Hi All.

I have been dabbling in this solar thing for about a year and a half now.  Started with one panel and a gel battery now up at 4 batteries and just purchased a 200a kit from Lithium Batteries. Also have SRNE 30a mppt controller and 2000w Chinese pure sine inverter

I have been nursing my gel batteries to ensure they don't discharge below 60%. Only use them during the day and then run genny at night to supplement. 

Decided it was time to try extend my power to a bit later in the evening to save on petrol and that's why I bought Li Ion. 

So decided to check the power on the battery and what is displayed on the mppt controller. On my multimeter directly from the batterie I get 12,4v but the mppt controller displays 13,2v.

Now i am worried that I may have damaged the batteries because I may have let them deplete further than i thought due to relying on the controllers details. 

I am also worried about the Li Ion batteries now.

On 2021/02/24 at 12:29 AM, Malcolm said:

On my multimeter directly from the batterie I get 12,4v but the mppt controller displays 13,2v.

That's a hell of a difference. Is your multimeter reliable? Was the battery charging at the time? Perhaps you have too-thin wires, with almost a volt drop across them when charging? Or perhaps a high resistance fuse or connection somewhere. Use your multimeter to measure the voltage drop from controller to battery (positive and negative wires, separately).

On 2021/02/27 at 2:01 PM, Coulomb said:

That's a hell of a difference. Is your multimeter reliable? Was the battery charging at the time? Perhaps you have too-thin wires, with almost a volt drop across them when charging? Or perhaps a high resistance fuse or connection somewhere. Use your multimeter to measure the voltage drop from controller to battery (positive and negative wires, separately).

Hi I have checked and seem to be in range with the wiring size and I have one 80a fuse in a snomaster box attached to the battery. Sorry not hundred % sure about measuring. In the picture attached. is controller measurement and the multimeter measure ment directly on pos and neg of battery.

1 hour ago, Malcolm said:

In the picture attached. is controller measurement and the multimeter measure ment directly on pos and neg of battery.

To rule out the wiring as an issue, it would be better to measure the voltage directly at the terminals of the charge controller. You might for example be dropping half a volt across a dirty contact somewhere (if charging or discharging). Preferably check at night or with the panels isolated, so there is no voltage drop across the wiring.

Can you read the battery voltage from the inverter, as a third reading? Edit: again, do when the loads are light, or else there may be voltage drops across cables.

Edited March 1, 20215 yr by Coulomb

 

On 2021/03/01 at 4:27 PM, Coulomb said:

To rule out the wiring as an issue, it would be better to measure the voltage directly at the terminals of the charge controller. You might for example be dropping half a volt across a dirty contact somewhere (if charging or discharging). Preferably check at night or with the panels isolated, so there is no voltage drop across the wiring.

Can you read the battery voltage from the inverter, as a third reading? Edit: again, do when the loads are light, or else there may be voltage drops across cables.

voltage directly at the terminals of the charge controller 12.14v monitor reading 13.1v

battery voltage from the inverter 12.16v

I would try to repair or replace the monitor gizmo. Maybe you can find the sense resistors and replace those to get the reading closer to accurate.

Hi

 

Just a thanks for the assistance. I managed to get to Major Tech today and they advised the issue was with the leads. The assisted and I can only highly recommend there service.