I think 70A is pretty low these days, consider upgrading to at least 100A.Hey all, OP here. Quick update.
Now that summer has fully set in and the temps are up, I've started using the central AC in my condo. When the AC system starts up, the inrush current usually trips the DCC. I guess that means it works.The downside is that it basically makes charging impossible whenever the AC is on because the 15-minute timeout cycle of the DCC usually aligns with the duty cycle of the AC system.
When the AC is running, I can start charging the car and the DCC won't trip. It only trips when the reverse happens (the car is already charging and the AC system's startup current surge trips it).
At this point I'm starting to think about possible solutions. The AC system is very old (30 years). I haven't replaced it because it still works, and why fix what isn't broken? A friend of mine suggested a startup capacitor kit. Seems a lot cheaper than replacing the whole system. Any tips?
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I live in a condo. The main breaker is only 70A. Now what? [Resolved]
- Thread starter andy92782
- Start date
brucet999
Active Member
It may be time to replace that 30-year old system anyway. You may be due for a compressor failure and/or possible refrigerant leak.Hey all, OP here. Quick update.
Now that summer has fully set in and the temps are up, I've started using the central AC in my condo. When the AC system starts up, the inrush current usually trips the DCC. I guess that means it works.
When the AC is running, I can start charging the car and the DCC won't trip. It only trips when the reverse happens (the car is already charging and the AC system's startup current surge trips it).
At this point I'm starting to think about possible solutions. The AC system is very old (30 years). I haven't replaced it because it still works, and why fix what isn't broken? A friend of mine suggested a startup capacitor kit. Seems a lot cheaper than replacing the whole system. Any tips?
Today's AC equipment is much more energy efficient than old ones and they use more eco-friendly refrigerants. I would get a couple of opinions/quotes from competent HVAC contractors. You might be surprised at how much the lower energy consumption of new equipment mitigates the cost.
The thread is about the prohibitive cost of upgrading in this case and the options.
Op - a start cap is cheap, if you can find someone that will install for a reasonable price. I’d try that. But do consider energy cost saved with a new system.
If you lower the current in the car 4-5a, does that put you under the cutoff point?
While it would be nice to have a more energy efficient system, so long as the existing system works (it does), there's no economic incentive to change it out. The climate is pretty mild here in OC and I only use it a couple months out of the year.
I dropped charge current from 24A to 16A and it still tripped.
Today I learned what "LRA" stands for (in the context of HVAC): Locked Rotor Amps. It's more or less the startup/inrush current spec for an AC compressor. The LRA rating on my 2.5 ton unit manufactured in 1989 is 83. I suspect the DCC has a problem with this.
Googling around, it appears a modern 15-seer unit with the same cooling capacity has LRA ratings in the low 60s.
On a start your AC (and any AC) has current about 5 times higher than it takes after start. Very short time, but voltage dropping pretty low, you probably can see as light is dim for a moment. This leads to your charger stop charging as a fire preventive measure. I do not think that new AC will have lower starting current. Problem here can be aluminium wires (if they are aluminium), long distance to transformer, low gauge supplying wires to the house and so on. Just try to charge car overnight when AC runs not too often, or you can ask you energy provider to fix this, but it can be costly.
Yep... looks like it’s time for a new AC system. Something with an inverted compressor like a mini-split will have an even lower inrush.
Carrier greenspeed, with a very nice ~20 SEER, in the 2-3 ton range has LRA of 24 amps. They also only want a 30 amp circuit breaker.
It's also a heat pump, in case you ever want heat in southern california.
It's also a heat pump, in case you ever want heat in southern california.
Personally, I’d try the motor start capacitor kit first. Don’t fix what isn't broken, and for those that worry about environmental reasons, junking a perfectly good AC system isn’t exactly environmentally friendly either.
Akikiki
A'-Lo-HA ! y'all
Congratulations on. Good read on all you went through. I am sure you already got your 2018 tax credit on the car. Separate from that, the feds re-enacted a rebate for EV charging. You are good a research. Take a look, I bet you can find it. Would help offset part of those costs. It is credited in the year you did it. I guess you will need to amend your 2018 to get it. Take everything they offer.
I also encourage you to look to your state, city and utility for a rebate on replacing your AC. They do it here if you pick the right one. Might be an option that pushes you to do that too.
