Can a lithium pack be charged by alternator alone?

InterBlog

Member
He was running his AC powered rooftop A/C off his alternator. :thumbdown:
Who was? I wasn't (I'm a she, not a he). I was running AC powered off the lithium battery with the T1N engine turned off, which is what my mechanical engineer husband and I specifically designed the system to do (Edit: We have a 2,000 watt Xantrex inverter and an EasyStart to handle this job). No involvement by the alternator whatsoever, except to re-charge the lithium battery once I re-started the engine and got back on the road.

We live in America's deep south, and when I drive cross-country solo, I need to take a nap in the middle of each day's slog. I drive about 5 hours, eat lunch and nap with the roof a/c running, get back up, drive another 5+ hours before boondocking overnight somewhere on the road. I can't nap in the summer in the deep south without the roof a/c running. Temperatures in my travel area have hit 103 F outside the van; you can imagine what they would reach inside without the a/c. The reason why I'm driving long-haul cross-country solo in the first place is to get the hell out of those conditions (I drive from Houston Texas to far northeastern Nova Scotia every year).
 
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autostaretx

Erratic Member
As far as i know, the original MB/Dodge/FL rear air conditioner DID use the engine-mounted compressor for the cooling.
The electricity just spins the fans.

If you remove your rooftop AC, you'll find two refrigerant hoses that go down the (US) passenger side wall on their way to the engine.

If you open the hood, you may even see an extra belt and the second compressor
(i forget if they have a 2nd compressor or if they mooch from the first one)

--dick
 

NobleOne

Learning Curve Climber
As far as i know, the original MB/Dodge/FL rear air conditioner DID use the engine-mounted compressor for the cooling.
The electricity just spins the fans.

If you remove your rooftop AC, you'll find two refrigerant hoses that go down the (US) passenger side wall on their way to the engine.

If you open the hood, you may even see an extra belt and the second compressor
(i forget if they have a 2nd compressor or if they mooch from the first one)

--dick
Thanks for the bad news, lol. I was hoping to be able to use it as my camping ac. I haven’t explored the ac yet, so I hadn’t discovered that bit of knowledge. Now I need the come up with another ac solution for when the engine is not running. (Sigh)
 

eslmooney

New member
I have bin using 2006 roadtrek in the last three years since I balt it, mostly use it on the weekends every two to thee weeks March thru November with a couple 5 to 6 days staying at one place with no hookup. All the led batteries are bad and I wanted go LFP. There is a 150 amp alternator now so why not go bigger? This what I found https://www.amazon.com/Eagle-High-300Amp-Alternator-Sprinter/ an use aexternal regulator Balmer Mc-614 . The three way fridge does not work will when you rely need it. Need a/c and heat. Looking at a small 120 volt.
 

HarryN

Well-known member
**OP beware.**

**Eslmooney beware.**

Even WITH the Sterling B2B, the extra wear on the alternator will make this configuration a very risky proposition.

How do I know? Because I have that exact Sterling and that exact Electrodacus in a T1N, and my Bosch 200 A alternator lasted a total of 16 months of very occasional use before its clutch pulley wore out. My alternator's effective lifespan ended up being measurable in mere HOURS.

What the alternator was DESIGNED to do and what we are ASKING it to do are two different things in this scenario, even if the numbers on paper seem to make sense. Numbers on paper are not equal to conditions of wear in real life.

At this point, I am 100% convinced that the only SAFE non-solar way to charge lithiums in a T1N is by using a second alternator. A second alternator is a very expensive proposition because of the mounting bracket availability issue. For the moment, I will omit those details and that research.

Rather than belabor the alternator failure details in this post, I'd encourage you to read this account of that failure below (non-monetized blog post).

Understand that if your alternator fails the way mine did, it could easily put your rig in danger, and your life in danger, because when its degradation causes the chassis battery voltage to fall too low and the computer to shut down, your T1N is just going to stop dead in the middle of the freeway, wherever you happen to be at that moment (possibly with a 70 mph big rig bearing down on you). That is what will happen if you don't catch that kind of failure in time to save yourself from an uncontrollable shut-down.

https://interstateblog.blogspot.com/2018/09/psa-alternator-clutch-pulley-failures.html
You have a very nice blog / site there. Thanks for posting all of that helpful information.

