EVSE Load Balancer: A Universal Load Balancer for your EV Chargers

Share your Projects! Custom Integrations
1

Hey everyone,

I wanted to share a custom integration I’m been working on to simplify EV charging for Home Assistant users, specifically (but not limited) at this stage: Load Balancing.

Like many EV Charger owners there’s a need to balance the EV’s charging with household power usage to avoid overloading the main fuse. I personally don’t like having an endless number of P1 devices in my cabin, especially not if there’s already a stable Home Assistant service running.
Instead of going down the road of harder-to-maintain automations I decided to build Hass EVSE Load Balancer: a lightweight, native component that turns Home Assistant into a smart, self-adjusting EV load balancer.

The idea is simple: if you already have energy sensors (like grid consumption, production, and voltage, or a DSMR smart-meter) and a charger that can be controlled via Home Assistant, you shouldn’t need vendor-specific dongles, extra P1 meters, or fragile automations. This component monitors your live power usage and dynamically adjusts the charging current or phase configuration of your EVSE — helping you protect your connection and maximize charging speeds when possible.

It’s designed to be easily extendable, supporting all kinds of different meters and chargers. It depends on other integrations to make sure the actual communication with the chargers or meters is properly maintained as well, for example easee_hass and DSMR Smart Meter.

More information on how it works and how it can be extended can be found in the repository:
:link: GitHub - dirkgroenen/hass-evse-load-balancer: Adjusts your EV Charger's current using existing sensors - no vendor lock-in, no extra devices.

Note that I’m releasing this quite early in its testing - so consider yourself a beta tester. I have it up and running at home (DSMR + Easee Charger), but I’m very interested in getting more adoption info and feedback. Definitely keep an eye out on what it’s doing at first and let me know if it’s behaving weirdly.

I’d love for others to give it a spin and let me know how it works in your setup. I’m keen to hear your feedback, edge cases, ideas, and real-world experiences. If it turns out useful to more people, I’m happy to continue building it out.

The current “load balancing algorithm” tries to find a balance between a) not being to hysteric, b) getting as much as of a charge as possible, and c) obviously not overloading the fuse. It does therefore for example allow for short periods of small overcurrents, like your circuit breaker also does.

Other features I have in mind to include are:

  • Add an input field to manually override the charger’s current
  • Add a toggle to force the charger to only use PV surplus

Eventually I have some other things in mind to make this an all-in-one package, allowing to also:

  • smart scheduling based on Dynamic Tarrifs
  • control and balancing amongst with other loads. Being either other chargers, or e.g. water heaters

Thanks for checking it out! Looking forward to any form of early feedback and input :slight_smile:
– Dirk

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2

Hello,

This seem to be awesome! I’ve just bought an Amina S which connects to HA through Zigbee2MQTT. I’m not a programmer but I’ll have a go at implementing the charger.

I’m using SlimmeLezer+ with ESPHome for energy meter. Would you suggest to use the custom configuration or should I give it a go to implement the ESPHome? I’ve not used the DSMR but after a quick look it seems to have a lot in common.

Jon

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Sorry - bit late of a reply. I noticed your PR coming through and will try to have a look at it in the next few days! Thanks already for taking the effort :slight_smile:

I’m currently doing a bit of a rework of the coordinator and power balancer. Especially as I noticed a bug in the code which causes the chargers to be increased way too late after a decrease. The change also makes the code a bit more future proof. I’ll see if I can merge your PR first, but if not I’ll do it after these changes are done and merged. Hopefully this weekend :crossed_fingers:

As for the SlimmeLezer+ implementation, you can definitely use the custom sensors - which will just do the job. The DSMR implementation (or other Meter implementations) are simply there to make life a bit easier.

I have no practical experience with ESPhome and the SlimmeLezer+ device, but as long as they expose a unique device, identifiable named entities, and a domain that’s equal for all SlimmeLezer+ devices the implementation could be straightforward.

The only problem I might see, but you’ll know this better then me from experience, is that you’re dependent on user configurable ESPhome device configuration files, which name the device and expose sensors? If that’s the case it might be hard to provide a “one-fit-for-everyone” implementation.

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This is very cool and I was actually looking for a generic version of this. I think the main challenge here is that if the server fails or the charger is unreachable what happens? The risk is that other loads could increase during this time but without the server telling the charger to curtail the main breaker could get tripped. If this isn’t a big deal to you on the super rare chance it happens then great you can ignore the rest :slightly_smiling_face:

Most of the commercial ways to do this either use a direct serial connection to a CT to measure the current (Siemens/span/most do this) and then activate a contactor from the same device that is measuring the current or they use a master/slave pattern where if the master fails to communicate with the slave then the slave won’t function (Tesla does this with their car chargers).

Afaik the only way to truly do a decoupled software based system is the second option but I think that requires extra software on each client device to essentially require a keep alive ping to the server. Unfortunately I don’t have firmware access to most of the loads in my house so this feels like a dead end to me.

5

I might have misunderstood “Enable offline mode”. But isn’t this what you want?

