New MPPT 100/20

[Nina Lucia]

I just bought Victron MPPT 100/20 smart, we have starter battery and two domestic, Cyrix battery combiner and Victron battery monitor 712 , Victron shore power Charger with three outputs and just one 80W solar panel at the moment.
How to wire MPPT? PV connection is to the solar. Battery + to the domestic plus and negative to the negative bus bar after the shunt, and load?
I checked some wiring diagrams and looks like it’s only domestic battery that’s charged... what about load?
Any suggestions and or wiring diagram will be greatly appreciated. Thank you

 

[lustyd]

Yes that's pretty much how I'm doing it. My solar will just be to top up on trips so I have no need to charge the engine start battery, which will be disconnected anyway. The load connection is probably unnecessary for boat use but I think Paul Rainbow mentioned something useful for it once

 

[RupertW]

Yes that's pretty much how I'm doing it. My solar will just be to top up on trips so I have no need to charge the engine start battery, which will be disconnected anyway. The load connection is probably unnecessary for boat use but I think Paul Rainbow mentioned something useful for it once

Our 100:50 is also set up to domestic only after the shunt, but with a fuse between shunt and MPPT.

I wish the 100:50 also had a load output - instead I have had to spend money on a programmable VSR connected to a high current VSR to imitate the Load output. Basically we use the output to heat the immersion tank so that any extra solar gets used and if it’s cloudy we just have to put the engine on for 20 minutes - but it’s nice not to.

 

[jwfrary]

Load on a yacht installation shouldn’t be connected. If the charge voltage is sufficient then the cyrix combiner will close and your starting battery will charge.

be aware you will likely benefit from a firmware update and you could smart network your mppt to your 712 and the voltage supplied will be compensated.

the charge curve may also need adjustment. Easy to do from the victron connect app

 

[jwfrary]

Our 100:50 is also set up to domestic only after the shunt, but with a fuse between shunt and MPPT.

I wish the 100:50 also had a load output - instead I have had to spend money on a programmable VSR connected to a high current VSR to imitate the Load output. Basically we use the output to heat the immersion tank so that any extra solar gets used and if it’s cloudy we just have to put the engine on for 20 minutes - but it’s nice not to.

Yes there’s smart things you can do with it. For sure

 

[Nina Lucia]

Load on a yacht installation shouldn’t be connected. If the charge voltage is sufficient then the cyrix combiner will close and your starting battery will charge.

be aware you will likely benefit from a firmware update and you could smart network your mppt to your 712 and the voltage supplied will be compensated.

the charge curve may also need adjustment. Easy to do from the victron connect app

Thank you

 

[Nina Lucia]

Thanks, as usual, great support from forum!

 

[RupertW]

Thank you

But he’s not right on his first point - no reason at all not to connect if you have something useful for spare solar.

 

[Nina Lucia]

But he’s not right on his first point - no reason at all not to connect if you have something useful for spare solar.

Thanks Rupert,
Where shall I connect Load then? I have, at the moment only one 80W solar panel, shall connect load to the fridge? Immersion heater is 220V, I don't think it would help there? I can't see how how would work if connected to lights? I really don't understand that "Load" output... unless, we have a lots of solar panels
Thanks You

 

[Pete7]

Yep, ignore the load, you will need all of those 80w to keep the house bank charged on a yacht. What you might do is fit a battery sense widget from Victron and pair it on the network to the MPPT. This means the MPPT gets to know the exact battery voltage and temperature, particularly if they are separate. Had ours for a year and been really surprised how much the battery temperature varies. You will also want to fuse or use circuit breakers between the panel and the MPPT and between the MPPT and the batteries. Using the app can be addictive in use

 

[noelex]

The load outputs on a solar regulator are not commonly used, but if you wish these can be used to switch some loads intelligently.

For example, these terminals can be used turn on an anchor light at night, or a fridge off if the battery voltage drops too low (although this might need a relay). The capabilities depend on the solar controller, but the small Victron units can be programmed to perform several similar functions. The app will record the power usage delivered by these terminals which can be useful in some situations.

However, the load connections, despite the name, are not suitable for the majority of boat loads. In fact most installations do not use these terminals.

 

[jwfrary]

But he’s not right on his first point - no reason at all not to connect if you have something useful for spare solar.

true enough. But on the typical simple yacht it’s not usually used.

water heater switching is a good example but requires an altogether more sophisticated system.

I guess you could use spare solar to charge your phone!?

 

[PaulRainbow]

Thanks Rupert,
Where shall I connect Load then? I have, at the moment only one 80W solar panel, shall connect load to the fridge? Immersion heater is 220V, I don't think it would help there? I can't see how how would work if connected to lights? I really don't understand that "Load" output... unless, we have a lots of solar panels
Thanks You

Ignore the load.

 

[PaulRainbow]

Yep, ignore the load, you will need all of those 80w to keep the house bank charged on a yacht. What you might do is fit a battery sense widget from Victron and pair it on the network to the MPPT. This means the MPPT gets to know the exact battery voltage and temperature, particularly if they are separate. Had ours for a year and been really surprised how much the battery temperature varies. You will also want to fuse or use circuit breakers between the panel and the MPPT and between the MPPT and the batteries. Using the app can be addictive in use

No need to fuse between the panel and controller Pete. But yes, fuse from the controller to the battery, close to the battery.

 

[noelex]

No need to fuse between the panel and controller Pete. But yes, fuse from the controller to the battery, close to the battery.

In some applications fusing on the solar panel side (in addition to fusing between the battery and controller) is needed.

This is generally when there are three or more strings connected in parallel.

 

[Pete7]

No need to fuse between the panel and controller Pete.

Interesting, could you elaborate please. I have 7m run wire from the panel to the MPPT, that's a lot bends and twists some out of sight. What would happen if there was a short either between the L and N from the panel or say to a metal part of the yacht. The panel is 300w so 30v and about 10A.

 

[PaulRainbow]

Interesting, could you elaborate please. I have 7m run wire from the panel to the MPPT, that's a lot bends and twists some out of sight. What would happen if there was a short either between the L and N from the panel or say to a metal part of the yacht. The panel is 300w so 30v and about 10A.

It will likely stop charging, but it won't burst into flames or explode.

 

[PaulRainbow]

In some applications fusing on the solar panel side (in addition to fusing between the battery and controller) is needed.

This is generally when there are three or more strings connected in parallel.

The OP has an 80w panel.

 

[Ningaloo]

For example, these terminals can be used turn on an anchor light at night

I must be missing a trick here. You mean my solar works at night too?

 

[jwfrary]

I must be missing a trick here. You mean my solar works at night too?

The load outputs not used to supply the anchor light just switch it in this case using a relay.

but I’m not sure I would bother automating Nav lights personally