Re: [N8VEM: 2650] Battery operating the N8VEM

["Bill Beech (NJ7P)" <nj...@nj7p.org>]

Dimension Engineering sells complete switching regulators with linear 
pinouts. Beats assembling parts on a board. I use them in another 
project running off a a 12-cell NiMH battery pack. Low heat dissipation 
as compared to linear.

Bill

Richard A. Cini wrote:
> All:
>
> Take a look at the data sheet for the National Semiconductor 
> LM2596T-5.0 switching regulator:
>
> http://www.national.com/mpf/LM/LM2596.html
>
> The LM2596 is a 3A switching voltage regulator in a TO-220 case. It 
> requires two caps, a choke and a Schottky catch diode, plus a heat 
> sink. Rough pricing -- $10 in parts without the heatsink. I hope to 
> connect this to a 12v NiMH pack (preserving the 12v in case I need it 
> for a hard drive) and it becomes a cost-effective way to get a small, 
> light-weight high-current power system for the N8VEM.
>
> All-battery.com has custom NiMH packs for not a lot of money, but it 
> becomes a weight issue. It’s roughly 2oz per cell, which includes a 
> share of the weight of outer wrapping and connectors. For a 10-cell 
> 12v/4000mAh pack, that’s 20oz — 1.25 pounds. That’s a lot, IMHO.
>
> The alternative is a 14.8v LiOH pack which uses four 3.7v batteries. 
> Downside is that the charger is expensive and you’d need a second 
> regulator for 12v (the LM2596T-12). Upside is that the pack would be 
> pretty light.
>
> Just something to ponder.
>
> Rich
>
> --
> Rich Cini
> Collector of Classic Computers
> Build Master and lead engineer, Altair32 Emulator
> http://www.altair32.com
> http://www.classiccmp.org/cini
>
> >