Good morning,having purchased the entire Victron system( - 2 Lifepo 200Ah 24 v -,Multiplus II 24-5000 120,- Lynx Distributor 1000 -Lynx Smart BMS Cerbo GX,-GX Touch 50 - MPPT 75-15 and smart battery protect between MPPT and load bar, question is how to protect my Balmar 621-24v-70A with external regulator MC 624 from current spikes in case of sudden battery disconnection from the system during alternator spinning
Thasnks Giulio
take a look at this schematic. I know that the schematic is for an Alpha Pro regulator, but the same principle can be followed.
You need to wire the ATC (Allow to Charge) signal into the relay input. The Relay output to a SolidSwitch 104. The solid Switch 104 could then trigger a relay to disconnect the field or ignition feed into the Balmar.
You then need to configure the relay in the Lynx Smart BMS to be an alternator disconnect.
Two events can now trigger the alternator to stop charging, both before the main contractor opens and disconnects the batteries. The ATC can signal a shut down, or the relay opening, both remove the signal to the SolidSwitch 104, which when opened would break the ignition feed or field. If the main contractor of the Lynx Smart BMS is about to open, the relay will open first. So in all cases the alternator should shut down before the battery is removed and therefore the alternator has been protected.
Also take a look at this schematic. If you an swap out your regulator for a Wakespeed, there is a much tighter integration. No Solid Switch 104 is required as you an wire the relay output straight into the Wakespeed. This will trigger the Wakespeed to stop charging, it actually switches the regulator off. Further as the device can be connected to CAN, it will listen to the Lynx Smart BMS and set it's charge characteristics based no what the Lynx Smart BMS wants, so the alternator should never generate an overcharge event. If the Lynx Smart BMS only wants the system to charge to 27v, the Wakespeed will do so; if it wants 28.4 it will do so. If it wants reduced current it will do so. I am also aware of work going on to pull status information from the Wakespeed and display it on the VenusOS. IMO a much better solution.
All the best.
Included a screenshot of VictronConnect configuration or the relay mode:
Thanks a lot for your answer!
Just a follow-up question.
If the contactor would somehow fail or open prematurely (before it is able to shut down the alternator), wouldn't that due to an over voltage spike fry all electronics on board?
Would a better solution be to connect the positive of the alternator to the battery side of the Lynx Smart BMS?
As the shunt in the Lynx Smart BMS is on the negative it would still measure the output of the alternator and would still still stop charging when the external regulator is shutdown or even if disconnected with the load side.
