BYD VTL to Huawai Sun2000 M0 hybrid inverter

[byd-v2l]

you can buy 3kW Chinese AC/DC converter too, I dont use such setup yet but glad others figured it out too

[alain]

Sure. that brand sells converters up to 4kw. But it really depends on what export limits your car has. BYD Seal wont export more than 2 kw, so it would be useless to buy a 3kw converter unless you hack the car to increase the export limit.

https://www.lazada.co.th/products/24v12v36v48-dc-1000w3000w2019-i4819930909-s20017191519.html?

[alain]

but to be honest… i never tried to export more than 2kw. maybe it works…

@Svarky is the expert on that.

BYD Atto 3 V2L load testing - Vehicle-to-load power output

Here are the results from my BYD Atto 3 vehicle-to-load (V2L) testing. There was some conflicting information online about the power output rating from the Atto 3 being either 10A or 15A so I decided to find out for myself. I was assuming the power output would be closer to 10A continuous with a 15A peak output rating and it appears this is the case. My Test Setup: I have an off-grid solar-powered house running on a Victon Multiplus 2 inverter-charger (plus VRM and CCGX display) with a 15A inpu…

[Mart]

Running an aircon from the V2L BYD Seal

Continuing the discussion from BYD Atto 3 V2L load testing - Vehicle-to-load power output: I took a different approach with my V2L set up. I have an Alpha ESS inverter with 10kWh battery and 9.6 Kw solar panels. I just wanted to run my air con overnight from my EV battery as the existing 10kwh battery just wasn’t up to the job of running an 18000 BTU and 12000 BTU air con overnight (it was down to 20% after 4 or 5 hours) I installed wiring with ATS switches on my living room and bedroom whic…

[icecreamshootingsnow]

Yeah, you can totally use your BYD Seal’s battery to power your home at night with that setup. Just make sure everything’s compatible and the connections are solid. You might wanna double-check with a pro to avoid any risks of damage or fire, though. Better safe than sorry, right? Keep that innovative vibe going!

[Mservice]

Hey @alain @Svarky - I have a BYD seal and have wired the BYD v2L cable provided into BOTH gen inputs of our TWO DEYE hybrid 8kw inverters (10.4kw Solar PV each) through a 15amp breaker.

We then tell the DEYE inverter in the settings to limit the gen capacity to 2kw in the software (Even though BYD advise me it’s a 3.3kw limit actually) … and we do not connect the ground cable in the V2L cable through our breaker as for whatever reason this causes the system to not engage.

Strangely we find the same symptom as you … it operates fine for a couple hours providing about 1.5-2kw … but after a time (sometimes 20 minutes … sometimes a few hours ) there is a browning or flicker of lights (say if the aircon kicks in) and the V2L stops supply.

DEYE technical have shown me charts that suggests the V2L isn’t kicked out and instead it’s voltage at the input simply drops from 220V to 5 V … ie deye says it’s BYD issue.

BYD says - is there a problem with your car ? No? Then we are not interested …

So now I am stuck … because the plan was to buy this car to use overnight to protect the fully charged house battery … so that we had enough (20kwhr) to kickstart the distillery in the morning before the sun truly got the PV pumping …

PS @alain why did you go for only 1.5kw converter when you could go up to 3.3… or at least the 2.4kw stamped on the V2L cable ?

[alain]

Hi @Mservice ,
Actually i recently switched to a Deye inverter as well, after my PowMr inverter blew up one day.
But mine is a 3 phase inverter (20kw), and the Gen port is 3 phase as well. It’s interesting to see someone connected a BYD over the Gen input. In theories it should be way more efficient, since you don’t have to convert AC-DC-AC. Will check if converting from 1 to 3 phase would lose less energy. If so, i might adopt your solution.
To address your problem… I had the same issue with the 2kw converter I used previously. That’s why i switched to a 1.5 kw converter.
Now it runs continuously all night. But what it permanently does is supplying load in some kind of Pulses. The output of my converter constantly jumps up and down. Don’t know if it was the same with the 2kw converter, since that one did not have a display showing Amps.
But nevertheless it does not cause the car to shut off export anymore.

I don’t know if your Deye Inverter does have the same functions, but mine has one function you can select to switch Gen port to Grid port. If you have that too, and are off-grid, you might try connecting the BYD to the Grid input instead while activating that option.
Also make sure you activate the Gen-force option and set the max gen battery charging amps to 0 unless you wish to charge your home batteries using the BYD.

[Mservice]

Hi Alain yes indeed we have been considering using an auto transfer switch to exit the grid and switch over to the V2L but this requires a manual change of settings in the inverter (time of use settings change to prevent the house battery from being discharged.)

I liked the idea of yours because introducing the new supply as a light sensed based switch on a solar string enables the v2L to be prioritised over consuming the house battery (we use this to jump start the distillery for the first hour in the early morning before SPV comes online)… and it does this without having to make any settings changes on a daily basis in the time of use menu (or any other one)

My problem is still this instability … and I can’t seem to get to the bottom Of what’s causing it … some nights it will run for hours and other nights it kicks out after but a few minutes and eventually this behaviour coincides with the car going to sleep !

