Help, getting a 24v alternator made

[Firstascent]

I’ve mostly decided (90% sure) I’m going to add a 24v alternator in my truck, it’s intended purpose will be solely to charge my battery bank in my fifth wheel.

I’ve been talking with a company that will custom make one for me, 24v 150A.
I already have my battery back which is 14.3kwh of lifepo4 2p8s 280ah cells. But besides my battery’s and my Batrium BMS, that’s all I have do far for my solar setup.

with that being said, is there anything specific I should ask the company or verify any specs I need to be aware of?

From an install standpoint, I think it’ll be fairly straight forward. There is a factory bracket option for a second alternator, and since it wouldn’t be charging the vehicle I don’t need to worry about tying into the truck electrical system, I’d just find a way to run them back to my fifth wheel.

 

[MisterSandals]

That looks like it will take a significant bit of wire!
Looking at 24v, 150a and 30’ i am seeing 2/0awg necessary for just under 3% loss (23.3v at end point).

 

[Firstascent]

That looks like it will take a significant bit of wire!
Looking at 24v, 150a and 30’ i am seeing 2/0awg necessary for just under 3% loss (23.3v at end point).

Yes I will definitely have to take that into consideration. However, 150A is simply the max size they can offer me (I asked them what is the largest capacity) so if I wanted to make wire runs easier, and smaller, I could have them make me a smaller output alternator.

 

[Sabre36]

Make sure they understand you're charging LFP and that this use will be considered "continuous duty".. Most smaller auto type alternators are not at all continuous duty. I would also advise having them build it as externally regulated and use it with a Wakespeed WS500 Advanced Alternator Regulator..

 

[HaldorEE]

Or just buy an upgrade, continuous duty rated alternator and use a 12V to 24V boost battery charger. Like a Victron Orion TR 12/24-15 Smart Charger. That will draw 30A from the alternator and charge a 24V battery at 15A. It will also protect both your alternator from overload and your battery pack from overcharging.

 

[Firstascent]

Make sure they understand you're charging LFP and that this use will be considered "continuous duty".. Most smaller auto type alternators are not at all continuous duty. I would also advise having them build it as externally regulated and use it with a Wakespeed WS500 Advanced Alternator Regulator..

Thanks! I emailed them today with that and more info, I'll see what they say.

Or just buy an upgrade, continuous duty rated alternator and use a 12V to 24V boost battery charger. Like a Victron Orion TR 12/24-15 Smart Charger. That will draw 30A from the alternator and charge a 24V battery at 15A. It will also protect both your alternator from overload and your battery pack from overcharging.

I thought about that too. Either way, for me, I would've added a second alternator. I looked into adding a 2nd 12v alternator with a setup like you mentioned but then decided why not remove any conversions and just go straight to the source, and get up to 6x the output as well for faster charging (280ah cells), standard charge on these is 0.5C

But please definitely let me know if I say anything that doesn't sound correct as this is my first solar setup and learning a lot as I piece each section together and decide on which path I want to take

 

[HaldorEE]

Thanks! I emailed them today with that and more info, I'll see what they say.


I thought about that too. Either way, for me, I would've added a second alternator. I looked into adding a 2nd 12v alternator with a setup like you mentioned but then decided why not remove any conversions and just go straight to the source, and get up to 6x the output as well for faster charging (280ah cells), standard charge on these is 0.5C

But please definitely let me know if I say anything that doesn't sound correct as this is my first solar setup and learning a lot as I piece each section together and decide on which path I want to take

Why battery chemistry? LiFePo4? I would be very leary of connecting it directly to the alternator.

 

[Firstascent]

Yes LiFePo4, and @Sabre36 had a good idea about using an alternator regulator. I like the idea of that but truthfully I haven’t looked too much into alternator regulators yet.
For now, I’m making sure I know all I would need to go the 24v alternator route, then can make a better informed decision.

 

[svfalkor]

@Firstascent , I am curious why you are looking into having an alternator "made" instead of buying one? E.g. Ballmar offers 24V alternator with external regulation.
Are the "made" ones cheaper, better? Just curious..

 

[HaldorEE]

Thanks! I emailed them today with that and more info, I'll see what they say.


I thought about that too. Either way, for me, I would've added a second alternator. I looked into adding a 2nd 12v alternator with a setup like you mentioned but then decided why not remove any conversions and just go straight to the source, and get up to 6x the output as well for faster charging (280ah cells), standard charge on these is 0.5C

But please definitely let me know if I say anything that doesn't sound correct as this is my first solar setup and learning a lot as I piece each section together and decide on which path I want to take

I meant just replace you current alternator with a higher capacity one. What is your vehicle again?

