MASTER THREAD: Powering house or other things with Model 3

[miimura]

Excellent idea. I didn't think of that. What would you use to connect it?

I like these Renogy DC-DC chargers. The model linked is 20A, but it has a current limiting mode that tells the unit to only draw 50%. At that 10A level, you could use the 12V power socket in a Tesla or other EV to trickle charge your Aux battery. As long as your average load is less than 120W DC, that would keep it charged indefinitely. It has DIP switch settings for lead-acid Gel, Flooded, AGM, and sealed. It also supports 12V lithium batteries with voltages between 12.6 and 14.6 VDC without float.

12V 20A DC to DC On-Board Battery Charger

The best 12v battery charger. Free shipping. The DC-DC Battery Chargers are the most effective method to charge your home batteries from the starter battery

www.renogy.com

 

[rootusrootus]

The main benefit to that kind of setup is that you can power the surge load from the external battery and recharge it slowly and continuously from your EV. Whether the external battery is lead-acid and separate like that, or lithium, or part of an integrated battery / inverter / mobile device charging system doesn't matter.
If you have a setup like that but only charge it from utility power, you've basically built a UPS. The main benefit in that case is that you can choose any size battery you like.

Better to use an LFP these days, though. Lead acid too expensive, AGM in particular is wildly overpriced. Especially when all the components are otherwise bargain basement chinesium.

 

[miimura]

Better to use an LFP these days, though. Lead acid too expensive, AGM in particular is wildly overpriced. Especially when all the components are otherwise bargain basement chinesium.

Agree. There are so many integrated LFP batteries in common "12V" format on the market that you can use just like AGM. It just doesn't make sense to buy lead acid in most cases.

 

[PianoAl]

I like these Renogy DC-DC chargers. The model linked is 20A, but it has a current limiting mode that tells the unit to only draw 50%. At that 10A level, you could use the 12V power socket in a Tesla or other EV to trickle charge your Aux battery. As long as your average load is less than 120W DC, that would keep it charged indefinitely. It has DIP switch settings for lead-acid Gel, Flooded, AGM, and sealed. It also supports 12V lithium batteries with voltages between 12.6 and 14.6 VDC without float.

12V 20A DC to DC On-Board Battery Charger

The best 12v battery charger. Free shipping. The DC-DC Battery Chargers are the most effective method to charge your home batteries from the starter battery

www.renogy.com

Brilliant, thanks!

 

[n2mb_racing]

Agree. There are so many integrated LFP batteries in common "12V" format on the market that you can use just like AGM. It just doesn't make sense to buy lead acid in most cases.

Those are really common. I'm on the fence about 12V vs 48V. I have ebike batteries that I would use. 48V also makes the wires from the battery to the inverter much smaller and easier to deal with. I have a 1500W 48V pure sine inverter on order.... 48V LFP batteries are also starting to be common, but in larger sizes like 48V 100 Ah.

 

[miimura]

Those are really common. I'm on the fence about 12V vs 48V. I have ebike batteries that I would use. 48V also makes the wires from the battery to the inverter much smaller and easier to deal with. I have a 1500W 48V pure sine inverter on order.... 48V LFP batteries are also starting to be common, but in larger sizes like 48V 100 Ah.

IMHO, anything over 1000W should use a battery voltage higher than 12V. There are not many devices available at 24V, so you might as well jump up to 48V nominal, which is really up to 58VDC. The reason that there are not many inverters and other devices above 48V nominal is that the safety protocols take a big step up for anything above 60VDC.

 

[n2mb_racing]

IMHO, anything over 1000W should use a battery voltage higher than 12V. There are not many devices available at 24V, so you might as well jump up to 48V nominal, which is really up to 58VDC. The reason that there are not many inverters and other devices above 48V nominal is that the safety protocols take a big step up for anything above 60VDC.

Yeah, that's the frustrating part. My biggest ebike batteries are 60v and 72v (sur Ron) but there aren't any high quality inverters at that voltage.

 

[n2mb_racing]

I bought this one when it was on sale for $279. We'll see how well it works when it arrives.

Amazon.com

 

[PianoAl]

The deep cycle battery that I use during outages fails after about 2-3 days. I have the parts to do this:

1. Plug inverter into the Tesla's 12 V plug
2. Plug this device into the inverter and use it to trickle charge the deep cycle battery:

Is that silly, or would it work?

