Help with settings on Victron MPPT charge controller

[jonyjoe101]

check the voltage at the actual battery.... you might have some voltage drop. On my controller I have a .5 voltage drop. When the controller reads 14.4 volts the battery only reads 13.9 volts. To compensate I raise the the controller to 15 volts and the battery reads closer to 14.4 volts when fully charge. Otherwise the battery will never get a full charge on solar. And your controller the victron doesnt have a display built in that you can glance at.

At 13.9 volts its almost float voltage. This is very important with lead acids, they need that higher voltage to get a good charge. Also no problem leaving the float voltage at higher voltage like 14.4 volts, to prolong the absorption. Sometimes the absorption quits too soon. Don't worry agm's can handle being at higher volts all day long, you not going to damage them especially the oddeseys, they prefer those types of voltages. With a 100 watt panel you are at most trickle charging oddesey batteries, you run out of sunlight before they can ever get a full charge. Thats why someone recommended a wall charger.

Float voltages in the 13.6 volt range is only needed when you got the battery connected to a wall charger 24/7 weeks on end. The battery will actually get a full charge in that situation, and can be maintained at the lower voltages.

Your biggest risk is undercharging your batteries, they don't tolerate that very well.

 

[john61ct]

Better to locate the controller close to the bank and use a fat enough cable to reduce that voltage drop to .2V or lower.

It actually will vary with current level, so just boosting SC setpoint will not be consistent.

And accuracy is best for temperature compensation as well.

 

[DharmaInitiativePhoenix]

thanks so much for all the info and feedback. I've been battling issues with my brakes for the past few days and haven't been able to check the thread and reply. Getting ready for a week long trip up the coast and to the Redwoods starting next Sunday. I'll make sure I have all the settings dialed in before going. Lots of stuff left to wrap up and unfortunately I'm traveling for work most of next week. I was able to mount the SC inside the dash just on the other side of the firewall from the battery. Maybe a 2ft cable run at most.

 

[john61ct]

Only problem there is that SC doesn't have a temp sense wire like the bigger ones, so if temps are different on the other side it won't vary the voltage to suit.

Not a huge issue maybe, depends on the situation.

Just wanted others to be aware, best if the SC is right at the bank, in the same space, unless it is the type with a dedicated temp sense wire.