Thread: Using a relay to auto-power on HDD and power inverter

Well, that I can agree on. Optima has leveraged themselves well in the market so they're doing something right, and with that like anything else comes the most complaints. Just like with LCD monitors here. We have 2 main manufacturers. Sales may be about 10:1 and complaints are 10:1 as well. Same complaints too. Different prices though, lol.

With AGM technology, I don't know the difference between X and Y brand. To me it's all the same chemistry and if I shorted one brand or the other, I'm going to assume the same resulting festival, but I also agree that the any claims can be assumed as intended purposes, so they should be very careful when boasting and not explaining the details and limitations so people can make assumption and blow half the car up. But to me, I'm glad the tech is available to anyone who wants it. Rseponsible or not.

Originally Posted by Curiosity

With AGM technology, I don't know the difference between X and Y brand. To me it's all the same chemistry

That's part of the fun - a lot of batteries are identical - just 3x the price!

Of course they claim to be hardened or extra AGM with a higher concentration & denser but lighter monocrystaline lead with lower resistance gauze (... yeah - I'm making that up!), but they ain't.

But sometimes there can be a difference - even though you know Brand-X is an inexpensive Yuasa, how do you know if it's a higher-spec Yuasa. IE - like some faster CPU chips or brigher halogen bulbs - they are the same product and line as the slower/dimmer ones, but happen to test & run faster/brighter etc. (Anyone remember the old "Mil-Spec" chip days? 10x the price for the better chips.)

It's like how in old days, the 2% resistors were merely the closer tolerance 5% resistors.
These days they can make a tighter consistent tolerance resistors to the all then to be 1% or 2% whatever. That's due to technology &/or quality/Demming etc.

But batteries are AFAIAmAware still a bit of an art.... like Biology - a cross between Art & Science.
BattTechs like AGM may tighten production, and I think LiPo etc more so, but even though AGMs may have a better or easier Demmings quality outcome, they may still be more fickle than wet lead acids. Thermal runaway for example is a characteristic of their non-wet construction.
And of course there is the type of user they attract - from the rarely used expensive showcar to the bling-only installation.


Alas I do not know market shares etc.
If Optima are that big (did I sniff VHS vs Beta marketing?), then all the more reason to make certain data available - unless it is the VHS of AGMs.

Interestingly, the failures and problems I hear of tend to be Optima. Even if 90% market share, I'd still expect at least 10% of failures to be with other brands.
But my last reply involving vehicle power issues related to a 5-year old Optima. So that suggests not all Optimas fail as other recent posts seem to insist...

In another forum - in response to a big sound system and a std 45A alternator (where, as usual, the reply(s) where get a cap or bigger battery!) - an acquaintance wrote get a bigger alternator (yes, there are some non-morons around) AND recommended an Odyssey AGM to handle the surges.
Alas I only read that last night and I haven't had the chance to quiz why....
But this dude is smart and knowledgeable, and I suspect he has a reason for not including other AGM brands.
Maybe it's just that Odyssey doesn't put you through the red yellow blue confusion that Optima does.
[ OptimaJim confused it even more! - I thought blue was marine (fine - usually just a terminal issue, or "sealed" wets), red was crank and yellow deep cycle (or whatever). But it seems they are different, but all the same, with the same internals.... Or maybe it was that yellow-XYZ was the same as red-ZYX, but the other reds & yellows were different....? Or maybe I just read it too fast.]

But there must be differences....
When I was involved, it was not acceptable to charge AGMs above 2.40V/cell (14.4V) - the gassing voltage. And there was a current limit. But they had changed from the original "constant current" charging to "constant voltage with current limit" which officialy made them acceptable for cars etc.
But now there is 2.5 & 2.6V/cell (15.0 & 15.6V) and without current limiting.
Some even recommend charging way above the old "10%" current limit rule - say 40%.
I think Optima state (for some) that 15.6V unlimited current is acceptable provided the battery stays below a certain temp (~50C? ~120F?). Now as I recall - excluding normal resistance & chemical effects - if a battery heated up, it was being damaged. (Maybe acceptably - ie, some charging systems use "heat increase gradients" to reduce or stop charging.)
Also interesting that an ambient temp isn't stated - you might be hard pressed to find a battery under 120F in an Australian engine bay - but I can well imagine charging an Optima at room temp or below freezing and it would worry me if it reached 50C/120F - especially if its rate of temp change was high.... Alas I haven't yet had the need for extra research....

Gotta love batteries! I've seen experienced site managers & techs get sucked in by the hype - like 20-year UPS batteries (which were the SAME as the 10-year batteries!) where - if they did fail - you paid pro-rata anyhow so the thing was a joke. (Besides, you don't replace old with new - that kills the whole string!)
And mere mortals often fail to see the misleading or contradictory info. Bagless vacuum cleaners anyone?

Someone said batteries are the devil you know. He was referring to a specific case where someone kept replacing their $350 battery with the same brand & model each time it failed after about 3 months (3 times that I know of).