 

[n2mb_racing]

The deep cycle battery that I use during outages fails after about 2-3 days. I have the parts to do this:

1. Plug inverter into the Tesla's 12 V plug
2. Plug this device into the inverter and use it to trickle charge the deep cycle battery:

View attachment 893646
Is that silly, or would it work?

Too slow and a little bit inefficient. You can get a charger that goes direct from 12v to 12v.

 

[n2mb_racing]

Such as this:
Renogy 12V 20A DC to DC On-Board Battery Charger for Flooded, Gel, AGM, and Lithium, Using Multi-Stage Charging in RVs, Commercial Vehicles, Boats, Yachts, 20A https://a.co/d/giMIlup

 

[n2mb_racing]

Such as this:
Renogy 12V 20A DC to DC On-Board Battery Charger for Flooded, Gel, AGM, and Lithium, Using Multi-Stage Charging in RVs, Commercial Vehicles, Boats, Yachts, 20A Amazon.com

Or this, but could be faster:

ISDT Q6 Nano Lipo Battery Charger/Discharger, Balance Charger Discharger 8A 200W DC 2-6S LCD Display Digital Smart Battery Balance Charger Li-Po Li-Hv Li-Ion Li-Fe NiMH Ni-Cd Pb https://a.co/d/0wZmXa6

 

[n2mb_racing]

Or this, but could be faster:

ISDT Q6 Nano Lipo Battery Charger/Discharger, Balance Charger Discharger 8A 200W DC 2-6S LCD Display Digital Smart Battery Balance Charger Li-Po Li-Hv Li-Ion Li-Fe NiMH Ni-Cd Pb Amazon.com

This one will let you pull 12a from the outlet. ISDT Air8 Lipo Battery Charger, Balance Charger Discharger 20A 500W DC 1-8S LCD Display Digital Smart Battery Balance Charger Li-Po Li-Hv Li-Ion Li-Fe NiMH Ni-Cd Pb Amazon.com

 

[stesta5074]

I bet less than 1% of the population would ever power their house with their car. Why you'd want your $80k-$160k supercar to be used like that instead of a $300 generator escapes my comprehension.

 

[n2mb_racing]

I bet less than 1% of the population would ever power their house with their car. Why you'd want your $80k-$160k supercar to be used like that instead of a $300 generator escapes my comprehension.

The model 3 isn't a supercar. It's the California corolla. It's $36k base now.
I'd much rather use my car to power things in a power outage than run a noisy gas generator.

 

[cuti]

The model 3 isn't a supercar. It's the California corolla. It's $36k base now.
I'd much rather use my car to power things in a power outage than run a noisy gas generator.

I used to "play" with this technique daily for few months and luckily right moment when the hot wire started melting I were standing right next to the car and able to stop the potential of car burning. Now I have solar panels on my roof and generating so much of electric, I just realized extracting electric from the car is not worth it at all, it carries ALOT OF RISKS and degrade the HV battery much faster, DC_DC converter box is very hot after 1 hr extracting, replacing this box from Tesla already cost you over $3K ..anyway, I did not regret but it was a fun learning experiences to make it work

 

[n2mb_racing]

I used to "play" with this technique daily for few months and luckily right moment when the hot wire started melting I were standing right next to the car and able to stop the potential of car burning. Now I have solar panels on my roof and generating so much of electric, I just realized extracting electric from the car is not worth it at all, it carries ALOT OF RISKS and degrade the HV battery much faster..anyway, I did not regret but it was a fun learning experiences to make it work

True, solar makes a lot of sense. But, adding dedicated batteries for power backup doesn't pay off. Using the battery in your car for the once per year outage makes sense.

 

[n2mb_racing]

Also, if you have LFP batteries in your Model 3, then there is no degradation. You could charge and discharge daily and not have much impact at all on battery lifespan.

 

[stopcrazypp]

Also, if you have LFP batteries in your Model 3, then there is no degradation. You could charge and discharge daily and not have much impact at all on battery lifespan.

Note this is not strictly true. The impact is less given LFP has higher cycle life, but it's not zero.

 

[cali8484]

I used to "play" with this technique daily for few months and luckily right moment when the hot wire started melting I were standing right next to the car and able to stop the potential of car burning. Now I have solar panels on my roof and generating so much of electric, I just realized extracting electric from the car is not worth it at all, it carries ALOT OF RISKS and degrade the HV battery much faster, DC_DC converter box is very hot after 1 hr extracting, replacing this box from Tesla already cost you over $3K ..anyway, I did not regret but it was a fun learning experiences to make it work

Melting wire? What kind of power were you drawing?