Converting 24v to 12v

Thread Starter

Jades

Joined Jun 17, 2020
4
Hi all,

I have two of these batteries: https://www.electricmotorsport.com/gbs-12v-4-cell-100ah-lifemnpo4.html. I've wired them in series to be 24v (I was told that 24v is better than 12). This is for a van conversion I'm doing with 24V solar panels. I need to get from 24v to 12v to run the LED lights, fan, fridge, water pump (pretty much everything is 12v). Is a converter the best way to get from 24 to 12 volts. Something like this: https://www.invertersupply.com/index.php?main_page=product_info&products_id=189672&gclid=EAIaIQobChMIyerv65WK6gIVER6tBh2S1Qu3EAYYASABEgKJ5vD_BwE.

The thing I don't understand is that this is rated for 5amps (60watts); I don't know how that equates with a 24v battery (200amp/hours) that I want to convert to 12.

Thanks much,

James
 

nsaspook

Joined Aug 27, 2009
7,478
Last edited:

debe

Joined Sep 21, 2010
1,178
If most of your stuff is 12V then make the whole system 12V not 24V. Not very efficient running 24V then converting it back down to 12V.
 

Thread Starter

Jades

Joined Jun 17, 2020
4
If most of your stuff is 12V then make the whole system 12V not 24V. Not very efficient running 24V then converting it back down to 12V.
Thanks, someone told me 24v was more efficient...and that I could additionally use more of the 24v solar panels. But I assume there are costs for converting energy back to 12v? Are there more efficient (or cheaper) methods than a converter; I assume one of those larger Orion converters will be pricey.

I'm trying to figure out the best way forward.
 

nsaspook

Joined Aug 27, 2009
7,478
I have a 24vdc system using this controller. https://forum.allaboutcircuits.com/threads/project-solar-wind-pic-controlled-battery-array.32879/post-1482098
You need about 50vdc from the solar panel array for it to operate normally (efficient MPPT) with at 24vdc energy bank.
https://forum.allaboutcircuits.com/threads/project-solar-wind-pic-controlled-battery-array.32879/post-1513872

Each voltage conversion will lose (realistic numbers instead of what's printed on a datasheet) in the range of 3 to 8 percent of energy transferred so it's best to keep that at a minimum. At higher power, a 24vdc energy bank is typically more efficient than the equivalent 12vdc bank mainly from the reduction in IR losses with reasonable cable sizes and connections. Down converting to 12vdc will eat a large chuck of that advantage.
 

Ylli

Joined Nov 13, 2015
976
If your final needed output voltage is 12 volts, then use a 12 volt battery. Outputting to 24 volts and then downconverting to 12 volts will not be more efficient.
 

Thread Starter

Jades

Joined Jun 17, 2020
4
Okay, it sounds like 12v is the way to go. @nsaspook , is this for a van conversion or a house (if for a van, you must have 12v needs, how do you deal with those?) I also need to get a BMS for the batteries: since it seems like 12v is the way to go--this should fit my needs, right? : https://www.aliexpress.com/item/32921412658.html?spm=a2g0o.productlist.0.0.66e73a8dyJ0zzH&algo_pvid=01f9b394-ef28-4c58-8ce6-6878ae3529f6&algo_expid=01f9b394-ef28-4c58-8ce6-6878ae3529f6-21&btsid=0be3743615925108686001846e36d4&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_
 
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