Enable offline (binary)

Enable offline mode when connection to the network is lost. Value can be found in the published state on the enable_offline property. To read (/get) the value publish a message to topic zigbee2mqtt/FRIENDLY_NAME/get with payload {"enable_offline": ""}. To write (/set) a value publish a message to topic zigbee2mqtt/FRIENDLY_NAME/set with payload {"enable_offline": NEW_VALUE}. If value equals enable enable offline is ON, if disable OFF.
Time to offline (numeric)

Time until charger will behave as offline after connection has been lost. Value can be found in the published state on the time_to_offline property. To read (/get) the value publish a message to topic zigbee2mqtt/FRIENDLY_NAME/get with payload {"time_to_offline": ""}. To write (/set) a value publish a message to topic zigbee2mqtt/FRIENDLY_NAME/set with payload {"time_to_offline": NEW_VALUE}. The minimal value is 0 and the maximum value is 60. The unit of this value is s.
Offline current (numeric)

Maximum allowed amperage draw when device is offline. Value can be found in the published state on the offline_current property. To read (/get) the value publish a message to topic zigbee2mqtt/FRIENDLY_NAME/get with payload {"offline_current": ""}. To write (/set) a value publish a message to topic zigbee2mqtt/FRIENDLY_NAME/set with payload {"offline_current": NEW_VALUE}. The minimal value is 6 and the maximum value is 32. The unit of this value is A.
Offline single phase (binary)

Use single phase charging when device is offline. Value can be found in the published state on the offline_single_phase property. To read (/get) the value publish a message to topic zigbee2mqtt/FRIENDLY_NAME/get with payload {"offline_single_phase": ""}. To write (/set) a value publish a message to topic zigbee2mqtt/FRIENDLY_NAME/set with payload {"offline_single_phase": NEW_VALUE}. If value equals enable offline single phase is ON, if disable OFF.
6

Some chargers, but unfortunately not all, have some “offline_” settings which allow you to define fallback settings for when the charger loses its connection to the server. An example of the Easee one: Offline Current.

I’m also assuming that that’s actually the setting most vendor load balancers use.

There’s currently nothing baked into the EVSE Load Balancer component, but nothing would prevent you from setting those “offline settings” on your charger to very sane and safe values.

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Released 1.0.0 over the weekend with two major changes:

  • Support for the Amina S charger - thanks to @JonD :pray:
  • Rebuild load balancer which now properly deals with manual overrides during a charge session, is prepared for multiple chargers, and has overal improvements to the way how to decreases/increases power.

Next up on my list is support for “surplus charging”, allowing to reduce the charger to available solar power.

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Great work @dirkgroenen! Hopefully this will get the attention deserved since I believe this will have the potential to be a better alternative to the commercial load balancers.

Question, do you prefer to have general discussions about the integration at this place?

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Thanks @JonD. Feel free to have open discussions or questions here and open GitHub issues if you experience specific issues.

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Hey, i’m trying to get this working with a Home wizard P1 meter.
But once the charging start the L1 available current is -9366A so i think i need to change something there…

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How have you configured the sensors? Without specific info about your setup I can’t help. My guess would be that you’ve configured the wrong sensors.

Looking at the docs the P1 meter returns a “power” and “voltage” sensor, not a seperate consumption and production one. I would assume, but have not tested, that in this case you’ll have to provide a bogus sensor (just an empty 0 sensor via the helpers e.g.) to production and use the “power” sensor for consumption.

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indeed it looks like the imput was wrong, i changed the P1 meter to the Easee P1 meter and now it looks beter. i think the load balancing does something altouhg i can’t seem to set the max. charger.
I have 3Kw solar panels so i want it to remain around that. but the Charing goes to the max. 25A(5,8Kw) and count’s down from that so ithe available L1 current goes down between 20A - 25A instead of between 6-11A.

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I’m not entirely sure if I understand your setup and problem, but it’s indeed correct that the integration will initially reset the charger to the max configured current - after which it will monitor the loads and adjust where needed.

If you want me to help you debug please provide me with all details of your configuration:

  • configured sensors in the EVSE Load Balancer
  • max Fuse Size configured in EVSE Load Balancer
  • max circiut current of the Easee installation
  • max charger current of the Easee installation
14

Hey i thin indeed that i will need to create a fictive Sensor.
Right now i have 3 sensors from my P1 Meter :
Power Phase 1-2-3 : which goes from negative when producing energie fyi -750 when putting 750W on the net.
I could also make the current available if that would be easier?

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It calculates the available current using the given power and voltage. Try creating a fake helper sensor and use it for the “production” side. Then check if it works with using your power sensor.

I haven’t tested it so I’m not sure.

16

Same problem for me. The available sensor goes bananas and shows high negative values (A).
Or is this expected?

I limited the charger (Amina S) to 16A (main fuse 16A). Started the induction hob with boiling water. Phase 1 peaked 25A but the load balancer never limited the charging current.

See snapshots below from when house is in standby mode:

Skärmbild 2025-06-17 210010
Skärmbild 2025-06-17 210010442×530 14.5 KB

Skärmbild 2025-06-17 210039
Skärmbild 2025-06-17 210039416×348 5.13 KB

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@flaektrem @timmyvercr could it be that your sensors are returning values in Watt, instead of KiloWatt? The current implementation assumes to receive values in kW, which might explain the factor.

Can you provide me with some more details on the sensors you’ve configured, such that I can reproduce?

18

To anyone reading this thread and having a HomeWizard P1/Energy meter: I’ve just added support for the HomeWizard meter natively to the component, but I’m looking for someone to test it.

Anyone able to test the following branch? [#27] Add HomeWizard meter support by dirkgroenen · Pull Request #28 · dirkgroenen/hass-evse-load-balancer · GitHub

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Yes, both Amina and P1 sensor (import/export) shows W, not kW.

I’ll try changing that later today.

What is the expected readings from the “available” sensors?

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Ah that might explain. The integration expects atm kW when providing custom sensors.

It will then do the following:

  • compute active current based on power (Kw) and Voltage
  • subtract that from the configured fuse max
  • show that as Available Current
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