Why does not my 100W Solar Panel fail to charge my two small 12 40Ah solar batteries?

[dede2002]

Hello,

You can also control the short-circuit current of the panel alone, without battery. It should provide 5 or 6 Amps.

For the connections on the battery, I recommend tightly screwed contacts instead of the clamps which are likely to make sparks, a battery at the end of the charge it can explode ... (it happened to me already, it makes the ears whistle and luckily the acid didn't hit anyone!)

A+

[dirk pitt]

Hello,

You can also control the short-circuit current of the panel alone, without battery. It should provide 5 or 6 Amps.

For the connections on the battery, I recommend tightly screwed contacts instead of the clamps which are likely to make sparks, a battery at the end of the charge it can explode ... (it happened to me already, it makes the ears whistle and luckily the acid didn't hit anyone!)

A+

don't scare everyone either. you will never boil an 80Ah lead battery with a 100Wp panel even mounted directly on the battery.

[dede2002]

Sorry I didn't mean to scare, just warn.

I can not help it, since I experienced it it is not forgotten ...

Amha I would never say, it depends on the condition of the battery, and our friend is talking about buying a bigger panel.

[SEIRMIC]

Hello everyone!

thanks for the messages, I'm fine connected wires.

I tried the new digital regulator as I said, to my surprise the evening when I returned I had just 11,8 volts unfortunately I feel that my charge is limited to this because since even with the analog regulators it was almost the same.

What is the solution now, I really feel that it is not obvious frankly.

[Did67]

The low voltage at the end of the day will depend on one of two things:

- or a faulty regulator, which "limits" the charge to a certain voltage (this is its function, but only when the battery is full, around 14 V - specialists will specify this).

- either the battery is only very weakly charged, its voltage is therefore low, quite naturally ...

[the voltage of a battery, without anything being connected - or running - depends on its charge level].

I think you can dispense with "collecting" regulators. They do not seem to me to be involved.

It is the charge of the battery.

And we are returned to the power of the panel, or a failure of it.

If you want to check without spending anything more, unplug all the devices that consume and just leave the regulator and the panel. And you read the voltage (voltage) every night ... It should go up, and after a while, tell you that the battery is starting to be full. And then, one fine day, it will not go up any more, indicating to you that the regulator plays its role: cutting the charge, to avoid an overcharge (and a decrease in the life of the battery).

Starting from an "empty" battery (the regulator cuts your consuming devices, to avoid too deep a discharge, which would also be destructive), if you raise the voltage in this way for a few days, until it no longer rises, and you give us the characteristics of the panel, of the battery, we can see if all this is coherent.

[izentrop]

In view of the previous comments, the breakdown comes to 95% of the panel.
To verify this, it has already been explained by dede2002 to verify the short-circuit current. Has it been done?

[chatelot16]

the 100w of your panel is the maximum power which even in Africa does not happen often ... and does not arrive until noon when the sun hits the panel right, the rest of the day with the angle power decreases

100W / 12v = 8,3A

for a 40Ah battery, 40Ah / 8.3A = 4.8h

so it takes 4,8h of full sun to charge a completely empty battery ... a normal day is not enough to charge a battery, and even worse with 2 batteries

we must therefore increase the number of solar panels

having started by increasing the number of batteries is an error: a battery wears out when it is empty ... when there is not enough panel to properly charge the batteries it is wasteful, the batteries sulfate, their performance decreases and it charges even worse ... and it ends with dead batteries

on the contrary when we increase the number of panels it does not waste anything, a panel does not wear out more than its power is taken by a battery or that its power is useless because the battery is full

[torinopol]

Hello SEIRMIC;
first of all, I'm sorry for all the expenses you made, you bought 4 regulators?
I advise you not to buy the 150 W panel before solving the current problems, and before buying it, count the number of its photovoltaic cells. If there are more than 36, drop it.
in my opinion, and after all the tests (thanks for the photos) that you did, your concern comes from the batteries. According to the photos, these are AGMs that are not intended for your application. Also avoid car starter batteries and see if you can't find slow discharge batteries (traction type even in 6V that you will put in series). In your area, you should have 250 Wh solar produced per day, see http://www.cipcsp.com/generateurs/generateur-solaire.html, I hope your problems are solved. Regards and good luck.

[Did67]

This is discussed.

How do you explain when charged outside, they "hold" while connected to the panel, they do not "hold".

It is not the internal resistance of the batteries which explains the low charge, a priori. Otherwise, we would have an increase in voltage, which is not the case.

So I do not share the diagnosis. Even if the batteries are probably not the most adequate!

Thirty years ago in Chad, I only worked with truck batteries. And a simple sign. I was lighting up, and I had a daily HF radio vacation with the management (this HF radio was very greedy, because it was a transceiver).

The problem with these batteries is their short lifespan in tropical environments (fully charged, by 40 °, they break down). This does not prevent it from working. There is the ideal, often it is not accessible in "the bush". And the sub-optimal, accessible, is then preferable. The combine harvester is not the most efficient harvesting tool in the bush either!

Self-discharge is not a problem when using the electricity recovered during the day in the evening.

[Christophe]

The problem with these batteries is their short lifespan in tropical environments (fully charged, by 40 °, they break down). This does not prevent it from working. There is the ideal, often it is not accessible in "the bush". And the sub-optimal, accessible, is then preferable.

A simple solution would be to bury them, right? I do not think that at 50-80cm the temperature exceeds 20 ° when it is 40 ° on the ground ...