smoke.python
New Member
TL;DR: I am looking for a way to have many dissimilar batteries (different ages, manufacturers, and capacities) used for solar energy storage. Can this be achieved with a Runtime Balancing or Lossless Balancing battery management system? If so, are there any systems one can purchase or would you have to build your own?
Rant/Problem Statement:
Unlike what seems to be the case for most people, I live in the real world without infinite money. I recently learned (after purchase) that you can't just plug two dissimilar batteries into your inverter and expect things to work. Given that batteries are the most expensive part of my solar installation, it seems crazy to me that the common recommendation is "just buy all of your batteries at the same time, from the same manufacturer, and when one breaks replace all of them at once. Here in the real world, the following are all true:
1. You don't always have enough money to buy everything at once, sometimes you start small and scale up.
2. You often don't know which manufacturer is good until you try their product, so you want to buy one item and use it a while before buying more.
3. Manufacturers *frequently* stop making a given model of a thing and replace it with a different newer model.
4. Manufacturers go out of business and you have to switch brands.
5. Your energy needs may increase over time, requiring you to scale up your system later.
6. Not all hardware fails at the same rate, it is likely one your batteries will fail before the others.
Solution?
I have been trying to do research into this problem to figure out why the standard practice seems to be so incredibly wasteful and non-modular. I came across https://www.batterydesign.net/cell-balancing/ which talks about different kinds of battery balancing systems and noticed that Runtime Balancing and Lossless Balancing sound like they may allow one to build out a modular battery storage solution that doesn't suffer from the problem of needing to buy and discard all of your batteries at once.
The Runtime Balancing system of having DC-DC converters on each battery sounds promising as it is conceptually quite simple, but I worry a bit about how battery charging would be managed by the inverter if the witnessed voltage is always exactly what it is supposed to be with no fluctuations near top/bottom of charge.
The Lossless Balancing system sounds complicated, which of course is always worse than simple, but maybe that is necessary to solve this problem.
This post is specifically about Runtime and Lossless Balancing systems and their use in a solar installation, but if anyone has any suggestions on how I can solve the more general problem of battery modularity in some other way I would love to get some advice/insight! I posted another inquiry trying to solve the same problem in a different way, but it seems that comes with its own set of problems. https://diysolarforum.com/threads/multiple-inverters-independent-battery-and-panels-on-each.82745/
Rant/Problem Statement:
Unlike what seems to be the case for most people, I live in the real world without infinite money. I recently learned (after purchase) that you can't just plug two dissimilar batteries into your inverter and expect things to work. Given that batteries are the most expensive part of my solar installation, it seems crazy to me that the common recommendation is "just buy all of your batteries at the same time, from the same manufacturer, and when one breaks replace all of them at once. Here in the real world, the following are all true:
1. You don't always have enough money to buy everything at once, sometimes you start small and scale up.
2. You often don't know which manufacturer is good until you try their product, so you want to buy one item and use it a while before buying more.
3. Manufacturers *frequently* stop making a given model of a thing and replace it with a different newer model.
4. Manufacturers go out of business and you have to switch brands.
5. Your energy needs may increase over time, requiring you to scale up your system later.
6. Not all hardware fails at the same rate, it is likely one your batteries will fail before the others.
Solution?
I have been trying to do research into this problem to figure out why the standard practice seems to be so incredibly wasteful and non-modular. I came across https://www.batterydesign.net/cell-balancing/ which talks about different kinds of battery balancing systems and noticed that Runtime Balancing and Lossless Balancing sound like they may allow one to build out a modular battery storage solution that doesn't suffer from the problem of needing to buy and discard all of your batteries at once.
The Runtime Balancing system of having DC-DC converters on each battery sounds promising as it is conceptually quite simple, but I worry a bit about how battery charging would be managed by the inverter if the witnessed voltage is always exactly what it is supposed to be with no fluctuations near top/bottom of charge.
The Lossless Balancing system sounds complicated, which of course is always worse than simple, but maybe that is necessary to solve this problem.
This post is specifically about Runtime and Lossless Balancing systems and their use in a solar installation, but if anyone has any suggestions on how I can solve the more general problem of battery modularity in some other way I would love to get some advice/insight! I posted another inquiry trying to solve the same problem in a different way, but it seems that comes with its own set of problems. https://diysolarforum.com/threads/multiple-inverters-independent-battery-and-panels-on-each.82745/
