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93 E350 7.3 idi battery killer

Discussion in '6.9L IH & 7.3L IDI Diesels' started by lonnoid, Dec 3, 2019.

  1. lonnoid

    lonnoid Registered User

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    I have a recurring issue with my batteries. After a few months, they are shot. I have put an upgraded hi torque starter on. The alternator is working. There is no phantom load on the electrical system. It starts fine until one day, it doesn't, and the batteries are shot. ???????? All connections are clean, no corrosion. The batteries show 12.6v, but it cranks too slow and runs down in seconds. Any thoughts?
     
  2. Clb

    Clb Another old truck Supporting Member

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    You're missing something...
    phantom load, leak to ground, alternator issues, start circuit, correct class batt.?
     
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  3. DaveBen

    DaveBen Supporting Member Supporting Member

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    I agree with Clb, you have a bad ground somewhere. Grounds are as important at the positive lead! If you do not have good grounds, you have a big problem. Start looking at the chassis grounds and go from there.
     
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  4. lonnoid

    lonnoid Registered User

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    Thanks for the replies Clb and DaveBen. I use the specified batteries, Group 65 and 50. The chassis grounds are tight and not corroded. I have tested for ground leak, none. And besides, if it was chassis grounding, it wouldn't turn over like a raped ape right up until the time the batteries go bad. The only thing I haven't done is have the alternator charge controller tested. I know it charges, but maybe it is over charging? When I get the new batteries in, I will take it in to have the alternator tested.
     
  5. chillman88

    chillman88 Supporting Member Supporting Member

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    It's very possible it's overcharging. You could always test battery voltage running.

    I noticed you said Group 65 and 50... Does your van have two different sizes of batteries? That doesn't sound right but I've never had a van either.

    Are they both being replaced at the same time? What brand are they?
     
  6. yARIC008

    yARIC008 Drives really slow

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    Yes, vans typically have two sizes. As long as they maintain voltage in similar fashion they won’t fight each other. I did figure out a yellow top optima group 31 fit where the small battery goes because the optima in that size is narrower than a normal battery due to the offset spirals.
     
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  7. lonnoid

    lonnoid Registered User

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    Yes, Chillman88, it takes two different size batteries, and I replace them at the same time. The "big" one is from Walmart, and the group 50 is from O'reillys - they list it as an emergency vehicle battery, i.e. ambulance. Group 50's are hard to find.
    And yARICOO8, thanks for the hot tip on the Optima, I have always wanted to get away from the group 50!! I will check it out. Question: Is the Optima a lead acid battery?
     
  8. Cubey

    Cubey Full Access Member

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    65 fits on both trays in my 85 E350 RV. I bought them for the F250 two months before I got the RV.

    It had mismatched (31 and something else) bad batteries that don't properly hold/crank very well so I just swapped the new 65s over. I almost couldn't get the 31 out because it was so big and it would catch on things when tying to lift it out at an angle like you have to do.

    Oreilly lists the size for it as 34 (AGM, 750cca), 24 (flooded, 725cca), or 27 (floodeed, 840cca). The 27 is close to the 850cca that the IDI trucks call for, but you might as well get 65s since they fit fine.
     
  9. u2slow

    u2slow Plan B

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    My '97 E350 had similar battery issues. The cables were badly corroded, and the frame-rail battery was impossible to access under the mini-bus body.

    I rewired two #65's inside the van with new welding cable (#2/0 and #4/0) directly to the starter. It never started so good.

    I like group 31's, but they don't always fit as nice (taller) and Costco/Walmart doesn't carry cranking ones. I have to deal with Napa or Interstate or get something with more than 18mo warranty.
     
  10. Cubey

    Cubey Full Access Member

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    They are AGM.

    Officially, there are no Optimas to fit an IDI as far as I can tell. I tried searching my 85 6.9 E350, my 87 6.9 F250, and also 1990 F250 7.3 for good measure. All say no batteries fit.
     
  11. Cubey

    Cubey Full Access Member

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    That's why I got Walmart's 65Ns. $94 each with 3 year free replacement. No one can complete with that. I got JC made ones, but a year ago they had switched to Exide. Mine have 11/18 stickers for when they were made, the last run of them by JC I guess. I have seen some stores carry 65S instead of 65N. 65S has a lower CCA, 750 I think?. 65N is 850.

    I can walk into any Walmart with 65N and swap them out for replacements if they go bad and they cost a good $60 each less to buy to begin with.
     
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  12. yARIC008

    yARIC008 Drives really slow

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    No problem, it's an AGM. I have one installed now in mine. I actually just replaced my two older Yellow top Group 31 Optimas from 2011, I got some fancy X2 battery for the large spot and put a new optima in the small spot to see how that works.

    You have to rig up a custom strap if you want to strap it down as it won't fit in the tray properly. For years I just had it sitting there with no strap. It wedges tight enough where it doesn't really move anyway.
     
  13. lonnoid

    lonnoid Registered User

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    Cubey, LUCKY YOU! If I could fit a 65n on the small tray, it would already be done! u2slow, I might have to do what you did, and mount a battery somewhere else. It would be nice to have two group 65's, it seems like they would be better balanced, and more cranking power.
     
  14. u2slow

    u2slow Plan B

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    Keeping them together helps with load/charge balancing because the wiring is equal lengths. I used the shallow plastic OBS battery trays since they fit 65's, screwed them to the floor, and used the nylon strap (from the usual RV/boat battery boxes) to tie them down. They just fit under the one set of bus seats I left in there. YMMV.
     
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  15. Cubey

    Cubey Full Access Member

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    Which is the small? Mine are all rusted out, the driver side so much that I put a new plastic one. Passenger side is there enough for the hold down anchor points so it's usable. You could probably cut off the edge on one end to make 65 fit.

    Drivers side as I got it:
    20190210_102940.jpg

    Removed as much as I could:
    20190210_111049.jpg

    New plastic tray:
    20190210_113802.jpg

    Passenger side.
    20190210_102931.jpg
     
    Last edited: Dec 4, 2019

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