18 Ah AGM battery, Will it alone be able to.....?

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2,205
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california
Will it alone be able to Start my overnight cold LA318 V8( 5.2 liter) engine in~ 70F ambient temps with PP 10w-30 SN+ in the sump? I suspect this 18 AH made in China AGM battery would have about 170CCA, if it were rated. It supposedly has 18mΩ resistance and I have measured its resistance to be in this range. I'll have ~ 3 feet of doubled 8awg wire passing current from 18 AH battery to battery cables. They will be removed from the main battery. My starter is rated at 1400 watts, or 140 amps at 10 volts. The Highest I have seen my Digital ammeter go during starting has been 128 amps, but I have not watched it lately since my reqular starting battery has aged significantly and its voltage retention is not as good as when i did note the 128 amp reading. Most of the reason I got this 38$ AGM battery was for assisting my well Aged current battery when it becomes too compromised tp start the engine by itself, at some point in the future. So anybody want to guess whether this new, healthy, fully charged UB12180 chinese AGM battery, can start my engine by itself? If SO, how low will its voltage fall? Guesses? My engine usually cranks for less than a second with the full size battery before catching, and I have not started it in two weeks. I'll have actual Data captured as to Peak Amperage and Wattage, and minimum voltage when I perform the test Midday tomorrow. If this battery can indeed start this engine, it will give good indications just how much degradation has to happen to a much larger starter battery before it fails to start an engine. Seems most people will say a battery is still 'going strong', Until the day it fails, when its CCA rating( and capacity) is basically falling since day one, the rate at which it falls dependent on how well the battery is recharged to full, how long it remains in an undercharged state, and the average battery temperature.
 
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7,900
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The Midwest
Why not be a normal person and replace the aging battery with the correct one when needed? Why would you blow $38 on a worthless battery to assist your main battery when it craps out in the future? You'd be better off driving around with a charged jump pack in your truck if so worried. Obligatory face palm:

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25,689
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Upstate NY
+1 on getting a proper battery replacement. Having a small second battery does not seem like a good idea. In my pickup where each battery is full size, properly mounted and connected it's beneficial (until it comes time to replace both). But that is not the case with the OP situation. You can get a value battery at Walmart that hopefully is not made by Excide. Or a good battery pulled at a junkyard.
 
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2,131
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missouri
if you used the small odyssey then yes it would easily crank the engine we used to crank over a built 440 with one for racing. Note that race engines usually crank easier because of all the cam shaft overlap. Now though lithium is the hot ticket and even lighter. Rod
 
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Jupiter, Florida
Originally Posted by wrcsixeight
Seems most people will say a battery is still 'going strong', Until the day it fails
This is true in the small aircraft, general aviation world. Plenty of claims about Concorde AGM batteries lasting 7, 8 or even 9 years. Reality: Lead acid batteries start to degrade almost immediately. Aircraft example: A 40 AH Concorde AGM battery may actually produce 50 or even 52AH when new. After a year it will still be above it's 40AH rating. After 2 years it will still be above it's 80% of rated capacity (the legal limit) At 3 years it won't pass the test and will probably be at 70% of "rated" What this means is that the highest quality lead acid battery available today goes from 52 AH real world capacity to 28AH in 3 years. The fact that a battery still starts the engine is meaningless with regard to battery health. In the aircraft world the battery may be called upon to keep avionics/radios/transponder operational if the alternator fails.
 
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9,274
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Virginia
I think this is a experiment... More than anything else. My answer... Yeah the vehicle in question will start... 90 amps weakened starter + 170 amps at 70°F it should be fine. Voltage drop... Probably not much less than say 11.4 while starting at 70°... Now if the op was in say North Dakota... Nope. Dead as a hammer. Ain't happening.
 
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36,409
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ME
Data point, my 85 w250 with probably 7:1 compression and rotella 10w30 just clicked at 2'F. I added a booster group 65 3-year old valu-power battery (that I pulled from my Ford because it was getting tired) hanging on lousy 10 gauge cables and she cranked over nice and fast. Any temp that's any higher and it cranks fast with its normal battery. This engine/starter combo seems to either really fly, or just not work.
 

wrcsixeight

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2,205
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california
The UB 12180 is the same battery which comes in many jumper packs. Most jumper packs with this battery are a heck of a lot more than 38$. I have needs for an easily portable 12v source. I am also tired of other drivers with their hood up and jumper cables out looking at me with a raised eyebrow. I do not want to be like them. I am not installing this battery in place of the correct size battery. This is a one time experiment. My existing battery had zero issues cranking my engine in sub 20f temps 2 months ago. But it is 5+ years old with 1000+ deep cycles on it. I am not replacing it until it is truly done for and that day is not today. And might not be until next winter. Obligatory facepalm at false assumptions. Second cup of coffee nearly done. Experiment to be performed soon.
 
