Incorporating high power 24v alternator

[Seven30]

Hello.

First post to this forum. Its a fantastic resource but I did not quite find this specific topic.

Im converting an old highway coach (bus) which has a very high power 24v oil cooled alternator designed to output well over 200amps continuously.

Im stuck on how to safely (current limit) utilize this capacity without resorting to the amperage limitations and expense of a DC-DC charge controller.

There are some interesting alternator voltage regulators available but apparently without current monitoring ability.

Any ideas on how battery charge could be current limited?

 

[grizzzman]

It will only output what is needed up to its max amps. That is controlled by voltage through the regulator. Control the voltage and you control the amps.

 

[HRTKD]

Seven30, what is your objection to using a DC-DC charger?

 

[dr.diesel]

I'm currently building something very similar. I'm using a 2-cylinder Kubota diesel out of an APU unit and two standard 24v 10si 40a alternators. Current will be limited by the control system (adjust engine RPM) which will measure each alternators output/temp including engine oil pressure/temp and react accordingly. Unit will automagically start and stop at the appropriate battery voltage.

 

[DWrvsolar]

If you're adding a LifePO4 bank I know of no "cheap" way to get a good result. I've got a Delco 50DN gear driven, oil cooled alternator. After a lot of reading and talking to people who seemed to know, I went with two Victron Orion-TR smart chargers.

If you want to do direct alternator charging look at this: https://balmar.net/?product=regulator-mc-624-h This external regulator uses a temperature sensor, and will give you the charging profiles you need. It also has a feature called "Belt Manager" and will allow you to de-rate or limit total output. Balmar tech support is pretty good if you have questions.

I would also suggest a alternator protection device. If your house battery BMS shuts down while the alt is charging you will destroy the alt. This is designed to prevent the damage: https://www.sterling-power-usa.com/SterlingPower24voltalternatorprotectiondevice.aspx

Some people suggest connecting your starting batteries in parallel to your house batteries so the lead acid batteries can adsorb the load if the BMS shuts down, but this can can introduce more problems and complications.

 

[HRTKD]

I would also suggest a alternator protection device. If your house battery BMS shuts down while the alt is charging you will destroy the alt. This is designed to prevent the damage: https://www.sterling-power-usa.com/SterlingPower24voltalternatorprotectiondevice.aspx

Playing Devil's Advocate to this, there are millions of snow plow equipped trucks out there, drawing huge amps from their system, hundreds of times a day that have no alternator protection.

 

[Hedges]

Some people suggest connecting your starting batteries in parallel to your house batteries so the lead acid batteries can adsorb the load if the BMS shuts down, but this can can introduce more problems and complications.

How about a stack of diodes, couple volts drop from BMS & house batteries to starting batteries? That would clip any voltage spikes.

One could also consider a low-voltage lightning arrestor such as MOV. Voltage range across temperature would have to be considered.

Playing Devil's Advocate to this, there are millions of snow plow equipped trucks out there, drawing huge amps from their system, hundreds of times a day that have no alternator protection.

Do those perform a load dump AND not have lead-acid batteries still connected to absorb the current?

 

[DWrvsolar]

Playing Devil's Advocate to this, there are millions of snow plow equipped trucks out there, drawing huge amps from their system, hundreds of times a day that have no alternator protection.

Snow plow trucks, or any application with always connected lead batteries do not need this protection.
If you instantly disconnect the load from a charging alternator it will fail. A house battery with a BMS could disconnect without warning. If you could have the BMS disconnect the field to the alternator before shutting down the battery that would work too.

 

[DWrvsolar]

How about a stack of diodes, couple volts drop from BMS & house batteries to starting batteries? That would clip any voltage spikes.

One could also consider a low-voltage lightning arrestor such as MOV. Voltage range across temperature would have to be considered.



Do those perform a load dump AND not have lead-acid batteries still connected to absorb the current?

I think this all depends if the starting and house banks are always connected, or connected through an isolator or combiner. I was suggesting off the shelf solutions and ultimately went with the DC to DC chargers for my bus.

 

[dr.diesel]

Delco 50DN gear driven, oil cooled alternator.

This is REALLY what I wanted to use for my project, but WOW are they pricey and I could not find a used one.

 

[Hedges]

How about a stack of diodes, couple volts drop from BMS & house batteries to starting batteries? That would clip any voltage spikes.

