Number of batteries "needed"

[adic27]

At the moment, I have on brand new group 31 battery and was wondering if that's absolutely enough to start my dt466e engine. My old batteries tested bad even tho they hold high voltage for days at 35-40°f. Bad cells I guess.

Anyway, I am trying to troubleshoot starting issues and want to confirm one is enough for sure before I move on to other possible issues. I don't want to use two while troubleshooting if I don't have to since it's possible the issue can kill the new battery. Don't wanna kill two of them.

Also, what batteries would you guys recommend? Any group 31 battery with the right CCA RC specs? I have been using 2 super start heavy duty fleet batteries since I purchased the bus. Replaced them and the original ones due to an issue that turned out to be the alternator a while back. I saw similar batteries from auto advance auto with more CCA CA and RC but 6 months less on the warranty.

Thanks

 

[adic27]

Huh tho???

 

[Jolly Roger bus 223]

i think you would need two 8D batteries.
disconnect them and charge them when not trouble shooting.

 

[magnakansas]

adic 27

Do I think one group 31 is adequate?

No.

My bigger bus, I have two 8D I expect to be able to run with a broken alternator and use the big big batteries as a back up.

Me, I would have as a minimum two group 31.

After seeing so many people not be able to use their buses. I advise to keep your bus mobile at all times... use it as often as you can.

william

 

[HamSkoolie]

No way a single group 31 is sufficient. TWO 8D's as designed SHOULD be installed. Batteries Plus has a Duracell 1100 CCA model for $150 and 1400 CCA for $210.
Even with the big 8D's in our '96 AmTran I have to charge them from time to time during the build (all those "does it still start" starts take a toll) and plan to replace both before taking the rig out full time.

 

[Delos356]

I could be wrong and I am sure someone will tell me if I am, but I think it depends somewhat on how clean your electrical system is. My bus is a 99 Amtram Genesis with the DT466, when I bought it the bus had 3 bad batteries and had been sitting. I got it running on one brand new Group 31 with 950 CCA and 1170 CA, and after going through the electrical and removing unnecessary auxiliary systems like dome lights and vandalock, it will start every single time first try on that one battery. I may add a second just for the extra piece of mind, but so far it starts and runs great on the single battery, even in the cold.

My point though, is I suspect the reason I am able to get away with this is because the electrical in my bus was carefully streamlined. I went through EVERYTHING, and anything I took out, I took it out the right way to avoid a ghost draw or gremlin.

I would take the advice of the guys here and do two batteries set up correctly until you figure out what your issue is.

 

[cadillackid]

No way a single group 31 is sufficient. TWO 8D's as designed SHOULD be installed. Batteries Plus has a Duracell 1100 CCA model for $150 and 1400 CCA for $210.
Even with the big 8D's in our '96 AmTran I have to charge them from time to time during the build (all those "does it still start" starts take a toll) and plan to replace both before taking the rig out full time.

Wow 2 8D. I’ve rarely seen a school bus with 2 8D, most are 2 group 31s , often if a bus has factory A/C it will be updated to a single 8D.. I’ve seen most coach busses run dual 8D.

I run the batteries plus blue top AGM in all my busses. Dual group 31s, my superior is a single group 31 for now till I install AC then it will be 2.

 

[HamSkoolie]

Wow 2 8D. I’ve rarely seen a school bus with 2 8D, most are 2 group 31s , often if a bus has factory A/C it will be updated to a single 8D.. I’ve seen most coach busses run dual 8D.

I run the batteries plus blue top AGM in all my busses. Dual group 31s, my superior is a single group 31 for now till I install AC then it will be 2.

Ours is strange. Two battery boxes sufficient to hold THREE 8D's each. One 8D in each box. I'll haven't looked at how they're tied in yet as I'm working on the inside including deleting more than half the factory wire harness.....and still pulling out wires.
I suspect when I start digging into the batteries that I'll find one is for starting and the other is just because it was a team bus with lots of lighting, triple A/C systems, and the like. At the least I'll be putting the two into a single bay after which I may try to deepen the othe rbay to accept my Lithium's.

 

[cadillackid]

Ours is strange. Two battery boxes sufficient to hold THREE 8D's each. One 8D in each box. I'll haven't looked at how they're tied in yet as I'm working on the inside including deleting more than half the factory wire harness.....and still pulling out wires.
I suspect when I start digging into the batteries that I'll find one is for starting and the other is just because it was a team bus with lots of lighting, triple A/C systems, and the like. At the least I'll be putting the two into a single bay after which I may try to deepen the othe rbay to accept my Lithium's.

the triple A/C and team bus is why it has so much battery... they planned on that bus idling a lot with the A/C running.. even the best of alternators have a hard time keeping up at idle with bus A/C.. on my DEV bus if I run all my A/C on high.. my front condenser pulls about 35 amps, my rear condensor pulls 30, my rear evap on high is 20, mid evap is 15 and the front is 12.. thats on a purely mechanical engine so no computers or such.. on an electronic engine you add the injection system, camera system, any lights.. and oh boy poor alternator!!



since I think you siad you pulled out the A/C and all the factory lighting and such.. makes sense you go down to 1 8D and then use the other bay for house batts.. great idea!!

 

[HamSkoolie]

...since I think you siad you pulled out the A/C and all the factory lighting and such.. makes sense you go down to 1 8D and then use the other bay for house batts.. great idea!!