- I read through quickly, so I probably just missed it, but what capacity rating (amps) of Sterling B - B charger do you have?

- You are exactly correct though - hot summer use of an alternator is much harder on it than cooler weather. There are some high performance alternators out there. Interestingly one of the more common uses is for cars that are used for ultra power audio systems while idling.

- I am not so sure that you are doing yourself any favors by disabling the alternator decoupler pulley function. It is there for a reason and can affect the engine operation substantially. These higher power alternators have quite a lot of rotating mass, and if it starts fighting with the engine rpm, even bigger things can break.

What might be helpful is to replace the alternator decoupler with an upgraded version, for example Gates makes very decent ones:

https://www.gates.com/us/en/power-transmission/power-transmission-components/c/133
 
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eslmooney

New member
Who was? I wasn't (I'm a she, not a he). I was running AC powered off the lithium battery with the T1N engine turned off, which is what my mechanical engineer husband and I specifically designed the system to do (Edit: We have a 2,000 watt Xantrex inverter and an EasyStart to handle this job). No involvement by the alternator whatsoever, except to re-charge the lithium battery once I re-started the engine and got back on the road.

We live in America's deep south, and when I drive cross-country solo, I need to take a nap in the middle of each day's slog. I drive about 5 hours, eat lunch and nap with the roof a/c running, get back up, drive another 5+ hours before boondocking overnight somewhere on the road. I can't nap in the summer in the deep south without the roof a/c running. Temperatures in my travel area have hit 103 F outside the van; you can imagine what they would reach inside without the a/c. The reason why I'm driving long-haul cross-country solo in the first place is to get the hell out of those conditions (I drive from Houston Texas to far northeastern Nova Scotia every year).
This what I Am going for, what battery and what did you have to do with the charging system? :cheers:
 

HarryN

Well-known member
I would probably not purchase a no brand alternator with essentially no reviews or detailed specs off of amazon.

Perhaps consider nations, mechman, etc. A supplier that gives real, detailed info on their alternators, such as an RPM vs current output curves.

A good quality, high output alternator will have at least 6, perhaps 12 phases, and the supplier will be providing a lot of info (frankly bragging) about how great it is and why. Designing and building a quality, high output alternator is non trivial, so the people who are good at it are recognized as such for a reason.
 

HarryN

Well-known member
As far as i know, the original MB/Dodge/FL rear air conditioner DID use the engine-mounted compressor for the cooling.
The electricity just spins the fans.

If you remove your rooftop AC, you'll find two refrigerant hoses that go down the (US) passenger side wall on their way to the engine.

If you open the hood, you may even see an extra belt and the second compressor
(i forget if they have a 2nd compressor or if they mooch from the first one)

--dick
Usually, the compressor for the factory rear air conditioner occupies the same space that is used for an auxiliary alternator. In other words, if you want to use an RV / 120 vac air conditioner, and run it from power pulled from the auxiliary alternator, then the conventional compressor needs to be removed.

I have built power systems like this - expensive but it works.

Another option is to look at Orion's van build. He has an under-mount generator, I think in the spare tire position.
 

InterBlog

Member
You have a very nice blog / site there. Thanks for posting all of that helpful information.

(1) - I read through quickly, so I probably just missed it, but what capacity rating (amps) of Sterling B - B charger do you have?....


(2) - I am not so sure that you are doing yourself any favors by disabling the alternator decoupler pulley function.

....
What might be helpful is to replace the alternator decoupler with an upgraded version, for example Gates makes very decent ones:
(1) From memory without verifying, I'm thinking it's 60 A.

(2) Heck of it is, we are not. The repair shop explained this to my husband, so something might be lost in translation here, but apparently there WAS a circumvention method that people were using because of these clutch pulley failures, but Bosch reconfigured their alternator to prevent people from making that workaround. So we are stuck with their OEM.

I don't know why - because Bosch would prefer us to repeatedly repair their crappy $500 alternators?! Where is the sense in that? I never did get a handle on their thinking on that point.

Bottom line: we repaired using identical materials, which means that our repair unit is no better than it ever was.

And the jury is still out on whether we will go to second alternator due to the cost. I managed to get through 35 consecutive off-grid days on the road last year using solar alone for 34 of those days (plus about 1 hour of propane generator when it was raining). But I still need to be able to run the roof a/c and recharge the lithium more quickly on those deep south dog days of summer, so there's that.
 

