can someone invent us a magic box?

Schrockstudio

Hi, I haven't found this specific discussion and I apologize if it's already been addressed as I imagine it has...

Does this "Magic" box exist or does anyone know how to build one?

Concept:
-take an assortment of random old, new, different chemistry, different voltage etc.
-wire them each into the magic box
-The box then "reads" the batteries, and charges them accordingly. (stopping before over charge)
-The box or another box will then pull power from each battery at an appropriate rate and disconnect before the battery is too low.

I am not an expert (this is probably obvious) I just would imagine that this magic box would be possible to build and I'm sure I'm missing something as to why it is not.

-The charging of the batteries seems possible through essentially small chargers for each battery,
-there's most likely an economical way to do this?
-The main problem I see would be pulling power,
-say you want to pull a big load, the batteries would be switching a lot as one would imagine some very crappy batteries in the mix would quickly discharge,
-the power could be "cleaned" with a capacitors bank?

PLEASE invent this! haha!  Or if anyone actually knows how to build this system economically let me know and I want to do it!

otherwise do I just throw away all my random mostly functioning lead batteries and purchase lithium batterys? Wish I could just save them though  

Ampster

I have already thrown away Lead batteries 8 years ago and have thought about your proposal for a Lithium Frankenpack that I have with some used Nissan Leaf modules. I don't think there is much market unless one has the lots of time and Arduino programming skills. On the other hand I could bin my Nissan Leaf modules to more adequately have them balanced in my pack but even with downtime with COVID19 I am not sure the reward is worth the effort. 

Schrockstudio

hey Ampster! When you say the reward isn't worth the effort, is this because all of the programing? Or do you imagine the components would just cost more than buying new batteries anyway

jonr

One could attach a bi-directional DC-DC converter to each battery, which would allow independent control of charging and discharging taylored to the battery.  But it would be expensive.

Ampster

Schrockstudio said:

hey Ampster! When you say the reward isn't worth the effort, is this because all of the programing? Or do you imagine the components would just cost more than buying new batteries anyway

It is a combination of both. I honestly don't know much about extending the life of Lead Acid batteries. I would prefer to put my energy into extending the life of Lithium batteries because the odds are greater. I have had better luck nursing a Lithium pack that only has 70% of capacity. I am also not proficient in programming and value my time, leisurely as it is, so that is my personal indifference curve. Your mileage may vary. 

Schrockstudio

I hear ya

Schrockstudio

Is this the magic BOX??
https://www.victronenergy.com/battery-isolators-and-combiners/cyrix-battery-combiners

Ampster

Schrockstudio said:

Is this the magic BOX??
.....

That is the concept but it is not programmable. I didn't look into the details to see if it would work with different Lead Acid chemistries. 

Schrockstudio

ya, that one is for Lithium... I suppose if you're spending 100$ per box per battery, doesn't really make sense, unless you work at a junkyard and have 100's of batteries just coming through your door... that'd be cool to make... alas I don't have a junkyard