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Legacy Products


We are dedicated to supporting our legacy products. We have our FAQ section, manuals, and software downloads for our former Soliton product line.

Evnetics Important Notice:

Please upgrade to version 1.5.2 of the controller software immediately – a serious bug in the code affecting versions 1.4.1 through 1.5 has been identified and corrected.

Frequently Asked Questions

Which controller should I get, the Soliton1, the Soliton Jr or Soliton Shiva?

Setting budget considerations aside, it really comes down to how heavy your vehicle is and how fast you want to accelerate. We tend to recommend the Soliton1 for performance applications and/or vehicles weighing 3000# (1400kg) or more, and the Soliton Jr for vehicles weighing under 2500# (1200kg). In between those two weights you could go either way depending on whether you are more performance or economy minded. We recommend the Shiva for racing applications only or in cases where extreme performance is required.

What kind of motors can the Soliton1 and Jr drive?

Our controllers were specifically designed to drive Series DC motors of 8″ to 13″ diameter, but they can also be used with PM DC motors as long as there is at least 10uH of inductance and/or the maximum operating voltage and/or current are reduced. Note: “BLDC” motors require an AC inverter and are not compatible with the Soliton1, Jr. or Shiva

Can these controllers do regen (regenerative braking)?

Regen braking of either a series or PM DC motor first requires that the controller be able to change its operating mode from a buck (step-down) converter to a boost (step-up) converter. The Soliton1 does have this capability but it is not currently enabled in the firmware. We did test regenerative braking of a series DC motor with special code under “lab” conditions, and while it did work, it required a couple of kludges we weren’t real happy with. PM motors do not require these kludges to do regen so we may revisit this at a later date. Note that the hardware in both the Soliton Jr and Soliton Shiva models cannot do regen braking.

Can I use the Soliton1/Jr/Shiva as a rapid charger?

Technically speaking, yes, but there are a number of caveats, not least of which is that you must insert at least 50uH of inductance in series with the battery pack. We are contemplating modifying the code to allow switching the function of the controller from motor controller to charger, but until such time this is not an approved use.

What happens if the motor inductance is too low (like in a PM motor)?

As motor inductance goes down, the peak to peak ripple current goes up. Our motor controllers strive to regulate the average current but the “desaturation” detection circuit (which detects overcurrent) will trip if the peak current exceeds a certain threshold. In general, with lower inductance PM motors you will need to run the controller in Quiet mode (14kHz) and/or with a lower maximum battery pack voltage and/or a lower maximum motor current. That said, the practical lower limit for motor inductance is 10uH. The popular NetGain WarP-9 has approximately 100uH of inductance even at 500A, hence there is quite a margin between it and the lower limit for our controllers.

What is the maximum voltage I can run with a Soliton controller?

The limit recommended in the manual is 340V for the Soliton1 and Soliton Jr, and 425V for the Soliton Shiva (actual voltage, not “nominal”, since nominal has no formal definition). The actual limit (displayed in the web interface) for the Soliton1 and Soliton Jr controllers is 350V, but that is to accommodate inevitable errors and drift in the voltage measurement circuit – after all, these are motor controllers, not lab grade measurement instruments, so allow for at least 2% error in voltage and current measurements!

Also note that the maximum motor current limit is reduced to 900A in the Soliton1 and 500A in the Soliton Jr any time the battery pack voltage is above 310V. The Soliton Shiva has no derating with voltage.


What type of sensor should I use for the tach input?

We overwhelmingly prefer industrial inductive proximity sensors from Automation Direct. More specifically, standard and extended sensing distance models with shielded 3-wire cables and PNP outputs (require a 1k pulldown resistor from TACH to SGND – see p9 of the manual).

Standard sensing distance: AM1-AP-1A

Extended sensing distance: AM1-AP-3A

What is a good pump to use for liquid cooling?

Many of our conversion shops have had good results with the plastic body version of the Laing D5 pump (there is also a version with a bronze body for solar water heating applications but that is not necessary here). The typical retail price of this pump is $75-$100.

The web interface page won't load.

Approximately 5% of our customers contact us because they can’t connect to the controller’s web interface page. We aren’t IT experts, and we have yet to duplicate such problems ourselves, which makes troubleshooting this type of problem exceptionally difficult, but over the years we have learned a few tricks that usually work:

  • Try using a different laptop.
  • Try using a different browser, specifically Chrome or FireFox on Windows systems.
  • Disable your firewall if you specifically installed a 3rd party program (the built-in Windows firewall does not cause any problems).
  • Make sure there is no malware or viruses on your computer – we recommend avast! for antivirus protection and Malwarebytes and Spybot Search and Destroy for anti-malware removal and protection.
  • Disable any anti-virus or anti-malware real-time scanning software (re-enable after you are done changing the controller’s settings!)
  • Restart the computer while the controller is still on and connected
  • Cycle power to the controller while the computer is still on
  • Hopefully one or more of the above will solve the problem. If not, then please send us an email to with your contact information and someone will try to walk you through the process.


The web interface page keeps hanging.

This is also a rare problem, but one we can duplicate at will with a Toshiba laptop at our shop. The cause in this case seems to be trying to scroll up or down on the web interface page before it has finished (re)loading. The line of data displayed by Logger will also pause when this occurs.

Sometimes this issue will automatically resolve itself after 15 seconds or so, but you typically have to cycle power to the controller to fix it. Additional info: our suspicion is that activating the “touch to click” functionality for the mouse pad on the laptop is the real culprit.

There is pack voltage between the Soliton controller's terminals and the vehicle frame - what's wrong?

There is almost always some leakage current to the vehicle frame (aka a “frame leak”) from brush dust in the motor. First thing to do is disconnect both motor cables from the controller and see if the leakage current goes away even when the controller is on. If so, then turn off the controller and reconnect the motor cables then place a 10k resistor across your meter’s probes and see if the voltage drops below 10V. If so, then you have 1mA of leakage current which is enough to give you a tingle, but not considered harmful (in the US – other countries may have different rules concerning

Another common cause of frame leaks is condensation and/or electrolyte on the batteries, particularly lead-acid and Ni-Cd types. You can usually spot the exact battery/cell leaking current by holding one meter probe against the vehicle frame while testing the voltage difference from one battery/cell terminal to the next. When you read ~0V at the meter you’ve found the exact terminal which is leaking current. Wiping down the tops of the batteries/cells with a clean rag dampened with distilled water is the best way to remove electrolyte.the acceptable level of leakage current!). In any event, you should routinely blow out accumulated dust from the brush area with compressed air.

Checking the traction circuit wiring for breaks in the insulation shouldn’t need any explanation. Make sure no cables rub against metal and you shouldn’t ever have a problem with this.

Why does the fuse to my DC/DC converter keep blowing whenever I accelerate?

Probably a combination of the pack voltage sagging, so that more current is required to deliver the same output power, as well as ripple from the controller causing excessive AC current to flow through the input capacitors of the DC/DC converter. The ripple can be blocked by putting an inductor in series with the positive supply to the converter. A toroidal inductor is preferred, but a rod or drum type can be used, too, as long as it is at least 100uH and rated for between 1.5x and 2x the current required by the converter. Examples of suitable part numbers are Vishay/Dale IH10BQ101K, Bourns 2312-H-RC or 2312-V-RC, etc.