Dual Alternators

[budbud7]

Guys have you all seen or added another alternator to a bus? I know there are kits for pickups. I would like that setup so that I would not use my bus alternator for charging house batteries. Solar is so far into the future and a generator set is not what I really want at this time.

The current rig I'm considering this for is my 2007 I/C RE 300, DT466e, that has 2 a/c compressors on the engine. Please tell me what you think. Thanks.

 

[Jolly Roger bus 223]

a picture of your current belt and pulley configuration would be helpful.

 

[Rucker]

Another thought is to see if your current alternator has capacity, or if not, can you replace it with a larger capacity one?

You'd need to use a DCDC charge controller, but overall it might be a cleaner install with the DCDC charger controlling what goes to the house batteries.

 

[budbud7]

On my RE access to the engine is thru the side doors. The rear door gives access to the radiator and charge cooler, therefore I can't get the ideal picture from the front of the motor. According to my build sheet, my alternator shows to be 12v 270 amp. That's if it has not been changed. But regardless, I don't want to use the bus alternator for house battery charging.

 

[Rucker]

I'll just point out that 270 is frickin' huge and a test with an amp meter would tell you what kind of headroom you have.

 

[1dmpo]

270 is big enough

Your 270 amp alternator will charge house and chassis batteries no problem. My 2007 Thomas with a 5.9 Cummins and two a/c units has a 200 amp and handles it just fine. I have house and chassis batteries connected together with a battery separator that charges chassis first then charges house and then leaves them connected until one falls below 12.4v at which time it splits them leaving the chassis battery with enough volts to always start the bus. We're not full timers but have had this set up for almost four years and have been border to border and coast to coast and no problems. I'm sure your 270 amp will handle both. The folks at allbatterysalesandservice.com were a huge help to me.

 

[Mike A-SKO]

Balmar 24v 90a

We have a 2003 DT466E and removed the 2 AC compressors and installed a 24v 90a Balmar alternator in their place wired to the house batteries. It now has its own belt.

 

[cadillackid]

270 amp shold be enough.. there are leese neville 330 amp units available however you will pay a grand or more for them... im not sure what your goal is..


my DEV bus has a 200 amp alternator, 3 indoor A/C evaoorators, 2 3 fan condensers, and 2 compressors.. going down the road im able to not only keep all my A/C maxxed out but am putting some amperage into my AGM house batteries as my system voltage will typically be in that 13.4 - 13.7 range... at idle I do drop below the magic 12.6 number, however at idle I typically dont need all of my A/C to keep cool inside so I can do fine slowing down on the A/C.. at 1000 RPM high idle im charging again so on super hot days where i want to hang out.. (my bus is a mobile office) then ill just run 1000 RPM..



directly alternator charging my AGM house batteries I can reach about 90-92% state of charge.. they wont reach 100% as an alternator system doesnt put out the full charge voltage the batteries like.. i could fix that with a DC-DC charge controller..

 

[BamaBus]

... be 12v 270 amp. That's if it has not been changed.

The label for the alternator is visible in the first picture, so you should be able to tell what the rating is.

 

[Cannabus]

Can you mix lithium and acid together

 

[flattracker]

I added a second alternator to the "new Crown". I used a 250 amp Load Boss alternator for the second alternator for the second one. It work very well to charge the house batteries and keeps the school bus electrical system isolated from the RV electrics. Using this setup will allow me to run a roof mount air conditioner while driving. The 1000 watts of solar provides adequate reserve power during the day.

 

[cadillackid]

I added a second alternator to the "new Crown". I used a 250 amp Load Boss alternator for the second alternator for the second one. It work very well to charge the house batteries and keeps the school bus electrical system isolated from the RV electrics. Using this setup will allow me to run a roof mount air conditioner while driving. The 1000 watts of solar provides adequate reserve power during the day.

definitely a good way to keep both systems isolated.. he already has 2 A/C compressors.. i was looking at various bracket kits and found one that allowed for 2 compressors and an additional alternator as an add-on.. however its discontinued.. the layout of the belt train on the DT makes it a bit difficult. the small pulleys of alternators present a challenge n belt routing to get them to spin.. cant just stick one anywhere unless wanting to make a plate with a couple idlers and still hope the engine pulley can spin it all.. there are kits which use an add-on pulley on the front of the original, however his A/C uses that method already and you dont have the room to stack another on..



that particulat model of bus has access issues too.. I never liked those for the reason.. the radiator is in the back so the only access is the side panels and the inside shelf access..

 

[budbud7]

Great Idea

Guys, thank you for the replies. Though I think my idea of dual alternators but isolated systems, is a great idea, it is apparently the wrong engine/accessories for my idea. I looked at my Thomas ER and I think someone could with a little effort, build and Install a second alternator with little trouble. Likely a generator set is the most feasible option for me. Thanks again.

 

[OhioSkoolie]

definitely a good way to keep both systems isolated.. he already has 2 A/C compressors.. i was looking at various bracket kits and found one that allowed for 2 compressors and an additional alternator as an add-on.. however its discontinued.. the layout of the belt train on the DT makes it a bit difficult. the small pulleys of alternators present a challenge n belt routing to get them to spin.. cant just stick one anywhere unless wanting to make a plate with a couple idlers and still hope the engine pulley can spin it all.. there are kits which use an add-on pulley on the front of the original, however his A/C uses that method already and you dont have the room to stack another on..



that particulat model of bus has access issues too.. I never liked those for the reason.. the radiator is in the back so the only access is the side panels and the inside shelf access..

Sorry for the late reply to this but I have a 2006 dt466e international ce300 without any ac compressors, so if I could find out who made the kit to add a second alternator and pulley I would much appreciate it. Cwkits one only works if you already have the AC they basically told me via email.

 

[Mr P]

A single, high amp alternator can charge a LOT of batteries "with no problem", except for one problem....charging too fast. Alternators are generally regulated to charge at about 14.5 volts. Depending on the type of house batteries, that might charge them too fast. It's "hard" on a very discharged lead/acid battery to charge it at 14.5 volts. I'm looking to manually control the alternator output to solve that problem.

 

[flattracker]

It is my understanding that newer GM alternators are controlled by one of the computers in the system. My 2018 GMC will show different voltages going down the road because of this. I don't have any details about the commands sent to the alternators, or the interface. If someone had that info and could share it, it would be useful. The newer vehicles need a lot of power to run everything so the alternators would have a high capacity.

 

[Mr P]

As a general rule, IF I recall correctly, the power in the field winding controls output. Search for schematics/diagrams of the individual alternator to determine if that's true, and, if so, how to add some "manual" reduction of charge control.

 

[sportyrick]

DT 466 have a huge front cover making it xtra hard to add accessories and yes you will have to get the belt to cover 180 degrees of the pulley or it will just slip. That means idlers to do that and they take up room also. Luckily they now make lots of different length belts so you shouldn't have much of a problem there.

 

[ewo1]

I'll just point out that 270 is frickin' huge and a test with an amp meter would tell you what kind of headroom you have.

very sound advice!

 

[magnakansas]

I just purchased four 51.2 volt 100ah batteries. And two inverter/chargers. No solar panels. The batteries will be charged by shore power through the inverters, OR a 56 volt alternator. So I have to find/build mount for a 2nd alternator

William