I think Hawaii borrows a lot of HOA rule ideas and language from CA. I have solar. I was the first in a 350+ unit HOA to install Solar. So, I know the hill you will climb. But did it. Added two more times before city said whoa. I agree with what P85_D said regarding state law/rules insures you get to do stuff that HOA does not like or think about yet. Persistence pays.
I was trying to add more. City required that I upgrade the dual service panel for my neighbor too. The upgrade from dual 100 to 200 panel was $3,000 part covered by solar tax credits because it was required by city for the solar install. Helped.
So 4 Solar installs (why? that's a different story), and service panel upgrade later, plenty of power and PV to power the car, the ACs and the house.
I also encourage you to look to your state, city and utility for a rebate on replacing your AC. They do it here if you pick the right one. Might be an option that pushes you to do that too.
I think Hawaii borrows a lot of HOA rule ideas and language from CA. I have solar. I was the first in a 350+ unit HOA to install Solar. So, I know the hill you will climb. But did it. Added two more times before city said whoa. I agree with what P85_D said regarding state law/rules insures you get to do stuff that HOA does not like or think about yet. Persistence pays.
I was trying to add more. City required that I upgrade the dual service panel for my neighbor too. The upgrade from dual 100 to 200 panel was $3,000 part covered by solar tax credits because it was required by city for the solar install. Helped.
So 4 Solar installs (why? that's a different story), and service panel upgrade later, plenty of power and PV to power the car, the ACs and the house.
I literally just ordered a start capacitor off Amazon. It'll be here tomorrow. I'm hoping it'll do the trick.
A part of me wants the AC system to die so I can replace it, but.... They just don't make 'em like they used to, and I agree, if it ain't broke, don't fix it.
Many of those old systems just keep chugging along, consuming twice as much power as a modern system. The energy savings of a new system might completely offset the energy used by the car.
Let's say a new AC system consumes $100/mo less in electricity than the system I have now. I use it approximately 3 months per year (again, the climate is mild here), so that's $300 in savings per year. The ballpark price of a new HVAC system is approximately $8000. Simple math says it will take over 26 years to recoup my investment.
Watts_Up
Well-Known Member
In case the usage of a capacitor might not be sufficient, I was thinking about a little hack:
- Could you use your AC thermostat to also control an electrical relay?
If so, I was thinking to add a relay between your UMC and the plug where you connect your UMC.
So when your AC thermostat trigger the AC compressor, the relay can be used to disconnect the UMC at the same time.
Then, using a timer, after 30 seconds or one minute, you can again have the UMC connected again while the AC is running.
Note: This hack might be similar to what the DCC is doing, but the DCC don't let you have the UMC running while the AC is ON.
darth_vad3r
Well-Known Sith
Are you comparing that to your old system lasting another 26 years?!
This would work, and even better, if you could get into the signal-lines of the HPWC you wouldn't need to get an enormous relay to essentially replicate the contactors built into the HPWC. I wonder if the power-sharing protocol of the HPWC's is published and could be used to turn the charge level down to 0 or some similar tiny current for a minute when the AC is starting.
Yes you can do things like this, there are a few threads here on TMC that discuss hacking the HPWC load sharing protocol (New Wall Connector load sharing protocol), but the OP originally wanted something off the shelf that was up to code.
Personally, I think a little black box that turns off a HPWC via a signal cable would be a neat little product, but I don’t know how big the market would be or if anyone has built such a gizmo.
Yup. Hard to justify, but yours won’t last forever. However with the minimal use i’d likely agree with you.
Might also test / replace the run cap. It’s cheap and if it’s going bad it will make things worse.
⚡️ELECTROMAN⚡️
Village Idiot
I think you should open the windows and enjoy some fresh air and quit using that energy hog AC unit. What temperature is your thermostat set at?Hey all, OP here. Quick update.
Now that summer has fully set in and the temps are up, I've started using the central AC in my condo. When the AC system starts up, the inrush current usually trips the DCC. I guess that means it works.
When the AC is running, I can start charging the car and the DCC won't trip. It only trips when the reverse happens (the car is already charging and the AC system's startup current surge trips it).
At this point I'm starting to think about possible solutions. The AC system is very old (30 years). I haven't replaced it because it still works, and why fix what isn't broken? A friend of mine suggested a startup capacitor kit. Seems a lot cheaper than replacing the whole system. Any tips?
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