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Installed on an RV with solar system on coach batteries. Batteries wire as shown in photo. My Cyrix-ct was connected last evening. The coach battery was 13.6V, the vehicle's was 12.3. The Cyrix flashed and then engaged. The next morning both batteries settled at 12.83V and Cyrix remaind engaged. This afternoon (solar charge) both batteries are at 14.6V, Cyrix remains engaged. When should I expect to see the unit dis-engage? Do I have Battery 1 and 2 wired correctly.
Here's the photo again. My question is Battery 2 connection the terminal closest to the wall or the furthest?
Did you ever work out which battery should connect to which terminal?
It doesn't matter where you connected which battery at the normal Cyrix-ct.
The Cyrix-li-ct is labeled with "lithium battery" and "starter battery".
What kind of batteries do you have?
The cyrix-ct starts to disengage at 12.8V but not immediately, there is a delay depending on how fast the voltage is falling. At exactly 12.8V it can take hours.
If you disconnect one battery you still have the voltage of the other battery on both sides of the cyrix (because it's closed), you have to disconnect the (-) to open the cyrix.
If you look at the manual there is this table. If the voltage is below 12.8v for more than 3 mins it will close/disconnect.
There is also some good information in this thread.
https://community.victronenergy.com/questions/42660/how-does-cyrix-li-ct-work.html
Thanks Matthias. So the Cyrix-ct should have disengaged if both battey banks were at 14.6 volts, correct?
No, why should it disengage at 14.6V?
It will disengage if the voltage drops below 12.8V for the time mentioned above.
Maybe I don't understand the usage of this device. I would think that once both batteries are up to charge the unit would disengage/open.
So, if Bat1 is above the threshold, (after delay) the Cyrix-ct engages in order to pass the charge on to Bat2 and remains engaged as long at Bat1 is producing sufficent charge to keep both Bat1 & 2 above disconnect threshold. And vise versa.
I guess what has me confused is the chart shows (V), but there are two battery banks in play (V1 & V2). Does (V) refer to the battery bank that is highest in charge voltage for engaging, and the lowest of the two battery banks for disengaging?
What restricts the possible overcharging (boiling) of the wet cell (vehicle) battery from the AGM (coach & Solar) charging system?
If the voltage of one of the batteries is higher than 13V the cyrix will engage after a few minutes.
As long as the cyrix is engaged both batteries have the same voltage and if that voltage drops below 12.8V the cyrix will disengage after a few minutes.
With the AGM charging algorithm (14.4V) you can't get a wet battery to boil.
You have the connect/disconnect parameters above but to further make the point, cyrix will disconnect only when both batteries are below certain voltage (12.8) or above (16). It will not detect when either battery is full or anything like it. It acts purely on voltage.
In my view, while not ideal, the better option would be one of the lithium cyrix models that have the disconnect voltage somewhere above 13V. An AGM will often have a resting voltage above 12.8V so the cyrix will not disengage until the batteries are discharged somewhat.
Cyrix is also not ideal because for the engine/starter battery it makes no sense to continue charging all the time when not in use. A better option (if at all required) is a dual output solar controller that diverts a small (1-2A) amount to the starter battery.
the cyrix ct works perfectly with agms. however they are lead-acid batteries. As soon as he starts using the agm, the voltage will drop to 12.8v pretty quickly. And the cyrix will open. It is possible that it will initially close again if we shut down a load. but it will reopen. Nothing bad happens. And nothing bad happens even if we charge the starter battery every day. Lead-acid batteries like to stay charged continuously. Solution is a switch on the negative 86 of the cyrix. so we can manually exclude it if we want. The manual does not provide this. I do not know why.
