Solar panel and battery noise

[canicon25]

Hello all!

I am running 2 6VDC deep cycle batteries in series on my travel trailer. I recently bought a 120W solar panel that is for a 12V circuit.

I hooked up the solar panel using the charge regulator that came with it. I connected the +VE to the first battery +VE and the -VE to second battery -VE (leaving the interconnecting cable in place). The charge regulator indicated that the batteries were charged and displayed a green light.

I turned on all the lights in the RV and the charge regulator indicated that that the batteries required charging and displayed a yellow light.

A short time later I put my ear to the batteries and I could hear then kind of sizzling. The charge regulator said the batteries still needed charging at this time. I immediately disconnected the solar panel.

The charge regulator has a cutin of 13V and a cutout of 14.2.

My question is why did the batteries start to make a sizzling sound?? When using a solar panel to charge batteries should everything in the RV be turned off? Please help me by sharing your knowledge.

Thank you!

[opnspaces]

Just curious what is the actual voltage when you hear the batteries bubbling?

[Bobbo]

Boon Docker wrote:
Always thought that 13.6v was the typical charging voltage for LA batteries

That is only for the cheap single stage chargers. A quality 3 or 4 stage charger goes to 14.4v or 14.6v.

[ktmrfs]

Boon Docker wrote:
Always thought that 13.6v was the typical charging voltage for LA batteries

not for a flooded cell charge cycle. once charged float level, yes, but even in todays cars it's common to see a charging voltage in the 14+ V range if the battery is partially discharged or just after starting. Once charge current drop then the regulator will drop back the voltage to the 13.2-13.6V range.

Now non FLA batteries, (AGM etc.) have a different charging profile

On many of our camping trips when we boondock have other campers ask how we can get buy with only running a generator for an hour or so and not have dead batteries. (with my charger I can stuff 100A into four 6V GC batteries if they are down below about 70%) Well, with a proper charger, no problem. with the typical WFCO charger that is installed, I go over, hook a clamp current meter and voltmeter to their battery and show them how low the charging current is and why they need to run the generator many many hours and the battery still doesn't make it through the night.

Then I explain the FLA charging profile and the problem with a charger only putting out 13.6V or less and what the options are in terms of better chargers.

[Boon_Docker]

Always thought that 13.6v was the typical charging voltage for LA batteries

[ktmrfs]

Boon Docker wrote:

ktmrfs wrote:

canicon25 wrote:
I went and found the manual for the power converter/charger. It is an Elixir ELX-45. In the specifications section it says DC output is 13.5Volts 45Amps.

It also says "...designed to output a constant voltage of 13.5-13.6 volts at no load and 13.1 volts at full load to ensure trouble free service of all 12volt DC appliances."

Does this mean when plugged into shore with everything turned off the batteries would only be receiving 13.5-13.6VDC max? Kinda sounds that way to me.

yup, and your batteries will NEVER become fully charged and likely never get to the point where you see any bubbling. That also means since they never get fully charged, battery life will suffer.

Therefore it is likely that the solar controller is trying to get the batteries fully charged. hence the bubbling and noise. Assuming they are connected correctly to the solar controller.

Where did you get that information from?

FLA battery mfg will show charging requirements.

to fully charge a flooded cell lead acid battery, the battery voltage must rise to between 14.2 and 14.6 V for a period of time until charging current drops to a certain level. Level depends on the battery AH and other conditions.

For further info look at how a progressive dynamics chargers work. Even the infamous WFCO will CLAIM to rise to 14V. (but it won't) Another issue is that at 13.6 V charging current will be VERY low, it will take a long time to partially charge the battery.

Once the battery is FULLY charged, then the charger needs to drop back to between 13.2 and 13.6V (depending on battery and temperature)

If you don't get the 14+V charging the battery has a high risk of developing plate sulfation and an early death.

