question

Simon Glet avatar image
Simon Glet asked

Orion XS Engine Start Detection and Multiplus II Starter Battery charging

Hi,

We have a motorhome on a Ford F53 chassis and currently upgrading our electrical system. We went full Victron on the Inverter, Solar Chargers, etc.

The Multiplus II (MPII) is set to trickle charge the starter battery and I was wondering if it would interfere with the Orion XS Engine Start Detection feature.

The MPII states the max Starter Battery amperage is 4 amps but nothing about the voltage.

The graph below is today's Starter Battery voltage (engine stopped) plotted on our VRM:

starterbatteryvoltage.png

The Orion XS manual states the default voltage to start charging is 14 Volts but I wonder if it will detect the engine has started.

So, do the MPII and the Orion XS play well together?

Thanks

Simon

Multiplus-IIstarter batteryorion xs
starterbatteryvoltage.png (24.4 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

2 Answers
pwfarnell avatar image
pwfarnell answered ·

The trickle charger is a basic system which is a current limiter and diode, the diode stops current flowing from the starter battery to the house battery if the house battery is low. The diode means that the starter battery will typically be about 0.3V lower than the house battery if the engine is not running. This means that if you have another charger that can take the house battery above 14.3V then you may get the starter battery to 14.0V. Create a custom widget in VRM with your house and starter battery voltages on the same scale and they will follow each other when the engine is not running.

Here are mine on a boat, twin alternator one for starter and one house. They start at about 10pm, starter battery is still full from days cruising and the domestic are declining under load so no trickle charging. 07:00 solar charging starts but not very well, by 09:00 when the house battery rises to 13.4V the starter battery increases to 13.1V, 0.3V behind. 13:00 to 16:00 we cruise, the two alternators dominate. after mooring up we have solar on the house battery and the trickle charger keeps the starter at 13.2V until solar is lost.

screenshot-20240706-221703-kindlephoto-1082531217.png

hope this helps you.understand how this works.

ps, the bog dips in starter battery voltage is the bow thruster being used.



screenshot-20240706-221703-kindlephoto-1082531217.png (40.9 KiB)
5 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

Simon Glet avatar image Simon Glet commented ·
Are the chemistries of your starter and house batteries the same? Or it doesn't matter?
0 Likes 0 ·
pwfarnell avatar image pwfarnell Simon Glet commented ·

Mine are both lead acid. If you have lithium house and lead acid starter then the trickle charge is not ideal because the higher lithium voltage will keep the starter battery permanently on charge with a permanent drain on the house battery. Depending upon your lithium battery BMS and load shut down, the trickle charger may not get isolated on a low battery voltage as it is not a controlled load, it is connected to the main DC power on the Multiplus.It is not recommended to use the trickle charge with lithium house batteries.

It works properly with lead acid on both because it only trickle charges when the house battery is being charged. It would probably be OK with lead acid house and lithium starter.

1 Like 1 ·
Simon Glet avatar image Simon Glet pwfarnell commented ·

You got me a little worried there ... I looked for Victron documentation but cannot find anything you mentioned. Could you point out in which manual I could find that information? Thanks

0 Likes 0 ·
Show more comments
kevgermany avatar image
kevgermany answered ·

@Simon Glet

From your graph it looks as if you have an intelligent/smart alternator. And starter battery voltage isn't going to trigger the engine detection properly. @pwfarnell graphs confirm this.

Might be easier to use the LH pin method to control the Orion on/off. There should be an unused switched connection in the wiring of the truck. Or use the switched radio positive, tapping into that.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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