High current alternator charging for 24v/48v?

[Charleswgibbs]

Anyone have any guesses on how some people are able to accomplish high power alternator charging of 24v or 48v lifepo4 banks?

I've seen more than a few van tour videos of the high-end builders where they claim their electrical systems can do 3000w+ alternator charging on 24v or 48v banks, one was even claiming 6000w while driving.

Obviously they must be using high output secondary alternators, but when it comes to dc-dc chargers nothing on the market even comes close to those charging levels.

Victron's Orions max out at 15a for the 24v models and I don't believe they even make one capable of 48v output.

Sterlings are a bit more powerful but I believe their highest output is like 30a @24v and 15a @48v Their site mentions higher power models are coming, and I've seen a data sheet showing a 160a 12v-12v model, but the 24v and 48v models were still anemic.

Maybe they aren't using a dc-dc charger and instead are using 24v/48v alternators directly connected with some basic current limiting? Or maybe they have some as-of-yet released high power models? Maybe just exaggerating their vans capabilities? I doubt they are using 15 Orions or 6 sterlings ganged together.

I would ask in the comments on the videos, but every time I've ever asked technical questions in the past I get told I'm asking for secrets they can't divulge.

Thanks in advance for any ideas!

 

[Vigo]

LOL "secrets", i guess that means they are trying to make money from people who would rather spend than learn. Which yeah, if they are that's fine, but 'secrets' makes it sound so much more scandalous than what it is.

Anyway, yeah multiple possibilities. There are some large 12 to 48 boost converters. Apparently some parts of trucking industry are starting to have both voltages in their systems. Look at this thing:
Big buck/boost converter

Or if you're just trying to go one direction:
~1kw 12 to 48v
~1kw 12 to 24v

Most likely thing is they are using alternators specifically wound to create 24 or 48v outputs. Still have to cool it and control it, but they are out there. When not DIY they are very pricey, although i have seen one ebay ad for a guy selling a fairly big 48v permanent magnet generator in an alternator housing for ~$300. You can also put 12v alternators in series if you isolate from chassis ground.

Probably funniest solution, is large 12v or 2 12v alternators, large 12v to 120 or 230 volt ac inverter, and large 120v or 230v to 24/48v charger/power supply. It may only be 70% efficient but is probably cheaper than an actual high capacity 48v alternator.

Although i am not using them this way, i do own the following devices:
12v 1500w 230v inverter
~500w 48v Charger $26

Technically that inverter + 3x power supplies gets you 1500w of 48v charging from your 12v system AND you can plug all the solar you can fit on a vehicle into it, for ~$350. If you don't need the solar controller part you could get a 1500+w 12v inverter much cheaper than $250. I would imagine using the cheapest possible power supplies and 12v inverter you would probably be around $120-150 per KW of 12-to-24v or 48v charging. I have been able to adjust those 48v power supplies up to around 52-53v on the potentiometer.

 

[FloaterBoater]

There is a company called Balmar which makes 48v alternators designed for charging lithium batteries. Very expensive. in the £3600 / £4000 mark.

I've looked long and hard at how I could charge a 48v bank off a 24v alternator and, at least to date, haven't come up with a good / cost effective solution.

 

[FloaterBoater]

These guys also seem to make 48V alternators in the US. Similar costs: https://www.nationsstarteralternator.com/searchresults.asp?Search=48+VOLT&Submit=Submit

 

[LB3]

They’re using 24v and 48v secondary alternators. ADV rarely gives away their model or branding info of their suppliers but I believe one of the Balmar alternators is shown in the video below.

 

[John Frum]

one was even claiming 6000w while driving.

Link please.

 

[Zwy]

Anyone have any guesses on how some people are able to accomplish high power alternator charging of 24v or 48v lifepo4 banks?

I've seen more than a few van tour videos of the high-end builders where they claim their electrical systems can do 3000w+ alternator charging on 24v or 48v banks, one was even claiming 6000w while driving.

Obviously they must be using high output secondary alternators, but when it comes to dc-dc chargers nothing on the market even comes close to those charging levels.

Victron's Orions max out at 15a for the 24v models and I don't believe they even make one capable of 48v output.

