Bossrox
Solar tinkerer
Thought some of you might find this intresting. I got a hold of 2 tesla powerwall 2's, both for $700 which are 48v, 13.5kw each. I had to figure out a way to use them in my 24v system & came up with using a Growatt solar charger to convert the 48v down to 24v. It's not a perfect marriage but here's how they interact with each other.
I'm using separate chargers for charging the Tesla's from my 24v chargers & what happens is the Tesla will not put out power til the lifepo4's drop down to a certain voltage or a heavy load kicks in. As the night goes on & the lifepo4's voltage drops, the Tesla's starts increasing it's output eventually taking over most of the work towards the end of the night.
So what I get is the 2 battery chemistries doing work at different parts of the night & sharing in between.
The trick to getting them to share an equal amount of overall drain between the 2, is setting the conversion chargers output just right. Too high & the Tesla does most of the work. Too low & the lifepo4's do the same. Just 1/10th of a volt adjustment makes a huge difference. So there's a sweet spot you got to find where both chemistries end up near equally drained at the end of the night.
So if you get lucky like I did to get some massive battery power cheap, you can make it work with what you got.
I couldn't tell you how it would work out if you had a 48v system. Being a 16s lifepo bank starts out at around 55v & the max charge on a powerall is 50v, you may not get anything out of a tesla til your lifepo bank drops down to near the level of a Tesla.
I'm using separate chargers for charging the Tesla's from my 24v chargers & what happens is the Tesla will not put out power til the lifepo4's drop down to a certain voltage or a heavy load kicks in. As the night goes on & the lifepo4's voltage drops, the Tesla's starts increasing it's output eventually taking over most of the work towards the end of the night.
So what I get is the 2 battery chemistries doing work at different parts of the night & sharing in between.
The trick to getting them to share an equal amount of overall drain between the 2, is setting the conversion chargers output just right. Too high & the Tesla does most of the work. Too low & the lifepo4's do the same. Just 1/10th of a volt adjustment makes a huge difference. So there's a sweet spot you got to find where both chemistries end up near equally drained at the end of the night.
So if you get lucky like I did to get some massive battery power cheap, you can make it work with what you got.
I couldn't tell you how it would work out if you had a 48v system. Being a 16s lifepo bank starts out at around 55v & the max charge on a powerall is 50v, you may not get anything out of a tesla til your lifepo bank drops down to near the level of a Tesla.
