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miya asked

Possible Faulty Cerbo ? Not allowing MPPTs to charge under External Control

Hi All

I am seeking any help and support on this problem.

Sailing yacht - all Victron equipment - Smart lithium batteries, distributors, Lynx Smart BMS, Cerbo with Touch, Battery Protects, and 4x MPPTs. All products have latest firmware and are up-to-date. The system has been working perfectly for 18 months since installation.

The MPPTs have worked perfectly - always charging until the lithium reaches 13.5v - unless a new charge cycle has been started - in which case they charge to 14.2v for 3 hours. Working perfectly.

In the middle of the day, last week, all MPPTs stopped charging. Lithium voltage starts to drop below 13.5 and the MPPTs do nothing - no charging. MPPTs are set to lithium, with absorption 14.2 V and float 13.5 V and all show external control by the BMS.

Since they stopped working, they have intermittently, for short periods, tried to charge the batteries but stop again at less than 13.5v. Nothing has changed on the system. And there is no logic to when they start and when they stop charging.

I have removed each MPPT and tested them with a lead acid battery outside of the system. They work perfectly under their own control. Under external control by the BMS this intermittent fault continues.

BMS would appear to be good showing - ATC yes, ATD yes, CVL 13.5v, CCL 600A and DCL 600A.

I think the problem must be with the Cerbo - controlling the MPPTs ?

Please can anybody offer advice or help?

Thanks

Tim


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Alexandra avatar image Alexandra ♦ commented ·

@Miya

You could remove bms control under DVCC and reset the mppts to stand alone with correct voltages and test them in the system without the bms control.

This allows wiring/set up etc checks.

And rules out the bms control as the problem. (Which connecting onto lead acid would have also done.)

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miya avatar image miya Alexandra ♦ commented ·

Thanks Alexandra

Did that - and problem persisted - so was nothing to do with the Cerbo or the BMS.

I did find this issue - so it is now solved.

Thanks for responding. Appreciate it.

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