Super Capacitor Modules & Batteries used for Energy Storage?

We have been using 16V SC in Parallel my vehicles & in 24v forklift, where 1x 16V SC is in Parallel with an old dying LAB, and we replaced one LAB with another 16v SC in Series with with the LAB.
Besides Starting very well, all works perfect.

Manufacturers don’t recommend using 48V Super Capacitor (SC) Modules & 48V LAB or LiFe Batteries be used Together for Energy Storage.

Anyone know if there is any underlying issue with doing this ?

As I have seen Youtube videos of various domestic Modules feeding into an existing system.

I’m guessing due to the very high charge/discharge the SuperCaps would have a much lower internal resistance compared to LiFe. They also operate at very different charge voltages leading to potential overcharging of the SC’s and undercharging of LiFe. I would never mix SC with any type of Lithium!

I am of the understanding every SC module, commonly have individual CMS circuit boards.
CMS is the same as BMS, and should come with each SC Module, I believe each cell has a Voltage Diode.
Well the SC modules I’ve been using are only 16V, the Vehicle’s systems Rail Voltage are 12V & 24V, some with Failing LAB for Testing.

However, commonly most Residential Energy Storage systems are 48VDC, where a SC module would be approx. 52VDC.

I am Not a qualified Electrician
From our Tests when Charging a Mixed Systems;

The SC Module will/should Charge First, then from what I understand, as the SC Cells reach 2.7V, the CMS Cell Diodes Stop a Charge going to that Cell, SC Modules are commonly a slightly higher Voltage.

Discharging a SC Module’s GREATEST aspect is 100% DOD with NO Damage, and said 30’000+ Cycle life!

I have found SC Energy Storage # long term = Month+, being very good, as Energy Storage in Not really about Long term storage, it is about Consumption on a Daily basis & during extended bad weather.

(#) If SC module is wired to a Failing Battery/System that drop’s down less than the Set Voltage when Not charged, the SC module will safely sacrifice it’s energy in an attempt to Charge the Failing Battery Cell/System.

So, Why should be an issue with Charge Voltages ?
SC appear Happy to be Punch Charged with High Amps or Trickle charged to the Buss-Bars Rail Voltage.

As for the Inverter, is it not the Inverter that instigates the BMS Voltage Settings of say 48VDC etc.?

Am I missing something, becides a few grey cells :wink:

For max battery performance and lifespan the charging, float and cutoff voltages should be set according to the battery manufacturers specifications. Sure this would be a fun experiment but I wouldn’t be recommending mixing different cell technologies unless it’s for a very specific application.

Another issue is that you will never have an accurate SOC for the entire battery system as each battery will have a different SOC depending on the load and charge voltage.

What is the absorption voltage of the SC’s and the Lithium?

By Absorption Voltage do you mean the Charge Voltage &/or Amps ?

If all DC Voltage, say 48V is connected to a Common + & - Bus-Bars, I just can’t understand that what the issue is ?!

Now we have tested Vehicle SC’s, we are looking to forwards to Testing 1kWh, 3.6kWh & 8.5kWh, 48v Graphene SC Systems soon.
Being able to pair SC with Cheaper NiFePO4 Batteries a better investment, as the SC Cost is currently cost $

SC modules with inbuilt CMS, appear happy to act as a Slave, as they can Quickly or very slowly take any excess energy, not been Distributed elsewhere.

Yep, the absorption voltage is the charging voltage. Ie. most LiFe 48V batteries have a charge voltage around 56V and float of 55V. What are the charging specs of the SC in the configuration you are using?

I can see how combining SC’s with something like NiFePO4 Batteries could make sense in terms of reduced cost and increased performance, but combining SC with LiFe doesn’t seem to add any real value since LiFe already has very good characteristics - very good efficiency, high charge and discharge rates etc