Options for 12v car audio equipment on 24v lifepo4 battery

[orangezero]

I want to find a way to use two old home theater subwoofers with failed amplifier boards. I also have two Jensen XDA92rb car audio amps which run on a typical 12v car battery, around 240w rms @4ohm (600w peak) which matches well with the subwoofers. I have a 24v 200ah lifepo4 battery charged with solar panels offgrid. I've used a smaller 14v lithium titanate pack to test one of the amps and subwoofers and it works well.

I'd prefer to run them both from my solar/battery on 24v and not use AC at all. So, do I need to get a 24v to 12v converter... that seems expensive to get a proper sized one... or is it possible to wire the two Jensen amps in series? The amps are 16v max input listed, so it can't be as easy as 26v/2 gives each amp around 13v? Is it? I assume there are good reasons to not do this, but can anyone point me to a discussion of why?

I seem to remember my inverter didn't like powering one of these subs when it was using its built-in amp, meaning the inverter would reset occasionally.

As I write this out, I'm wondering if the best answer is to just use the lithium titanate pack and keep recharging it. Didn't really want to go down the path of figuring out how many hours of use I could get before needing a recharge.

thanks

 

[Batvette]

AFAIK only thing is a big buck converter for 24v down to 12. You cant wire the amps in series like that. Or maybe you can and Ive just never heard of it done. I see home subs used at goodwill all the time for about $40, because theyre old ones without hdmi. Be cheaper to get one and use their amps.

 

[v_green57]

Take a look at the inexpensive Class D amps on Amazon. A lot of them run directly off of 24VDC.

I've used a couple and they are pretty damn good.

 

[billvon]

As I write this out, I'm wondering if the best answer is to just use the lithium titanate pack and keep recharging it. Didn't really want to go down the path of figuring out how many hours of use I could get before needing a recharge.

Get a smallish charger-compatible Meanwell DC/DC (cheap) and charge the 12V from the 24V system continuously.

 

[AntronX]

Use 12V LFP battery to power your amps. Continuously charge that battery via Victron MPPT fed from 24V system. I use this technique to run my 12V computer equipment from my 48V pack using Victron smart solar 75/15 as a charger.