question

Chris Michael avatar image

Cyrix-Li-Ct not charging house battery in RV

Hello. I have an RV with a standard lead acid battery connected to the alternator, which is then connected to a Cyrix-Li-Ct. The Cyrix-Li-Ct is then connected by about 15 ft of 2 gauge wire to the house battery, which is a Renogy 100ah LiFePO4. I'm trying to diagnose why the house battery never seems to charge from the Cyrix-Li-Ct. The voltage from the starter battery seem to be in line with the spec sheet when the alternator is running and I have a ground wire ran back to the starter battery on the 86 Bat terminal. I've verified that the house battery has a proper ground to the system. Are there any additional troubleshooting tips that I can try? Thanks!

Cyrix Battery Combiner
10 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

2 Answers
Matthias Lange - DE avatar image

A cyrix-li-ct needs a + from the BMS on contact 85.

If there is no + the cyrix will not close.

1 comment Share
10 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Hello,

My supplier sold me a superpack battery (with internal BMS) and a Cyrix-li-ct to connect both start battery (lead) and leisure battery (super pack) to the engine alternator.
As the 85 signal "+" is mandatory, what the required tension is to be able to charge both battery?
Thanks,

Cyril

ejrossouw avatar image

I'd check the basics as below. Assuming a couple of things given no schematic, I'd suspect voltage drop has something to do with it the given length and AWG

https://docisolation.prod.fire.glass/?guid=9d9ec711-4d98-41f5-1af0-3595facddea3

2 comments Share
10 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

I'm getting a Symantec link validation error when trying to open your hyperlink.

Sorry, our corporate firewall at work. Here is link just to be sure your connections are 100% correct. I also noticed a large voltage drop for the cable length / AWG combination you have and wondered if that could play a key role. From memory the drop was almost 4V, but to be checked again as I do not have all the detailed specifics of your system.

https://www.victronenergy.com/upload/documents/Manual-Cyrix-Li-ion-230-A-EN.pdf