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Old 01-07-2022, 12:35 PM   #1
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Are my starter batteries shot and

I've been having a lot of issues with battery drain since we bought our bus. They have drained below 11v a few times. I installed a disconnect switch on the positive side of the batteries and that seemed to work for a while, but now the thing will be dead overnight even when the disconnect is cuts off the power.

I think my batteries are shot. There are 3 of them. I think I need to replace them, and I'm hoping that'll solve it. Seem reasonable?

My only concern in the long term is that I may have installed my disconnect incorrectly. There are 2 large positive wires (4/0 gauge) and two small positive wires (about 4 AWG) that connect to the 3 batteries. My disconnect is only interrupting the two large positive wires. That appears to prevent power going to the bus. Any idea what those two smaller wires would be? Should i disconnect them as well? I'm not sure if i would be able to disconnect those smaller ones in addition to the larger ones with my current setup. The bus is a 2007 International with a removed handicap lift.

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Old 01-07-2022, 02:12 PM   #2
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It usually takes awhile to diagnose but if you do have any "parasitic" draws on your batteries, it is best to address them vs putting in a disconnect.

Sometimes there will be a minor para. draw due to electronics needing to stay powered even after the engine is shut down.
Example: your radio if you have one. They use a miniscule amount of power to maintain your preset stations and clock features.
There are potentially others depending on your year and manufacturer, but they shouldn't drain the batteries overnight!

Is there any way to tell how old your batteries are?
For best long term results, it's always best to replace all starting batteries at the same interval.

Good luck...
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Old 01-07-2022, 02:51 PM   #3
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I would think that you need to interrupt all current flow to rule out your batteries being bad. How about placing the disconnect in series with the ground leads? Maybe there are only one or two of them? That will serve the same purpose.
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Old 01-07-2022, 04:25 PM   #4
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The batteries are from 2020 and 2021… so they shouldn’t be going bad naturally, but I think that the deep draining on them earlier on may have killed them.

I previously disconnected the ground and they still drained. I thought there might be another ground somewhere in the system. For that reason the disconnect went to the positive side.
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Old 01-07-2022, 04:34 PM   #5
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Mixing old and new batteries that are interconnected is not recommended as the old batt will draw down the new to whatever state they are in.
Hopefully you can get away without replacing all of them, hopefully!
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Old 01-07-2022, 05:19 PM   #6
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One bad cell in a string of batteries can drain them.
If you take off all the battery terminals do they still go dead?
Big batteries take a long time to charge, usually 24 hours at a low rate.
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Old 01-07-2022, 05:46 PM   #7
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Smile

Quote:
Originally Posted by Booneandthebus View Post
Any idea what those two smaller wires would be?
No, but my battery compartment has the same setup, and I remain curious myself.

Quote:
Originally Posted by Booneandthebus View Post
The batteries are from 2020 and 2021Ö so they shouldnít be going bad naturally...
Yikes. You are right to be alarmed.

Why and how long were the batteries drained below 11 V? Yes, that can kill them, but given how new they are, you may be able to have them replaced under warranty. That goes double if you bought them brick-and-mortar. Otherwise, make sure your charger/tender is able to deliver a fair amount of current (at least 6 A or so).

Currently, my batteries fail a load test, but they start the bus just fine and show good voltage.

Side Note

Professional truckers typically change their starter batteries (e.g. four Group 31 batteries) every three years or so. Ask around, and you could score some hand-me-downs that might keep you on the road for a few years or even more.

On the flip side, professional truckers demand a lot from their starter batteries, so any hand-me-downs probably haven't been babied... Still, though: You can hardly beat free.
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Old 01-08-2022, 12:23 AM   #8
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Sometimes it is more effective to put the disconnect switch on the negative side of the battery, because all leads go to ground.

And, your batteries are toast.
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Old 01-08-2022, 07:34 AM   #9
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Quote:
Originally Posted by Marceps View Post
No, but my battery compartment has the same setup, and I remain curious myself.



Yikes. You are right to be alarmed.

Why and how long were the batteries drained below 11 V? Yes, that can kill them, but given how new they are, you may be able to have them replaced under warranty. That goes double if you bought them brick-and-mortar. Otherwise, make sure your charger/tender is able to deliver a fair amount of current (at least 6 A or so).

