"Zephyr" - Finally, the "v4" Fechter/Goodrum/Hecker BMS...

The schematic for the cell circuitry shows the "+" C101 (47uF) cap going to the base of the BD136.

However, when I look at the board with the BD136's mounted on top (with the part #writing down) it looks like the "-" of C101 connects to the base of BD136. The instructions and photos show the - of C101 on the left when mounted on the top of the board.

In short, are we mounting the electrolytic 47 uF in backwards?
shouldn't the C101 caps be mounted on top of board so that the "-" is on the right side?
Maybe I am mistaken.
 
The + side of the 47uF cap goes to the base of the BD136. I'll look at the layout and see if it's mismarked.
 
fechter said:
The + side of the 47uF cap goes to the base of the BD136. I'll look at the layout and see if it's mismarked.

Are u Sure :O i have build all the board ... and i have installed as picture show ... (-) on the base ... This is very important to reverse that 47uf ??? If yes i will rebuy 32 :(

Tanks
Chris
 
I checked again, and it does appear the photos in the instructions are wrong. The + side should definitely go to the base of the BD136. Sorry about that.

Hopefully you can desolder the caps, clear the holes, turn them around, and resolder them without having to buy anything. A vacuuum desoldering station would make pretty fast work of that.

Yes, it is pretty important. The caps could fail or do bad things if reversed.
 
GGoodrum said:
Sorry about that. The instructions, which are linked in the 1st post of the this thread, have been corrected.
-- Gary
All the pictures in the instructions still show the "light colored stripe" on the left. Is that correct or is the wording in the instructions correct? Instructions say - "with the exception of the 47uF electrolytic versions on each cell circuit. For these, the negative side (with the light-colored stripe) goes in the right hole."

The board needs to have a square pad for these since they are polarized right? Every picture I see on this forum, with the one exception of the cap under the board, shows the light stripe on the left. I assume the light stripe is the negative like most caps. Did you have to desolder all the caps in the pictures?
Man, I just soldered these on! :x Beta is frustrating! Wait even Andy's board in the video post hast the light stripe on the left...
- Nate
 
If it makes you feel any better, both Andy and Gary have to re-do a bunch of them too. Apparently they work with the caps reversed, but I would expect early failures if they are not correctly polarized. They could also increase the standby drain quite a bit if reversed.

Yes, a square pad on one side to mark the polarity is what we will probably do on the next batch.
 
Ha, NO Way! I feel sorry for all of us, but I guess that is what we get for living on the bleeding edge...

Should switch out the pictures or at least get a disclaimer on the ones in the instructions ASAP. If there is ever any confusion I always refer to the pictures.
- Nate
 
Yes, we're working on correcting the pictures. Have to switch all those damn caps around first. :wink:
 
Nate said:
Ha, NO Way! I feel sorry for all of us, but I guess that is what we get for living on the bleeding edge...

- Nate

Don't feel sorry for me, I didn't solder any of mine in backwards. I checked it before I put in the caps.
 
I guess it may depend on experience but I NEVER take any notice of marks on boards. Everything gets checked against the schematic. But then I have been at it for 50 years.........where did they all go............ :shock: :mrgreen: :mrgreen:
 
velias said:
Don't feel sorry for me, I didn't solder any of mine in backwards. I checked it before I put in the caps.
Thank you for finding that before I powered up my board! :)
 
probably a question for Gary. Can you see any problem with setting up a Cell-log in parallel with the bypasses on the board to monitor the voltages while it is charging?? Is their impedance high enough to avoid probs???
Thanks
Greg
 
Gregb said:
probably a question for Gary. Can you see any problem with setting up a Cell-log in parallel with the bypasses on the board to monitor the voltages while it is charging?? Is their impedance high enough to avoid probs???
Thanks
Greg

This is not a problem at all. I do this all the time. :)

-- Gary
 
velias said:
Don't feel sorry for me, I didn't solder any of mine in backwards. I checked it before I put in the caps.
Oww! That hurts! :D

In my defense, I didn't have instructions. ;) (Pretty shaky, no? So much for assuming...)

Crap. Just reversed the caps on my 21 channel V4.3.6 board. 19 good, 1 slightly swollen, one leaking like, well, a popped cap.

Thanks for the catch, guys.
 
Swapped electros sometimes reverse their own polarity, but most leak, or if they are larger values, explode (ahem. Never trust screenprinting on vintage UREI's! :) )
 
AndyH said:
velias said:
Don't feel sorry for me, I didn't solder any of mine in backwards. I checked it before I put in the caps.
Oww! That hurts! :D

In my defense, I didn't have instructions. ;) (Pretty shaky, no? So much for assuming...)

Crap. Just reversed the caps on my 21 channel V4.3.6 board. 19 good, 1 slightly swollen, one leaking like, well, a popped cap.

Thanks for the catch, guys.

I feel your "pain", Andy. I'm just starting to redo the 20 caps on my GEM booster pack BMS boards. :roll:

Wow, Greg, that took forever, getting through Customs. Usually, door-to-door to your neck of the woods is only 4-5 days, tops.

-- Gary
 
How important are the specs for F1?? I somehow missed that in the order and it is going to cost me $20.00 for a 60c bit.
Is it really an 80ma hold with a max 1.2A and a trip of 180mA???
The others I can get locally are trip of 1.5A minimum and Resistance of 10ohms. doesn't give any other parameters.
Thanks
greg
 
Gregb said:
How important are the specs for F1?? I somehow missed that in the order and it is going to cost me $20.00 for a 60c bit.
Is it really an 80ma hold with a max 1.2A and a trip of 180mA???
The others I can get locally are trip of 1.5A minimum and Resistance of 10ohms. doesn't give any other parameters.
Thanks
greg
That should work fine. It's just there to prevent fire in the event of parts shorting out. Actual circuit draw is about 10mA max, so a smaller one might work better.
 
I have my board, and I've ordered my mouser parts list (and paid the rip-off VAT for UK import). However, looking at the instructions, I see a lot of wires being used and have no clue what type I should get to connect the bms to the cells, and to the charger and main terminals of the battery bank.

What grades and types of cables should I be using here?
 
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