跳转到主内容

修复你的物品

维修的权力

配件 & 工具

帮助

原帖由: K9GL ,

文本:

Yes,   search eBay for a ‘DC Buck converter’.  These are inexpensive devices that convert a higher voltage to a lower one, efficiently.  Get one that is rated for more amps than you require.

You need to understand the capacity of your battery.  a 18V 5AH battery has about 90 Watts of capacity.  That means it can deliver approximately 18V at 1 Amp for 5 hours or 18V at 5 Amps for 1 Hour.  When you convert the voltage to 12V, it will still deliver near 90 Watts, so you can get 12V at 1 Amp for 7.5 hours or 12V at 7.5 Amps for 1 hour.

If you look at your CPAP it will require 12V at some current level.  As you can see, if it needs more than 1 Amp, a single 18V 5AH battery will only work for 7.5 hours.  You can parallel the batteries together for nearly double the capacity.

Batteries do not supply voltage at a perfectly linear level, meaning they supply a higher voltage initially, and drop down lower as they discharge.  Your DC Buck Converter will fix this problem, as it will supply a constant voltage output.  Also, battery capacity lowers, as the current draw increases.

状态:

open