Allan,
First, depending on the age of that Sunfrost, it might be OK to use on
either a 12V or 24V system directly. The older ones are 12V only, but
I'm not sure when the changeover occurred. An email to Sunfrost should
give you that data.
For over 15 years we've used a Vanner Voltmaster. Don't know if they
are even available anymore and you need to have a battery system that
you can tap at 12V into equal sections. Basically, they look at both
halves and switch from one to the other based on a very small voltage
imbalance. In the 98% efficient category. The Voltmaster will be way
more money than your other choices and needs two CBs on it's input
rather than one, but if max efficiency is more important than initial
cost, they are hard to beat.
Bob-O
On Oct 6, 2009, at 10:04 PM, Allan Sindelar wrote:
Wrenches,
Simple question, I know: what has worked well as a 24V – 12V DC-DC
step-down converter for a Sun Frost? I am doing a design to completely
rebuild/replace an early-90s off-grid 12V system with a new system at
24V. The only DC load is a Sun Frost. I think it’s an RF16, so dual-
compressor. I know of at least three converters: Solar Converters; BZ
Products; ICT; and I’m sure there are many more. What has worked well,
with minimal ghost load?
Thank you,
Allan Sindelar
al...@positiveenergysolar.com
NABCEP Certified Photovoltaic Installer
EE98J Journeyman Electrician
Positive Energy, Inc.
3201 Calle Marie
Santa Fe, New Mexico 87507
505 424-1112
www.PositiveEnergySolar.com
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