Need easiest way to power my Analogger

My latest build is all buttoned up with wiring neatly tucked away, and I go look at the manual for the Analogger, which I planned to plug to my CA3 for power. My pack voltage is 31s, 128V fresh off the charger, but the Analogger needs 12-100V. My CA has only pack voltage, 5V, and 10V for a torque sensor....arggghh.

Since I can still get to my CA3 and Analogger, and they already come with a nice way to connect them, is there something simple (like just add a resistor or something) to step my pack voltage down to a voltage the Analogger's internal DC/DC convertor can handle?

Even better would be that someone in the know can assure me that just like common switchers can handle a much wider range of voltage than on the label, that my Analogger will be just fine at my pack voltage.

...not good foresight that the Analogger can't always plug to a CA3. What good is a pack voltage output on my CA3? A 12V out seems much more useful. I prefer as few pack voltage wires as possible on my handlebar...typically none on my builds.

I like nice and simple and would like to log a run today. Don't you guys want to see what 28-30kw looks like?

I got the answer from Justin, and that is to put a 30V Zener diode on my CA3's pack voltage output to step the voltage down below the 100V max threshold of the Analogger...nice and simple like I like. 8) Now hopefully a 30V or more zener isn't too hard to track down here in Costa Rica. :?

You could also use a series of lower voltage zeners in series. six 5v zeners would do it, or three 12v (which would drop 36v), etc.

If you have any old electronics with low-power linear (transformer) power supplies, it's possible that some or all of the regulation is done with zeners.

I have a couple of old TV's with the circuit boards, if that would help.Just ned to know what to look for and where they might be located. 1 board is already out of the cabinet.

Zeners come in different power ratings. You probably want to get the highest power one you can find. Stacking several lower voltage ones in series as Amberwolf suggested is good as this also increases the power rating.

If the load has capacitors on the input, a zener might blow (short) from the inrush current. Adding some resistance in series with the Zener will reduce the chances of this. We would need to know what the load current is to get an idea for what would be a good resistance value.

If you have to order the Zeners, I'd recommend getting TVS diodes instead. They are like Zeners but can handle short bursts of high current. They are both cheap.

I don't think there's much worry about power dissipation or inrush current, as the Analogger uses essentially the same power regulator that the older Cycle Analysts (<100v versions) do.


Regarding the TV boards, they could use zeners in a number of places that voltage has to be clamped. Zeners are two-leg parts, usually cylindrical like resistors, and can come in glass (which often looks reddish due to seeing the leads/etc thru it) or black plastic. They look just like any other diode, so you have to look up the part number that is printed on one to see which kind it is.

If you look up schematics for televisions of the era your boards are from, you'll see symbols here and there that look like arrows with a line on the end. The ones with straight lines are diodes, and the ones with a sort of minimalist S or Z instead of a line are zeners. Knowing where they are in teh schematic might help point you to the general area of the board tehy're physically located in, if the schematic is laid out similarly, even if it is not for the same brand or model, as many are laid out the same way.

I have harvested zener diodes from circuit boards before. In many cases, the part number is not visible or is an in-house number you can't look up. To test, I set up a power supply with a very low current limit (or any voltage source with a 1k resistor in series), then apply voltage across the diode in both directions and measure the voltage. A zener will look like a regular diode in one direction and have a higher voltage in the other direction. On a board, you can lift one leg of the part and test.

Thanks for the scrounging zeners info, guys.

I stopped at one of the electronics shops I frequent, and a 30V 1 watt zener was less than $1, so I got several. They're tiny, so I'll just add one to each of my CA3's pack voltage out, so they're always Analogger ready.

Unfortunately I forget the number one rule to keep controllers alive on high powered rigs where in normal use you push a controller to pretty warm levels. That is NEVER go easy on the throttle with heavy loads, IOW in my mountainous terrain, don't go slow up steep hills. I'll start a new thread on the topic.