Direct Solar PV to HV charging?

[Johnny 5 is alive]

I have a spare 10-panel array of solar panels that in series will give approx 360v DC / 2700w maximum output in direct sunlight. I'm looking into using them for a stand-alone solar charging system but it seems pretty inefficient (and expensive!) to use storage batteries and inverters as there are losses involved with both.
As the MG5 charges using generated DC when going downhill especially on KERS3, is there not a process whereby the car's HV battery can be charged directly from the panels?
I realise the battery / inverter arrangement is to "smooth out" the supply (for the benefit of domestic chargers which don't like power variations) but there is little more variable or intermittent than the charging the HV battery receives from KERS!
I've probably overlooked something obvious but I would have thought in times of rising energy costs and conversely reducing solar panel costs, this would have at least be a consideration?
Hopefully someone better positioned than myself on these matters can shed some light on this.

 

[JohnInFrance]

I have no idea of the answer to your question, but "10 spare panels" - now I'm super-jealous, haha.

 

[rpannell]

I have a spare 10-panel array of solar panels that in series will give approx 360v DC / 2700w maximum output in direct sunlight. I'm looking into using them for a stand-alone solar charging system but it seems pretty inefficient (and expensive!) to use storage batteries and inverters as there are losses involved with both.
As the MG5 charges using generated DC when going downhill especially on KERS3, is there not a process whereby the car's HV battery can be charged directly from the panels?
I realise the battery / inverter arrangement is to "smooth out" the supply (for the benefit of domestic chargers which don't like power variations) but there is little more variable or intermittent than the charging the HV battery receives from KERS!
I've probably overlooked something obvious but I would have thought in times of rising energy costs and conversely reducing solar panel costs, this would have at least be a consideration?
Hopefully someone better positioned than myself on these matters can shed some light on this.

An interesting question. If you could break into the connection between the motor and batteries, to be the equivalent to regen charging, then there may be a way to use the intermittent DC from a solar panel. Here is a more general answer to your question, based on using the normal DC or AC charging ports of the car - Is there a DC car charger I can use with a DC solar panel system?

 

[Gomev]

I have a spare 10-panel array of solar panels that in series will give approx 360v DC / 2700w maximum output in direct sunlight. I'm looking into using them for a stand-alone solar charging system but it seems pretty inefficient (and expensive!) to use storage batteries and inverters as there are losses involved with both.
As the MG5 charges using generated DC when going downhill especially on KERS3, is there not a process whereby the car's HV battery can be charged directly from the panels?
I realise the battery / inverter arrangement is to "smooth out" the supply (for the benefit of domestic chargers which don't like power variations) but there is little more variable or intermittent than the charging the HV battery receives from KERS!
I've probably overlooked something obvious but I would have thought in times of rising energy costs and conversely reducing solar panel costs, this would have at least be a consideration?
Hopefully someone better positioned than myself on these matters can shed some light on this.

Plug in direct via the CCS port, or is that too obvious.

 

[Johnny 5 is alive]

After much research I've actually decided to take the battery and inverter route.
I can get 8 x 100a/h car batteries for around £500 ( 2 parallel banks of 4 in series = 24v @ 400a/h) and a 3kw (6kw surge) 24v pure sine wave inverter for another £200, which is a lot cheaper than a comparable 4.8kw/h commercial storage system. The granny charger is rated at 2kw so that should be big enough to run it reliably.
My only hurdle now is charging the 8 batteries from the 10 solar panels... connected in parallel their outpur would be max 36v @ 2.7kw, so will I need to find another unit to do this function?

 

[Dave]

Use Leisure Batteries or make sure they are AGM batteries. You will need an MPPT Controller for your PV array.

This guy is worth watching….

 

[Gomev]

After much research I've actually decided to take the battery and inverter route.
I can get 8 x 100a/h car batteries for around £500 ( 2 parallel banks of 4 in series = 24v @ 400a/h) and a 3kw (6kw surge) 24v pure sine wave inverter for another £200, which is a lot cheaper than a comparable 4.8kw/h commercial storage system. The granny charger is rated at 2kw so that should be big enough to run it reliably.
My only hurdle now is charging the 8 batteries from the 10 solar panels... connected in parallel their outpur would be max 36v @ 2.7kw, so will I need to find another unit to do this function?

Yes agree with @Dave use leisure batteries, not car batteries.

I have a very very small setup with 1 panel on my shed roof, MPPT, 1 battery and a 1kW pure sine wave inverter. I use this for powering shed lights (12v) and also for charging power tools, leccy bike etc on DC. I also run some small power tools direct from the battery via the inverter and also a 400/800w heater for the colder days.

 

[Johnny 5 is alive]

This has been useful too

How To Build A DIY Solar EV Charging Station - Climatebiz

A DIY solar EV charging station is a self-sustaining power point for your car. It will enable you to independently re-charge your EV.

climatebiz.com

 

[Ealing Guy]

After much research I've actually decided to take the battery and inverter route.
I can get 8 x 100a/h car batteries for around £500 ( 2 parallel banks of 4 in series = 24v @ 400a/h) and a 3kw (6kw surge) 24v pure sine wave inverter for another £200, which is a lot cheaper than a comparable 4.8kw/h commercial storage system. The granny charger is rated at 2kw so that should be big enough to run it reliably.
My only hurdle now is charging the 8 batteries from the 10 solar panels... connected in parallel their outpur would be max 36v @ 2.7kw, so will I need to find another unit to do this function?

Please check the current you need at 24V. Towards the end of the discharge the 24V drops to say 18V at the battery terminals so for 2kW granny charger you need 111A to 150A (with inefficiencies) to feed the inverter. You would need expensive cables and very good connectors to avoid overheating. These currents would be halved and be more manageable on a 48V system like discussed at the start of the video/previous video.

 

[Johnny 5 is alive]

Yes I'll definitely consider a 48v system to keep the current draw on the batteries down, however the idea is more around charging during sunlight whilst the panels are producing significant power, in which case the batteries are mainly being used as a voltage stabiliser for the inverter running the granny charger. I have no intention of draining the batteries down to the lower extent of their capacity.

 

[Coulomb]

Plug in direct via the CCS port, or is that too obvious.

It won't work because the contactors won't come on. To make them come on, you'd need complex CAN bus commands and PLC (Power Line Communications) hardware. The protocol document costs big money to buy, though you might possibly find the answers on-line.

Damien McGuire is attempting CCS charging for DIY EV conversions, using BMW hardware, so that is a possible approach.

But then there is the problem that the charging is totally unregulated.

And 360V is a bit low, it would have to be higher voltage than the battery, else the PV panels turn into giant infra red LEDs, loading the battery. So every cloud would discharge the battery.

Then you need DC rated fuses to protect your wires from a short circuit in the panels. The panels have a low short circuit current, but the battery could easily cause a fire.

So for many reasons, the AC path is way more practical. Higher losses, yes, but way safer (though of course 230VAC can still kill), and way more control.