Panels should not be damaged despite spark
They are happy to be short circuited.
They are essentially lossy current sources in more than about 5% of sunligh=
t.
Spark is probably contact splatter as wire makes connection. An eg
100W 12V panel is producing ~=3D 6A x 18V at full sun.

A 12V panel has 36 cells and is rated at about 18V loaded.
Very inefficient when not used with a buck converter (ideally in a
MPPT controller)

Panels will happily cook his batteries if applied to a fully charged
LA battery. Charger (if not MPPT) is mainly a device to shut charging
off and do proper cycling.


He'd be hard put to get 24V from a 12V panel even OC.
If he does it's at low low current.

What did he pay per Watt max power?

NZ ONLY:  I now have a very good Chinese contact for large PV panels
and  I am probably going to import some panels and will have them
available at best price in NZ for fully warrantied panels. Better
prices are available for end of line specials from bankrupt suppliers
(of who there are many) but you get no guarantees. BUT they are all
pretty good anyway these days. Mine will have full underwritten
warranties by insurance companies. Probably 25% less than very very
cheapest on market - possibly even lower.


         Russell


> But in the meantime, he's connecting the panels directly to the
> batteries, bypassing the charger, as he says in full sunlight the panels
> put out 26V which is "enough to keep the batteries topped up"
>
> What concerns me is that he says he connects the panels only when
> their output is over 24V and sees a spark. The supplier has suggested
> he not do this, which sounds reasonable to me. 'menace'claims (based
> on what, I don't know) that this spark will do the panel no harm, and
> rang me for reassurance that he is correct. To my mind, a spark when
> a power supply is connected to a load means something is under stress,
> for better or worse, and if they were my panels I'd not be tempting fate
> by blowing an internal connection, thereby getting lumbered with a non-
> returnable damaged panel
>
--=20
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