High Current (100A+) Alternator charging?

I've got twin alternators, total 440A. A 190A primary and a 250A secondary.

I use a Sterling BB12180 180A B2B charger which is an excellent product. Prior to this I used the Sterling 60A model which also worked well.

This charges a 1120A LiFePO4 bank.

jwelter99 said:

I've got twin alternators, total 440A. A 190A primary and a 250A secondary.

I use a Sterling BB12180 180A B2B charger which is an excellent product. Prior to this I used the Sterling 60A model which also worked well.

This charges a 1120A LiFePO4 bank.

Click to expand...

Oooh.,, have a link?

I didn’t know they had a 180a variant and don’t see it in their site

SoCalKevin said:

Oooh.,, have a link?

I didn’t know they had a 180a variant and don’t see it in their site

Click to expand...

The 120A and 180A are just starting to ship, the 60A has been out for awhile. Give them a call to order. I've not seen the 120A/180A listed with any of the online resellers yet.

Supposedly high current 12/24 units coming as well.

jwelter99 said:

https://www.sterling-power-usa.com/library/B2B120%20sheet.pdf

The 120A and 180A are just starting to ship, the 60A has been out for awhile. Give them a call to order. I've not seen the 120A/180A listed with any of the online resellers yet.

Supposedly high current 12/24 units coming as well.

Click to expand...

Awesome!

Thanks.

I currently have the 60a but I also have 440a of dual alts so may go bigger

This is actually something I'm also looking into for a future truck camper build. It's hard to find a stand alone dc to dc charger that outputs high amps (100+). I've been looking at the Xantrex Freedom Xc Pro 3000 Inverter/Charger - 3000w - 150a - 120v - 12v. I'm a newbie, so i'm trying to get some feedback on this unit coupled with an 220amp alternator. Don't expect to charge at 150amps, but somewhere around half the alternator output of 110-120amps.

mrp4rk said:

This is actually something I'm also looking into for a future truck camper build. It's hard to find a stand alone dc to dc charger that outputs high amps (100+). I've been looking at the Xantrex Freedom Xc Pro 3000 Inverter/Charger - 3000w - 150a - 120v - 12v. I'm a newbie, so i'm trying to get some feedback on this unit coupled with an 220amp alternator. Don't expect to charge at 150amps, but somewhere around half the alternator output of 110-120amps.

Click to expand...

For longevity of the alternator, I’d try to keep it around 25% or so

mrp4rk said:

This is actually something I'm also looking into for a future truck camper build. It's hard to find a stand alone dc to dc charger that outputs high amps (100+). I've been looking at the Xantrex Freedom Xc Pro 3000 Inverter/Charger - 3000w - 150a - 120v - 12v. I'm a newbie, so i'm trying to get some feedback on this unit coupled with an 220amp alternator. Don't expect to charge at 150amps, but somewhere around half the alternator output of 110-120amps.

Click to expand...

I should take pictures of my setup on the Duramax that hauls my truck camper. I installed a second alternator, 250A in addition to the 105A factory alternator. I had already removed the backseat to haul the Dometic CFX95 freezer/fridge and installed a Giandel 2400W inverter against the back wall. Power from the front 12V electrical system is ran thru 2/0 under the body (all wrapped for safety) and comes up under the cab below the inverter. At the rear bumper, I installed a 30A RV outlet, ran a 30A RV cord from the inverter to rear bumper. I have a short 4 foot cord that plugs into the cabinet on the outside of the truck camper that houses the 24V Growatt SPF3000.

I usually only charge with 30A on the Growatt, about 750W. I could go 60A (1500W) if needed, this setup will handle it easily as 1500W would only be 1/2 the ouput of the 250A alternator.

SoCalKevin said:

For longevity of the alternator, I’d try to keep it around 25% or so

Click to expand...

Does this also apply if this is a secondary alternator? Thought 50% was ok. Thanks!

Zwy said:

I should take pictures of my setup on the Duramax that hauls my truck camper. I installed a second alternator, 250A in addition to the 105A factory alternator. I had already removed the backseat to haul the Dometic CFX95 freezer/fridge and installed a Giandel 2400W inverter against the back wall. Power from the front 12V electrical system is ran thru 2/0 under the body (all wrapped for safety) and comes up under the cab below the inverter. At the rear bumper, I installed a 30A RV outlet, ran a 30A RV cord from the inverter to rear bumper. I have a short 4 foot cord that plugs into the cabinet on the outside of the truck camper that houses the 24V Growatt SPF3000. View attachment 96410

I usually only charge with 30A on the Growatt, about 750W. I could go 60A (1500W) if needed, this setup will handle it easily as 1500W would only be 1/2 the ouput of the 250A alternator.

Click to expand...