[Mservice]

You can see here the saw tooth profile of my V2L kicking in and out through the night as it charges the house battery (slowly) and runs the (minimal) loads through the night

(attachments)

[alain]

@Mservice

ery (slowly) and runs the (minimal) loads th

I just asked Deepseek for advice and got an interesting answer:

question:
I connected the vtl plug of my byd seal to an 1.5kw AC-DC converter connected to a solar string input of my Deye inverter. At night i use it to power my home. what i noticed is that the power output seems to constantly jump up and down (in the power production statistic of my inverter it shows a zigzag line). what could be the reason for that and should i worry about it?

Deepseek:
The fluctuating power output (zigzag pattern) from your BYD Seal V2L (Vehicle-to-Load) → 1.5kW AC-DC converter → solar input of Deye inverter setup can be caused by several factors. Here’s a breakdown of possible reasons and whether you should be concerned:

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Possible Causes of Power Fluctuations

1. V2L Output Instability

• Some EV V2L systems (including BYD) have pulsating or non-sinusoidal AC output, which may not be perfectly compatible with your AC-DC converter.
• The converter might struggle to maintain a stable DC output, causing the inverter to see erratic power.

2. AC-DC Converter Issues

• Cheap or undersized converters can have poor voltage regulation, leading to fluctuations.
• If the converter lacks power factor correction (PFC), it may interact poorly with the inverter’s MPPT (solar input) algorithm.

3. Inverter MPPT Confusion

• The Deye inverter’s MPPT (Maximum Power Point Tracking) is designed for solar panels, not a fixed DC source like a converter.
• The MPPT may constantly “hunt” for an optimal power point, causing the zigzag pattern.

4. Grounding or Noise Interference

• Improper grounding between the V2L, converter, and inverter can introduce electrical noise, leading to unstable readings.
• High-frequency switching in the converter may also interfere with the inverter’s sensors.

5. Battery Voltage Variations (BYD Seal Side)

• If the BYD Seal’s battery management system (BMS) adjusts discharge rates (e.g., due to temperature or load changes), it could cause power ripples.

6. Overloading or Throttling

• If the setup nears the 1.5kW limit of the converter, voltage drops or thermal throttling could cause instability.

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Should You Worry?

• Moderate Concern:
  • If the fluctuations are small (±50W), it’s likely just MPPT noise and not harmful.
  • If the system keeps running without errors, it’s probably fine for occasional use.
• High Concern:
  • If the inverter frequently faults or the converter gets very hot, there’s a risk of component damage.
  • Large swings (>200W) could indicate compatibility issues that may stress the system long-term.

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Recommended Fixes

1. Bypass the MPPT (Best Solution)

• Connect the converter’s DC output to the inverter’s battery terminals (if supported) instead of the solar input.
• This avoids MPPT confusion and provides stable power.

2. Use a Dummy Load or Capacitor

• Add a small resistive load (e.g., 50W heater) to stabilize the converter’s output.
• A large capacitor bank (e.g., 10,000µF) on the DC side may smooth fluctuations.

3. Upgrade the AC-DC Converter

• Use a high-quality, PFC-enabled converter (e.g., Victron or Mean Well) rated for continuous 1.5kW.

4. Adjust Inverter Settings

• Try setting the Deye’s MPPT voltage range manually (if possible) to match the converter’s output.

5. Check Grounding & Wiring

• Ensure all devices share a common ground and use shielded cables to reduce noise.

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Final Verdict

• Short-term: If the system works without overheating/faults, it’s probably safe, but monitor closely.
• Long-term: Bypassing the MPPT (by connecting to battery terminals) or using a dedicated DC-DC converter is the most reliable fix.

Would you like help finding a compatible converter or wiring diagram for a more stable setup?

Question:
how about connecting directtly to the Gen input of the inverter? would this cause any issues?

Answer:

Connecting your BYD Seal’s V2L output directly to the generator (Gen) input of your Deye inverter could be a viable solution, but there are key considerations to avoid damage or instability. Here’s what you need to know:

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Pros of Using the Gen Input

1. Designed for AC Power Sources

• The Gen input is meant for grid/generator power, so it should handle the BYD Seal’s V2L output better than the solar (MPPT) input.

2. Stable Voltage & Frequency Handling

• Unlike the MPPT (which expects variable DC from solar), the Gen input accepts AC and synchronizes with it, reducing fluctuations.

3. Bypasses MPPT Confusion

• No more “zigzag” power hunting since the inverter treats the V2L as a standard AC source.

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Potential Issues & Risks

1. Frequency & Voltage Stability

• Some EVs (including BYD) have non-standard sine waves or slight frequency drift in V2L mode.
• If the Gen input expects perfect grid-quality power (50Hz/60Hz ±0.5%), it might disconnect or fault if the V2L output isn’t stable enough.
• Test with a multimeter/oscilloscope to check voltage (220-240V?) and frequency (50/60Hz?).

