My PowerWall 18650s in this one though


What sort of batteries are they… Was gearing up to use18650’s myself. How many kw is the battery pack… @ 48 watts I presume?

I think we worked it out to be nearly 8kWh just with those batteries. @buzz also has a 6kW solar system coming shortly. It will be cool to see a finished (local) powerwall project.

HeadWay 38120L 10000mAh 3.2v nominal 3.7v peak LiFePO4 cells in 16x12 configuration. Each cell here is equivalent to about 5 normal 18650s … so there’s equivalent of about 1000 18650 cells there.

I’m keen to see the results in terms of kWh usage over the day, discharge and charge currents etc over a few weeks.

awesome project :slight_smile:

We were talking about inverters at the Tuesday meeting and was wondering what you thought of this.

Seems to have grid connect add well

Hybrid from mppt solar in taiwan. Doeant have au approval. They do a 15kw 3 phase unit with 10kW charge too! Would perfect if it passed!

2 or 3 strings? It has quite a higj string requirement so it falla into high voltage. meaning caged off and not end user accessible.

I could be wrong tho.

I want to startup liquid redox cell design project. Could be cheap! Need mechanical, chemical, electrical engineers :slight_smile:

my custom BMS - it’s monitoring cell voltages right now.



1 Like

… now with active top-balancing/discharging and error reporting! … as well as the other stuff mentioned earlier… cell voltages, logging , webpage etc.

1 Like

Yesterday i worked out enough of the circuit for the SM-004-5v (sanmim sm-plg06a) isolated 5 volt power module that I can now adjust the voltage to anywhere between 3v and 9v. It just required unsoldering two fixed resistors and soldering a 5k ohm pot in their place. Its now giving me a stable 4.2 volts.

So to spell it out, you can use a string of these to charge a series-connected string of LiPo cells in your battery because the DC side of each is 100% isolated.

Because these things are set to a fixed voltage, it means they they reduce the current to maintain stable voltage as a pack charges, so as the battery approaches 4.2v, then the current being put into the pack decreases toward zero… so you can ( in theory) leave it connected to a fully-charged cell and it won’t over-volt or over-current.

1 Like