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Aren't those batteries designed primarily for deep cycling, not starting currents? Not that it won't, a few times, at your mild temperature. I'm using an otherwise similar 35A-h AGM battery in my Prius. After almost 4 years, it still functions adequately, and was a lot less expensive than ones sold for this application. Boot-up current it must supply is a lot lower than current to start an engine, though.
 
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Raleigh NC
Originally Posted by ragtoplvr
if you used the small odyssey then yes it would easily crank the engine we used to crank over a built 440 with one for racing. Note that race engines usually crank easier because of all the cam shaft overlap. Now though lithium is the hot ticket and even lighter.
Going off on a tangent here, but if there is a lithium starting battery out there that's reasonable in price (under say $400), will last a reasonable length of time in daily use (a couple of years anyway), and won't cause other issues in a modern vehicle, I'd sure like to hear about it.
 

wrcsixeight

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california
I did pull a battery labelled as UB12120 froam a jumperpack purchased last century. Which lasted 5 years before it did not have enough juice to assist a weak engine battery. The battery I bought is actually marketed towards the stereo crowd. But when i contacted the company about recommended charging specs they said use the ub12180 recommendations. Which say no more than 5.4 amps charging current. Ive already deeply cycled this battery once and fed it with a 40 amp power supply. 38 amps instantly brought voltage to 14.7v. 5 minutes later it was still accepting 20+ amps and my IR temp gun showed minimal temperature gain. I did however lower the pressure so only 10 amps were flowing as i was uncomfortable exceeding the recommended max rate by a factor of 5. This particular battery rests fully charged @13.17+ volts, A week off the charging source. Perhaps its electrolyte is denser/stronger than a branded ub12180. Perhaps the internals are designed for high rate applications. The same size batteries marketed as high rate claimed the same weight. I have strong suspicions that they all come off the same assembly line. Whomever markets them. Proof of these suspicions would require other marketed models for comparison. I am not spending the $ to prove or disprove my suspicions. But i will post the results of my experiment on this battery marketed by mightymax.
 

wrcsixeight

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2,205
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california
Ok the results are in. The battery was 83f at the time of the test( I am in SW florida ATM) The engine was 81f. The battery barely was able to start the engine, which has not been started in 2 weeks. It took about 3 seconds and at one point during the end of second 1, almost stopped turning the engine. The battery voltage dropped as low as 8.71 Peak Amperage consumed was 205 Peak Wattage consumed was 1786. After successful starting, by the time I walked around to the front of the engine, the 18Ah battery was accepting only 10 amps at 14.7v from the alternator. I do not have the tools to measure peak charging amperage, the meters used in this testing of discharge current, are unidirectional. So my 1400 watt starter, which is NO less than 17.5 years old and could be as old as 30.5 years old, is drawing nearly 400 watts more than its rating. What I will take away from this test is that this battery could not be relied upon to singlehandedly start my engine if it were overnight cold in less than say 70F ambient temps. And that my possibly antique starter motor, which is apparently drawing close to 400 more watts than it is rated to pull, is perhaps not long for this world. Now 400 more watts being dissipated over the cabling, and accounted for in measurement error, is highly unlikely in my opinion. Though some measurement error is no doubt occuring, I will estimate my data is 90% accurate. My Shunted ammeter does not record minimum voltage, or peak amperage, and only refreshes its readings perhaps 2 times a second, so i cannot rely on it to capture the exact wattage the starter is consuming. With the perhaps strong possibility that my starter is not long for this world, I will now research replacement or rebuild options, rather than be completely caught out and at the mercy of the nearest AP store which has a replacement in stock. My 5+ year old, 1000+ deep cycle full size battery( group 27 Northstar AGM), orignially rated for 930CCA now stays above 11.3v cranking the engine when fully charged, and when ~30% charged stays above 9.5v in 60f+ ambient temps. When new and fully charged, it would stay above 12v and crank the engine scary and alarmingly fast. It has been the most impressive lead acid battery I have owned, and it ain't dead yet. Its exceptional lifespan so fan and performance, can be attributed to the fact that it was not exposed to engine heat for very long before being relocated, and that i can indeed fully charge it, by holding voltage at 14.7v until amperage tapers to 0.5% of capacity, which is 0.4 amps. This battery also responds wonderfully to 40+ amps from a well depleted state. and more so to 65 amps of plug in charger, and laughs at my alterntor's 108 amps. Low and slow trickle charging would have destroyed this AGm long ago, in my regular and frequent deep cycling application.
 
