90V solar panel to charge12v battery

[knagtegl]

Hi

I have some old solar panels that I want to use to charge a 12V battery bank.
The problem is that they deliver around 90Volts at max 0.5 Amps per panel.
I wonder if I can pulse charge a battery by using a transistor between the panel and
the battery and connect the base of the transistor to a SSG so i gets real short pulses.

I would like to know if it can destroy the solar panels (maybe put a capacitor over it).

Before I try this I would like some thoughts on this or other suggestions to charge the batteries
with these panels.

Karel

[John_Koorn]

Karel, I would recommend a capacitor discharge circuit. Something like a small uF, high voltage capacitor should work.

John K.

[knagtegl]

John,

I just tried it today, it's a good sunny day and the panel is giving max 90 volts at 0.5 Amps.
I put a capacitor 400v 47 mfd n the end of the line just before my transistor (MJL21194).
I have put the transistor from positive solar to collector and emitor to positive of battery.
I took the puls from my 9 coil SSG to the base of the transistor and got a nice squarewave
on the collector. My battery was raising very well (old 60 Amp/h)

The transistor was staying cool and is has been running for 15 minutes now and battery is up to 13,20v.

I tried to put a 12v lamp in series with the batt and it was not lighting up (it is very bright if done on a SSG.

Then I tried a little neon lamp in series with the battery and it was not on, when I did the neon instead of the batt it was on.

It looks very interesting I have a lot of these panels and this way i may be using them to charge a big batery bank without
sulfation and not with negative energy.


Karel

[John_Koorn]

Hi Karel, even though it appears to be working that's not what I meant.

I meant for you to charge up a capacitor with the solar panel and than discharge that capacitor into you battery. This is another form of radiant energy charging, by using fast pulses of current.

John K.

[knagtegl]

I found that the connection to the capacitor was disconnected so I did the tests direct from the solar panel and that worked fine.

I configured a pulse generator to the base of the transistor and found that around 600 hz square waveI got the best results ( about the same freq as my SSG).
Then I connected the capacitor direct to the solar panel 47 mfd there was a lot more power going to the batt now but my transistor heated up
it was switching to much current I think. I am not sure what will be better do I need the cap and bigger transistor (more parallel) or less capacity on the cap?
I connected a 12 volt 5 watt lamp in series with the battery and with the cap on the panel I got the most current on around 5000 hz but transistor really heated
up than. I don't want to charge the battery with to much current.
If I use more panels Is it better to put them parallel or in series and go for high voltage very low current or maybe take more capacitors in series and lower the voltage by taking the power of the capacitors one by one than just some thoughts.

Karel

[LeroyWebster]

Hi

I have some old solar panels that I want to use to charge a 12V battery bank.
The problem is that they deliver around 90Volts at max 0.5 Amps per panel.
I wonder if I can pulse charge a battery by using a transistor between the panel and
the battery and connect the base of the transistor to a SSG so i gets real short pulses.

I would like to know if it can destroy the solar panels (maybe put a capacitor over it).

Before I try this I would like some thoughts on this or other suggestions to charge the batteries
with these panels.

Karel

hello friend have you got these batteries? I am looking to get portable charger so please help me with your experience.

[knagtegl]

Hi Leroy,

I don't realy understand your question, I did some experiments with charging a car battery with a 90V 50Watt solarpanel.
I pulsed the power with a power transistor to the battery and it seemed to work. I will have to do some more experiments
but have no time for this at the moment.

Karel