Thread: D2a TD5 Auto Cranking Battery

That's a bit rough!

You got 'corrected' ... hopefully you learned something from it. And that is, not to always believe the bloke trying to sell you something.
They told you not to do something, that's perfectly acceptable to do, not because it was the wrong thing to do, but to scare you into believing some garbage, so they can sell you a battery that you don't need.
(assuming the AGM you used wasn't this 'house' type AGM, not designed to be used in a car).

And then to personally attack someone that has possibly helped in some way ... I don't get it!

He did not just correct me he was rude. I'm over it and I suspect Tombie is too.
John

Originally Posted by AK83

And that is, not to always believe the bloke trying to sell you something.

100% agree with that, especially if somebody wants to sell you a AGM battery to fit it in a vehicle with a rudimentary charging system designed for "classic" flooded battery, IMO the D2's charging system is not up to AGM requirements... that's why "AGM" must be selected on chargers too for them, i'm not against AGM, i just say that they are not good for a D2

Originally Posted by sierrafery

100% agree with that, especially if somebody wants to sell you a AGM battery to fit it in a vehicle with a rudimentary charging system designed for "classic" flooded battery, IMO the D2's charging system is not up to AGM requirements... that's why "AGM" must be selected on chargers too for them, i'm not against AGM, i just say that they are not good for a D2

But what if the specs on the AGM claim that 'rudimentary' charging is acceptable? Still no?

In my experience with at least the yellow top Optima, there is no problem.
While the redtop has appeared to be affected, this is more likely due to product failure, rather than the fact it's connected to the D2.
The yellowtop and redtop are fitted in the same area(old battery setup removed for the dual), and both fitted at the same time.

Originally Posted by AK83

But what if the specs on the AGM claim that 'rudimentary' charging is acceptable? Still no?

If that's staed on the battery then no probsI know that many D2 owners had good experience with the yellow top but that doesnt mean to me that AGM batteries in general are good for a D2. If you have a smart charger with AGM function do you select it or not if you put an AGM to charge? If you do then think that the D2's aternator has no such function

I understand what you're saying, not really disagreeing, but I guess pointing out some relevant info.

Theoretically, and maybe long term, an AGM in a D2 should be totally fine, if you look at what the charge rate is supposed to be for a 'generic' AGM(that is, not specific to one brand or model of AGM).
Had a quick look at a couple of well known charger manuals, and they have an overall consensus: that is, an AGM starts off at a higher voltage than a std D2 alt can supply. No disagreement there.
But once charged and voltage is stable, the AGM then gets charged just like any other SLA.. that is float charge is down to 13.8(ish) volts.

Think about the usual way you would drive a D2 that seemingly can't provide for an AGM. You start, drive and then it settles to a regular float charge after some time for the AGM.

But, for an AUX battery, the AGM doesn't make sense .. in that most aux batteries are used in a way where they will be required to use up a lot of their charge(ie. deeply discharged), and this is where the AGM kind'a makes no sense in a D2, as the D2 can't properly recharge the aux AGM .. deep cycle or not. In this instance you are correct .. AGM really shouldn't be used in a D2, maybe without a DC-DC charger that charges AGM correctly.

BUT!! .. this is all postulation and hypotheticals .. and not always reflective in the real world.

I personally haven't seen it pan out as the theory(or proposal) says it should.
In fact totally opposite in that the much used deep cycle battery(yellow) is holding up fine in the D2, but the red main/starter id deteriorate after a couple of years. They are now both in the 5 year old range, with many charge typical cycles under their belts(ie. they got used for their intended purposes. Due to lockdowns, the D2 did need to sit for a short time with no usage(I think maybe about 4 weeks or so), and this is what killed the redtop(but note, NOT the yellow top).
After the prolonged no use situation, the redtop doesn't hold charge for more than a few(maybe 4-ish), where it used to hold for a couple of weeks no problem.
It cranks the TD5 like it's new tho, belying it's lessened state of health .. so you wouldn't think the redtop is not 100%.

Having fitted a std century in my Tdi tho, the exact opposite has been true. IMO, a totally useless battery .. fine when about 6 months new, but then it simply fails to provide enough cranking power unless it's above about 20°C or so.
So while the Tdi is same old world tech as the D2, in that not really suited for AGM battery types ... my gut feeling is that I reckon it'll be better to do so(based on actual experience, rather than theoretical understanding).
Due to the probable lesser quality that many are recently reporting out of their Optimas, I reckon I'll give SSB a try next time around.

I have had one of these in for 2 years so far

iTECH1420CA Lithium Car Battery 12V Stop Start 1420amp 60Ah– iTechworld


can hold it up with one finger gotta shave weight were you can, but it was a lot cheaper when I bought it back then and on sale.

Originally Posted by AK83

......................
Due to the probable lesser quality that many are recently reporting out of their Optimas, I reckon I'll give SSB a try next time around.

I found the yellow tops were good when made in the US, the now made in Mexico not so much.