question

chromebin avatar image
chromebin asked

Selecting a charger and inverter for a 100V/50Ah/5kWh LiFePo4 battery

A 5kWh 96V LiFePo4 battery fell into my lap, a it's a SonnenModul4. Ever since I've been studying up on solar systems, as I plan to go to Africa, to live and work from a solar powered camper, exclusively, for the next 5 years. I never thought I'd be able to put in such a powerful and reliable battery. This feels revolutionary.

I presume a solar system built around such a battery looks like this:

  1. a single string of 3 or 4 solar panels of around 40V each, each with 375W. They have to fit a 170x400cm roof area. During most of the day that should give me 750W or 1000W, ample.
  2. a MPPT charger with overcharging protection to connect the PV to the battery. It should be able to comfortably work with 160V DC in
  3. an inverter, to give me 230V from the battery voltage. at least 2kW allows me to cook without switching of appliances like the fridge. I could even run a basic air conditioning.

I suppose this battery has a BMS to re-balance the cells, but I don't know about any protections like overcharge or over-current (short-circuit). My questions:

  1. is the system complete? would I need anything else?
  2. what protections should I take care of?
  3. what devices would be recommended?
  4. maybe there is an inverter with an integrated MPP tracker?
  5. is there a way to run the inverter directly of the solar panels, switching to the battery only when needed?
  6. bonus: how to keep the solar panels cool (as they'll get very hot)?

Though I work with electronics, I'm still a newbie when it comes to best practices, the market and how to layout a system. Any advice would likely be taken ;-)


MPPT Controllersbattery chargingBattery Protect
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Victron don't have any product working with that voltage.
If you want to use Victron products you have to split the battery.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

chromebin avatar image
chromebin answered ·

Victron doesn't have one, hum.

If I were to split the 96V in 2x 48V, would that remove features currently integrated in the pack? In other words, the unit is probably nothing more than a set of individual cells?

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

nickdb avatar image nickdb ♦♦ commented ·

You really need to speak to someone who knows their technologically. They seem to have their own power solutions so it may or may not be that simple.

Does it have existing battery management?

Do you really want to be configuring your own if you’re new to this?

Do you know if the battery/cells are in good condition?

You need to solve your battery challenges before we can give any advice on the product range, ultimately this community isn’t for design advice as the internet is a challenging medium for that with many opinions.

1 Like 1 ·