24V battery bank with solar - pros and cons

In quiescent mode they will use a small but perhaps (?) significant (aggregate total of) amperage. Worth appraising. Therefore switch the converter. I have had unfailing success with DROK brand buckers. Several have been functioning with LED lighting for thousands of hours. The voltage hasn't even drifted >.2 vdc. But I found output current in excess of 12 amperes really heated the devices, necessitating the use of a 40mm muffin fan. I chose 24 volt model fans as they screw a perfect amount of air over the booster or bucker at 12 vdc, are dead silent and consumption is negligible.

Sounds good.

What about deleting the big 24/12V converter and get many small dc/dc converters. They sell them at ebay for under $10. Install them in front of fridge, and everywhere else that needs 12V. Install them in the light fixture so they're on only when the light switch is activated. Or you can convert some, or all lights to 24V.

There isn't that much that needs 12V. Operating a big 24/12 converter 24/7 seems energy wasteful. You'll do much better with individual converters that are only on when activated.

eb145 wrote:
hopefully I could wire a 24V battery bank in a way that lets me easily convert it to a 12V battery bank on the road if needed.

That's do-able.

OP here.

as usual, thanks for the great information and especially for the small debate which helps expose potential problems.

For my use case, I plan to be traveling for a few months at a time starting next year and want the option to visit non-electric camp sites for days or weeks at a time while providing my dear wife and I reliable basic electricity to (at a minimum) run the fridge (on propane), the water heater (on propane) and the LED lights on batteries. We have done this already with our previous Travel Trailer with a 140 Watt roof mount solar panel and 100 Watt portable solar panel so nothing new there. And when i am able to harvest lots of sunshine it would be nice to be able to run the microwave, watch more TV, use the vacuum cleaner, etc...

My new 5th wheel has an Onan 5.5KW on-board propane generator and my truck has an alternator so I have two emergency charging sources when needed. And I have a 100W portable folding solar panel in case I am parked in shade with abundant sunshine very close by.

It sounds like to me, converting to a 24V battery bank has mostly "pros" with the "cons" being limited to:

1. buying, installing and relying on a Buck converter to convert 24V to 12V (sized to handle my max current requirements)

2. buying and installing a 24V converter to charge the battery bank on shore power.

To mitigate these risks, I could leave the current 12V converter on board for emergency use , and hopefully I could wire a 24V battery bank in a way that lets me easily convert it to a 12V battery bank on the road if needed.

Did I miss anything for my use case?

Ed

Ground Loop 101

Pretty easy to contain the entire circuit, alt, reg, battery and inverter totally insulated. Fishing vessels do not use a grounded hull for obvious propeller and zinc-eating reasons. Different on an RV. Flaunting my precautionary note will prove to be pricey.

The issue for the 32 battery bank is a set of four 8-volt batteries.

The Kelley II had 480, 3-phase, 240 three phase, 240 and 120 single phase, 24 - and 12 volt DC systems. Every light switch was a T rated toggle. A pair. 120, and 24 adjacent to one another. When the generator, hydraulic and main engines were online I had a veritable festival of alternators and batteries that needed to be managed. Since the alternators were self-excited, rectifier type isolation was out of the question. Ever try to manage an engine that had two starter motors? 90 degree learning curve.

MEXICOWANDERER wrote:
.....But it must be an isolated negative unit.

Serious question: why is that?

School of hard knocks...

Let's say a single B-belt lasts 10 months driving a 100-amp 32 volt alternator.

By changing to matched B-belts, a pair, the belts will last 4 times as long, minimum. You can come to your own conclusions as to "why".

One dragger with a blower-driven alternator (Detroit) had nothing but problems keeping batteries charged with an HSC-4006-U Motorola 100-amp alternator. I changed the blower pulley to a max allowed 8" and alternator drive pulley to a 1.85" diameter pulley. Gilmer cog belt drive.

On many full scale pickups or motorhomes adding a small 24-volt alternator is not the-end-of-the-world difficult. But it must be an isolated negative unit.

OP, What do you think about a 24V setup given this thread?

CA Traveler wrote:
If my alternator failure were mechanical, say frozen, then it would have to be repaired before driving due to the single belt. So would a 2 belt setup be more reliable?

Don't forget suspenders.