Question about battery circuit

[Brad Clark]

Now if my current set up as (1) 100Ah battery, and I want to add a 190Ah battery to the circuit. Can I do this? Or do I need to get the same size as the original, 100Ah?

 

[smritte]

Lithium, AGM, lead acid?

I can find you all kinds of data showing if you don't match your batteries, the world as we know it will end. I truly believe this data is based on pre 1970's batteries. More than anything you should match battery types. This is due to diffrent charging voltages.

Being the rebel that I am, none of my batteries have ever matched. I get full life out of my batteries. I don't think I will parallel a lithium with the others. Right now I have two diffrent sizes of AGM and their fine. One is about two years old and the other is about three. In the past I have paralleled diffrent sizes of AGM and lead acid. I do try to keep the battery type the same though.

The lithium's should have a built in BMS. That will ensure the cells inside each charge evenly. Lithium's are made up of a bunch of smaller batteries in a box. A 12 volt battery can have as few as four or over thirty six. Each has its own BMS lead.

A battery will draw power at diffrent rates until its charged. If one is lower than the other they will charge at diffrent rates until their full. I think the biggest problem you can cause is putting an old battery with a new. "If" the old battery starts to short, it will drain the new battery.

 

[Crossfit Jeep]

Interesting, I feel like I just got schooled. So OP, hope you don't mind me chiming here seeing that I don't have an answer. But I'm curious though, smritte just to clarify, you aren't mixing your AGM with Lithium batteries right?

 

[smritte]

Not yet.
I have one Lithium I'm playing with at the moment. If I add another battery to that system, it will be another lithium only due to the weight. One of my way too many obsessions is batteries. The more I learn, the more I experiment. Its amazing how many myths I have blown away over the years.
The more I learn about the diffrent lithium battery types the more misinformation I find. It was the same for lead acid and AGM. I truly believe its all about marketing.
I'm sure sooner or later I will be mixing lithium with my AGM's (I don't buy lead acid anymore).

So far the data shows they are compatible but the lithium will never see full charge. It would be better to slightly undercharge the lithium than over charge the AGM. As I said, still researching and experimenting.