samatch avatar image
samatch asked

Super Cycle Bubbling and charge rates

Hi all,

I have a 100 Ah Super Cycle AGM battery, which I am charging with a Smartsolar 100/20.

The guy from the store told me to use the Spiral Cell preset, which sets absorption to 14.7v.

I tried this out for a short term (i.e. < a couple of hours) as I could hear the battery bubbling furiously. I lowered to 14.4v, as it was right in the middle of the documented "cycle service normal" on the Victron datasheet... This also produced a bubbling (sounds aggressive when I put my ear to the side of the battery).

My understanding is "bubbling is bad - no bubbling is good - avoid bubbling"

I've since dropped back to 14v and no bubbling... This seems low though...

I recently bought a second super cycle battery, and immediately noticed that the one I had had for a couple of weeks, with which I had been changing the charge profiles on, was a little bulgy in comparison...

Any ideas?


battery charging
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1 Answer
kai avatar image
kai answered ·

are your batteries new?

I would not have expected to hear any sound from batteries unless they were FLAs.

re: contrast between spec'd charging voltage and bubbling sounds. Take your cue from the lack of bubbling sounds.

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samatch avatar image samatch commented ·

Thanks Kai,

Yep, I figured the electrolyte won't be convinced not to bubble, despite how much I read it the spec sheets :-)

The "old" battery is <2 months old. Interestingly, the "new" one is exactly the same model, but the battery itself looks quite different... Did Victron recently have a design change, or is there a chance I have been given a super old one from the back of a warehouse? These are 100Ah 12V super cycle batteries...

The new one also bubbled at 14.7v. I only have them running like this for a few minutes, as I'm a little touchy with them. Quickly removed the charge, and then once they settled I tried at 14.4v, which bubbled (though not as furiously). After that I just left them at 14v.

Is the slight bulge on the slightly older one anything to worry about? It's about 5mm at it's peak, compared to the rest of the case.


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kai avatar image kai ♦ samatch commented ·

A few things to check I can see:

1) What is the resting terminal voltage? -> use this to check the state of charge.

2) What is the ambient temperature? -> use this to check if charge voltages require adjustment

I'm curious that the Victron datasheet for the supercycle doesn't contain the tempco information. There's no way that its immune to the effect.

After all that, check if warranty replacement is an option with the reseller. Bulging case imo is not a good sign - its indicative of internal pressure. Was the case bulging when you got it?

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samatch avatar image samatch kai ♦ commented ·

Thanks Kai,

I didn't notice any bulging when I got it... it's really very slight. You can see it if you stand over the batteries, but it becomes really obvious if you place a ruler along the side.

Given it's my first battery, there is equal chance that I overlooked a bulge when I first got it, only noticing it when I got a second battery side by side, or that it has developed over the past 2 months.

Ambient temperature should be fine. It's in our laundry. Temperature in the house fluctuates between no less than 18 degrees and no more than 24 degrees Celsius

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