Tate

Its the batteries. My dually does that all the time with the single battery. Once the grids go off, the voltage comes back up.

torquefan

My battery of choice is from Battery Direct, a Canadian company. Mine just crapped out, and they were in the truck when I bought it, almost six years ago. They never leak acid or vent gas, so I never once had to clean my connections, and my hold-downs still look like brand new. I just replaced them with their Platinum series, in group 27 like our trucks call for. 750 CCA, with a 5 year free replacement warranty, then prorated for the rest of the 84 months. There are much cheaper batteries out there, but I'm sure happy with these.

www.batterydirect.com and they are sold at Auto Parts Plus jobbers.

nickg

I never had good luck with my grids, they would cycle on and off with every hot start (once it got cold out) edventually the OEM grid relays stuck on, Check gauges lite came on, I drove home, shut off truck, went to bed, next morning, went to diagnoise problem, found stone dead batterys because the relays were stuck on.
I ended up putting in 2 ford starter relays , and instead of letting the ECM turn them on I wired them on a momentary switch, the WTS light still comes on I just hold the button till it goes out, then I start my truck, for me its win win, no extra electrical load on the alternator, and I know the ECM is not cycling them.
Mike I'd suspect the grids are hauling the voltage low enough to trigger the check gauges, you could disconnect the feed lead to the grids from the drv side battery to see if the issue dissapears, or wire in a led to the grids so that when the grids are powered you can tell from inside the cab.
another possibility is the ECM is not turning on the regulator, so therefore the alt is not charging

...or the alt is on its last legs (LOL)

John Faughn

Its normal for the grids to cycle of & on , below about 1,200 RPM , and not go on at all above 1,200 RPM .
As for nic , your symptom , sound like stick starter solenoid contacts .
I any problem , guessing at problems should only be used to figure where to start using test equipment , for Alt. , starter & battery , a load tester is the way to go .

nickg

John
It might be normal for the grids to cycle, but when your truck is used for commercial purposes, and is started and stopped 20-30 (might actually be more)times a day, having the grids cycle on a hot engine is excessive and unnecsssay load on the alternator, and the grid relays (they are too small, its no wonder they are known to stick on)

I dont have any issues with my starter contacts (two systems not related) if they did stick the starter would keep turning even with the key off/ or they would just"click" and the starter would not turn

agreeed on the load tester/ test equipment, this will help find where the fault is when under load.

Mike Holmen

I was just wondering why the grid would cycle in/out just on engine rpm's. I can understand intake air temp. So everyone elses truck does the same thing? I just noticed it for the first time. No wonder that my batteries are on there last leg. I looked at the group 31 batteries, wow they are big.

So you can fit them in under the hood.

Dr. Evil

Yes, they should fit. Like I said, I took a grinder and cut out 1 side of each of the battery trays. As well, you will need to make longer battery hold down rods. I used 4 mm ready rod and two nuts tightened against each other.

The biggest thing is to make sure you have enough slack in your oem battery cables to reach the group 31 posts, and to make sure you can close your hood without shorting the posts (that would be fun).

Group 31's -





Optimas for comparision -

Tate

I've got Group 31's with stock hold down bolts. The cable was a stretch, but it just works. I had to adjust my hood higher on both trucks when I put them in, they are about an inch larger in all dimensions.


Nick, if the engine is hot, don't wait for the WTS light to go out, just crank it. It is sensed off of intake air temp. If it was just running and shut off and restarted, there will be cold air in the manifold causing it to want to run the grids. If you let it sit for 5 or 10 min, the engine will heat the air to the point of not wanting to kick the grids on. So just crank it up if its already hot.

Mike Holmen

Dr Evil, how come you engine compartment is so clean. Man you could almost eat my supper of those valve covers. Everywhere I touch under the hood of my vehicle I get a nice coating of grease.So I think the front axle is well lubercated.

I sized up those group 31, man they are biggies. I whimped out and just but a set of group 65 again. I have to many mods under my hood to fight with everything, the 65's fit in nicely. These new batteries have a 5 year warranty, for any reason, they don't work, I get a new set of batteries. Right off the bat, I noticed that my voltage didn't drop as much with the new batteries, and no check engine light.

nickg

Tate
Yeah I never wait for the light when hot, it did not matter what I did, new sensor, as soon as it got cold out, it would cycle the grids, think its a programming glitch,
Mine are manually controlled now,(have been since Dec 08) and since my truck sleeps in a warm garage, its very rare for me to even cycle them

I second the Nice clean engine bay!!!

Mike Holmen

Dr Evil, did you put on different battery cables? Those don't look factory and the battery clamps look way nicer than what I have. I think you posted that earlier, but just want to clearify that abit. The battery cable end clamps don't look factory either.

Dr. Evil

Yes, you are correct Mike, that is 2/0 welding cable which is quite a bit larger than the stock cable. You can also see the heavy duty ring terminals (I believe they were Thomas and Betts) that I crimped on when I had access to the tool crib at the power plant.

The clamps that i am currently running are brass marine type available from Parts Source or Cambodian Tire. They are nice because they are not soft like lead, but I have broke one (on my way out of town on a long weekend !) due to the engine vibration and weight of the heavy cable.

The first ones pictured are the military style clamps. They were pretty good, soft because they are lead, but on the other hand, its nice to have that big mass of lead there - sure helps to conduct the juice. I got them from these guys: http://www.pullpal.com/terminals/terminals.html

The major problem with doing this is that there are so many cables running from that Drivers side +terminal (I have 6 cables running from the drivers side +terminal - 1 to the other battery, 1 to the starter, 1 to the grid heater relays, 1 to the PDC, 1 to my alarm, and another to my BD Torquelock)

I have a few links for the HD Ring terminals if you want to go that way, or they can be had from Gregg Distributers, or Acklands.

Let me know if you need any more info - Id be more than happy to help you out Mike.


BTW, my engine compartment isnt that clean - its photochopped

Mike Holmen

I don't believe it that you fixed the pcitures, you have to get some miles on the sweetie. I bet its one of those rare, collector trucks that Dale Earnhart sat in during a smoke break??? I don't think that I've seen your truck, at least under the hood yet. Can you believe that I got an over voltage check engine light today. I charged up the new batteries last night real good.

Dr. Evil

Im pretty sure you seen it before....hey, shes got 120k miles on her.

streetsmoker

I found this thread doing a search for upgrading to group31 batteries. Actually got me to make the leap. I don't live in the extremes you guys do, but travel to extreme places like Colorado and Minnesota (extreme for us warm weather folk). And 100*+ weather in the summer is hard on batteries also. Anyways, the photo above is of a rebadged Deka also. I wound up with the same battery, but was a Super Start brand.

For what it's worth, in the 3rd gen's, I didn't have to do anything to the battery trays to make them fit. The plastic boxes have just enough flex and were big enough that they just wedged in. The 3rd gens also have the battery clamps at the bottom, so had to use/adapt a 2nd gen/universal style holddown. As stated earlier, cable length is a concern. All but one took just some re routing to gain slack. Only had to replace the passenger side battery-to-alternator cable cause it was too short.