On Mon, 14 Aug 2017 21:14:18 -0400, rickman wrote:

> UPS typically use SLA, sealed lead acid, batteries, I suppose because of
> the cost.  Notice it is very hard to get capacity info on most UPS
> units.  They are happy to tell you how many amps or VA they will provide
> (less often watts), but almost never a WHr rating.  
>
Tell me about it! I ran into that gotcha when shopping for my UPS a few
years back. Fortunately I knew about a decent supplier, who I'd been
buying SLAs from for a long while: one with real people who know the
products and who answer their phones.

They sell Yuasa NP7-12 SLAs for $US 21.60 - quite a reasonable price.

Yuasa is the most consistently reliable SLA type I've found. I use them
for starting model engines and as in-flight power in my sailplane as well
as in my Riello UPS, though as I haven't replaced those yet, I'm
uncertain of the model number since they were pre-installed.

> I wrote them a note letting them know the lack of a 3 pin connector is a
> problem for me and that they should consider making a unit specifically
> for the rPi with an external 5 volt PS and physically smaller.  I don't
> expect them to follow up on that though since their core competence is
> SLA batteries and that would almost demand a Li battery.
>
If I was feeling keen and was planning to do anything with my RPi that
needed a UPS, I'd just plug a wall rat into mine. My ADSL modem isn't on
it as yet: that would take precedence as IIRC BT exchanges have been on
UPS systems for years.


--
martin@   | Martin Gregorie
gregorie. | Essex, UK
org       |

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