My start batteries are needing replacement.
I have 3 8D Interstate AGM batteries that are currently the house batteries. I have Lifepo4 batteries that I will be replacing the AGM batteries with as well as an upgrade to inverter, etc.
Does anyone have experience using a single 8D AGM battery as a start battery? I have the Cummins ISL 400.
I guess I will try it and see how it goes. If it works sufficiently the only down side that I see is that it's 160lbs in a single unit rather than spread across 3 group 31 batteries. I should be able to test it on a dolly under the coach before I go to the effort of placing it in the tray. I'll have to rig up a ramp of some type to get them out of the house battery compartment too.
I'll be selling the AGMs so it doesn't matter if its 2 or 3. It will likely close to cover the cost of 3 new group 31s if I go that route.
Thoughts?
others will chime in but I don't think one battery will have enough CCA to start the engine-- it might on the 8.3
Chris
Not a direct answer to your question due to our coach having a slightly smaller 8.3L engine, but I am using a single AGM8D for engine start. It has worked perfectly in the 4 years since I made the change.
My battery charging setup allows great flexibility in how I charge my batteries and how I use them. How I got to where I am is a rather long story, but if you are interested the first link below covers the Forum discussion that revolved around my initial question concerning starting battery options. The second link covers the final result of my changeover to a single start battery.
Engine Start Battery Options (https://www.foreforums.com/index.php?topic=34528.0)
'93 U280 Isolator Panel Upgrade (https://www.foreforums.com/index.php?topic=34743.0)
FWIW, and just to complete the story, the link below covers the last evolutionary step in my battery/charging setup.
Delco Remy 28SI Alternator Installation (https://www.foreforums.com/index.php?topic=40778)
An 8D starting battery will have no problem starting your engine but the batteries you are pulling
will be deep cycle so they won't work.
I have an 8D AGM starting battery and it starts the 10.8L ISM engine very well
Nope.
Before making a flat statement about whether or not a given battery will "work" as a starting battery it would be a good idea to look carefully at the specs.
Some "deep cycle" batteries are designed to serve in a "dual purpose" application, and will work just fine for starting big diesel engines. One example of a dual purpose battery is the O'Reilly AGM8D which has been very popular with Forum members. I have used this battery to start our C8.3 for the past 4 years.
OTOH, some deep cycle batteries might
not be suitable for engine start duty. When in doubt, consult with the manufacturer.
https://www.oreillyauto.com/detail/c/fleet-heavy-duty/marine---boat/batteries---marine---deep-cycle/deep-cycle---marine-batteries/6bf1f04ea895/super-start-fleet-heavy-duty-battery-group-size-8d/ssbl/agm8d/v/a/28812/automotive-car-2008-ford-focus
Bruce,
Several years ago I replaced my three engine start batteries with a single 8D battery which I got from a marina on the coast of Florida. It was quite adequate for several yeart but didn't last as long as I expected. I have since reverted to three 12 volt batteries in parallel.
I suspect that you won't be able to get that much for the used 8D's so you might as well give one a try as a start battery and see how it works out.
Richard
Odds are in favor of your AGM working just fine as a start battery for your ISL 400. The easiest way to tell is to look up the specification sheet for your battery and see what the Cold Cranking Amperage is actually.
FWIW When I needed a new battery for the Siata, Lynn wasn't with me, all he knew was that I was out to buy a battery, and there was an Interstate AGM in stock. Since the battery is underneath the gas tank, I installed the service free AGM.
There is a major construction difference between a true deep cycle battery that limits their ability to deliver high currents of elections. The vast majority of "Deep Cycle" batteries should more properly be named deeper cycle.
Art
Might load test the 8D before installation. This is the easiest weather for starting a diesel. Late Fall and Winter will be the test, especially up at altitude. Veteran batteries probably won't have quite as many CCAs, depending on the age.
Pierce
When we first got our GV it had two 8D batteries and one was adequate for starting our DD 8.2 L turbo-charged V8.
