three Li battery banks - charging and loads

Question

question

engmarc asked Aug 25, '23

three Li battery banks - charging and loads

I'm adding new 24v Li battery bank to existing RV.

I have older 24v Li batteries (two sets - different brands and different ah capacities) and am buying a new set of another brand. So, will have three 24v LI battery banks.

How should I isolate them by brand/size.

Ideally, I'd like to use all three as a load source

Ideallly would like to charge all three from the available charging sources (solar, alternators both 12v and 24v) and shore power 110v (Victron Quattro 5000 24v likely).

I'm open to ideas and here's some of what I've found:

- I might be able to use the Victron Argo battery combiner to use the three battery banks but not sure on the three bank as it has two inputs.

- a bit fuzzy on charging but contemplating using the Orion DC-DC systems.

All three will be individually fused with disconnects so getting a huge draw from a single bank will be partially protected. Should I use a smart shunt to-from each bank?

Open to ideas but please refrain from scare/fear tactics. I'm an experienced Mechanical Engineer with a lot of background in both thermal and electrical systems.

battery charging Lithium Battery Battery Protect orion dc-dc Battery Balancer

2 |3000

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

Modifications Space

Node Red Space

Answer 1 · 2023-08-26T05:03:55Z

Alexandra answered · Aug 26, 2023 at 05:03 AM

@EngMarc

You can bus bar them and use them all at the same time. That way they will work as one bank.

With equal current share though the smaller ones will deplete "faster" that the others as the capacity is smaller. I have an experiment at home with 2x48v batteries and totally differenct capacity and that is what I see. The 100AH has a lower SOC by the morning. But it is sized so that it is taken down to 24% max.

You could try pair the two smaller together (daisy chain or parrallel to the bus bar) so they add their capacity together there. And behave as cone battery' on that connection.

2 |3000

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

Answer 2 · 2023-08-26T05:18:34Z

engmarc answered · Aug 26, 2023 at 05:18 AM

I think I'd rather have some individual current limiters on each battery bank and also charge limiters so if the whole bank combo is being charged or has a load each bank doesn't give more than it is capable of doing.

1

2 |3000

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

Alexandra ♦ commented · Aug 27, 2023 at 08:22 AM

Are they completely separate banks for completely different uses and powering different systems?

Or is the idea a shared bank?

Are any of your charge sources enough to over amp the bank? Or a combination of them able to do so?

If you are alternator charging you do need an orion charger to limit the current so the alternator isn't trashed.

There are two types of Orion 1.dc to dc converters and 2. dc to dc charging.

Smart shunt to each battery is only really necessary if you like alot of data and plan on isolating each battery from the rest of them. Otherwise one for a bank total is fine.

0 ·

question