SLA / AGM batteries - determining quality?

[mitaux8030]

Replacing two 12v 7Ah sized SLA batteries in a solar gate opener, and wondering if there's a rule of thumb for determining quality of the SLA / AGM batteries?
I thought that weight would be a reasonable indicator of quality... for example the Fullriver 7AH type weighs 2.7kg, but cheaper VABY002A "9Ah" battery only weighs 1.6kg. While both are touted as deep cycle AGM types, I'm sceptical that the VABY002A with it's claimed higher capacity and lower weight would be better than the Fullriver battery. Is that a valid assumption to make?

[Uncle Fester]

Higher capacity is possible with less weight if the electrodes are thinner but this COULD lead to a shorter service/cycle life.
However higher capacity could also lead to less required cycles or more importantly a more shallow depth of discharge, which could extend the service life. Personally I have more trust in thicker electrodes.

Thinner electrodes would also suggest lower conductance (lower startup current) but I don't know if that is relevant for a gate opener. I would say only if it is a rather heavy gate.

If you live in an area with plenty of sun then I would choose the heavy one but if your ocean rock is Tasmania then the higher capacity lighter one might be of benefit, IMO.

[george65]

It's the assumption i would make. More lead, more weight more plates, more capacity.

Specs mean nothing now especially with anything made in China. Don't get me wrong, I love SOME Chinese stuff but other is just mislabeled ripoff crap. I think Chinese sellers and manufacturers have no scruples or credibility with a lot of things. They put on a bigger number than their competitor and that's it. In many cases if you find they are not up to spec they lie and try to put it over you.
I would certainly be going by weight in a lead battery.

Having used dozens of these batter's over the years for various applications, I would say they are anything BUT deep cycle. In my repeated experience they are far better suited to stand by and backup use-age than deep Cycle. Any over charge kills the buggers REALLY quick which stand to reason given their design. I have used a lot of them in cyclic applications where I do discharge them pretty low but I get them on a charger ASAP. I buy the things for $20 ea now so even if I kill them on one Job, cost of doing business and probably less than I spend on food and Coffee for a day so hardly a concern.
They do tend to hold up fairly well for the abuse I give them but longevity is not their strong suite I have found.

Mate of mine has a solar gate opener and was going through batteries so did the wrong thing and bought a couple of marine type Deep Cycle batteries. I told him he did exactly the wrong thing. The solar cell was this pissy little maybe 20W thing that was in the shade of the over hanging trees. By going to bigger batteries the panel would be flat out floating them even if they were charged up.
I got him a couple of the used panels I had been buying and installing and hooked them up through a decent cheap flea bay charger. Installed them further along the fence line on what was the old electric pole. This way they get a couple of hours direct sun per day and I offset them a bit to make the most of it. Goal was not max power but useful power for as many hours as possible.
Even semi shaded they put out good amps and certainly enough to keep the batteries charged and make up the load they were getting.
He's checked the voltage a few times and they are right where they ought to be. In sunlight the panels produce more than the draw of the opener so won't even scratch the battery charge.
Should last a good while now.

From what I have seen, many solar devices are under paneled so it's not a bad idea to put something else on them.

[Tiny]

FullRiver make very high quality batteries, I have one in my shed on a solar only system in Tasmania & I torture it in winter.
It takes the torture very well.
Since weight is not of concern for you, I wouldn't let that be a factor.

Agree with nomeat on incoming power availability being the deciding factor in keeping a solar system running above terminal entropy.

[ol' boy]

Solar Gate opener.... Everyone i've done, the owner just dropped an old car battery there, they are still in use 8 years later, cost, zero.

Lifeline, Full River (the older ones, some people claim the new ones aren't what they used to be) and eSolar are well respected

[LeroyPatrol]

i remember the old Fullriver being good too. Unsure about the new ones. The only real way to see how good a battery is is to cut it apart! Mate used to do this after all his charge/discharge testing where he worked. Generally the heavier ones were better.

[GT250]

What about a Lithium battery?

I have a Yamaha XV1100 and had a lithium in that for 3years (seems to handle a normal unregulated 'car' battery charger - maybe it has circuity to handle that, as I thought Liths liked a nice regulated one), and it's never let me down.

Good luck anyway.
GT250.

[mitaux8030]

Just received a pair of Fullriver HGL7.2-12 SLAs. Strongly suspect their origin is China as all the printing is skewed, the use of Chinglish and the serial number of each battery is the same... hmmm. The Celltron battery tester gave a value of about 160 mhos for each, quite a bit short of the reference value of 200 for an equivalent Yuasa NP7-12. So either the current generation of Fullriver batteries are not as good as they once might have been, or these are counterfeit copies.

[shred]

Skewed writing and Chinglish doesn’t sound at all like the Fullriver batteries that I have and have seen.

The serial numbers being the same might be due to the serial number actually being a date code?