Low WS500 field drive controlled by Lynx BMS

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heureka asked Oct 5, '23

Low WS500 field drive controlled by Lynx BMS

All Victron. 800Ah (4 200 Ah smart lithium batts). Lynx BMS system on boat. Wakespeed external control (Lynx) in slave mode. Twin identical Valeo 125A alternators on one engine. Proper dual alt WS500 harness. Target alternator voltage 95C. Latest firmware. No errors / faults.

BMS (set to “alternator mode”) seems to be deregulating alternator field to 30% as shown on cerbo despite battery at 72% charge and alternator temperature steady at 62C. During install testing was experiencing much closer to 100% field as temp rose to target temp. What could be wrong if anything?

system design lynx bms

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Answer 1 · 2023-10-05T19:29:39Z

pwfarnell answered · Oct 05, 2023 at 07:29 PM

Things I would check. These do not relate to the Lynx BMS as I do not know that.

1. When the field is so low what voltage / current is measured vs what you are expecting for absorption / float.

2. Are you using the feature in wire to set float voltage or zero current. Has this got a poor connection as this would reduce field drive.

3. Check what the target voltage / current are in the DVCC settings and see if these are being met and are in line with expectations.

4. Check the battery voltage reported by the batteries, the Lynx BMS and the WS500 sense wires and make sure that there is no mismatch.

5. Check the power and field wire connections on the WS500 and alternators for poor connections.

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