AEVA Forums

Well i have persuaded friend Matjaz who is programmer to write me a simple program interface. It takes hex values from txt file and translates them in mV in CSV file with semicolon separator. That way excel just opens the file and you are making pretty graphs of your cell values. Be sure that you pu...

Hi long time since ive been on this forum :). Yeah this inverter looks like DIY project because Johannes is a software guy not a machinnist. But inverter works i can assure you with my 370Vdc 300A system that works now a year and cca 30kKm. Heh once i even drove on 2 phases home due to my stupid mis...

This topic hadnt had an update for some time. Last couple of months i was thinking of designing a new concept BMS for my LiPos that are packed 8S. Well not one DIY BMS todate has ability to monitor 8S packs in one PCB. There is always a limit like 32V Vmax for controlling chip etc... So i thought wh...

Neville Can you advise me on sth? I have built another BMS system for my LiPo cells. It works fine and can protect cells while charging and regen etc... However there is one limit onb theese cells - 270A max! While i use them normally on highway i burn 100 - 200A. But when i enter highway or climb h...

Hi all! My friend and i bought each a set of LiPo cells to put in our cars. He keeps them as primary movers but i use them as range supplement in parallel with my LiFe pack. We messed about with voltage sensing ADC and came out with reliable software for use with LiPos. Those modules now go up to 4....

Excellent work Astroboy! I cant wait to see your LCD code improvements... Have you come up with a current measuring module then? Also my BMS works great and has saved my cells a number of times from my own stupidity :(... The last time i assembled one cell wrong and when i started to drive system we...

I have found this BLDC motor that can produce 10kW nominal, either out or in. http://www.goldenmotor.com/eCar/HPM96-10000Curve.pdf I would load this with 3phase bridge, capacitor and battery on other end. No controller needed. You think it would produce 147VDC at 4000RPM? The other one i found is 12...

Yes I am thinking of using honda GX690 or other V twin industrial engine. This should give me some 15kW of power. Generator i havent decided yet. I would need either 400VAC normal triphase output with my 12kW charger or 92VAC output that i would rectify with six power diodes and cap bank to create s...

It's surprizing how many folk consider a genset in the early days of thinking about an EV conversion (me too) then don't go ahead with it. I'm not saying you haven't thought about it so I could be quite wrong but... A 15kW genset would require either it interfaced directly to the controller or batt...

Ouch! Neville, i am aviation engineer as well as glider pilot... I spent my share of time at gyros though and have to disappoint you. They are exellent DIY machines and very safe providing you use them for what they are made - recreation flying. However i dont believe you could convert one to electr...

Heh I would choose a larger comfortable car this time. With A/C, warmed seats, sunroof and servo steering. I am eying BMW 520 or 325. Also i would eliminate transmission, since it takes cca 3kw of power just to turn wheels! Cells i would make the Tesla way, out of panasonic 18650 cells. I got a good...

I was thinking of a celltop module that does the normal voltage and temperature measuring but also interfaces to the hall effect device so it can also measure the current. So all communication (including SOC resets) would be over the existing BMS comms link. As i said i dont think normal module wil...

Huh that is not a bad idea actually. LEM would be mounted on a side PCB powered by 12V. Optocouplers would be used to output signal to cell comms for isolation. You could also use a boost converter to fully supply 5VDC from one cell. Only i dont know how much it drains. You dont want that cell unbal...

Hi Nevilleh What kind of Hall sensor did you use? LEM module? I saw you made a circuit that uses only single input on PIC16F. As i recall there is now RA0 pin unused in your design since you autotimed the LCD. I seeyou use exactly the same pin with your Ammeter... My question is could this be used t...

I must agree with Neville. System now works without a hitch for 23000Km now. It monitors charging and keeps charger low when balancing and in the end it takes the charger off. What more could you wish for? Maybe only more effective comm port dump. I would like to save data to .csv directly in ascii ...

Hi 4springs

I made one more master and cell board and would like to test your software before i put it in my car. I never used XC compiler before. Can i compile your code with my CCS compiler? Is there anything special with your program that i should know of?

tnx

Arber

Hah, this is what i noticed with original code also. When i start master and connect input line first modules that were connected start balancing, while others that are connected later dont. I tried to put some delay in program init but didnt work. Then i simply built in a reset switch that cuts pow...

My appologies You are correct. I seem to have changed from SMD to DIP on my boards, but here i had enough room to have LM connected level. But on your PCB i had to change to vertical placement since there was no room. It seems i connected the wrong pin. DOH! Good that you found out. I will try to co...

I dont think it is the celtop modules. Have you tried checking the masterPCB drawing i gave you? Actually i remember i had similar problem using first iteration master untill Neville sent me the next. Try tracing your master board with this... CellTopBMSMaster_-_PCB.pdf CellTopBMSMaster_-_Schematic....

Hi Can you send me .pdf or .jpg of your master PCB. In my package i have totaly compatible master PCB and schematic. It is some 5th iteration that Neville and I tried. Only addition i made is the .01uF cap i added across the R1 to stabilise opto comms. You can try this also if you havent already. La...

Good for you... Last week ive been driving on gas!!! My clutch gave way and i had to get a replacement. It seems taking off in 4th or 5th made a mess of springs inside. I will have to be carefull, taking off only in 2nd. For the record; previous month i passed 20000km electric mark. I celebrated thi...

Hi Neville Your BMS works in my Mazda dayly now. And now i have 12000km on it. I noticed something when i tried to calibrate charger. When i added high voltage charger off function in the code and set it for 3,8V, master was reset if one cell went over it. When i fiddled with it i lost my patience a...

It could be a high resistance connection between the terminal and the next cell + BMS - at 40 amps, a resistance of 10 mOhm will give you 0.4 volts higher reading (and put out 16 Watts). Very well, i will try to sand-in my terminals and retorque them. Maybe it will help some, but i doubt it. In add...

Can you post a picture of your UTP? My understanding of UTP was "Un-Twisted Pair" - just a single wire. I don't have any 12V anywhere near the comms at the moment. There is almost nothing powered in the car, probably just the clock! http://2.bp.blogspot.com/_DZhhZp9of5I/THIJMdxkdZI/AAAAAAAAC5E/AnPv...

I've connected all the cells of my BMS in the car, and I'm having some comms problems. I haven't driven anywhere yet, so it shouldn't be interference from controllers etc. You are probably picking up your 12V power cables. Check your cables: 1. are you using twisted pair for communication? normal U...