 

[psolver]

you can get some very large alternators for heavy duty freight truck some are even 24v in both heavy equipment and trucking

 

[AREA351]

Or just buy an upgrade, continuous duty rated alternator and use a 12V to 24V boost battery charger. Like a Victron Orion TR 12/24-15 Smart Charger. That will draw 30A from the alternator and charge a 24V battery at 15A. It will also protect both your alternator from overload and your battery pack from overcharging.

Disregard, Google flipped the numbers on me and took me to the wrong charger.

Thanks for the info BTW. I was looking for something to charge my 24V LiFePo4 battery bank from my 12V alternator in my Sprinter and didn't think it was possible without adding a second 24V unit.

 

[owenfi]

Like a Victron Orion TR 12/24-15 Smart Charger. That will draw 30A from the alternator and charge a 24V battery at 15A. It will also protect both your alternator from overload and your battery pack from overcharging.

Is this roughly equivalent / better than a dedicated alternator protect device such as:

Sterling Power 24 volt alternator protection device

Sterling Power Alternator Protection Device for 24v Volt Alternators

www.sterling-power-usa.com

The downside there is it's effectively one time use.

I've ordered this kit, which it or a similar one might be useful to op:

Mercedes Sprinter Van Dual Alternator Kit with 24 Volt 150 Amp Alternator (2007-UP 3.0L Diesel)

Mercedes Sprinter Van 3 Belt Dual Alternator Kit with 280XP High Amp Alternator (2007-2018 3.0L Diesel)

www.nationsstarteralternator.com

it does include a lithium charge controller, would that be sufficient to calm fears over "connecting alternator straight to LiFePo4"?

I'm wondering about the best way to protect the alternator, for instance if it (or something else) goes over voltage, and the BattleBorn/etc BMS disconnects suddenly then there is no load and it goes up drastically. Would a 24 -> 24 V current regulator such as the Victron smart DC options prevent that issue (thinking it through: maybe the BMS disconnect happens, then the smart charger load goes to zero, but the alternator doesn't shut off instantly, so a high voltage goes to the smart charger, frying it, but perhaps saving the alternator electronics?)

The other idea I've been looking into is running a small 24V (2 12V for flexibility in emergency jumping) AGM bank in parallel with the lithium bank. I'd consider it more as a protection device/current sink, I wouldn't really care if it's battery life was negatively impacted by being on a lithium charge algorithm, provided it continued to offer protection for a few years. I'd probably want a relay in this case to connect it only while the car is running.

Thoughts on which way is better?

 

[Reed Cole]

Is this roughly equivalent / better than a dedicated alternator protect device such as:

Sterling Power 24 volt alternator protection device

Sterling Power Alternator Protection Device for 24v Volt Alternators

www.sterling-power-usa.com

The downside there is it's effectively one time use.

I've ordered this kit, which it or a similar one might be useful to op:

Mercedes Sprinter Van Dual Alternator Kit with 24 Volt 150 Amp Alternator (2007-UP 3.0L Diesel)

Mercedes Sprinter Van 3 Belt Dual Alternator Kit with 280XP High Amp Alternator (2007-2018 3.0L Diesel)

www.nationsstarteralternator.com

it does include a lithium charge controller, would that be sufficient to calm fears over "connecting alternator straight to LiFePo4"?

I'm wondering about the best way to protect the alternator, for instance if it (or something else) goes over voltage, and the BattleBorn/etc BMS disconnects suddenly then there is no load and it goes up drastically. Would a 24 -> 24 V current regulator such as the Victron smart DC options prevent that issue (thinking it through: maybe the BMS disconnect happens, then the smart charger load goes to zero, but the alternator doesn't shut off instantly, so a high voltage goes to the smart charger, frying it, but perhaps saving the alternator electronics?)

The other idea I've been looking into is running a small 24V (2 12V for flexibility in emergency jumping) AGM bank in parallel with the lithium bank. I'd consider it more as a protection device/current sink, I wouldn't really care if it's battery life was negatively impacted by being on a lithium charge algorithm, provided it continued to offer protection for a few years. I'd probably want a relay in this case to connect it only while the car is running.

Thoughts on which way is better?