When the batteries went belly-up I replaced the 8D start battery with 0ne 950 CCA truck battery and did not have any problem starting the coach.
My reason for switching? The replacement 8D had a one year warranty and the truck batter had a pro-rated three year warranty.
Also, was about $30 cheaper.
Since then, I have added ANOTHER 900 CCA truck battery to the first start battery. Reason? Redundant start capacity, even tho we have the "BOOST" switch.
Been three years now on the three batteries.
I have single LA 8d start batt for my 10 liter
Works swell for 3 yrs
I'll might give it a try just to see as I am moving things around.
The house batteries were already installed when we bought the coach 3 years ago. The only specs I can find on them from Interstate is a 250AH rating. There was one mention on a non Interstate website for discharge current of 2500A for 5 seconds. 5 seconds is far from the 30 seconds rating for Cold Cranking Amps (CCA). I agree if is a true "deep cycle" design then it is not suited for starting.
For 3x $160 for new group 31 batteries its not worth it to conduct an experiment while out on the road. It sure does seem that a multi-year warranty is hard to find on a battery anymore. 18 months is the common upper end.
Thanks for the comments
I bought 3 Autozone 31 series Duralast for $300 out the door after asking for a discount for quantity. You do have to ask, they won't volunteer. The heavier the battery, the better. Check Walmart, Sam's Club, etc but make sure to check the weight in the specs. Prices will have gone up in the last 3 years but bargain for them. I also had three core batteries.
Pierce
,my thought +$5. U get a happy experience at S bucks, if u like them.
I LIKE 1 BIG BATTERY, 8D or 4D with less chance if something goes wrong. WHY 1? (12v) 6 cells, 2 battery's 12 cells, etc'
If 1 Cell fails the whole show is gone?
Had a experience with a prior POS. 8 golf cart battery's, on the inverter/charger 1 cell failed in the center. Ate up the tray, killed the rest (don't put new in with old) etc. a real mess.. replaced with similar capacity 8D. Lot fewer & bigger cells.
, happier I am.
As someone mentioned above, lead acid battery's are sold by weight. Fewer cells/amp hr/$ is my thought.
Why I'm not in love with a big battery:
They are really heavy for one person to lift and really hard to get into compartments and up on a rack even with two people. As it is, one 31 series weights about 60 lbs and is about the maximum I can lift without straining my back.
The CCAs are not enough for all seasons and all altitudes for the larger engines.
Since we have an Autozone here and in most places here, Mexico and Canada?, I like the warranty coverage and discounts for several batteries.
An Autozone 8D has 1400 CCA. Enough to start our 6V-92 easily in summer and at our 2000 foot altitude. We need less than 1000 CCA to start in warm weather and a bit more in cold weather at low altitude.
But, our turbo Detroit has a compression ratio of 17 to 1 compared to the non turbo's 19 to 1. This means that at high altitude and cold weather, the compression heating is less so the cranking time is increased putting more load on all of the starting system from battery terminals to the starter motor. No starting aid like a heated screen on the Cummins means drastically longer cranking and ether is needed unless shore power and a proper (not what a U300 comes with) block heater is fitted. For these reasons, three 24 series batteries are standard on a U300.
So, two 8Ds are really needed and will have 2800 CCA By going with 3 Autozone Duralast 31 series, we have 950 CCA for each battery for a total of 2850 CCA. Overkill? No, with sub-freezing weather coupled with 8000 foot elevation, starting becomes very difficult. But we go in the Summer months, right? Wrong. We were in Yellowstone in late June and it was snowing, temp was about 17 degrees and with the vast majority of campsites, there is no electricity so we had to use the generator (after a couple of minutes trying to get it started), ether and melted one of the battery terminal connectors.
We just returned from June Lake in the Sierras where our campsite was at 7900 feet. Almost 90 degree days and reasonable nights meant that the Detroit started in about one second mid morning even at this altitude. We were toadless so used it as our primary vehicle every day.
So, seasonal changes, altitude changes, battery age, cable fittings, engine condition, all are factors in how easily or not so easily your diesel may start.
Pierce