Are you done evaluating? 
1 Like
We demands our evaluations & opinions
No, as I said, all I understand so far, is that diodes only allow flow in one direction.
The price of that electrical check valve being inline on circuit, is a loss of ~0.7 volts.
1 Like
I decided, that I would simply add two more p groups, and make it 14s. This allows the luna pro charger. that has 1 to 5 amps, and 80 90 100 switch. And get me at least 5 to 6 mph more. I really think 14s is the sweet spot, as many ebikes are 14s.
Youâll only think this until you try 16s, 18s, then 20s, and so on⌠
But kidding aside 14s kicks ass. Go for it
4 Likes
The D100s did the talking. Switch is ready to go. 14 s is childsplay. Makes my wiring more effective. More torque. More efficiency. More range. More speed. More brake. Moar fun.
1 Like
Iâm doing 33s! 3shul cl700 Vesc
1 Like
Ive heard you make a mistake on that battery and it is a defibrillator.
With dc itâs not nearly as dangerous. There was a thread here awhile ago and someone was touching something pretty high. Iâm doing lifepo4 so really only 119v. 120v dc is considered some threshold.
This says 100v. I assume they mean dc and ac cuts through the body resistance much more easily. https://www.d.umn.edu/~sburns/EE2212/L-Safe-Levels-of-Current-in-the-Human-Body.pdf
I ordered. Havenât seen anywhere that explains how these drop the voltage. Please tell me how it works.
Ur schematic looks simple enough to follow as far as wiring it in. The power supply only does 150watts and want to drop from 87.5 to about 85. If I were to use a power supply that did more current would these still be ok to use?
Diodes are basic electrical components like resistors or capacitors. There are different types of diodes, and this one is a Schottky. They are normally used to block the flow of current in one direction up to a certain voltage, but allow it in the other direction. The drawback to the âallowâ direction is that you get some voltage drop because they are not 100% efficient.
In this case, we can actually use that voltage drop to our advantage by lowering the charger output voltage. If you wire these backwards, the charger just wonât charge since the charger voltage is well below the 650v blocking voltage of this diode.
The other drawback is that this voltage drop creates heat, and the higher the current, the higher the heat. The datasheet specifies 20A, but thatâs only if you can keep the diode at a specific temperature. With the package type, itâs probably best to heatsink these then seal it up in epoxy. Might work, might not. You can calculate it, but would just be easier to try it and see. Just keep in mind if you use two diodes in series, and heatsink these, either electrically insulate one of the diodes from the heatsink, or use two heatsinks that are electrically separated.
This is the chart in the datasheet that is the most important, and why we arenât just using the âforward voltage dropâ of 1.65v specified on the datasheet.
It shows that at no current and room temp, forward voltage drop is about 0.80v. As current rises, so does the voltage drop (and the temperatures of the diode which also changes the voltage drop). When in the CC charging stage, you might see as much as 1.25v drop on a 10A charger, but once you are at the end of the CV charging stage, with like 100mA of current flowing, voltage drop will settle to the bottom of that chart.
2 Likes
Do I have these diodes oriented correctly? Battery will be on left. I see no markings for which direction current flows in the diode. I guess I could figure it with some experiment but never have.
The diode symbol itself is an arrow that indicates current flow direction. In this case, from pin 2 to both pin 1 and the case. The first graphic in your post also gives you a clue with its references to âinâ and âoutâ.
You can use pin 1 or the case or both. No real benefit in this case to use both.
Iâll leave it to you to now determine whether youâve got things set up correctly or not. 
2 Likes
With these particular parts and this particular circuit, it would be really hard for you to break them by wiring them up wrong, so plug it in and go for it.
Looks okay to me.
You could place the diodes face-to-face (heatsinks on opposite sides) and solder the two pins together instead of using a short wire between them.
The heatsinks canât touch.
Iâve got both pin 2 connected to red input and both of the case output connected to the output
It dropped only from 88v to 87.5.
Or should I put them in series? I think so n try that
Down to 86.8v in series.
Was that with current flowing?
The voltage drop increases as the current goes up.
2 Likes
