The plot thickens if you read the victron manual for their MPPT controllers - it actually shows a fuse on the solar input. Pretty weird…
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- Thread starter VANLIFETerry
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The plot thickens if you read the victron manual for their MPPT controllers - it actually shows a fuse on the solar input. Pretty weird…
Victron mppt’s have a fuse on the solar in side. If you connect the solar panel after connecting the output the fuse blows. Whilst technically you can’t replace the fuse it can be done but it’s a pain and can damage the casing. The solar isolator would prevent this, alternatively you need to cover the solar panel unless working at night to prevent solar generation when connecting up. Unfortunately I didn’t pay attention to the connection sequence and couldn’t cover the panel and blew the fuse. I tried following several videos on you tube but I wasn’t happy with the state off the board so replaced ounce I’d covered up the panel
I could have the wrong end of the stick completely here, but:-
You have to connect the solar panel before connecting the battery. If you connect the panel whilst the output of the MPPT is connected to the battery, the internal fuse blows. Have I interpreted this correctly?
If so, then having an isolator in the solar side would increase the chances of this happening. You want the solar permanently attached with the chances of it being disconnected/reconnected reduced to a minimum. If this situation arose in an industrial setting, there would be some kind of mechanical interlock which prevented the solar from being connected if the output from the MPPT was connected.
Like I said, I may have got this arse about face
@Salty Spuds that’s correct regarding the sequence of connecting up the mppt. However and I’m not an electrician it’s always suggested that when connecting the solar panel to the mppt the panel is in the dark, why I don’t know as whether you cover it or use an isolator once power is restored surely there’s no difference in what the mppt gets so it can’t be a surge or similar. Interestingly so far the only controllers it seems to affect are Victron regarding blowing the fuse. Whether other makes aren’t fused I don’t know and perhaps it’s part of the way the mppt monitors charge in and need I really don’t know
According to the Victron manual, it's the other way around. When starting the unit you have to ensure the battery is connected before the solar panel (and when shutting down you must disconnect the solar first) so an isolator would help to achieve this.
Seems like a daft design flaw if not doing this does actually cause the unit to blow an internal fuse. All it would take is for the battery to shut down (which lithium batteries can effectively do to protect themselves) or disconnect and you'd run the risk of blowing the MPPT??
Seems like a daft design flaw if not doing this does actually cause the unit to blow an internal fuse. All it would take is for the battery to shut down (which lithium batteries can effectively do to protect themselves) or disconnect and you'd run the risk of blowing the MPPT??
