bigmoose said:I liked the MAX11081 too: wished the LVC range extended up a few tenths of volts more though.
Gawd I wish I could find the link - but I read an article awhile back aimed at small entrepreneurs on how to price things. Most small businesses sell things below a sustainable cost, and pay the price. IIRC you should be charging at least 2.7 * the nominal cost of parts & labor.methods said:... I do have them over-priced - hence why I am searching the internet for that maxim protection chip. :wink:
-methods
fechter said:Where are those boards from?
mj2412 said:Hi,
after long time on the shelf, i soldered a 16s Zephyr 4.4.2, but the cell circuit test shows 3 Ohms at circuit number 8 and 16. I changed nearly all parts, checked everything twice but could not figure out any mistake. Does anybody have an idea what could be wrong. Stange that it is on 8 and 16.
Thanks in advance.
Martin
Zenid said:FYI. The latest "Zephyr" v4.4a is in stock now
http://endless-sphere.com/forums/viewtopic.php?f=31&t=55125
Buy one and help the designers breathe life back into this great project!
Yes! Here:cal3thousand said:Are there any working iterations out in the wild yet? Besides Fechters and GGoodrums
:lol:fechter said:It seems to have risen from the ashes again.
Maybe I should change the name from Zephyr to Phoenix.
Richard? One for you. If there are any technical specs missing from the manual, maybe this could be added to the information in the first post of this thread. It would be nice if alternative resistor values could be calculated to enable people to specify their LVC/HVC/shunt values etc.(as with the LiPo/LiFePO4 differences) Perhaps a couple of equations could be improvised.2007blueprius said:What I am looking for in it's current format with the current BOM, at what values all these features come on?
for example HVC is 3.65v I believe
LVC 2v
at what voltage do the shunts come on? I know I read this somewhere it comes on half way at first, to a max of 1 amp current, which got me even lore confused if you are charging at 20A those resistors wont be able to hold the high cell there for long and HVC will trip so I suppose the sistem will survive that is what it's refered to as rating for 20A not that it can keep up if the pack is severely out of balance.
the LVC at 2 v seems rather low particularily for my project, but I asume as the rest of this build beeing based on voltage dividers this could be changed by changing the resistor values
if somebody could clear this up for me I'd much apreciate it
fechter said:There are several ways to do that. Standard TC54 voltages are
1.4 TC54VX14
2.1 TC54VX21
2.7 TC54VX27
2.9 TC54VX29
3.0 TC54VX30
4.2 TC54VX42
4.3 TC54VX43
As you can see, there's a big gap between 3.0v and 4.2v, but there are some alternate parts that might have in between voltages that could work with the existing board layout.
By adding a diode in series with the input, you could raise the voltage by about 0.6v, depending on the diode used. You can also use a resistor divider, but that would add some drain unless you can use the same divider as the HVC.
For low discharge rates, a higher cutoff voltage may be a good thing. At higher rates, there is more voltage sag, so the cutoff voltage will really be higher than the TC54 setting as the voltage will 'bounce back' after the load is removed. With really stiff Lipo cells, there is not as much rebound.