AGM battery off gassing hydrogen sulphide

[squowse]

This is a 12V 110Ah AGM battery as a leisure battery in a vehicle.
Charged by a PWM Renogy solar kit and a split charge relay.

Solar seems to overcharge it (causing off gassing) in summer and I can't see why.
Only thing I can think of is that the PWM charge controller temperature sensor isn't connected and it should be reducing the charge voltage in summer. Temperatures get up to about 20 degrees C so far this summer, possibly 30 inside a vehicle with no ventilation.

Is there any other reason it might emit hydrogen sulphide?

 

[squowse]

This is the charge controller

Wanderer Li 30A PWM Charge Controller

Renogy Store sells the best PWM charge controllers including our The Renogy Wanderer. This advanced negative-ground controller 30A is designed for off-grid solar applications. Call or order online today!

uk.renogy.com

 

[Suijkerbuijk]

Well if it gas now .
Its broken or damage .
Reason i stop using agm battery.

What you can do is reprogram the pwm if it can be done to a lower volt on charge.
Or your pwm is broken .
Your split relay is broken and use volt.
I think normal you can not use a relay for it ?

This is the reason today a lot of charge are not charge 14.4 volt .
And are stuck on 13.6 volt against over charge.
So to program this unit you need a bluetooth connection what is sell lose.
And set the float charge lower .

Personal i trow a pwm away in a trash can and go for mppt .
I only use them for drip charger with a low solar panel like 25 watts for the winter

Wat are u using this systeem for ?


About those relays .

DON'T USE SPLIT CHARGE RELAYS!!! — Offgrid Power Solutions

If you're putting an electrical system into your van, then this email is for you! We see so many people using Split Charge or Voltage Sensitive Relays (VSR) on their van builds, but there is a way better option!

offgridpower.solutions

 

[OzSolar]

Is there any other reason it might emit hydrogen sulphide?

Sounds like you need to reduce the charging voltage.

 

[mikefitz]

This is the charge controller

PWM controllers typically have poor charging profile and tend to kill batteries. Add this factor to an ageing lead battery and you could/will have an overcharging situation. If the AGM is off gasing then it's failed and need to be replaced.
Replace both the charger and battery.
The split charge wont have caused the problem, but once the battery has lost electrolyte , the battery will overheat from any charging source. Its not unknown for AGM batteries to enter thermal runaway.
The hydrogen sulphide is accompanied by hydrogen and oxygen, an explosive mix. Disconnect the battery and store outside.

 

[squowse]

Thanks all!

 

[Brett V]

If your AGM bat has vented, it’s toast unfortunately.

 

[grizzzman]

Keep in mind that a internal short will cause out gassing even at correct voltages.

 

[squowse]

Keep in mind that a internal short will cause out gassing even at correct voltages.

Yes thats what I’m wondering. Attention has now turned to the vehicles starter battery. The batteries have now been been isolated so we can hopefully tell which one is off gassing.