Thanks for sharing your setup! I also own a CFX95 Freezer fridge. Was wondering if your fridge compressor stays on for more than its off. I just purchased mine two weeks ago and I've noticed the compressor is almost always running, I'm running both a fridge/freezer atm.

I never really paid much attention, the CFX doesn't use much power. Most likely you are noticing initial cool down, if you fill it with cold food and beverages, it probably won't run as often.

I also ran a power line from my truck camper LFP bank with a disconnect that comes into the rear of the cab. This allows running the CFX off the solar system and not off the truck batteries while parked boondocking.

mrp4rk said:

Does this also apply if this is a secondary alternator? Thought 50% was ok. Thanks!

Click to expand...

The problem with the OEM alternators is the rating is somewhat fictitious. For example yea it can do the 140A it is rated at redline after the vehicle has sat overnight in a cold environment. But as soon as up to engine bay temps the OEM models need pretty significant derating; as well as for RPM.

If a good quality "supply" alternator they can be run much higher to their limits without issues. Wakespeed, Balmar, etc, etc. I would not hesitate to run those at 75% of rated. They are built to withstand high levels of output -- or you would not be buying one.

So as an ASE Master Tech I think some of yall would be surprised to find out how close to the alternator's rated capacity a vehicle's draw can be.. Most especially luxury vehicles in cold climates. Take something like an Escalade and turn on 2 rows of seat heaters, both blower motors on high, F+R wipers, heated steering wheel, defrost grid on rear window, base of windshield, both side mirrors, turn on all the exterior lights, etc and it's surprisingly close to the limit. Close enough that as the alternator performance begins to fade it often can't keep up with 'peak demand' at idle, and the only reason a whole bunch of people don't have dead batteries is only due to how rarely people sit at idle for long periods with everything turned on. How often do those load conditions occur? Any time a family goes anywhere in cold + precipitation!? Do alternators have a high warranty return rate in those conditions? Not really. I understand that the cold outside temp ameliorates the hardship on the alternator, but I also suspect that while the current output of the alternator might go up ~25% from idle to 2000rpm (engine speed, not alt), the safety factor of the internal fan's performance probably goes up 200%, plus you get lower ambient temp by flowing more air through the entire engine bay. A parked car can hit ~170f air temp under the hood, i think. I'm sure boats are similar in some respects. If you can keep it cool i see no problem operating closer to the rating than 50%. The issue i think is taking 'regular' alternators such as vehicle alternators, and running them at high load at idle for long periods.. High internal AND ambient temps combined with lowest fan speed. Because if the only reason the engine is even running is to spin the alt, then of course it's at idle! Unless someone knows better.

So cool the alt one way or another and feel less bad running it over 50%, is my combination of experience and educated inference as an ASE Master Certified auto tech. Take it for what it's worth..

Vigo said:

So as an ASE Master Tech I think some of yall would be surprised to find out how close to the alternator's rated capacity a vehicle's draw can be.. Most especially luxury vehicles in cold climates

Click to expand...

Slight diversion but:
Can add to this with experience with a BMW 550, the N63TU motor which I think was 2011 to 2016. BMW screwed up on the algorithm for charging from the alternator and it was killing batteries. They keep it close for MPG ratings. They could not just update the ECU to increase the output from the alternator as it would get them in trouble on the MPG ratings. That motor already had free oil changes, due to a recall, as it would consume a quart every 1000 to 2000 miles. Now with the charging / battery issues, they would change the battery at each oil change as well.

Yes, post Dieselgate everyone is a little more gunshy than they would have been in the past.. Newer cars practically turn off their alternators some of the time and let the system voltage drop well into the 12s at times where old cars basically never went below 13.0 unless something was failing. I think there was also a learning curve on how to make starter batteries have decent lifespans in the era of auto stop-start. I read a paper studying the effects of stop-start 'microcycling' on lead starter batteries and the kinds of changes they made to try to make them live, like putting features on the cell partition walls to 'circulate' the electrolyte during normal vehicle movement to minimize 'stratification' of the acidity of the electrolyte, blah blah.

It was kind of interesting but for people who had cars at the bleeding edge of the tech it just meant more hassles and problems until the technology improved.

One thing i've noticed is that really 'high stakes' vehicles that push into new market segments tend to be actually overbuilt or managed more conservatively and end up being more reliable than some of the lower stakes existing vehicles. A 2011 Model S and a 2012 Chevy Volt for example, i think exceed the 'average reliability' of most cars from those years, over the past ~10 years, because they HAD to go right for their companies. I'd feel better about a 170k Model S or Volt than most other ~2011s with 170k today.