I would choose the APD, it's smaller and cheaper than an AGM battery bank and if your system is well designed and installed then the bms disconnecting should be a rare occurrence. You could get at least 6 APD's for the price of two 100ah AGM batteries and according to the manual it's not guaranteed that the APD will be destroyed in the event of some type of failure.

Also it looks like they recommend installing the APD as close to the alternator as possible so it will protect against any failure from the alternator out.

If you are already getting an alternator with a lithium charge profile that you are satisfied with I don't see the point in getting an additional 24v to 24v charger, unless you had all Victron components then there might be some marginal benefit in them talking to each other.

 

[Samsonite801]

If you could find a BMS which has the ability to control an external cutoff relay (like Chargery style), you could wire it to the field circuit on the alternator to open if/when the BMS cuts off, so it halts the charging in the event the BMS breaks the circuit.

I've also pondered about the possibility of using a large capacitor like the car stereo guys do, to act like a battery (same like your idea to have an AGM battery in the circuit, essentially a buffer to absorb the shock sitting in the middle.

But for me I'd still want to have something to kill the alternator field circuit (or turn off power to the regulator circuit, in turn killing the field voltage), to shut off the alternator when it's no longer needed (even with an APD or a capacitor in the circuit).

Maybe you've already looked into that, but just thought I'd mention it...

 

[ermina00]

I’ve mostly decided (90% sure) I’m going to add a 24v alternator in my truck, it’s intended purpose will be solely to charge my battery bank in my fifth wheel.

I’ve been talking with a company that will custom make one for me, 24v 150A.
I already have my battery back which is 14.3kwh of lifepo4 2p8s 280ah cells. But besides my battery’s and my Batrium BMS, that’s all I have do far for my solar setup.

with that being said, is there anything specific I should ask the company or verify any specs I need to be aware of?

From an install standpoint, I think it’ll be fairly straight forward. There is a factory bracket option for a second alternator, and since it wouldn’t be charging the vehicle I don’t need to worry about tying into the truck electrical system, I’d just find a way to run them back to my fifth wheel.

I am looking for someone that can put together a system similar to what you are doing. Would you mind giving me the name of the company you are working with.
Thank in advance.

 

[bedpan]

Is there a reason more people don't go with AC rather then DC for this type of situation? I bought a 50a 12V Renogy and it works quite well. I have 20' of 2 gauge wire from the battery to the trailer hitch, then another 10' or 2 gauge from the trailer hitch to the DC2DC charger.

If I had it to do again (and I likely will as I think I will go to 24 or 48v) I would look seriously at putting a 2000w inverter in the cab. Then run a heavy duty extension cord from the cab to the inverter charger in the trailer. You could support at 75a at 24V charger at this...

Again maybe not what you need/want but something to think about. Maybe I am missing something?

 

[Firstascent]

I am looking for someone that can put together a system similar to what you are doing. Would you mind giving me the name of the company you are working with.
Thank in advance.

There were a few companies but the latest company I worked with was https://www.dcpowerinc.com/

I never did go through with it though because I ultimately stuck with 12v. I did want 24v but I was set on using the new Victron Multiplus II 2x120 inverters and it was only 12v options available for the U.S.

 

[Firstascent]

Is there a reason more people don't go with AC rather then DC for this type of situation? I bought a 50a 12V Renogy and it works quite well. I have 20' of 2 gauge wire from the battery to the trailer hitch, then another 10' or 2 gauge from the trailer hitch to the DC2DC charger.

If I had it to do again (and I likely will as I think I will go to 24 or 48v) I would look seriously at putting a 2000w inverter in the cab. Then run a heavy duty extension cord from the cab to the inverter charger in the trailer. You could support at 75a at 24V charger at this...

Again maybe not what you need/want but something to think about. Maybe I am missing something?

Not sure but my guess is typically you want this to charge your batteries which are DC. If you had an AC alternator you’d have to have converter to go to dc before going to your batteries. So one extra device that isn’t needed.

 

[bedpan]

Not sure but my guess is typically you want this to charge your batteries which are DC. If you had an AC alternator you’d have to have converter to go to dc before going to your batteries. So one extra device that isn’t needed.

Most people have an AC charger anyways, or an Inverter Charger.
So you skip the DC2DC Charger and get an Inverter that you put in the Tow Vehicle. This now gives you a decent inverter in the truck that can be used for other things as well where a DC2DC is for single purposed.

Price wise I would say its cheaper. You don't have the big run of large gauge cable and the associated connectors.

I may well be missing something and not meaning to distract from the OP's post.. Just something I have been mulling for my rebuild.