MPPT: which one?
- Thread starter xavpil
- Start date
BentleyJ
Solar Wizard
What is the voltage of your batteries? Assuming they are 12V or 24V and not 48V. Something like 2 x Victron 100/30 charge controllers would be a good choice.
12v.
May I ask how you calculate?
BentleyJ
Solar Wizard
Apologies, your OP did say 12V. There was another post today asking a similar question, got confused. Here is a general description of the process.
1) Most charge controllers are of an MPPT BUCK converter type meaning the PV input voltage must be at least 2-5V higher than the batt charging voltage.
2) Voc of the PV panels can never exceed the max input voltage of the charge controller.
3) The charge controller can be over-paneled with regard to Imp because any extra Amps available will be ignored and the system will perform better on poor solar days. Over paneling is usually limited to 20-25%.
4) The Victron 100/30 charge controller is rated up to 440W for charging a 12V battery so is a good match up with the 400W panel.
1) Most charge controllers are of an MPPT BUCK converter type meaning the PV input voltage must be at least 2-5V higher than the batt charging voltage.
2) Voc of the PV panels can never exceed the max input voltage of the charge controller.
3) The charge controller can be over-paneled with regard to Imp because any extra Amps available will be ignored and the system will perform better on poor solar days. Over paneling is usually limited to 20-25%.
4) The Victron 100/30 charge controller is rated up to 440W for charging a 12V battery so is a good match up with the 400W panel.
yabert
Solar Enthusiast
Victron for sure.
MPPT 75/15 is the cheapest and can be enough for your needs.
If you have more $$, MPPT 100/30 is more powerful than the panel, so perfect for you.
Tomthumb62
Solar Wizard
- Joined
- Sep 25, 2022
- Messages
- 1,871
.
Last edited:
yabert
Solar Enthusiast
Yes, it's why I edit my post.
''Can'' be enough because 400W panel will really give 200-320W depending of many parameter.
So obtain a real 15A at 13.2V (around 200W to battery) can be enough depending of the consumption.
''Can'' be enough because 400W panel will really give 200-320W depending of many parameter.
So obtain a real 15A at 13.2V (around 200W to battery) can be enough depending of the consumption.
so what do you suggest? (and thx for the input)
sounds good. I don't mind a little extra $ when justified.
Tomthumb62
Solar Wizard
- Joined
- Sep 25, 2022
- Messages
- 1,871
If he only needs to top it off, sure. But if he needs to fully recharge, then 150A would fill an 800Ah battery in 5.3 hours. Versus 53 hours at 15A.
WOW!!!!! Thx so much.
Tomthumb62
Solar Wizard
- Joined
- Sep 25, 2022
- Messages
- 1,871
Sorry I deleted my post since I'm unsure on the math. But it depends whether you just want to keep an 800Ah bank topped off or if you intend to drain it heavily. If you need to drain heavily, then you need more like 150A of charging power. If you only intend to use it lightly, then sure 15A might be enough.
150A = 5.3 hours to fully recharge your 800Ah bank
15A = 53 hours to recharge
60A = 13 hours
MisterSandals
Participation Medalist
<dumb post removed, sorry/>
Last edited:
Tomthumb62
Solar Wizard
- Joined
- Sep 25, 2022
- Messages
- 1,871
He said he has 2x400W panels and 2x400Ah 12v batteries. How could this ever be enough solar to charge an 800Ah bank? My math says that 150A of MPPT will charge in 5.3 hours, but the most I've seen recommended here is 60A (2x victron 100/30, one for each panel)
yabert
Solar Enthusiast
So, if you don't mind, buy more solar panels
Fill a 10.2 kWh battery pack from 800W of solar is a bit short.
Really depend of your consumption, but if you use power everyday on this boat, more solar is certainly a good idea.
Probably available space is challenging, right?
MisterSandals
Participation Medalist
Doh, i really got that wrong. I'm out. Carry on.
Similar threads
