over paneling and lowering max charge current in MPPT Solar charge controller

[akumd]

Some MPPT Solar charge controllers have the capability of supporting over paneling AND limiting the maximum charge current for the battery below SCC's max limit.
e.g. SRNE (or BougeRV), EPEVER, eSmart

What I mean by over paneling here is utilizing a lower wattage by using a higher wattage PV array (mainly targeting lower sun light conditions)

My question is (generally for over paneling supported + Current limiting capability present SCCs), if we lower the charging current (via it's configuring interface), does it also lower the maximum over paneling limit ?

e.g.
- Say we use a 60A MPPT SCC with 3 times over paneling capability (i.e. if max PV power for 12v is 720W, SCC can safely handle a PV array of up to 800x3=>2160W)
- Then we configure it's max charge current to be 20A (instead of 60A)

Can the SCC still handle a PV array of 2160W ? or does the max limit comes down to 720W (2160/3) ?
[My gut feeling is that it should still be 2160W, i.e. max PV power SCC can handle is NOT dependent on the actual current flown through the SCC. Since a lower current can anyway be present if the battery is fully charged and the load on the battery is low].

Sorry, I know this is a question for individual manufacturer of the SCC. But I am having a difficulty in getting timely responses from the manufacturer of the SCC I am eying on. Hence seeking help from this forum to get at least a generalized answer on this.

 

[timselectric]

Overpaneling refers to connecting more PV amperage than the SCC can use.
(VOC must never be exceeded)
Any SCC can be overpaneled. Current must be drawn, it's not pushed.
Having more available does not hurt anything. But it can be wasteful, sometimes.

 

[akumd]

Overpaneling refers to connecting more PV amperage than the SCC can use.
(VOC must never be exceeded)
Any SCC can be overpaneled. Current must be drawn, it's not pushed.
Having more available does not hurt anything. But it can be wasteful, sometimes.

Some SCCs specify a maximum limit (regardless a low current is drawn)
e.g. EPEver specs say over paneling limit is 3 times the rated value.
MakeSkyBlue clearly says NOT to over panel

60A 24V MPPT Solar Charge Controller for 24V Li-NMC and LifePO4 Lithium battery V120 PV Start ON&BMS Activation

60A 24V MPPT Solar Charge Controller Intelligent Maximum PowerPoint Tracking technology Built-in High-Performance DSP controller PV Start ON&BMS Activation ( Very important for Li-NMC and LifePO4 battery ) Three-stage charging optimizes lead-acid battery performance Charging voltage accuracy is...

makeskyblue.com

 

[littleharbor2]

Some SCCs specify a maximum limit (regardless a low current is drawn)
e.g. Ever specs say over paneling limit is 3 times the rated value.
MakeSkyBlue clearly says NOT to over panel

60A 24V MPPT Solar Charge Controller for 24V Li-NMC and LifePO4 Lithium battery V120 PV Start ON&BMS Activation

60A 24V MPPT Solar Charge Controller Intelligent Maximum PowerPoint Tracking technology Built-in High-Performance DSP controller PV Start ON&BMS Activation ( Very important for Li-NMC and LifePO4 battery ) Three-stage charging optimizes lead-acid battery performance Charging voltage accuracy is...

makeskyblue.com

View attachment 210112

 

[hwy17]

Over paneling limits are a dubious concept. I think they have more to do with the manufacturer not wanting to accept the safety considerations of the higher short circuit current available.

If the above is true, then lowering the configured battery amps output should not change the overpanelling limit I think, as the short circuit safety factor for the physical components remains the same.

 

[Mattb4]

Think of it this way. What happens when your battery gets full and the SCC cuts amperage down to almost nothing? What factor of OP (over paneling) exists then?

 

[Pi Curio]

If you are within your SCC Voc and Isc limits and have more array wattage than the SCC can use at specific system voltage, lowering the charging current to 20A from 60A does not affect the array size you can install, or over paneling for that matter.

Only the SCC Voc and Isc limits can limit the array wattage you can install.

 

[timselectric]

Some SCCs specify a maximum limit (regardless a low current is drawn)
e.g. Ever specs say over paneling limit is 3 times the rated value.
MakeSkyBlue clearly says NOT to over panel

60A 24V MPPT Solar Charge Controller for 24V Li-NMC and LifePO4 Lithium battery V120 PV Start ON&BMS Activation

60A 24V MPPT Solar Charge Controller Intelligent Maximum PowerPoint Tracking technology Built-in High-Performance DSP controller PV Start ON&BMS Activation ( Very important for Li-NMC and LifePO4 battery ) Three-stage charging optimizes lead-acid battery performance Charging voltage accuracy is...

makeskyblue.com

View attachment 210112

It can't hurt anything, unless the SCC develops an internal short.
If concerned, just add a fuse rated at the limit.
But if the SCC develops a short, it's already toast anyway.
The fuse can only limit the aftermath.