Re: #ubitx Powering options? #ubitx

Art Howard

I get 75 amp hour gel cells here for fifty bucks. They are the size of a regular car battery but a real good power source

On 16 Jan 2018 11:32 pm, "Clark Martin" <kk6isp@...> wrote:

Clark Martin

On Jan 16, 2018, at 12:18 PM, various people wrote:

Those small jump-start batteries should work fine for powering a radio.
Cheap because it's a mass market, there's millions of cars.
But ads are aimed for the mass market as well, and stretch specs as far as they think they can get away with
in order to get a click before all the other badly inflated ads do:
See also this old thread:

I have the Harbor Fake Viking jumper starter pack, speced at 12V @ 12A-h.  If you look inside there are four 2.9 A-h cells.  The multiplied the A-h rating by the number of cells which is correct for parallel wired cells but is wrong for series wired cells.  It’s not even 12A-h if you multiply by four, it’s 11.6A-h.  

I consider the A-h rating for any mass market battery pack to be wrong until proven otherwise.  This applies to both jump starters and USB packs.

If you are concerned about safety, be aware that those jump-starters can give 100A or more.
Rather amazing, and also rather dangerous.
If shorted, those batteries could heat up, potentially explode with a lithium fire.

The pack I have (see above) has overcorrect shutdown protection (on the utility outlet, not the cup starter outlet).

Another thing to be aware of when buying these battery/ power packs is that the charger in most them does not balance the cells of a lion battery. This will greatly reduce battery life

The above pack does have cell balancing.

I also like it because it can charge off of 12V.  A lot of 12V battery packs don’t so this is a nice feature.

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