We're in the process of retrofitting an RV (06 jayco on ford F450 gasoline chassis) and are going to run a 48v solar / inverter setup with LFP batteries. The 'secondary' power solution is an alternator (2nd, dedicated unit) that will drive off of the truck's main belt and do just under 5kW up to 56v (operator defined) to charge / power the setup while driving or if the 4kW worth of solar (3kW installed, 1kw deployable) for some reason can't cut it (Also a 2kw inverter gen also kept on-hand as they're handy). Going to start with a ~14kWh battery with the provisioning to add a 2nd / tap into a stationary system located where the RV will spend just over half of the time. RV's 12v system will remain mostly untouched sans the addition of a float charger that can go up to 6a of charge if required to maintain it.

Bit of a tangent, my F150 hybrid will output 35kw (~290v DC) at 1k rpm idle that I'm looking to be able to tap in the future with the use of a high-current DC-DC converter. It's also got a belt driven hybrid starter generator that produces 280a at ~14.4v when the gasoline engine is running. There's also a DC-DC converter to take the HVB (~300v) down to ~14.4v @ 220a to run 12v systems w/ engine off. That's 500a worth of "12v" production capacity natively built in. Granted it's also got a 7.2kWh inverter built in making my choices for a travel trailer for it to pull a bit more difficult. At today's fuel prices ($3.30/g) it costs $.47 cents per kWh to produce electricity.

The Powerboost is sort of a tragic figure because it's incredibly interesting in its own right and almost noone realizes it exists because.. Lightning.

I'm not sure what a 3.5L naturally aspirated engine can actually make at 1000rpm, but 35kw+efficiency losses is ~50hp and that's probably pretty close to maxed out for a 3.5L engine at 1000rpm where the turbos aren't helping, if it's possible at all. So I would verify that before assuming it to be possible. It's likely the engine can't actually make enough power at 1000rpm to max out the electrical conversion capability.

The Ford strategy with dual alternators is to run only one at a time, letting the other cool off. Should the load require it, both alternators will operate.

My F-350 has the OEM dual alternators, producing a maximum of 397 amps. It was mentioned a few posts up that one of the car manufacturers had a "bad" charge profile that cooked batteries. Ford may have a similar problem with the 2017+ Super Duty trucks. They have replaced a lot of batteries due to cooking the crap out of them, usually the driver side battery in the dual battery setup.

They have replaced a lot of batteries due to cooking the crap out of them, usually the driver side battery in the dual battery setup.

Click to expand...

Well, with the batteries paralleled as they usually are (can't claim to remember specifically noticing anything about a 2017+ super duty) you are susceptible to the imperfections of the wiring and there may not even be current sensing for the individual batteries. I would guess that it works fine out of the factory until the first filthy human touches the battery connections, at which point it becomes a total crapshoot (without current monitoring each battery) whether you feeding each battery at an acceptable C rate, or whether you're unintentionally pushing 300amps into a single battery while the other one heats a terminal to 150f flowing a piddly 40a because it's barely connecting.

Diesel truck battery terminals have got to be one of the top locations for human error introduced into vehicles, because it seems they operate on 'thinner margins' as far as the ability of the electrical system to crank the engine sufficiently well in all conditions, such that diesel battery terminals get 'messed with' a lot more often than the terminals on other light duty vehicles. Maybe it's not that simple and ford DOES have current sensing on both batts, maybe even a way to split/distribute charging.. but if not, it is almost certainly down to 'bad battery connections'. Which could be considered poor circuit design because honestly, i wouldn't trust most automotive battery terminal connections to do 200a without serious heating on a long enough duration (cranking doesn't count), and if you are relying on the quality of those battery connections to be the difference between 2 batteries getting 200a and 1 battery getting 300+, i'd say you got yourself a rather poor idea. It's also possible that since diesel trucks tend to work their batteries harder than most light duty vehicles, the 'drifting' of the individual batteries IRs away from each other over time might be enough to cause the other one to receive an unacceptable charge current such that one of them continues slowly dying, but the other one rapidly dies in spite of not being the original 'culprit'.

So hopefully Ford has installed at least 2 current sensors if not direct temp sensing (rather than inferred, which is common in cars) to protect against the vagaries of how bad your typical battery terminal connection that's been touched by a human is on a diesel pickup, and account for the possibility of the batteries themselves differing in IR over time.

There is no current sensing of individual batteries. It's a simple parallel connection between the two batteries, but I haven't dug into it to see if one battery is seeing more current than the other.

Gotcha. Its quite common now to have current sensors near car batteries but as far as ive noticed so far it’s for more accurate tracking of the battery on vehicles with startstop and i dont even think any 3/4-1ton diesels have start stop, so if any had current sensors it would be news to me. Now that im a teacher the main way i find out about newer vehicles is through random training seminars and webinars i attend, but its a tiny sampling of whats out there. If they are trying to manage a 400a cannon of a charging system i imagine current sensing will eventually show up on those trucks. ?