Wall Connector Powersharing Question/Help

[terranx]

What size breaker do you have feeding your sub? I was checking my setup and I'm going to be replacing a NEMA 14-50 plug so I may be limited to a 50 amp feeder breaker. So in this case I'm just trying to figure out the best approach to get maximum charging using power-sharing.

I'm thinking feeding the sub panel with the 6/3/ 50 amp feeder, then doing two separate 50 amp breakers in the sub and feed those to the wall connectors. Limit the power sharing to the two connectors to 40 amps and call it a day. Would that work?

I have a 60A breaker feeding it. Technically if I'm splitting 65A * 0.8, I guess I should upsize 70A breaker using the round up rule, but it doesn't trip with 52A being drawn and nothing is running off the sub panel to actually exceed 60A for a non-continuous load. The wiring itself is good for 65A, so there's no fire hazard.

You can do what you plan - but your wiring does support 55A. So you could theoretically install a 60A breaker feeding the sub, configure the two connectors to 48A, and set the network limit to 44A -- that will limit each connector to 44A (so you're not exceeding 55A * 0.8) individually and combined

You cannot set the WC to 48A, your choices are 15, 20, 30, 40, 50 or 60 so please elaborate.

It's been a while since I did the initial commissioning so maybe during that setup it has you select the breaker size. In which case set your breaker and the limit to what your wiring supports. The wall connector will draw 80% of that setting.

During the power sharing setup, it asks for the actual current draw, not the breaker size. So set the power sharing limit to whatever continuous load your wiring supports.

 

[brush1]

I have a 60A breaker feeding it. Technically if I'm splitting 65A * 0.8, I guess I should upsize 70A breaker using the round up rule, but it doesn't trip with 52A being drawn and nothing is running off the sub panel to actually exceed 60A for a non-continuous load. The wiring itself is good for 65A, so there's no fire hazard.

You can do what you plan - but your wiring does support 55A. So you could theoretically install a 60A breaker feeding the sub, configure the two connectors to 48A, and set the network limit to 44A -- that will limit each connector to 44A (so you're not exceeding 55A * 0.8) individually and combined


It's been a while since I did the initial commissioning so maybe during that setup it has you select the breaker size. In which case set your breaker and the limit to what your wiring supports. The wall connector will draw 80% of that setting.

During the power sharing setup, it asks for the actual current draw, not the breaker size. So set the power sharing limit to whatever continuous load your wiring supports.

Well that's good news as I'm trying to get the full 48amps. Do you know if it matters what size subpanel is needed? Would a 100amp suffice or would I need larger?

 

[terranx]

Well that's good news as I'm trying to get the full 48amps. Do you know if it matters what size subpanel is needed? Would a 100amp suffice or would I need larger?

Just needs to fit the number of breakers you need and it either has a main lug input or a main breaker that's at least as large as the breaker that's feeding it. There's no harm in oversizing though - and if you eventually plan on having more than just the Tesla chargers coming off it, having the capability to have a little more capacity is not a bad thing.

 

[Sophias_dad]

Well that's good news as I'm trying to get the full 48amps. Do you know if it matters what size subpanel is needed? Would a 100amp suffice or would I need larger?

You are confusing me. You earlier stated you have 6-3 NMB in the wall now. You can only draw 44 amps continuously from that.

As far as panel size, certainly 100 amp is fine. There may even be >some< 60 amp subpanels that would allow you to install dual 60 amp duplex breakers, but it would certainly be strange.

 

[qdeathstar]

I think you missed the point. I do not use load sharing and was trying to confirm from what I have read.

I think you missed the point. I do not use load sharing and was trying to confirm from what I have read.

When using load sharing you set the maximum capacity (breaker size) for use by all units in the share pool, the 80% number does not apply. For example if I ran an 80 amp circuit to the subpanel where each wall connector braniched from, then the circuit limit would be set to 80 amps to match the breaker. With just one unit online an 80 amp circuit is available but since the wall connector is set to 60 amps it uses only 48 amp. If two units are online then each is told they are on a 40 amp circuit and each wall connector would use only 32 amps (80%).

Can someone who is using sharing confirm or correct this?

When using load sharing you set the maximum capacity (breaker size) for use by all units in the share pool, the 80% number does not apply. For example if I ran an 80 amp circuit to the subpanel where each wall connector braniched from, then the circuit limit would be set to 80 amps to match the breaker. With just one unit online an 80 amp circuit is available but since the wall connector is set to 60 amps it uses only 48 amp. If two units are online then each is told they are on a 40 amp circuit and each wall connector would use only 32 amps (80%).

Can someone who is using sharing confirm or correct this?

Well, you said load sharing so which is it? Load sharing or not.

Being that you set the controller to max current draw (48 amps) the controller will only allow both units to draw up to 48 amps combined.

 

[brush1]

You are confusing me. You earlier stated you have 6-3 NMB in the wall now. You can only draw 44 amps continuously from that.

As far as panel size, certainly 100 amp is fine. There may even be >some< 60 amp subpanels that would allow you to install dual 60 amp duplex breakers, but it would certainly be strange.

Everything I've read is 55 amps continuous, let me know if that's wrong. My plan was to remove a NEMA 14-50 plug, replace the 50 amp breaker at the main with a 60 amp breaker. There is 6/3 nmb wire that will be previously run in the walls inside. I'm then going to extend the 6/3 wires to the 100 amp sub panel. From there I'll have two 60 amp breakers that will each run to a wall connector. I'll limit powersharing between the two to a max of 48 amps. Hopefully that sums it up.

 

[terranx]

Everything I've read is 55 amps continuous, let me know if that's wrong. My plan was to remove a NEMA 14-50 plug, replace the 50 amp breaker at the main with a 60 amp breaker. There is 6/3 nmb wire that will be previously run in the walls inside. I'm then going to extend the 6/3 wires to the 100 amp sub panel. From there I'll have two 60 amp breakers that will each run to a wall connector. I'll limit powersharing between the two to a max of 48 amps. Hopefully that sums it up.

6 AWG NM-B is only rated for 55A intermittent or 44A continuous

 

[brush1]

6 AWG NM-B is only rated for 55A intermittent or 44A continuous

Oh ok thanks, I'll limit it to 44amps with the power share

 

[STBR0510]

This is all seeming overly complicated. Gen 3 connectors require a separate circuit for each unit. I have one connector currently and about to add the second. First one is run directly from 200amp panel, 50 amp breaker using NMB 6/2. Second one will be run from same 200amp panel using 50 amp breaker and NMB 6/2. Each unit will be registered that they are on a 50 amp breaker and wifi power share link will be made. This is a better setup because there is a reduction in cost by eliminating the 125 amp breaker, the extra thick wiring needed to connect the sub panel, the sub panel itself. It will also reduce risk of fire by eliminating the additional connection points.