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svaeolus avatar image
svaeolus asked

Cyrix-Li-Charge not supported with SmartSolar MPPT?

I have a Cyrix-Li-Charge which I am trying to get working with a VE Bus BMS charge disconnect, and a Victron SmartSolar MPPT 75/10 solar controller. I also have an alternator I want to connect through the Cyrix-Li-Charge, but I am just trying to get the solar working first.

This is all exactly as these components are shown deployed in the example system diagram here:

https://www.victronenergy.com/upload/documents/VE-Bus-BMS-example-with-3KW-12V-MultiPlus-230-Volt-revision-B.pdf

That diagram was the basis on which I designed my implementation. I assumed it was all supported as depicted.

I can't get the Cyrix-li-charge to close the connection and allow the charge current to flow.

I had thought that the li charge unit just did what the BMS charge disconnect wire told it to do, but on reading the documentation more closely I see there are other conditions, such as over or under voltage. It says it won't connect if voltage is less than 13.7. Is this the cause of my problem? At the start of bulk charging, it takes a long while, definitely more than 10 minutes, to ramp up over 13.7v. But if it isn't connecting with the battery, I think it never ramps up the voltage. Correct? Seems like a potential chicken and egg catch-22.

When I contacted my Victron distributor from whom I purchased the Cyrix-li-charge for help with my installation, he told me he has never been able to get it to work and does not recommend or support them. He just sells them I guess. He says when he has asked Victron about this, they just say to use a Battery Protect in the reverse configuration (solar as "IN" and battery as "OUT"

This is a little frustrating to hear from the dealer who sold me the product that it won't work and he won't help me to get it working.

Should it work?

What support or warranty recourse do I have given that the dealer won't support it?

BMS
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3 Answers
justmurph avatar image
justmurph answered ·

I run a cyrix-li-charge in my system with four MPPTs and it works as advertised. When the MPPT starts up in the morning, the load will be disconnected, so the voltage should go over 13.7 pretty quickly, which should trigger the cyrix to close. The voltage will then get pulled down to whatever the battery is at and the cyrix should stay closed.

I'd start by verifying the voltages on each side of the cyrix. You need at least 2v on the battery side and 13.7 on the charge side.

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svaeolus avatar image svaeolus commented ·

Thanks for this confirmation of a working setup.

A Victron employee has provided me with more information. They say that the key element I am missing in my implementation is a connection to a battery source on both sides of the Cyrix. In their example system diagram this is being provided by the starter battery connected through the ArgoFET Isolator, which I don't have. According to them a setup that only has MPPTs is not supported and won't work.

"The Cyrix needs to see voltage on both sides to be able to switch, its not intended to switch a charge source as a MPPT , then a battery protect can be used." is what I've been told.

I'm not sure why the MPPT itself doesn't fulfill the requirement to see voltage on both sides. It does show voltage on its charge outputs, and the Cyrix shows a brief change in its otherwise-constant fast flashing indicating an alarm state when the MPPT is turned on or off, so it registers on some level but never closes.

Part of my conundrum is that I don't even know if my Cyrix-Li-Charge is working or has failed.

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justmurph avatar image justmurph svaeolus commented ·

Whoever said that is straight up wrong and may be getting confused with the Cyrix-li-ct which is intended for parallel connecting two batteries. A few things to note:

a) In the above example, the argo FET will only be closed when the engines are running and the alternator is charging, therefore there isn't a battery on the charge side most of the time

b) My system has no battery on the charge side and it works fine (four MPPTs and an Orion TR)

c) The example schematic in the Cyrix Li datasheet also has no battery

The cyrix is just monitoring for voltage and doesn't know the difference between the voltage coming from the MPPTs, a battery or any other power supply.

As your next step, I'd still be getting out the multimeter and checking that you have the right voltages on each of the four pins (and that they're hooked up the right way). Check that the MPPT is bringing the voltage on the charge side up over 13.7V.

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svaeolus avatar image svaeolus justmurph commented ·

I'm sure the MPPT is wired up correctly. It works great when I take the Cyrix-li-charge out of the circuit. And I see high voltage, actually 16v, on the MPPT battery (charge output) terminals when it is connected to the Cyrix-li-charge. Not sure why so high, but I am guessing it has to do with the fact that the charge + circuit remains open/disconnected by the Cyrix, so the MPPT never sees a charge destination and doesn't adjust.

I am back to wondering if my Cyrix-li-charge is faulty. I am looking for a foolproof simple test that would verify if it is broken. That's what I thought I would be doing by setting it up with just the MPPT at first, but it never does anything but the blue LED fast-flash routine, with a brief pause when I toggle the MPPT off/on. I guess I need to try it with other charge sources. I have some other battery chargers that I can probably make produce > 13.7v as a test.

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stu-co answered ·

@svAeolus I am suffering from this exact issue with my mppt and my relay.

Did you find a solution to this problem in the end? Was it a faulty Cyrix-Li-Charge?

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svaeolus avatar image
svaeolus answered ·

Yes, I ended up scrapping the Cyrix-Li-Charge and using a Battery Protect 200 to control the charge sources

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