Reserve Capacity Question (Battery)

T-105 are sturdy. Though you can shorten the life of any battery if you don't treat it well. Most people don't. Those numbers 14.8V, 13.5V, 16.2V are there for a reason.

Interstate is a marketing company which puts their name on batteries made by others. Last I checked, their GC2s were made by Johnson Controls (case was the same as a Varta 300 208 000).

Ok, decision is made. 4ea Trojan T105's delivered $130ea + tax. 2yr free replacement. Thanks for the inputs!

Interstate does indeed publish all you need but it is not easy to find. Alas I do not have it on this computer nor can I find it on the website but perhaps I may be able to upload it tomorrow if I don't forget.

OK, Crowns are out even if they are great. Just can not afford. So now comparing Trojan to Interstate. T105 or Interstate 2300?

sjturbo wrote:
So I am asking the "rabbit hole" question as I am not as familiar with the Interstate brand and they do not publish much info compared to Crown.

To make a hole deeper yet, consider Trojan as well. Their published cycle life is impressive.

Thanks everyone. I actually had just found the Hour Rate for both. So I am asking the "rabbit hole" question as I am not as familiar with the Interstate brand and they do not publish much info compared to Crown. Maybe that should be my first clue.

I've measured my vehicles amp draw requirement just to run the engine. 8.2 amps at idle and 12.2 at 2K rpm.
YMwillV.

Its rather amazing just how little capacity a battery can have remaining, and still start a modern fuel injected engine in mild temperatures. I had one 7 year old wally world battery start my engine 'just fine' but if I tried to recharge my old tiny battery flipphone on it and not the house battery, it would not have enough juice to turn over.

I bet many engine starting batteries out there would come in at a fraction of their original capacity, if they had a 20 hour rate and were tested for the attempted 20 hours. I bet most of these vehicle owners would say their battery is 'still going strong'

As they have no Idea, and most think the alternator is magic free energy that can defy physics.

One time when my laternator failed, i remained unawares, as theOEM ammeter needle, instead of being 1/64th of an inch above neutral, was 1/64th below it. I did not notice until my flashers and windshield wipers were in slow motion. A digital voltmeter nice and visible would have made it obvious.

MEXICOWANDERER wrote:
Reserve capacity is figuring out how long a battery can last powering a car with fuel pump and ignition load (no lights A/C or other loads) until the engine utterly stops dead in the road.

Sucking down a battery to ten volts is hard on it especially if it's a thin plate engine starting battery. There are legitimate reasons to want a high R/C like extending runtime in very rural areas. But if that is your concern use multiple batteries.

This value can assist a buyer who wants to judge if CCA is impinging on ampere hour rating. But by itself it is almost worthless if extremely cold cranking amperage is vital or low amperage discharge capacity is concerned.

For cycling, ampere hours / weight is a lot more valid. As is the name of the manufacturer. Cold cranking amperage is the vital value when a battery attempts to crank over something tough like a diesel.

An intriguing reference is to compare a battery's 20 hour rate to it's 100 hour rate. Smaller batteries end up in fractions of an ampere. You'll never see a smaller battery's 100 hour rate. It's like sneaking up behind it and yanking down it's drawers. Or, maybe inquiring about plate thickness.

Interesting initial analogy. I once drove a class B Chevy van 30 miles on the interstate to a repair facility in Billings MT on just a GR34 Duracell Deep Cycle AGM. The alternator gave out 30 miles shy of Billings, but the battery got us there, and there was enough left in the morning to start it to get it into the service bay area. I was impressed.

YOu need to know the C/20 amp hour capacity. NOTHING ELSE MATTERS.
Reserve capacity only applies to teh STARTING batteries.

From Lifeline a Group 27 (one model) was 100 amp hours at C/20
From Optima Same size 66 amp hours at C/20

NOTE: for most all save OPTIMA that Lifeline rating (100 at C/20) will be within 10% or less (IE 95 is 5% less)

I've researched several battery makes. and though some offer multiple lines some with a slightly higher capacity.. That holds almost constant and even teh multiple lines it is usually +/- 10 Percent of a median figure (95 for the group 27)

Stick with True Deep cycle for the house. This means (For the most part) GC-x Batteries

US battery and Interstate and DEKA (3 major makers) the GC2 is 210=220-230 amp hours (DEKA (east penn) is 210 or 230 depending on model G-10 or G-20)

24's are a bit under 75 AH. 27/29 are just below/over 100 and Group 31 is around 110-130.

NOTE GC-12 (12 volt golf car) I do not remember the capacity and GC-2 you need TWO of them in sereies to get 220 amp hours at 12 volt. THIS is what I recommend.

Optima.. leave it alone.