Accessing J1772 (Level 2) EV Chargers to charge Van/RV lithium system

[berksrunner]

Does the Mean Well PSU have a LiFePO4 multi-stage charge profile? If not, then I would think you are asking for a shortened battery life if you forget to disconnect the charger after the battery reaches full charge.

I think a step-down transformer feeding the Multiplus would be a better solution.

It’s not multi-stage, but lifepo4 does not require multi-stage charging. The BMS protects my batteries from over voltage, but I do monitor and disconnect the charging once I am close to fully charged. True, it is best to avoid peak voltages in lifepo4 to maximize longevity, however, there is really nothing about a multi-stage charger that enhances lifepo4 longevity, assuming the charger is set to bring the SOC to 100%.

The other issue is the manner in which I use EV chargers. I don’t just park at EV chargers indefinitely. I’m there to pick up a quick boosting charger, and then I leave. So having the ability to float or pass through is pretty irrelevant.

 

[snoobler]

It’s not multi-stage, but lifepo4 does not require multi-stage charging. The BMS protects my batteries from over voltage, but I do monitor and disconnect the charging once I am close to fully charged. True, it is best to avoid peak voltages in lifepo4 to maximize longevity, however, there is really nothing about a multi-stage charger that enhances lifepo4 longevity, assuming the charger is set to bring the SOC to 100%.

The other issue is the manner in which I use EV chargers. I don’t just park at EV chargers indefinitely. I’m there to pick up a quick boosting charger, and then I leave. So having the ability to float or pass through is pretty irrelevant.

LFP either requires a 0.05C constant current charge to 3.65V (20 hours), or it requires a multi-stage charge to get to full. Period. Anything less is a partial charge - not that there's anything wrong with that. Multi-stage charging is also required if one wants to charge in a reasonable time frame.

So, I think you are probably doing a multi-stage charge without realizing it.

Stage 1: Constant current until peak voltage.
Stage 2: Constant Voltage - hold peak voltage while current tapers.

So unless you're charging at 56A up until the moment your target voltage is hit, and then you immediately terminate the charge (max voltage and max amps), you are actually conducting a multi-stage charge.

 

[berksrunner]

LFP either requires a 0.05C constant current charge to 3.65V (20 hours), or it requires a multi-stage charge to get to full. Period. Anything less is a partial charge - not that there's anything wrong with that. Multi-stage charging is also required if one wants to charge in a reasonable time frame.

So, I think you are probably doing a multi-stage charge without realizing it.

Stage 1: Constant current until peak voltage.
Stage 2: Constant Voltage - hold peak voltage while current tapers.

So unless you're charging at 56A up until the moment your target voltage is hit, and then you immediately terminate the charge (max voltage and max amps), you are actually conducting a multi-stage charge.

My solar charger tends to provide a nice little finishing charge.

 

[snoobler]

Nice. That's the beauty of LFP. As long as you don't exceed the maximum recommended, they'll take whatever you give them. Bulk charging FLA/AGM with too low a current degrades them.

 

[berksrunner]

Nice. That's the beauty of LFP. As long as you don't exceed the maximum recommended, they'll take whatever you give them. Bulk charging FLA/AGM with too low a current degrades them.

It's truly a revolution, and by the time it gains broader recognition, the pricing will be such that these systems are going to become a no-brainer for all sorts of applications! Just saw a video a few days ago of a guy putting a 23kwh 48v system in his van!

 

[snoobler]

Indeed. I have my first 280Ah cells en route from Amy. Very curious to compare them to my dozens of ragged out 40Ah CALB cells.

23kWh in a van? Yikes. Makes me question if the 39kWh I have planned for my future domicile is sufficient...

 

[berksrunner]

Indeed. I have my first 280Ah cells en route from Amy. Very curious to compare them to my dozens of ragged out 40Ah CALB cells.

23kWh in a van? Yikes. Makes me question if the 39kWh I have planned for my future domicile is sufficient...

This thing is amazing:

 

[HaldorEE]

Indeed. I have my first 280Ah cells en route from Amy. Very curious to compare them to my dozens of ragged out 40Ah CALB cells.

23kWh in a van? Yikes. Makes me question if the 39kWh I have planned for my future domicile is sufficient...

I am putting 7.2 kWh of batteries in my Ford E350 van conversion. They are going to be in a 2 x 4 orientation (24V) when done, just sitting on the bench right now. Building the cell compression frame this weekend.


hey