple of jumpers on the minus side as well!
Final Q, where would you fit the external thermistor on the prismatic cell?
I need 8S expect to have 4 and 4 in one squarish box. With the cells flipping positives and the need to compress them (probably use thick plywood and through bolts) means on each cell thereās going to be only one side accessible. Only the one will be by the positive the next one by the negative pole.
Is that OK or values will be skewed?
IOW, is this extra thermistor going to be of any use or is it waste of time?
cheers
V.
In the future youād like to be able to programme the cell modules with the controllers built in programmer.
Thatās the issue with the common ground.
Youāre trying to avoid dismantling the battery just to reprogramme the cells which youād still need to do with a laptop programmer if you canāt disconnect the cell from the module.
The i2c should be isolated so you shouldnāt need to disconnect them AFAIK.
My ambient temp is 10-40C and that is the more relevant temp you want to measure with these cells and take action if the cells get too hot or cold. Iām lucky thatās not likely to be an issue for me at my location.
Iāve put my cells in an acrylic box with holes cut for ventilation and a couple of NTC with similar properties to the SMD device and looked for indicative locations in the box.
thanks Andrew,
well initial plan was to put this EVE280Ah 8S in the engine room next to the trojan FLA bank. Temps easily reach 45-50 when engines are running for a few hours in the summer, so looks like Iāll relocate them above under the salon sofa.
Havenāt looked at the code yet, but if you have two ntc s one onboard the module and one stuck on the side of the prismatic cell, top one stays under 40, side one goes up (and due to air circulation the one onboard the module hasnāt picked that up yet) do you have different policies for them, or same thing like:
if either or ntc is over 45 do this
do you know?
attaching latest attempt with jumpers on both sides:
cheers
V.
After all. Idea to make a carrier PCB with 440 module above it, was not so bad IMHO.
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According to cell specs charge temp 0-55, discharge temp -20-55.
Youāre not worried about module temp since the PWM code will limit the discharge rate according to temp.
I was suggesting you donāt need an external NTC per module, just a couple per battery.
Someone else was reporting JLCPCB are now charging extra for the NTC board.
Sounds like you might want to consider forced cooling of the battery case controlled by the external temp sensors. The old controller can do that too.
yep, just not sure how the temp of a discharging battery develops.
Saw that mentioned, however I got my designs in JLCPCB and they donāt charge anything extra for the breakout NTC board, so will probably keep it, extra cost is the extra NTC chip, dunno few centsā¦
Being on a boat, not particularly keen on having forced salty wet air moving around tbh.
I guess itās a suck it and see situation, hence having the breakouts, may use them may not.
Planning on a fairly conservative charge/discharge plan anyway since I manage to survive with much less than 100Ah on a daily rate in the summer.
My main issue is getting the attiny841-ssu chips (Farnell has them!) and building the ESP32 controller board, that is much harder atm and Iād really like to test the victron canbus connectivity to a rpi. May have to spent a few days and nights working on it, impossible without the board though 
cheers
V.
well, even my modified version of this board was flagged as being two boards in one design by JLC staff. 11usd more for 10boards. Just a warning, could remove all perforation but then you should need a dremmel to carefully cut them and doesnāt seem a v.safe way of going ahead with this.
for the record, I just checked the specs of EVE280Ah cells Iāve ordered, and post spacing is 123mm and not 89mm!!!
V.smart considering 10boards shipped from JLCPCB today
this is how a 123mm spacing looks like!
will end up fabricating short stubs to bolt the one side of the pcb to the terminal.
V.
Mine that are Lishen 272 ah if they measure 89mm and now how will you do it, letās hope they are worth it.
Greetings
will source some brass flat section and half a dozen brass studs, cut/drill/weld and create small connectorsā¦
unless someone else wants them and I order new ones. we shall see, first I need to get them, solder the ATtiny and test them all, then weāll see. Batteries wont be here before Jan anyway
ok we are in contact
I have just looked at the technical sheet of the EVE 280ah batteries and I see that the distance between terminals is 90mm I send you the fileEVE_280Ah_DataSheet.pdf (685.7 KB)
solved by going a size up and getting the 304Ah version of EVE cells which have 90mm terminal distance 
only two months now for delivery (fingers crossed!)
Letās hope youāre lucky now, do you already have the modules?
not yet, FedEx says Wed (currently in BE, should be ok)
boards arrived, cannot claim that iāve done a stellar job fitting the ATtiny chip using solder paste and hot air for the first time in my life, but it looks okish. the right hand side looks v.bad, it isnāt itās the lighting:
Hope tomorrow to have a couple of them and a controller board ready to test coms. Will report when itās working.
Mind PCB is really hard almost impossible to cut the thermistor along the preforation. Much better the newer version with a cut along the length of the PCB, and two groves that a dremel will fit and cut across.
cheers
V.
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