InterBlog

Member
.... Now I need the come up with another ac solution for when the engine is not running. (Sigh)
Do the math carefully. It's only worth it financially as a relief mechanism for a couple of hours here and there. TMK, nobody has ever demonstrated a holistic system that will keep a Sprinter cool for extended periods in hot weather, unless you want to spend $300K for an ARV rig.
 

InterBlog

Member
This what I Am going for, what battery and what did you have to do with the charging system? :cheers:
TL;DR - 300 watt solar, 300 AH lithium iron phosphate, 2,000 watt inverter, Electrodacus BMS (which has worked better than some engineers predicted), and here below is a snapshot of the system as installed. Note that we retrofitted an existing rig, a 2007 Airstream Interstate built on a 2006 T1N 2500. We refused to forfeit valuable storage space for the new electrical system, so we spliced all the components into existing void spaces behind bulkheads, under cabinets, etc.




I have a partial description of our system. Regrettably, I haven't found the time to knock out the final parts of the write up, but here is this much:

General overview:

https://interstateblog.blogspot.com/2018/01/lithium-battery-upgrade-part-1-general.html

AC portion:

https://interstateblog.blogspot.com/2018/02/lithium-battery-upgrade-part-2-ac-system.html

Charging system and DC system are still pending description.
 

john61ct

Active member
No aircon setup can run long off grid from battery stored power.

All you're doing is time shifting the high-amps input, now doubled if you need aircon **and** recharging to be concurrent.

Figure 100AH storage needed per hour, and that's in mild heat, or excellent insulation.
 

eslmooney

New member
**OP beware.**

**Eslmooney beware.**

Even WITH the Sterling B2B, the extra wear on the alternator will make this configuration a very risky proposition.

How do I know? Because I have that exact Sterling and that exact Electrodacus in a T1N, and my Bosch 200 A alternator lasted a total of 16 months of very occasional use before its clutch pulley wore out. My alternator's effective lifespan ended up being measurable in mere HOURS.

What the alternator was DESIGNED to do and what we are ASKING it to do are two different things in this scenario, even if the numbers on paper seem to make sense. Numbers on paper are not equal to conditions of wear in real life.

At this point, I am 100% convinced that the only SAFE non-solar way to charge lithiums in a T1N is by using a second alternator. A second alternator is a very expensive proposition because of the mounting bracket availability issue. For the moment, I will omit those details and that research.

Rather than belabor the alternator failure details in this post, I'd encourage you to read this account of that failure below (non-monetized blog post).

Understand that if your alternator fails the way mine did, it could easily put your rig in danger, and your life in danger, because when its degradation causes the chassis battery voltage to fall too low and the computer to shut down, your T1N is just going to stop dead in the middle of the freeway, wherever you happen to be at that moment (possibly with a 70 mph big rig bearing down on you). That is what will happen if you don't catch that kind of failure in time to save yourself from an uncontrollable shut-down.

https://interstateblog.blogspot.com/2018/09/psa-alternator-clutch-pulley-failures.html

Im happy it work out well for you.
Yes common sense would apply to that type of alternator failure. I have had sort of same thing happen and I drove to a auto parts store (Napa) replace the part in the parking lot and if you don't have the write tool you buy one there.
There must be a way around over working alternator clutch and such all out constant load on the alternator . I can carry 16 180Ah of LFP batteries , there should be away to put some resombal amount charge in them. I'm new here at Sprinter-Form Lot grate info already. Thanks Joe
 

InterBlog

Member
You clearly don’t live in Texas, where temps can still be in the 90’s at 0200 Hours. :eek:
I clearly DO live in Texas, and have lived here continually since 1991. As john61ct notes, it simply can't be done. Not without the kind of money that makes it a non-starter for those of us who are not independently wealthy.

Let me put it in more concrete terms: husband and I have spent around $10K on our solar, electrical, lithium, and supporting components and materials (we did our own labor). That investment gets us about 2.5 hours of off-grid a/c use at a time (when I trust the alternator to bring the battery back up timely).

The FitRV couple has published extensive analyses of lithium systems (the husband is also an aerospace engineer, like my husband). In their rig, where the entire electrical system is sized larger than ours, IIRC they get about 3.75 hours of a/c use per battery charge. In other words, even the internet influencers can't do much better than our DIY job.

