WS500 with 48v Rec BMS


  • Hi guys, I have rebuilt one of the two engines (Volvo Penta D2-30) on our catamaran and changed the previous 12V/115a alternator to a Mahle MG1 48V/100A. The internal charge controller has been removed and both brushes / connections routed to the outside. i use the P cable set. When we start the controller, it outputs voltage up to 50v as field voltage, which is way too much. All + and - are connected to the alternator and battery as described in the manual. It is a 48v system separated from the 12v. Does anyone have any ideas or does the WS500 need separate e.g. ignition as 12v?


  • How much is the output voltage?

  • Should be 56v to charge the LiFePo4 battery controlled by a rec q bms

  • My tests in the workshop were about 10v-12v for the field

  • Here some technical details of the 48V alternator

  • See page 14+15 in the manual. I would prefere option #2.       1) Connect the ALT+ (Red) wire to a 12v source With this approach, the field power source is supplier from a 12v source by connect ALT+ (Red wire) to a 12v (perhaps chassis) battery. VBAT+ (Red/Yellow wire) still needs to be connected to the battery for proper voltage sensing, btu the WS500 does not require that both the target battery and the power source for the field be the same, not the same voltage. Such an mix of voltages is a bit more complex with regards to wiring, but the WS500 functions well in the type of design. Do note that some harness (ala, the Van hardness) combine ALT+ and VBAT+ into a single wire to simplify installs. In this case such a deployment will not work.   2) Apply a derate values ($SCA command) The $SCA command has three ‘Derate’ values which can be defined: Normal, Small Alt, and Half-power. These are typically used to reduce the output of an alternator to account for system cooling concerns (ala, alternator overheating), and/or to reduce the load on the driving engine. But they can also be used to in effect reduce the ‘Field Voltage’ from 48v to allow direct driving of a 12v field while the ALT+ wire is attached to the 48v battery. To so this simply start with a ‘Normal’ derate value of 0.25 (aka, 25%), and that will reduce the average field voltage to an acceptable operation range. Most 48v deployments use this technique.

  • Thank you for the information. I have tried to change the values via the WS500 Config tool. There seems to be a bug in the software. It is not possible to change these values to 0.25 there. I\'m on the boot right now and unfortunately I don\'t have a Windows PC, only a Mac with Parallels. There the WS500 tool but the firmware and config update unfortunately does not work, because the STN32 bootloader mode is not recognized correctly. Is there another way to transfer the config?

  • Hey Chris, What variable in the WS500 are you trying to change with the tool?  I will test it and confirm. And unfortunately when I last looked I was not able to find a MAC compatible version of the STM loader app.  If we could find the source code it might be worth a try to see if we could cross compile it. I had a Mac version of the tool working a while back but limited demand and high release costs would make it too expensive.  I don\'t think anyone would anyone want to pay $ 200 for it.

  • Hi Rick I tried to modify SCA / Derate

  • It worked fine for me. Did you press the \"Enter\" key after entering the value? Is your Windows PC set for European currency where the the comma and period are interposed?  (If so, you will need to et it to US number format as the WS500 will only accept a period delimiter, but Euro windows will not recognize it as a valid number Here is a snip with it working

  • In Norway we have the same issue. Works when choosing US Windows Language. But I have seen other installations where it did not even work with US language. Hope this will be fixed in next SW version..  

  • You are right, with the US language setting it works. A little bit strange. Thx for the help.

  • @Chris Hi Chris. I've planned to use Mahle MG1 48V 100A in my RV, just want to know the connectivity diagram from the WS500 to Mahle MG1. I've summarized the question need your input as following,

    1. WS500 with Mahle MG1, you use Wiring Harness P or N.

    2. Could you please kindly share the connectivity diagram or wiring of the WS500 with Mahle MG1?

    3. Is WS500 work well with Mahle MG1?

    4. Did you remove the internal regulator from Mahle whe you use the WS500?

    Thank you very much.
     


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