Solar panels boiling SLA batteries ?

[jimmyb]

I have just purchased a 100watt solar panel setup for camping, and shed lighting - on the back of which is the cheapest 10A regulator available (below)


When i plug the panels into my 2 new x 70Ah SLA batteries they start boiling within 30 seconds
I can only presume this isn't a good thing - at last check the panels were delivering around 4amp at 15.4v - much more than the SLA would expect for charging correct ?

Will the purchase of a better quality (I was looking at an MPPT capable one) regulator hopefully fix this ?
or should i just stick in some sort of line filter (as i've read SLA batteries would prefer)

stats for the solar panels are
Model Type RS-50
Peak Power ( Pmax ) 50Wp
Maximum Power Voltage ( Vmp ) 17.82V
Maximum Power Current ( Imp ) 2.81A
Open Circuit Current ( Voc ) 21.80V
Short Circuit Current ( Isc ) 3.14A

cheers
James

[Downunder35m]

I use the same regulator to charge my scooters, they are not the best but working fine if connected correctly.
You have to connect the batt first, and after about 3 sec. the power supply/panels.
The regulator usually is for 24/12V and this way it sets the voltage correctly.
Once full it will only flash, indicating a floating charge to keep the batt topped up.
And yes, my scooters use SLA batteries as well but two each to get to 24V.

[Learjet]

You have 2 x 70ah 12V batteries right? How have you connected them? Parallel? Series? Your solar panel specs are for a 50 watt panel. Do you have two of those? If so how are they connected? Parallel or series?

[gordon_s1942]

Are these SLA battery's a GEL cell type of battery or those so called Maintenance free with acid in them ?
If the acid type one be extremely careful to ensue adequate ventilation and flame and spark free as they can explode.
When the acid 'boils' it creates Hydrogen Gas and that is extremely volitile.
No battery should ever boil,bubble maybe bit but not boil.

[jimmyb]

the 2 x 50 watt panels in parallel
and the 2 x 70Ah batteries are also in parallel

the 'crackling' and 'popping' sound i'm hearing - would this actually be classed as boiling ?
or is this to be expected while charging - ie. gas ?

my concern was just that very high voltage coming out of the solar panels - over 15v... instead of <14v which is what i understand these batteries would prefer when charging

the batteries are labeled "Valve Regulated Lead Acid Battery" - they are sealed up

[jimmyb]

would these be a gel type ?
shaking them I can't hear any liquid sloshing around

[Downunder35m]

That seems to be normal batteries, no gel or anything. Gel would be called "sealed" and gel, yours say "lead/acid".
Having two batteries in parallel without a regulator always causes power to go from one battery to the other depending which one has a higher charge.
Same problem for the charge:
with two batts in parallel the charger does not get the info needed for a proper charge and will continue to charge at full power even if one batt is already fully charged.
I only see options with a setup like that:
1: get another charger and connect one charge, one panel for each battery.
If you need the full amps you will need a regulator in between, like for the dual batt systems on a 4WD
2: get a charger for 24V and connct the panels/batteries in series resulting in a 24V system.
You can either split the output with 2 powerful diodes to prevent bridging the batteries (with a voltage drop of about .7V),
or convert the stuff behind to 24V.
Since I have no clue what you intended use is I can't give more help at this stage.

[gordon_s1942]

I am sure these were sold in past times as 'Maintenance Free' batteries and had 'channels' cast into the lid that allowed the gas from the acid to accumulate and in a number of cases, an internal spark ignited that gas and blew the sides out of the battery.
EA had an article regarding Telstra using these batteries in remote locations and showed a photo of a set that had exploded, quite a mess they made.
A farmer told me of one such battery exploding when the ignition was turned on, fortunately it was on the opposite side to where he was.
I understand that the top or lid can be removed to allow the battery to be topped up but only by someone who knows how.
No battery should boil or really make any sounds as to me thats indicating unusual stress is being applied to the plates inside and could possibly shorten the battery life considerably apart from the dangers of the gas buildup.

[mickc]

get a better regulator
one with over voltage protection and under voltage cut out

[Learjet]

That regulator does have over voltage protection and low voltage cut out. I've got the same one.

[Downunder35m]

The regulator has it, as I said I use the 12/24V model both to charge my 24v scooters and to charge normal 12V batteries.
It has full protection and works fine, but if you attach 2Batteries in parallel mode no regulator can know which of the two batteries is full.
Since the internal resistance of such a system is different too the regulator will always overcharge.
Same for the panels, you can't simply bridge them to get more power unless they are designed for it and come with internal protection.
I'm almost certain his setup won't cause boiling batteries if he only connects one battery to the regulator.

I guess that is one the reason why you should have some electrical background before playing with batteries and panels

[Learjet]

AGM batteries would have been a better choice than VLRA, but you have to use what you've got I guess.

[Tiny]

I have just purchased a 100watt solar panel setup for camping, and shed lighting - on the back of which is the cheapest 10A regulator available (below)

When i plug the panels into my 2 new x 70Ah SLA batteries they start boiling within 30 seconds
I can only presume this isn't a good thing - at last check the panels were delivering around 4amp at 15.4v - much more than the SLA would expect for charging correct ?

Will the purchase of a better quality (I was looking at an MPPT capable one) regulator hopefully fix this ?
or should i just stick in some sort of line filter (as i've read SLA batteries would prefer)

stats for the solar panels are
Model Type RS-50
Peak Power ( Pmax ) 50Wp
Maximum Power Voltage ( Vmp ) 17.82V
Maximum Power Current ( Imp ) 2.81A
Open Circuit Current ( Voc ) 21.80V
Short Circuit Current ( Isc ) 3.14A

cheers
James

This setup should work fine as long as both the batteries are identical.
If one is smaller in capacity or older than the other they will need to be isolated with a diode.