Currently, my batteries fail a load test, but they start the bus just fine and show good voltage.

Side Note

Professional truckers typically change their starter batteries (e.g. four Group 31 batteries) every three years or so. Ask around, and you could score some hand-me-downs that might keep you on the road for a few years or even more.

On the flip side, professional truckers demand a lot from their starter batteries, so any hand-me-downs probably haven't been babied... Still, though: You can hardly beat free.

if the batteries are cheap branded and you have one single run-DEAD event they can defimnitely be destroyed.. I did it to a set of crappy rural king batteries on my red bus.. put em in during january one year and then had a parasitic load take them down to about 8.5 - 9 volts that summer, and that next winter even though they had been kept charged since, they had a hard time starting the bus with not a ton of cranking.. so I got thenm tested.. (40% of capacity) is all they had.. I started using good quality AGMs and havent had an issue since..



that triple 4 E engine bus though loves to have a small parasitic load of some sort all the time.. so its necessary for me to keep a Victron charger on it all the time when its parked.. if I dont ill have low batteries within 3-4 weeks.. it will still barely start but the voltage is low (11.5 or a little below).. so I keep them charged.. its not an issue for me when travelling as I drive the bus nearly every day or at ;least have access to it to run it when needed. s solar charger in the windshield even alleviates the issue.
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Old 01-08-2022, 10:24 AM   #10
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Update:

Batteries were indeed toast. Got em tested, two of three failed and i replaced all three. Bus fired up like it never has before....and it is only 30 degrees outside. I'll keep an eye on them and plan to do a lot more driving around now, which should help with keeping them good. Got a solar trickle charge and the disconnect installed, so fingers crossed that all of this is a good long term solution.

Thanks for the help!
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Old 01-13-2022, 07:47 AM   #11
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Battery Tender

Quote:
Originally Posted by Booneandthebus View Post
Update:

Batteries were indeed toast. Got em tested, two of three failed and i replaced all three. Bus fired up like it never has before....and it is only 30 degrees outside. I'll keep an eye on them and plan to do a lot more driving around now, which should help with keeping them good. Got a solar trickle charge and the disconnect installed, so fingers crossed that all of this is a good long term solution.

Thanks for the help!
Congrats! I 2nd the battery tender if you're gonna be parked more than a week. Just slightly drained batteries can make the difference between starting and struggling!

I bought my two batteries soon after purchasing my '99 International in Oct of '20. They are still going strong, but I start my bus every two weeks and drive it for 1-2 hours when not in use. This keeps everything lubricated as well, keeps tires from getting a flat spot, etc.

I also discovered a starting issue with fully charged batteries. It turns out both my battery cables where they go over the transmission each had about 12 inches where they were corroded and the insulation was completely missing. Luckily, I was able to cut off these bad areas, put new terminals on with the $20 compression tool off of Amazon. So made the fix for around $30 total. This damage was hidden under some rubber hose the school district must have added, but it had slipped off some and so there was major arcing. In any case, I suggest inspecting your cables closely if you have never done so. I chased my tail on this for a while, new starter, new glow plug relay... It needed the glow plug relay anyways...

Take Care,
Josh
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Old 01-13-2022, 09:34 PM   #12
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Quote:
Originally Posted by Booneandthebus View Post
I've been having a lot of issues with battery drain since we bought our bus. They have drained below 11v a few times. I installed a disconnect switch on the positive side of the batteries and that seemed to work for a while, but now the thing will be dead overnight even when the disconnect is cuts off the power.

I think my batteries are shot. There are 3 of them. I think I need to replace them, and I'm hoping that'll solve it. Seem reasonable?

My only concern in the long term is that I may have installed my disconnect incorrectly. There are 2 large positive wires (4/0 gauge) and two small positive wires (about 4 AWG) that connect to the 3 batteries. My disconnect is only interrupting the two large positive wires. That appears to prevent power going to the bus. Any idea what those two smaller wires would be? Should i disconnect them as well? I'm not sure if i would be able to disconnect those smaller ones in addition to the larger ones with my current setup. The bus is a 2007 International with a removed handicap lift.
Was there a problem before removing the lift? was all of the wiring completely removed, including any warning or limit switch circuitry?
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