Newbie here, need help switching from agm to lithium

[Nico408x]

Ok so I've been doing research and honestly I'm kinda stumped, I know I wanna go with lithium titanate but I would like to avoid building my own bank so I've been looking at cased cells

 

https://www.google.com/amp/s/store.soundsolutionsaudio.com/amp/ces-custom-electric-service-40ah-lto-battery-cased-lithium-10-spot-terminals-actively-balanced/

 

https://caraudiobargain.com/xs-power-ioxus-ix-3160-60ah-lithium-lto-battery-10-000-rms-handling/

 

But would I be able to hook my current battery terminals up to it without a battery delete since my battery is already in the trunk or do I still need to do a delete and run everything off that? I have a BMW e46 sedan with an h8(group 49) duralast agm in the trunk as my "under the hood" battery.

 

 

Still new to car audio and this is my second build (first was a single 12 on 800 watts) so I've got a lot to learn, any feedback is appreciated. Thanks

 

[SnowDrifter]

The whole 'battery delete' thing isn't indicating to remove the battery, just to avoid mixing chemistries. There are some other reasons, but they don't apply to your rig.

With your desired setup, there are 2 advantages here:

1. It's in the trunk. Away from the hood. Away from the heat of the engine.

2. LTO is a kickass chemistry.

So.... The usual advice for deleting the under-hood battery is geared much more around conventional battery installs, where running NMC/LFP batteries under the hood would well exceed safe operating temps for those chemistries. LTO doesn't mind it. And you're in the trunk. So honestly, if it fits, you can just toss an LTO battery in the stock location. Barring that, you can see about finding a 'dummy battery' - an empty battery case with terminals, serving as a placeholder.

Other considerations:
- It would be ideal to convert your alternator to external regulation, or find some other means to maintain a constant charge voltage that doesn't have hot-cold fluctuation. Granted, LTO is much less sensitive to this than other chemistries. But you still don't want to over-charge them. Or under-charge them.

- Quick glance at the given specs for the batteries you posted looks like it's in a 6s config. LTO cells are fully charged at ~2.8v. Which means you'd want your alternator set to about 16v. Charging in the ~14v range at stock voltage would mean that you have basically no battery capacity. If, however, you got a 5s battery, that would be fully charged at ~13.5v, and charging higher would be over-charging. Above 3v per cell would be over-charged (15v in a 5s config), causing accelerated wear. And above 3.2v per cell would cause rapid and immediate degradation of the unit (16v in a 5s config). Though, of note, LTO cells don't have a catastrophic failure mode as would other chemistries. So it'll just quietly stop working as opposed to turning into a flamethrower.