"Mis-use" of solar chargers

[Curacao]

Hi all ,
two simple question :
1. I have two cheap Chinese PWM chargers with a maximum PV voltage of 50 V . In case I install 2 x 37V panels in series (= 74V VOC) and install 2 x identical PWM chargers in series , will I blow the chargers ? Anybody tried this before ?

2. Can I mis-use a PWM controller as DC-DC converter (with a 48V battery bank input instead of PV) to get 12V DC out ouf it ?

Thx in advance

Andreas

[Mike90250]

1) I don't know, but it's unlikely to work well

2) No. PWM chargers don't work at all in that manner. They essentially have a switch inside to turn the PV panel on, and when the battery is full, turns the panel off. Panels can only deliver a limited amount of amps, and the PWM controller is only designed to manage a specific amperage. A battery bank will supply hundreds of amps into the circuit a PWM controller serves, and will almost certainly instantly fry the components inside.
Morningstar MPPT controllers are able to do this, and manage the power properly. Other MPPT controllers might or might not be able to work in the manner you require.
( I can't currently find their tech note describing this, but as I recall, it was possible. )
http://support.morningstarcorp.com/search/?document_section=&search_product=96
* Using a DC power supply as a PV panel substitute?
Description:

Can I use a power source other than a PV panel to charge my batteries?

We do not recommend using a DC power supply with any of our PWM controllers. While they appear to be similar to PV modules in function, DC power supplies have considerably more output capacitance. Connecting a DC power supply to our PWM controllers may cause excessive heating and premature failure.
MPPT controllers can be used for this purpose without issue.

[sdold]

Hi all ,
two simple question :
1. I have two cheap Chinese PWM chargers with a maximum PV voltage of 50 V . In case I install 2 x 37V panels in series (= 74V VOC) and install 2 x identical PWM chargers in series , will I blow the chargers ? Anybody tried this before ?

No, because there is no way to ensure that the input voltage is split evenly between the controllers, and especially not if you plan to connect the outputs in parallel on a 12V battery.

Mike covered #2