Sterlings are a bit more powerful but I believe their highest output is like 30a @24v and 15a @48v Their site mentions higher power models are coming, and I've seen a data sheet showing a 160a 12v-12v model, but the 24v and 48v models were still anemic.

Maybe they aren't using a dc-dc charger and instead are using 24v/48v alternators directly connected with some basic current limiting? Or maybe they have some as-of-yet released high power models? Maybe just exaggerating their vans capabilities? I doubt they are using 15 Orions or 6 sterlings ganged together.

I would ask in the comments on the videos, but every time I've ever asked technical questions in the past I get told I'm asking for secrets they can't divulge.

Thanks in advance for any ideas!

I should take some photos and consolidate it into one thread with some of the photos I already posted. https://diysolarforum.com/threads/how-to-modify-a-car-alternator-for-48v-charging.11988/post-464109

I have a 30A RV receptacle at the rear bumper, dual alternators for a total of 355A at 12V. One could have 500A if the original 105A was replaced with another 250A. https://diysolarforum.com/threads/a...osphate-on-a-travel-trailer.23576/post-280413

There needs to be a FLA battery in the circuit, explained in this post. https://diysolarforum.com/threads/d...ith-a-high-power-alternator.31329/post-379875

 

[Charleswgibbs]

Link please.

I'll see if I can find it, It was in an interview/tour with van builder Brandon buckley who makes some seriously impressive vans, there are several interviews and they aren't short.

They’re using 24v and 48v secondary alternators. ADV rarely gives away their model or branding info of their suppliers but I believe one of the Balmar alternators is shown in the video below.

Very interesting! Ill take a look.

These guys also seem to make 48V alternators in the US. Similar costs: https://www.nationsstarteralternator.com/searchresults.asp?Search=48+VOLT&Submit=Submit

Wow, very expensive alternators.

Thanks for the replies guys, I had thought of running an inverter off a second alternator and then feeding the output into the ac in on the main inverter and just using that to charge the main bank. Probably the cheapest option for the amount of power you get.

 

[John Frum]

Thanks for the replies guys, I had thought of running an inverter off a second alternator and then feeding the output into the ac in on the main inverter and just using that to charge the main bank. Probably the cheapest option for the amount of power you get.

The altnernator output is dc.

 

[Charleswgibbs]

Link please.

Found it! I got lucky lol

He makes the claim around 13:30

 

[Charleswgibbs]

The altnernator output is dc.

Yes the idea was to run a 12v-120vac inverter off the second alternator, and then run that output into the ac in on an inverter/charger to charge the main 24v or 48v bank.

 

[Vigo]

Thanks for the replies guys, I had thought of running an inverter off a second alternator and then feeding the output into the ac in on the main inverter and just using that to charge the main bank. Probably the cheapest option for the amount of power you get.

Yes for better or worse i think this ends up being the cheapest, especially since you already have the 2nd inverter able to do 48v charging and don't need the silly PSUs i had linked.

You still have to have the 12v output to support whatever Watts of charging you are trying to do. But adding a large secondary alternator and getting a bit over ~3kw of total 12v output seems relatively simple compared to some of the other options. I bought a 200a alternator for my RV for $130.


A related topic that i don't fully understand.. I assumed that since inverters are rectifying AC input anyway which effectively means they are only flowing current from the AC waveform near the peaks (is my understanding) that they might not care about being fed modified sine wave. But when i fed MSW to my Growatt spf5000es it 'sounded bad' in the same way a motor-driven device 'sounds bad' on MSW. I wasn't sure whether it was harmful or not so i just aborted the experiment. Now, i don't know if the only reason it happened is because it's an inverter that always tries to frequency match the input because it has a transfer switch in it, and that buzzing i was hearing was the inverter output trying to match the msw input, or if this would still happen even if it wasn't trying to sync its output to it (like a double conversion UPS or something). Because my general impression was that most things that are rectifying ac to dc anyway don't care if you feed them MSW or PSW.. must be either wrong or imcomplete..

 

[Nickvelo]

My guess is they’re spending around £4k on the alternator and other £1k on the regulator and not sure how much a REC BMS is. Balmar do an alternator and regulator and Wakespeed make a regulator that can communitcate with the BMS to control the alternator. It doesn’t seem like many people are doing it yet though!