Basically a FLA charging profile in the following order is
a) constant current or current limit till cell voltage hits a certain limit. ideally around C/10, but often higher is ok
b) constant voltage (14+V) until charging current drops to a certain limit limit is based on the AH and battery chemistry
c) low constant voltage to keep it charged (13.2-13.6V)

[Boon_Docker]

ktmrfs wrote:

canicon25 wrote:
I went and found the manual for the power converter/charger. It is an Elixir ELX-45. In the specifications section it says DC output is 13.5Volts 45Amps.

It also says "...designed to output a constant voltage of 13.5-13.6 volts at no load and 13.1 volts at full load to ensure trouble free service of all 12volt DC appliances."

Does this mean when plugged into shore with everything turned off the batteries would only be receiving 13.5-13.6VDC max? Kinda sounds that way to me.

yup, and your batteries will NEVER become fully charged and likely never get to the point where you see any bubbling. That also means since they never get fully charged, battery life will suffer.

Therefore it is likely that the solar controller is trying to get the batteries fully charged. hence the bubbling and noise. Assuming they are connected correctly to the solar controller.

Where did you get that information from?

[ktmrfs]

canicon25 wrote:
I went and found the manual for the power converter/charger. It is an Elixir ELX-45. In the specifications section it says DC output is 13.5Volts 45Amps.

It also says "...designed to output a constant voltage of 13.5-13.6 volts at no load and 13.1 volts at full load to ensure trouble free service of all 12volt DC appliances."

Does this mean when plugged into shore with everything turned off the batteries would only be receiving 13.5-13.6VDC max? Kinda sounds that way to me.

yup, and your batteries will NEVER become fully charged and likely never get to the point where you see any bubbling. That also means since they never get fully charged, battery life will suffer.

Therefore it is likely that the solar controller is trying to get the batteries fully charged. hence the bubbling and noise. Assuming they are connected correctly to the solar controller.

[canicon25]

I went and found the manual for the power converter/charger. It is an Elixir ELX-45. In the specifications section it says DC output is 13.5Volts 45Amps.

It also says "...designed to output a constant voltage of 13.5-13.6 volts at no load and 13.1 volts at full load to ensure trouble free service of all 12volt DC appliances."

Does this mean when plugged into shore with everything turned off the batteries would only be receiving 13.5-13.6VDC max? Kinda sounds that way to me.

[ktmrfs]

canicon25 wrote:
Thanks all. Just wanted to bring this up again. I upgraded my charge controller to a Renogy Voyager 10A. The battery was only receiving 4A today (not very sunny out) and I heard the batteries bubbling again. When connected to shore power I don't hear the bubbling. Why is that? Just want to make sure everything is working as it should.

Thank you!

if your charger when connected to shore power is the inFAMOUS WFCO, you will 99.99% of the time get a max charging voltage of 13.6V (a) not enough to ever fully charge the batteries (b) never enough to get the batteries to bubble if the batteries are FLA.

So, if the solar charger is connected correctly it is trying to fully charge the batteries. On a FLA that means getting the voltage up to 14.2-14.6V for a while which will result in the batteries "bubbling"

If by chance your charger is NOT an WFCO, another story.

[canicon25]

Yes. Polarity checks out. I believe the charge controller has a built in safety against reverse polarity.

[enblethen]

Have you checked the polarity of the solar panel?

[canicon25]

Thanks all. Just wanted to bring this up again. I upgraded my charge controller to a Renogy Voyager 10A. The battery was only receiving 4A today (not very sunny out) and I heard the batteries bubbling again. When connected to shore power I don't hear the bubbling. Why is that? Just want to make sure everything is working as it should.

Thank you!

[John_Burke]

I would not get a 10 amp controller. That is maxing out with a 120 watt panel. The panels can put out more than
rated on a good day. It will work your controller into an early death. I would get a 30 amp just in case you want to add another panel.

[Boomerweps]

Make sure you selected the correct battery type on the solar controller. If lithium is selected for your FLA batteries, you could be over charging them at a higher voltage level.