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Hey... Give me some credit I knew this was a experiment LOL Though I was rather off with my voltage estimate... It is interesting that this sized battery is pretty much like a jump pack but for a fair amount less money...
 

wrcsixeight

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2,205
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california
Yeah, it was an experiment, with actual data sharing, intending to enlighten, as opposed to misinformed opinion spouted with authority and mockery and attitude. I find it amusing that one poster suggested I was a fool for buying this battery and instead carry around a jumper pack instead, when this battery is the same or perhaps even larger than the battery which comes in many Lead acid jumper packs, for likely half the price. I already have 8awg cables with alligator clamps. I have added a second parallel run of 8awg to these clamps. Many jumper packs come with 10AWG cables inside their extra thick insulation. I was running the current through two wattmeters in parallel, each wattmeter rated for 130 amps burst. These both have 8 awg leads and 45 amp anderson powerpoles as quick connectors. These 45 amp connectors pass 40 amps easily continuously and only get slightly warm doing so. I could not feel any heat from them after starting the engine through a pair of them, but no doubt the extra connection and the shunt in the wattmeters themselves added some resistance. So basically with this38$ 18 AH 12 LB battery, I have an easily portable jumper pack that is likely more capable than most lead acid jumper packs on the market, and perhaps most of the lithium ones too, for a fraction of the price. I can jump others, jump myself easily by turning a switch, and carry the battery anywhere to power LEDs lights and fans and even a small inverter if I need 120Vac and do not have a long enough extension cord. Gee why not carry around a fully charged jumper pack for 2x the money and half the ability/function instead??!! Obligatory Facepalm. I was considering lithium jumpstarters a few years back when they first came out, but lithium batteries, for best longevity, need to be kept stored in the 40% to 60% charged range. Since I can attain and keep lead acid battery truly fully charged easily, and that is what lead acid requires for best capacity and performance retention, I don't care about the extra weight or size, and the AGM battery has much less chance of 'venting with flame'. So despite the older and less impressive technology, and marketing, it is my choice. Twice I have witnessed My neighbors busting out their Lithium jumper packs only to find tey were not able to assist their their batteries in starting their engines. Both are now being used by their wives as portable USB power sources to charge their phons. I could strip the guts of a USB car charger and stuff them under the handle of this AGM battery for the same function. Or just plug the USB charger into the anderson powerpoles through Blue seas powerport. 19.5v for powering a laptop, well I have a dc to dc converter for doing that already
 
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3,323
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Idaho
.....So basically with this38$ 18 AH 12 LB battery, I have an easily portable jumper pack that is likely more capable than most lead acid jumper packs on the market, and perhaps most of the lithium ones too, for a fraction of the price. I can jump others, jump myself easily by turning a switch, and carry the battery anywhere to power LEDs lights and fans and even a small inverter if I need 120Vac and do not have a long enough extension cord. ....
Does your DIY jumper pack contain 2 of these 18Ah SLA batteries, or just one?

The original SLA 22Ah battery in my Clore JNC660 jumper pack died prematurely about 2 years ago. I replaced it with a 22Ah MightyMax battery (made in Thailand) from Amazon (around $45) rated at 300A max. The MightyMax weighs 11.8 lb, and the original battery weighs 13.9 lb. An original replacement battery from Clore costs $165, more than the cost of a new jump pack !
 

wrcsixeight

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2,205
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california
I have no jumper pack, the battery stands alone, with 2 pair of 45 amp anderson powerpoles.

I needed a 24v battery for some hedge clippers, so I bought a 22 AH AGM, UB12220, to hook in series.
I believe it weighs 13 lbs, IIRC


It has no issues starting my 5.2 liter v8 engine in 65f Ambient.

Keyko marketed some 'high rate' AGM batteries, which if true, would be better for a jumper pack than standard..

But,

I'm not convinced there is any differences between these small asian AGMS, just different labels and stickers and sometimes the terminals.

I wont be buying different ones, and testing their voltage retention under load, just to compare and prove or disprove this hypothesis.

Starts my V8 by itself is good enough for my intentions
 
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118
I can tell you that Prius (factory) starting batteries fail like clockwork at 5 years. Funny, cuz normal Toyota factory starting batteries I have had always last at least 10 years.
 
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3,323
Location
Idaho
I bought a 22 AH AGM, UB12220, to hook in series.

It has no issues starting my 5.2 liter v8 engine in 65f Ambient.

Keyko marketed some 'high rate' AGM batteries, which if true, would be better for a jumper pack than standard..
So, a single 18Ah battery barely started your V8, but a single 22Ah battery starts your V8 just fine? Am I reading it right?

The original battery in my Clore jump pack is a 13.9lb "high rate" 22Ah SLA from B.B. Battery, model HRC22-12S. Clore claims this battery can provide 425 "cranking amps" and 1700 "peak amps". I am skeptical about the 425A, and the 1700A spec is useless. They provide no information about test temperatures or methodology.
 
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