15.4 volts is definitely too high for SLA Batteries.

Your battery manufacturer should have information regarding preferred charging & floating voltages for your batteries & should have been supplied with them. Possibly labeled on the side of the battery.

There are 2 reasons why the voltage would be going that high.

1: You have it wired up incorrectly, bypassing the regulator/charge controller.

2: The regulator/charge controller is faulty.

Also how accurate is your volt/multimeter?

You should measure battery voltage at or as close to the battery as possible.

A small amount of gassing is normal for a battery being charged & raising to 13.8 to 14.5 volts, it should sound like soft drink fizzing, not cracking & popping. A good charge controller/regulator designed for SLA or Gel cell batteries will not gas very long before returning the batteries to below 13.6v to prevent heat & pressure build up which will result in expansion of the casing & eventually a leak or explosion.

If your measuring the output of the solar array, it will be higher going in to the regulator than what the regulator is outputting to the batteries. As per ohms law there will be a voltage drop across the system as the components, ie: wiring, connections & regulator/charge controller circuitry absorb some of the available power.

[BCNZ]

I'm very skeptical of china sourced batteries. I have tried them in UPS before and they just don't cut it. In fact, when I put a brand new set of china batteries into an APC UPS, it told me they were faulty!
I took them back to the supplier and asked for genuine CSB brand batteries and everything was good. For that reason alone I feel there is a marked quality difference between china batteries and those being made in Korea or Taiwan etc.
China stuff is getting better, but I don't think it's there yet.

As for charge voltage, these batteries should be floated at 13.8 volts and no higher.

[jimmyb]

Thanks Guys !

yes, i do have a fairly extensive background in electronics - i just couldn't figure out why logically i would be getting such a high voltage from the regulator (under load) once connected to the batteries - I could only presume the *cheaper* regulator was the cause.

everything is brand new, the 2 x 50watt panels plus the 2 x 70Ah batteries which are identical.
I also pre-charged the batteries with a battery charger beforehand - and still i get the high voltage coming out of the solar regulator (and the crackling/popping/boiling sound), all while the regulator has 3 out of 3 lights lit for the battery level indicator.

the batteries i have tested individually attached to a camping fridge, and they last for the expected calculated period - so i'm presuming they are fine.

I have taken measurements with 2 different multimeters - analog and digital.
measured off the regulator directly, and where the batteries are clamped (not much different between them - 10m of heavy duty cable in between).

At this point I can only presume that the solar regular isn't functioning correctly - today I will split the system and use a single solar panel to charge a single battery - to see what happens, and i'll post back my results !


are these batteries officially classed as "SLA" batteries " or "VRLA" batteries ?
as they were referred to as "SLA" when purchased, but I didn't think much of it.

cheers guys
James

[Tiny]

OK jimmyb, according to this
The regulator should disconnect charge to the batteries at 13.7v (high voltage disconnect, so if you are in fact getting 15.4 volts at the battery when the panels & regulator are connected correctly then you have a faulty regulator or it is reading the system as 24v, possibly due to incorrectly wiring the panels & batteries to the regulator.

Try 1 panel to regulator & 1 battery to regulator as per the diagram in the pdf link above & test again.

Edit; sorry was writing this post at the same time as you, so do the single panel & battery test, however from what you just said I'd say the charge controller is at fault here.
The specs don't indicate that it is a true battery regulator, which is what you should look into as the preferred option.

are these batteries officially classed as "SLA" batteries " or "VRLA" batteries ?
as they were referred to as "SLA" when purchased, but I didn't think much of it.

According to the pic you supplied above they are labeled a VRLA so would assume that is what they are.

[Learjet]

It's starting to sound like the regulator to me too. 15.4V is too high. I have a couple of cheap regulators and none of them are the same regarding bulk charge. They range from 13.5 to 14.2V for the same model! Get another regulator.

[jimmyb]

single panel, regulator then a single battery - i'm still getting the crackling and fizzing sound from either of the batteries - and still getting the 15.4v

i'll contact the guys i got the solar panel from and ask for a replacement - otherwise i'm in the market for a new (higher quality) one

cheers
James

[jimmyb]

well actually, *is* 15.4v more than the solar panels/regulator should be putting out ? - or is this just a characteristic of this regulator ? (as opposed to being faulty)

as the batteries definitely can't handle that load - would a better quality regulator really be the only answer ?

cheers

[Tiny]

single panel, regulator then a single battery - i'm still getting the crackling and fizzing sound from either of the batteries - and still getting the 15.4v

i'll contact the guys i got the solar panel from and ask for a replacement - otherwise i'm in the market for a new (higher quality) one

cheers
James

well actually, *is* 15.4v more than the solar panels/regulator should be putting out ? - or is this just a characteristic of this regulator ? (as opposed to being faulty)

EDIT:

The regulator should disconnect charge to the batteries at 13.7v (high voltage disconnect, so if you are in fact getting 15.4 volts at the battery when the panels & regulator are connected correctly then you have a faulty regulator or it is reading the system as 24v, possibly due to incorrectly wiring the panels & batteries to the regulator.

as the batteries definitely can't handle that load - would a better quality regulator really be the only answer ?

cheers

The solar panels are not your problem it is the regulator or should I say charge controller as that is what it is supposed to be, however it is not delivering.

Contact the supplier of the CMP12 regulator & get it replaced, give that a try & then if you want get a better regulator.