Need to run some 24 volt loads off a 48 volt battery bank...

[openplanet]

I'm upgrading my system to 48 volts but still need to run some 24 volt loads: led lights, ceiling fan, small (SunDanzer) fridge, pressure pump).  From what I can see, my options are

1: 48-to-24 volt converter
2: small mppt charge controller charging small 24 volt bank from the 48 volt bank

Interested in knowing people's thoughts.  Thanks.

[ClassicCrazy]

I was using my Kid charge controller to 24v to charge 12v batteries. I just switched to using a Samlex DC to DC converter. Take up a lot less space and most likely more efficient - though I haven't tested the efficiency yet.

I am liking the DC to DC converter - nice to get those 12v batteries out of here ! And they were oddball AGMs that I had - noticed after I unhooked them and let them sit a day that one of them wasn't good - the voltage had dropped.

Check out Samlex - they make good products and are known to be reliable and fairly inexpensive.

Larry

[openplanet]

Thanks very much Larry.  I was looking at Meanwell DC-DC converters (I have a Meanwell battery charger that has worked flawlessly for me), but I will definitely take a look at Samlex.  And I agree, they make great products at fair prices.  The 24 volt inverter I'll be selling as part of this 24 to 48 volt upgrade is a Samlex, and it, too, has been excellent.

As an aside, it's surprising to me how few people seem to realize the huge quality difference between products made in Taiwan (R.O.C.) and China.  Anything made in Taiwan is absolutely tops, as good as Japan or South Korea.  Chinese products are still, for the most part, inferior...although this is changing.

Thanks again.

[kitestrings]

There's another option.  You can center "tap" a 48V bank to get 24V and then use a battery equalizer to even out the cells on either side.  Not all converters will allow this, but the beauty is that you can pull a heavy short-term load and have the back up of the batteries.  The equalizer catches things up over time and therefore doesn't need to handle your peak load.  Check out Solar Converters - that's the name of the company - from Canada (IIRC just the name .com).  They make boost & buck converters and battery equalizers, and some other products.  Good quality. Good service.  We've used this method for years for both 24V & 12V loads.

Good luck,  ~k

[kitestrings]

It looks like they make a 10A & a 30A Equalizer/Autotransformer for 48/24V

http://www.solarconverters.com/products/desulphators/battery-equalizer/eq-2448-30/

It's interesting that you can actually go both up or down with these things.  For a while, we transitioned to a 48V bank, but still had lots of 12V lights, refrig, etc...and we also had a 12V wind turbine.  Most of the time it was catching up the 12V tap for us, but when the winds were high we "pushed" the the low side and the balancer always kept the 1x/4x ratio on the two halves of the bank.

[ClassicCrazy]

It looks like they make a 10A & a 30A Equalizer/Autotransformer for 48/24V

http://www.solarconverters.com/products/desulphators/battery-equalizer/eq-2448-30/

It's interesting that you can actually go both up or down with these things.  For a while, we transitioned to a 48V bank, but still had lots of 12V lights, refrig, etc...and we also had a 12V wind turbine.  Most of the time it was catching up the 12V tap for us, but when the winds were high we "pushed" the the low side and the balancer always kept the 1x/4x ratio on the two halves of the bank.

They don't give specs on voltage range or limits for inputs  on that device .

Larry

[kitestrings]

Hi Larry,

It looks to me like they may be re-doing their website.  Quite a few products and manuals not there.  Here's another (on-line) way at it:

https://www.altestore.com/store/charge-controllers/battery-to-battery-dc-chargers/solar-converters-eq-2448-30a-dc-to-dc-updown-converter-p1295/

I found them to be pretty responsive to any questions that I've had via email.  ~ks

[ClassicCrazy]

Hi Larry,

It looks to me like they may be re-doing their website.  Quite a few products and manuals not there.  Here's another (on-line) way at it:

https://www.altestore.com/store/charge-controllers/battery-to-battery-dc-chargers/solar-converters-eq-2448-30a-dc-to-dc-updown-converter-p1295/

I found them to be pretty responsive to any questions that I've had via email.  ~ks

thanks yeah found the specs via that
Larry