2. Neutral-Ground Bonding Conflict

• EVs often have floating neutral in V2L mode, while inverters may expect bonded neutral-ground (like a generator).
• This could cause ground faults or nuisance tripping.

3. Power Limits

• The Gen input may have a minimum load requirement (e.g., some inverters ignore tiny loads).
• If your V2L output is <500W, the inverter might not recognize it.

4. Backfeed Protection

• If the inverter tries to send power back to the Gen input (e.g., during grid-tie mode), it could damage the BYD’s V2L circuit.
• Ensure the inverter is in off-grid/isolated mode with no backfeed.

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How to Test Safely

1. Check Inverter Manual

• Verify if the Gen input supports standalone AC sources (not just grid/genset).
• Look for settings like “AC coupling” or “Gen bypass.”

2. Use a Voltage/Frequency Meter

• Measure the BYD Seal’s V2L output:
  • Voltage: Should be ~230V (or your local standard).
  • Frequency: Should be stable at 50Hz or 60Hz.

3. Start with a Small Load

• Connect a resistive load (e.g., 500W heater) to the Gen input first to test stability.

4. Monitor for Faults

• Watch for error codes like “AC freq out of range” or “unstable input.”

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Recommended Setup

If the Gen input works:

1. Set the inverter to “Generator Priority” mode (if available).
2. Disable any backfeed/sell-to-grid functions.
3. Add an isolation transformer if grounding issues occur.

If it fails:

• Use a dedicated off-grid inverter (like Victron) between the V2L and Deye, or stick to the battery DC input method (safest).

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Final Verdict

• Try it cautiously: The Gen input might work well and solve your fluctuation issues.
• If unstable: Fall back to the battery DC input method (most reliable) or upgrade your AC-DC converter.

[end]

The advice with connecting to the battery terminal seems to me a bit risky, since you can’t disable charging for only one battery and not the other, even if you got 2 battery inputs on the Deye inverter.

But its interesting to know there is a “frequency drift”. Maybe the proposed solution Use a Dummy Load or Capacitor could help…

[Mservice]

Actually that is very useful. I KNOW there were issues with grounding that prevented the v2L being accepted (when connecting ground terminals of v2L to ground on the inverter ) … so we disconnected it …

But that being the case … and now knowing there may be this drift you mention - then what draws my attention is this mention of an isolation transformer … no idea what that is - but I do have a voltage regulator which is effectively a servo motor driven 1:~1 Tesla coil … ie it can move the secondary coils as the primary voltage drifts …

But I’m not sure how to smooth frequency drift

[alain]

had to resort to DeepSeek again:

The main difference between an isolation transformer and a voltage regulator lies in their primary functions and how they affect electrical power:

1. Isolation Transformer

• Primary Purpose: Provides galvanic isolation between the input and output circuits, meaning there is no direct electrical connection.
• Voltage Handling: Maintains the same voltage level (unless it’s a step-up/down transformer) but isolates the output from the input.
• Key Benefits:
  • Protects against electrical shocks by breaking ground loops.
  • Blocks noise and surges from the power line.
  • Prevents DC offset and high-frequency interference.
• Does Not: Actively regulate voltage—output voltage varies with input voltage.

2. Voltage Regulator

• Primary Purpose: Maintains a stable output voltage regardless of input fluctuations or load changes.
• Types:
  • Linear Regulator (simple, low noise, but inefficient).
  • Switching Regulator (efficient, but can introduce noise).
  • Servo-controlled regulators (used in large systems).
• Key Benefits:
  • Compensates for voltage sags, surges, and brownouts.
  • Ensures consistent power to sensitive electronics.
• Does Not: Provide isolation unless specifically designed (some regulators include isolation, but most don’t).

Key Differences Summary:

Feature	Isolation Transformer	Voltage Regulator
Main Function	Electrical isolation	Stable voltage output
Voltage Adjustment	No (unless step-up/down)	Yes (fixed or adjustable)
Noise Protection	Yes (blocks surges & noise)	Depends on design
Ground Loop Prevention	Yes	No (unless isolated)
Response to Voltage Fluctuations	Passes them through	Corrects them

When to Use Which?

• Use an isolation transformer when you need safety from shocks, noise filtering, or breaking ground loops (e.g., medical equipment, audio systems).
• Use a voltage regulator when you need stable voltage (e.g., sensitive electronics, computers, lab equipment).

Some advanced power supplies combine both functions for maximum protection and stability.

Seems like a standard voltage regulator won’t do the job. I found some isolation transformers in online stores, but they range from small components for less then a dollar over 100 dollar medium sized appliences to expensive industrial sized ones.. no idea what we would need for our scenario.

[Mservice]

Yeah I found that info too - thank you… I have been discussing with a transformer company in china to make one that is both (turns out they are rare and you normally have to buy one and then the other if you wish to regulate and isolate … seems very strange to me that others would not have seen this need before )