RJH wrote:
Would it be OK to charge on of these:


https://www.walteronline.com/en/tool...mpressor-p3155

(jump starter/compressor/light/USB) by connecting the jump leads to a car
battery charger, rather than use the supplied AC adapter?


Charger = 15V @ 500mA for K640046

https://www.walteronline.com/en/acce...arger-p3956016

Product pictures. Vorne and Hinten.





Switch for jump-starter leads.



Switch for compressor is not shown in detail. Noise warning sticker. 10 minute run limit.

https://www.walteronline.com/Produkt...nks

Note mains connector.

https://www.walteronline.com/Produkt...eraet@ 2x.png

Considering the battery could be a sealed lead acid with
limited regeneration rate, and the battery is 12V @ 17.2Ah,
that's probably a good rate. That's like a third of an
automotive battery. It could be a sealed battery, not
intended to leak hydrogen into the room (it still has to be
vented for safety - like a vent that opens at 5 bar).

If connecting your own charger, I'd use a smart charger
with charge current in the ballpark. Say, a 2A charger max.
Don't use an old dumb charger (transformer plus selenium
rectifier), because the current flow is rather uncontrolled.

Since you won't be running it all the way down, it will
never take 34 hours to charge with the included adapter.
Maybe 6 hours to top up, after a usage. The unit should
really have undervoltage cutoff, to protect the battery.
Since it has overcurrent protection, the protection
device can be used for more than one function (like, a
relay or contactor for heavy current).

Note that there is a switch to switch on the battery leads!
The switch contacts are not rated at 150A, but some other
contactor inside might be worked by the switch or something.
This might present some issues for forcing charge in
through the croc clips.

A battery that small is going to be limited on CCA.
You won't be able to start a vehicle with that unit alone.
The battery in the vehicle also has to help.

The larger Walter jump starter, has 240A max output. This
unit, no spec is offered for the max output (overcurrent protect).
Neither is there any mention of undervoltage cutoff. The
USB SMPS for the phone charger, that should have an
undervoltage cutoff, to avoid damaging the battery
by draining to zero.

But since Walter offers no downloadable manual, we're forced
to guess by looking at tiny pictures of the product. I don't
buy products without a user manual, for this very reason,
poor marketing materials online.

Paul