Hey guys.
I am thinking about buying two of these for my miniature boominator with Monacor SP-60.
7.5V 5.4W Solarpanel Solarmodule 12V MONOKRISTALLIN 6V | eBay
I have a 12V 12Ah (CT Leader CT12-12) battery in it.
If I put those in series I will get 15V which is very close to the maximum charging voltage for the battery. Is it possible to limit it with a voltage divider made from two resistors?
I am thinking about buying two of these for my miniature boominator with Monacor SP-60.
7.5V 5.4W Solarpanel Solarmodule 12V MONOKRISTALLIN 6V | eBay
I have a 12V 12Ah (CT Leader CT12-12) battery in it.
If I put those in series I will get 15V which is very close to the maximum charging voltage for the battery. Is it possible to limit it with a voltage divider made from two resistors?
There's no danger in putting them in series. In fact you have to.
Total power output of the panels in series is lower than 1/10 of the battery capacity. This is normally considered safe for permanent connection.
The voltage will not be 15V at any point either. The internal resistance in the battery will pull that down to about 13.8V absolute max, even when fully charged.
You will need a diode though, otherwise the battery will discharge itself into the solar panel which will get very very hot and probably take permanent damage.
Total power output of the panels in series is lower than 1/10 of the battery capacity. This is normally considered safe for permanent connection.
The voltage will not be 15V at any point either. The internal resistance in the battery will pull that down to about 13.8V absolute max, even when fully charged.
You will need a diode though, otherwise the battery will discharge itself into the solar panel which will get very very hot and probably take permanent damage.
Thank you Saturnus, I was hoping you would see this thread and give me your input, as my boombox is made out of your design, but with SP-60, and I didn't wanna ask in your thread
Will any diode do? Like a 1N4007 ?
Just use the one that is included with the panel
Well the answer is yes to both questions...you will get 15 volts in full sunlight, and sure a voltage divider can be made with resistors, but the resistors have to be large enough to dissipate the heat.Hey guys.
I am thinking about buying two of these for my miniature boominator with Monacor SP-60.
7.5V 5.4W Solarpanel Solarmodule 12V MONOKRISTALLIN 6V | eBay
I have a 12V 12Ah (CT Leader CT12-12) battery in it.
If I put those in series I will get 15V which is very close to the maximum charging voltage for the battery. Is it possible to limit it with a voltage divider made from two resistors?
The charging of a battery is better when done slowly, the faster the charge rate, the hotter the battery gets, the shorter the battery life will be. Slow charging prolongs the battery life.
And as many have found, overcharging the battery (too much current) can actually make it overheat and leak, or explode. Batteries do not like to be heated when charged.
And then as you already know, if there is less than full sunlight, the voltage drops.
This is why many have used a current regulator, to control the charge rate as the voltage rises and falls---instead of just resistors.
Just FYI'ing an estimate, but it looks like you'll need to anticipate a >2x ratio for recharge. I.E., if you run the amp for 1 hour, it will need more than 2 hours of recharge time. But I'm almost in WAG territory; someone correct me if I'm way off (and of course actual power used will determine actual power to replace).
The amp I am using is this: Indeed Class T Amp TA2020 Mini Amplifier 20WX2 Tripath | eBay
And as far as I have read around the forum, it will draw around 4,3W at full volume, and I dont think I will play at full volume ever - atleast rarely
The last concern I have is one that Saturnus might already have answered.
And yeah, I totally missed that there is a diode included in the package
And as far as I have read around the forum, it will draw around 4,3W at full volume, and I dont think I will play at full volume ever - atleast rarely
The last concern I have is one that Saturnus might already have answered.
Does this mean that I would actually be able to just hook the panels up to the battery with no regulator? It seems like it when I read the description on ebay.
And yeah, I totally missed that there is a diode included in the package
SLAs can burn off overcharge. If you have 10W hitting the panels and no electrical load, that 10W will go into the battery and be given off as heat. 10 watts of heat might heat up the batteries a bit, but provided they're sufficiently cooled (not sealed in an airtight/insulating chamber) it won't hurt them any more than putting them in a warm place.
If you're really concerned, find yourself a solar charge controller.
If you're really concerned, find yourself a solar charge controller.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.