How to wire a Lithium Battery Pack Q

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Discussion Overview

The discussion revolves around the design and wiring of a lithium battery pack for a project involving a wireless outdoor rolling credenza with various electronic components. Participants explore different configurations for battery setups, including series and parallel arrangements, and the implications for energy delivery and inverter compatibility.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant proposes using either four 12V lithium batteries in parallel with diodes for isolation or four 12V batteries in series to achieve 48V, questioning the feasibility of using a 4-cell charger for the series configuration.
  • Another participant suggests sourcing a single 48V ~29Ah battery instead of multiple 12V batteries.
  • There is a discussion about the need for headroom in energy delivery, with one participant expressing uncertainty about whether the 200W inverter's shutdown threshold (10.5V for 12V or 42V for 48V) would be reached during operation.
  • One participant mentions the potential for commercial solutions, indicating that while options exist, they may not be affordable.
  • Another participant humorously suggests using extension cords and saving money for leisure, though this is not directly related to the technical inquiry.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best battery configuration or whether a single battery solution is preferable. There are multiple competing views regarding the optimal setup for the project.

Contextual Notes

Participants express uncertainty about the energy extraction capabilities of the proposed battery configurations in relation to the inverter's shutdown thresholds, indicating a need for further clarification on these technical aspects.

Who May Find This Useful

Individuals interested in DIY electronics projects, battery management systems, or those exploring wireless power solutions may find this discussion relevant.

Physics_Kid
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hi all,
i am embarking on a new project, building a outdoor rolling credenza that has TV (with air operated TV lift), cd player, small receiver, 100% wireless (power and wifi, etc).

my design calls for a battery pack that can deliver approx 5x106 joules, this leaves me in the ballpark of 12v@115Ah, or 48v@29Ah
in general this is 200watt x 6hr @ 85% system efficiency.

true sine wave inverters run best at 48vdc, but a 12v inverter can also work.

(12v inverter) can i run 12v Lithium batteries in parallel if they are isolated via diodes and the charger has four independent cell chargers,
or, four 12v Lithium batteries in series for 48v (can a 4 cell charger straddle each cell in series and be ok?),
or do i source one 48v ~29Ah battery

any suggestions?
 
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Spinnor said:
Get one of these,

https://www.google.com/search?sourceid=chrome-psyapi2&ion=1&espv=2&ie=UTF-8&q=home depot extension cords&oq=home depot extension&aqs=chrome.0.0j69i57j0l4.6482j0j8

and use the rest of the money saved for good beer, wine or steak, enjoy your summer!
hah, i will need a short cord, but it will likely be mounted to the rolling cart via a wind-up mechanism, so that when not in use i can plug it into charge the batteries.

its a project, a completely wireless project, including wireless power, wifi, and Miracast. having a cord laying across my back patio as a tether is the old way, this is the new way. if it goes well, well, it might be my 2nd job fab'ing complete solutions like this, etc.
 
i am looking for just the batts, and ideas about design. 4 12v in parallel vs 4 12v in series vs 1 48v
delivered energy has to be around 5x106joules, but i am not 100% sure if i need some headroom in there because the 200w inverter i am looking at does a shutdown at 10.5v or 42v (12v vs the 48v model, etc).

can i extract that much energy from a 48v ~29Ah batt, or four 12v ~29Ah batts w/o the batt voltage reaching shutdown threshold of inverter?
 

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