That is precisely why I reverse-snowbird. I meet the laws of physics part way. We designed a system that covers us off-grid in certain limited scenarios. But for the most part, we just travel out of the heat.
 

eslmooney

New member
**OP beware.**

**Eslmooney beware.**

Even WITH the Sterling B2B, the extra wear on the alternator will make this configuration a very risky proposition.

How do I know? Because I have that exact Sterling and that exact Electrodacus in a T1N, and my Bosch 200 A alternator lasted a total of 16 months of very occasional use before its clutch pulley wore out. My alternator's effective lifespan ended up being measurable in mere HOURS.

What the alternator was DESIGNED to do and what we are ASKING it to do are two different things in this scenario, even if the numbers on paper seem to make sense. Numbers on paper are not equal to conditions of wear in real life.

At this point, I am 100% convinced that the only SAFE non-solar way to charge lithiums in a T1N is by using a second alternator. A second alternator is a very expensive proposition because of the mounting bracket availability issue. For the moment, I will omit those details and that research.

Rather than belabor the alternator failure details in this post, I'd encourage you to read this account of that failure below (non-monetized blog post).

Understand that if your alternator fails the way mine did, it could easily put your rig in danger, and your life in danger, because when its degradation causes the chassis battery voltage to fall too low and the computer to shut down, your T1N is just going to stop dead in the middle of the freeway, wherever you happen to be at that moment (possibly with a 70 mph big rig bearing down on you). That is what will happen if you don't catch that kind of failure in time to save yourself from an uncontrollable shut-down.

https://interstateblog.blogspot.com/2018/09/psa-alternator-clutch-pulley-failures.html
Pull a Prius toad as your genset maybe. . .


Tiltable Solar Trailer
 

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eslmooney

New member
I clearly DO live in Texas, and have lived here continually since 1991. As john61ct notes, it simply can't be done. Not without the kind of money that makes it a non-starter for those of us who are not independently wealthy.

Let me put it in more concrete terms: husband and I have spent around $10K on our solar, electrical, lithium, and supporting components and materials (we did our own labor). That investment gets us about 2.5 hours of off-grid a/c use at a time (when I trust the alternator to bring the battery back up timely).

The FitRV couple has published extensive analyses of lithium systems (the husband is also an aerospace engineer, like my husband). In their rig, where the entire electrical system is sized larger than ours, IIRC they get about 3.75 hours of a/c use per battery charge. In other words, even the internet influencers can't do much better than our DIY job.

That is precisely why I reverse-snowbird. I meet the laws of physics part way. We designed a system that covers us off-grid in certain limited scenarios. But for the most part, we just travel out of the heat.
If other people are able too, there must be away . On another old blog https://wheelingit.us/2016/03/06/th...upgrade-part-iii-installation/#comment-772235 cant ask how he makind out, this is what got thinking it can be done.
John Haywood says

March 7, 2016 at 12:56 pm

Great writeup! I am a full timer in a 2007 sprinter based Winnebago View. I have converted to total electric, even removing all of the propane system and appliances and the generator. I have 400w of Sinology lithium, bms system, Magnum 2000w sine wave inverter and 400w of AM Solar panels and all the safety, control and monitoring stuff. I am a geek of the first magnitude! i also installed a 280amp alternator (limited to 200a max) with an external controller (Balmar). I also have a dash mounted control switch to shut off the alternator or change it’s charge rate. I run my 12v refrigerator, expresso machine, microwave, toaster oven,induction cooktop, etc. Absolutely love the lithium system. Have done entire install myself, and the removal of propane and generator too. BTW, removing all that stuff and selling on Craig’s List went a long way to offset the high cost of the Lithium system! One more thing…I also use the lithium as my chassis battery system, completely disconnected the chassis battery. This vastly simplified the charging system, and provides more than enough power for everything. (I do still have the chassis battery as a backup, but have not had to use it in a year) Additionally, I have not plugged into shore power since I installed this system a year ago. (2 other notes, l live in southern California, so there is lots of sun, and I generally drive 400 miles a week or so. The charging while driving makes up for the 400 watts of solar. I regularly charge at 180 to 200 amps with the alternator)

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