question

saint-barra avatar image
saint-barra asked

Rectifier to Victron Smartsolar MPPT 75/15 charge controller (bluetooth)

Hi all,

Sorry if I'm way off the mark on this one but just wondering if I can connect the above Victron Smartsolar controller to the rectified output of my 30hp Yamaha outboard engine. It would be used to charge a lithium battery. (probably between 10Ah and 50Ah)


I currently have an 18Ah AGM battery directly connected to the output from the rectifier but note that sometimes the voltage will reach as high as 24 volts.

Thanks in advance for any guidance you can provide
MPPT Controllers
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.

1 Answer
wkirby avatar image
wkirby answered ·

This is risky. The maximum input short circuit current of the 75/15 is also 15A. This means that if the input goes low impedance during a PV scan then the input current could exceed 15A and the MPPT would be damaged. Perhaps the engine alternator could be damaged too.

Is the engine electric start? If so, it would be better to use an Orion to charger the Lithium battery from the starter battery.

4 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.

saint-barra avatar image saint-barra commented ·
Thanks for the reply. It’s a pull start engine
0 Likes 0 ·
kevgermany avatar image kevgermany ♦♦ saint-barra commented ·
That's a huge voltage for a 12V system. Could be wiring fault or a faulty alternator. If not faulty I would check the input voltage range for any DC:DC charger you consider. Guessing that's why you are looking at a solar controller.



If you can't find a charger that can handle it, consider a zener diode to earth away the excess voltage. British motorcycles used to have one housed in a heat sink. Crude... But it worked.

0 Likes 0 ·
saint-barra avatar image saint-barra kevgermany ♦♦ commented ·
Okay, thanks for that. Really appreciate your input.
0 Likes 0 ·
Andrew Jefferies avatar image Andrew Jefferies commented ·

Wkirby, please will you double check your reply.. I can understand that that would be the case with PWM but these are MPPT & should limit the current passed thro the load, I think the 2x(per say) panel SSC is mainly to do with the reverse polarity protection.. There is a connection thro the MPPT the -ve that has the current shunt therefore NO external or common ground would be permitted.. +ve & -ve Panel connections are floating wrt gnd & so should any other DC source..

0 Likes 0 ·