No announcement yet.

Charge Controller Size

  • Filter
  • Time
  • Show
Clear All
new posts

  • Charge Controller Size

    Hello all, I have purchased a Hanwha Q. Peak Duo L-G8. 3, 425 watt solar panel. I have used the calculators online for sizing for a charge controller as well as 425 divided by 12 and both come to around 35 amps. Using the calculator, I had trouble entering the information in the fields because the sticker on my panel does not give the exact same information as the calculators require or maybe its just worded differently and I don't know the difference. Either way, could somebody in the know, please have a look at the specs of this panel and confirm my thoughts that going with a 40 amp MPPT charge controller would be fine for the panel. I have included the link here, just look at the 425 watt model specs to see what you think or any other things with this panel that I need to be aware of. Many thanks in advance.

  • #2
    What was missing from the calculator?

    A 40 amp MPPT will be sufficient. Just make sure that MPPT input voltage is rated greater than your panel has. Although it looks like 50 volts is sufficient, when it gets cold voltage goes up. That's what the "Temperature Coefficients" are for. Most MPPTs will be rated to what you need, but occasionally there is a low voltage MPPT.

    Not sure how important the 40 amps is to you. Depending on how you mount he panel, you may or may not come close to 40 amp charging current. I have a couple sets of flat panels on my RV that don't come close to max output in the winter due to angle of the sun, but I have a set of panels that I angle into and point at the sun and they can put out close to rated wattage.

    Also, if you want to add more panels at a later date, you'd need a separate 40 amp controller to add a second panel.