The factory dome lighting came out. The school bus flashers were never installed as it started life as a Disney parking shuttle and they were never installed.....but the harness had all the wires for them. I've pulled those as well as the rear escape window and roof hatch alarm wires. I also pulled the entire passenger side harness which fed interior lights, speakers, the middle emergency door alarm and exterior light, the middle top clearance lamp, and the over front wheel turn signal. I am running the turn signal and clearance lamp across the roof from the right side harness. two runs of 14ga wire about 10' long replacing all the wire that went to the back of the bus and then back up. In the case of the over wheel turn signal, that wire wasn't even connected in the harness.

 

[cadillackid]

I left all my school light wires in.. since the flasher units were in the switch panel.. its given me easy wires for anything general purpose.. when I installed my rear A/C, those wires came in handy for control wires.. I had a reverse light wire go bad .. never could find the break so I used a school light wire for that.. I havent used any of the front ones yet but I do want ot put a couple speakers in that header panel so i may use a couple for that... they are 12 gauge so would be OK for general purpose speakers.. after all a bus isnt an audiophile room lol

 

[HamSkoolie]

I'll be keeping two spare wires from front to rear but I've pulled something like 15 of them. Along with the heater and AC cables it's well over 100 pounds of wires not to mention all teh compressors, evaporators, and hoses.

 

[cadillackid]

I'll be keeping two spare wires from front to rear but I've pulled something like 15 of them. Along with the heater and AC cables it's well over 100 pounds of wires not to mention all teh compressors, evaporators, and hoses.

if you had carrier A/C those multi conductor cables are nice to reuse.. I have more than a couple in my busses...


people often call me to pull out their A/C and I end up with all the pieces and parts of it.. most of it gets reinstalled in other people's busses who dont want to sweat on the road but some of it is total junk so I keep the wiring..


you probably took about 300 lbs of A/C stuff out by itself.. even before the hoses and wiring..

 

[WIbluebird]

My bus had factory Transair AC units and 3 group 31 batteries.

When I removed the (nonfunctional) AC system and got new batteries I downsized the starting bank to 2 batteries. I am in Wisconsin but don't use the bus in cold weather so 3 is unnecessary imo.

 

[cadillackid]

I run 2 in each of my busses and even in wicked cold weather they start it.. when I was in wisconsin and minneapolis over new years one night it was minus 10f and I started my DEV bus (it doesnt have glow plugs or grid heater and I didnt use the webasto that start).. and it started.. I never once had a feeling that the batteries were going to go dead.. anyone who has seen my cold start video on youtube has seen how tough it was.. so to me 2 good group 31;s are enough for starting

 

[somewhereinusa]

I downsized from 2 8Ds to two group 31s but, I never start it cold. I can either plug it in or run my heat to warm the engine. A lot of school systems specify 2 8Ds because of the extra electrical loads imposed when it is being used as a school bus.

 

[adic27]

I run 2 in each of my busses and even in wicked cold weather they start it.. when I was in wisconsin and minneapolis over new years one night it was minus 10f and I started my DEV bus (it doesnt have glow plugs or grid heater and I didnt use the webasto that start).. and it started.. I never once had a feeling that the batteries were going to go dead.. anyone who has seen my cold start video on youtube has seen how tough it was.. so to me 2 good group 31;s are enough for starting

I'm in Houston and have never had a problem starting as far as batteries. Always starts right up. I was told 1 group 31 at 950 CCA should start it just fine. I'm hesitant to get a second in fear I may mess up new batteries trying to diagnose my starting issue. Likely?

 

[adic27]

i think you would need two 8D batteries.
disconnect them and charge them when not trouble shooting.

So, simply keeping them charged would keep them from getting damaged?

 

[HamSkoolie]

if you had carrier A/C those multi conductor cables are nice to reuse.. I have more than a couple in my busses...

Yes Carrier systems, three of them. VERY nice cables. I have 155 feet of the 7 conductor cable from the A/C units and 80 feet of 3 conductor cable from the heater units. Nice heavy conductors too.

people often call me to pull out their A/C and I end up with all the pieces and parts of it.. most of it gets reinstalled in other people's busses who dont want to sweat on the road but some of it is total junk so I keep the wiring..

I'd love to resell the evaporators and condensers, even the cables if needed. Not much of a market here in southern Oregon or northern California apparently.
I have two EM1 and one EM3 evap units as well as three CM3 condenser units. All in working order.

I'd say AT LEAST that much as I pulled the evaporators, condensers, hoses (200 feet of those VERY heavy hoses), cables, control boards, EVERYTHING from nose to rear.

 

[Veloc]

If you're having issues with getting enough juice, I can heartily recommend Mechman alternators. I've used them on a couple of high performance pickup builds and they run flawlessly, with a 100 amp idle and 270 amp peak production. Looks like they've changed their lineup since I last bought, making even more power. These guys are capable of more power at idle than most OEM alternators can produce at their maximum speed. And, if need be, they can set you up with a dual alternator setup. I know they can handle GM, Dodge and Ford engines, and this should cover their diesel engines as well. Since Ford and Dodge have used Cummins and other make diesels in the past, they might be able to work on other bus alternators as well. Be worth looking into. If nothing else, ambulances are also made by the same people making buses, and ambulances have to be able to produce enough juice to keep injured people alive in all conditions. High performance alternators aren't cheap, but they'll make sure everything runs.

For the testing part - as long as the one battery has enough power to start the engine, it should be fine for testing, but not to rely upon. Don't go for a drive, you might not start at the next place. Don't expect to test on cold days either, diesels are harder to start when it's cold which is why they come with two batteries. Two 1000CCA 12V batteries wired in parallel will be the same as a 2000CCA 12V battery. But why kill a new battery? Visit your local salvage yard and buy two used batteries. Put them both on the charger, then test away. Save the new battery for when you have your electrical troubleshooting done.