AGM batteries and voltage variation

[frankz66]

Hello everyone, I have 3 batteries in parallel from 110 ampere 12v c100 for a total of 330 ampere.

For my personal technical increase, I had to ask for some information.

I know that lead-acid batteries, compared to lifepo4s, are very different both in type and performance.

Having 330 amps, I report some performance detected at sight with the regular software regarding the variation of the voltage under load.

The batteries have a constant load of about 43 watts for 24 hours and do not make a turn on performance or anything else.

Carrying out tests, then charging more watts of absorption up to a certain power example: absorption 90 oscillating up to 130 watts including the percentage of consumption of the inverter both at rest and in power delivery, the voltage of the batteries drops slightly, that is, if with 43 watts I have 12.50 with the load described above, it oscillates until it reaches 12.25 +- 12.30. This test load that I carried out for as many as 8 consumed and then dropped the voltage to about 12.05 volts (about 50%). As soon as everything is disconnected, the tension suddenly goes back to 12.35 + '12.40, making me understand the real consumption.

The question is: how much can an accumulation be pushed so as not to stress it? The supplier had told me that for this type of batteries I could also charge 3 amps (negligible figure considering the batteries and their capacity), perhaps because of their characteristic of being c100? How normal can a drop in voltage under absorption be considered normal?

 

[pollenface]

I would postulate that 90-130w is not enough to hold battery in absorption while loads are pulling your voltage down.

A charging rate of 3 amps does not sound realistic or practical.

 

[justgary]

Lead-acid batteries do not like to stay discharged at all. The recommended charge rate is ~0.15C, so your 330 Ah battery should charge at 50 Amps. Anything under about 35 Amps will degrade the life of the battery.

 

[frankz66]

I would postulate that 90-130w is not enough to hold battery in absorption while loads are pulling your voltage down.

A charging rate of 3 amps does not sound realistic or practical.

I don't understand what you mean, maybe the translation. But the batteries are currently charged by an epever 4210 controller, and 720 watts of panels in 2s2p configuration. In the morning they immediately take power, at 8.00 we also arrive at 380 watts. At 12.30 I'm already in a float. The manufacturer had told me from the beginning that I could have a load of about 3 amps, perhaps to respect the slow discharge and the characteristic of the c100 battery. I only know that they are new, considering my 500 watt and 1000w peak inverter and for the consumption I have destined for the system if I connect a drill or other 600 watt tool the batteries hold up very well during the day, indeed with the addition of the 4 panel if I load the system even at 400 watts the voltage change remains the same. In the afternoon I turn on the TV from 15.00 pm until 23.00 pm the load fluctuates between 90 and 120 and the batteries drop little or better vary little as as soon as the load is lightened they rise suddenly. I think it's the characteristic of the battery type and quality. I know that if I had bought trojans these variations are millennial, but a 110 amper c100 12 v battery ..... 180 euros I think 200 $

 

[frankz66]

Lead-acid batteries do not like to stay discharged at all. The recommended charge rate is ~0.15C, so your 330 Ah battery should charge at 50 Amps. Anything under about 35 Amps will degrade the life of the battery.

The batteries are charged according to what they ask for .... unfortunately in the epever 4210AN regulator it is not possible to select a fixed quantity in amperes of charge, so if for example on a cloudy day and until 11.00 the time remains covered the batteries take what the panels provide, but as soon as it clears as experience, the batteries required me up to 620 Not bad . When I have the economic possibility and have grown up in competence I will buy the lifepo4 . At the moment I am a beginner, but all in all I am happy with my plant. It sounds incredible but I enjoy testing and understanding more than using the implant !!