The specs for the MPPT 75/10 say it dissipates about 250 mW. I have an ultra low power application and this is a significant waste of power, especially when the sun isn't shining. My system knows when the sun is shining, so it could control the 75/10. How can I turn off the 75/10 during low light so power isn't wasted ? Is there another model that does not use so much power ?
What about using a relay to disconnect the MPPT?
You can find "latching" relays that consume power only when changing state.
Hi @NewtownGal
You could add a diode between battery and MPPT, but you'll have to account for the voltage drop, and have a diode that can dissipate the heat.
@Daniel: Doesn't the MPPT need a constant source of power ? I assume you're suggesting that the diode be oriented so power flows from the MPPT to the battery, but not vice-versa, so it would only have power when it gets it from the solar panel. And how could the MPPT monitor battery voltage to charge the battery properly if there's a diode in the way ?
@Kevin: I'm hoping I can send a command to the MPPT to enter a sleep state so its power consumption is almost nothing, rather than adding more circuitry, and then a wakeup command when the sun is shining.
Hi @NewtownGal
diode:
charging is no problem, but the unit will of course switch off when no sun is available.
You ask for something non-standard, so there are downsides...
How can the MPPT monitor the battery voltage to charge it properly if there's a diode between the MPPT and the battery, where the diode is oriented so it only allows current to flow from the MPPT to the battery ?
Since the MPPT is programmable, how about adding a sleep mode to it ? I would like to send a command to it to enter or leave sleep mode.
Can Victron please handle and solve this question? It is a quite urgent problem. A large customer group in Norway evaluate to stop using the Victron MPPT due to high unesesary idle consume. It should not be to hard to make a FW uppgrade which make it possible to reduce the (high) power consume when there is no sun. Example reduce the MPPT tracking to once per 5minute when no sun for a hour, or a custom variable in the setting? It exist MPPT systems which consume less than 1/100 of what Victron have.
Thanks