But during cranking when starter battery drops to 8V, would draw from house battery (unless diode stack was 6V worth. That would serve to clip spike to 14V + 6V = 8V)

 

[DWrvsolar]

This is REALLY what I wanted to use for my project, but WOW are they pricey and I could not find a used one.

They turn up on ebay from time to time, but the trick is to find one near enough to avoid shipping.

 

[HaldorEE]

Snow plow trucks, or any application with always connected lead batteries do not need this protection.
If you instantly disconnect the load from a charging alternator it will fail. A house battery with a BMS could disconnect without warning. If you could have the BMS disconnect the field to the alternator before shutting down the battery that would work too.

So does this only apply in the situation where you have a dedicated house battery charging alternator?

I am planning on using an Orion-TR DC-DC charger with my 24V house battery, but the alternator is always connected to the twin 12V starter batteries. In that case I assume that disconnecting the house battery should be not be a problem. Is this assumption correct?

I wonder if the Orion-TR provides the same alternator protection functionality that the Sterling Alternator protector does for dedicated house battery alternators? Kinda like a soft start circuit on a motor only in reverse (soft stop?).

 

[HaldorEE]

This is REALLY what I wanted to use for my project, but WOW are they pricey and I could not find a used one.

Man you are not kidding about that.

ALTERNATOR 50DN 24V 270A - 8600191

DetailsProduct DescriptionHelp maintain your truck's power with the high-performance Delco Remy Alternator 50Dn 24V 270A - 8600191, crafted to optimize your vehicle's electrical system. Designed for durability and reliability, these Alternators from the experts at Delco Remy deliver consistent...

www.jittruckparts.com

Even rebuilt ones go for $1300! That does include shipping for what it is worth.

Robot or human?

 

[Hedges]

Brushless.
Sealed.
Oil cooled.
Internal fan.

This isn't the alternator from your Father's Oldsmobile

https://www.jittruckparts.com/amfile/file/download/file/35/product/34464/

24V. That puts out 6.5 kW.

 

[DWrvsolar]

So does this only apply in the situation where you have a dedicated house battery charging alternator?

I am planning on using an Orion-TR DC-DC charger with my 24V house battery, but the alternator is always connected to the twin 12V starter batteries. In that case I assume that disconnecting the house battery should be not be a problem. Is this assumption correct?

I wonder if the Orion-TR provides the same alternator protection functionality that the Sterling Alternator protector does for dedicated house battery alternators? Kinda like a soft start circuit on a motor only in reverse (soft stop?).

I think you'll be fine with the Orion-TR. Even if the house battery BMS or fuse blows while charging the output is limited by the Orion and the FLA starting batteries can easily adsorb the spike. I believe this setup is safe by design and does not require the Sterling type protection device. My setup is a 12 volt 50DN with two 8D starting batts on the bus, and a 24 volt house bank. I'm using two ORI122436120 (largest 12 to 24 DC-DC charger Victron offers) they output 15 amp at 24v. Two give me 30 amps @ 24V to the house and + - 60 amp 12v load on the alternator.

 

[Seven30]

Seven30, what is your objection to using a DC-DC charger?

My primary objection is the alternator can output over 300amps continuously at ~24V and since my pack is ~24V a DC-DC converter anywhere near that current level would be very expensive and really serve as an expensive current limiter.

Im not really that concerned about the Lead start batteries and toying with the idea of replacing them with an 11 cell LTO pack at some point

 

[Seven30]

Missed the last post. The Orion-Tr would be just the thing if my system was 12v but since its already 24V I want to leverage that high output alternator.
I was thinking a Cyrix Battery Combiner might work. They can handle up to 400amps.

 

[HaldorEE]

Missed the last post. The Orion-Tr would be just the thing if my system was 12v but since its already 24V I want to leverage that high output alternator.
I was thinking a Cyrix Battery Combiner might work. They can handle up to 400amps.

How about the Orion-TR 12/25-15? Same watts as the 12V version only designed for 24V battery packs.

 

[Seven30]

I see a 24/24-5 model but its 5amps max. Id would loose hundreds of amps of potential charge power.
.
Even though these are oil cooled and designed for high loads a 2p-8s 280ah pack would still present an overload is an issue.
.
I dont know if the temp sensing alternator regulators work well with the oil cooled units but I wonder if the temp sensor input could be rigged/hacked to use a shunt output voltage.