 

[Checkthisout]

Why would you need that much juice?

Charging up large house battery bank quickly?

In other words your RV has a large has battery bank and no generator?

 

[Lostlable]

Why would you need that much juice?

Charging up large house battery bank quickly?

In other words your RV has a large has battery bank and no generator?

They are using a Cinderella Incenorator toliet.
Here are some links to these over the top builds.

I found the Batteries and Inverter used in this build.

Battery- https://bigbattery.com/products/24v-hawk-max-2-lifepo4-228ah-5-8kwh/

Inverter- https://www.aimscorp.net/6000-watt-...er-charger-48-volt-dc-to-120-240-volt-ac.html

https://www.aimscorp.net/ac-convert...art-charger-75-amps-listed-to-ul-458-csa.html



Here is Buck SD newest build

I myself am trying to learn as much as I can , I understand basics, but I am not sophisticated enough for a project like that.

 

[12VoltInstalls]

makes the claim

That’s some interesting work right there.

His recycler shower sortof bothers my head, though. Standing/tanked shower water (gray water) turns nasty with bacteria quickly. And it stinks.

While don’t ‘stealth camp’ I am off grid without a well so I haul water.
So water use is something to be mindful of - yet I can shower with fresh, hot water on 2-3 gallons including shaving and brushing my teeth. So two six-gallon water jugs can go 4-5 days. And no tanking dour smelling effluent.

But I can see why a big alternator is required because there’s not a ton of solar there.
Learning a lot here

 

[Charleswgibbs]

That’s some interesting work right there.

His recycler shower sortof bothers my head, though. Standing/tanked shower water (gray water) turns nasty with bacteria quickly. And it stinks.

While don’t ‘stealth camp’ I am off grid without a well so I haul water.
So water use is something to be mindful of - yet I can shower with fresh, hot water on 2-3 gallons including shaving and brushing my teeth. So two six-gallon water jugs can go 4-5 days. And no tanking dour smelling effluent.

But I can see why a big alternator is required because there’s not a ton of solar there.
Learning a lot here

Yeah the recirculating shower grosses me out too. There was another channel with someone who sampled the water in theirs after every shower for a week (or something like that) and had it lab tested.

As you would expect even with all the filters it became more murky after every shower and the amount of crud increased over time. One of the tests was for fecal coliform and only spiked on one occasion but was supposedly zero the rest of the time. Still gross.

And if you use soap it clogs the filters in short order. I'll take the 6000w charging but leave the shower

 

[Vigo]

I wouldn’t recirculate shower water but i WOULD implement a heat exchanger between drain water and cold supply to reduce hot water required to hit desired temp and stretch the capacity of a small tank heater. Or just get a small tankless and mostly shower during the day when it’s free.

 

[Checkthisout]

I wouldn’t recirculate shower water but i WOULD implement a heat exchanger between drain water and cold supply to reduce hot water required to hit desired temp and stretch the capacity of a small tank heater. Or just get a small tankless and mostly shower during the day when it’s free.

Put a heat exchanger on vehicle cooling system and only shower when changing to new hipster fake poor camp.

 

[12VoltInstalls]

Or just get a small tankless and mostly shower during the day when it’s free

If you work there’s too many winter months for a morning shower with electricity in my locale. But showering and cooking with propane (using tankless hot water heater and propane stove) May-Oct only costs like $35 and recharging by running the engine or driving probably costs similarly.

I have a recirculating line with a valve so I can run unused freshwater back to the freshwater tank until it’s hot at the shower supply connection. I have a tee and a valve. That saves a tad over two quarts, measured, of water going down the drain every time you want to shower.

At some point the fun, hobby side of my practical necessity for solar will make me test out solar electricity to power a heating element in an insulated tank. A heat exchanger may take some complexity that’s not as practical in an RV of any sort. In rectangular dollars it might not save that much, either.

Either way I can’t shower in a liter of water. A gallon is the absolute minimum (I’ve done it to experiment). I shut off the water while soaping, shampooing etc and therefore it only runs while initially wetting and the rinsing off.

If 5+ months of the year didn’t have short sun hours, or dark, no sun days id do electric hot water now.