Using a high output alternator to rapidly charge house battery bank

[unseenone]

Here is a link to a company that builds the custom alternators, including Ford ones specifically. They can also customize anything you want to your needs, including double, and triple alternators. http://www.nationsautoelectric.com/hpseriesalternators.html

Here are some Ford listings; http://www.nationsautoelectric.com/hpseriesalternators.html

I would suggest calling them before you order to ensure you get what you want, get your questions answered, etc.

 

[adam88]

I, too, have AGM batteries. The problem is not that your Ford cannot put out enough current; it certainly can. It is unlikely that your ECU will care, as long as you connect your camper batteries to the positive terminal of your starter battery. The problem is that unless your AGM's are discharged to 50%, they simply won't take that great a charge for that long. (All of this assumes that your cabling is adequate, say a minimum of 100mm2.) dwh has posted often and accurately on this subject.

With deeply discharged batteries you will see something like this:

First hour: 300A
Second hour: 150A
Third hour: 75A
Fourth hour: 35A

Actually, you will probably get a bit less. Real world numbers are probably closer to 100A per hour, max, with most of the charging in the first hour. This is way solar is so very valuable, it keeps charging after the engine is shut down. I have 500w, but 300 will still get you 15A or so.

N.B. Depending on insulation, temperatures, etc., you can expect your air conditioner to take about 25-50A per hour.

hey diplo. This is good stuff and makes total sense to me. What you have said about the charging rates, while it may sound detrimental to someone (the decreased charging as each hour goes by) is exactly what I want. I am only really looking for RAPID charging from about the 50% to 85% mark (the bulk charge phase I believe it is called). I know efficiency goes down from there. Essentially, what I would like is... if I am in my camper and my batteries hit 50%, I can remote start my truck with high-idle automatically set (with rpms auto adjusting as needed varying on load) and quickly charge my batteries in an hour back up to 80%. This would keep me going until I found shore power to top my batteries up to 100%. The solar, if I add it, will also help. A few questions/comments I have:

1) Another reason I think this will work well is I have a regular cab and this will be a camper, with the batteries mounted at the front. So we are talking 10 feet max of wire to run. I will use the highest quality gauge wire money can buy for this. Compare that with someone in a crew cab truck towing a 5th wheel and they might need 30 feet or more of wire. So the length of run will be very short. I will also have a new alternator putting out high steady volts in the mid 14's at all times.
2) Question (might be a dumb one), you mention 300a for the first hour, but... if my alternator is only 300a total, and the truck system requires some amps, then how would I get 300a? Or does it not work like that? Am I looking at amps in hours when I shouldn't be, e.g., does the truck alternator rated at 300a only put out 300 amps an hour, or are the batteries rated at 20 hours and the alternator is rated at some other output beyond that.
3) I know people say that batteries should be topped up to 100% every so often to ensure longevity. How often is it recommended batteries be topped up? If I cycled, theoretically, between 50% and 85% discharge for long periods of time, and only hit 100%, say, once every month, would that be bad?
4) Will a side effect of this setup be enhanced power for my winch? E.g., if I am using my winch, can I flick the switch on the blue sea acr to shift power from my house batteries to my truck batteries, causing basically unlimited winching power?
5) Any suggestions on a good monitoring solution to have hooked up to the house batteries to manage all of this, and to see the charging rate in real-time?

 

[adam88]

Here is a link to a company that builds the custom alternators, including Ford ones specifically. They can also customize anything you want to your needs, including double, and triple alternators. http://www.nationsautoelectric.com/hpseriesalternators.html

Here are some Ford listings; http://www.nationsautoelectric.com/hpseriesalternators.html

I would suggest calling them before you order to ensure you get what you want, get your questions answered, etc.

That's great, thanks a lot. The factory alternators on these trucks are pure garbage. Unbelievable Ford put these on. My stock alternator is 110a. It is the same stock alternator that comes on a Ford Fusion (same part #). People have all kinds of problems with low currents because of these crap alternators.
.
I am also looking at single high output alternators made by "DC Power Inc" (www.dcpowerinc.com) they come highly recommended. They have up to 320w single alternator, but I will probably go with their 270w or 300w which seem to be more practical. These are $$$ alternators, around $600 or more but I have heard nothing but good things!

 

[dwh]

2) Question (might be a dumb one), you mention 300a for the first hour, but... if my alternator is only 300a total, and the truck system requires some amps, then how would I get 300a? Or does it not work like that?

It works exactly like that. The alternator is "current limited" (hell, all chargers and power supplies are current limited) to 300a. That's all you get. So if your boom box sound system is drawing 100a, there won't be more than 200a available for charging.

Am I looking at amps in hours when I shouldn't be, e.g., does the truck alternator rated at 300a only put out 300 amps an hour, or are the batteries rated at 20 hours and the alternator is rated at some other output beyond that.

Apples and oranges.

The battery's "20 hour rate" means how many amp*hours you will get if you put a steady load on it that will drain it in 20 hours. Say a 100 amp*hour battery. Put a 5a load on it, and it's dead in 20 hours and you'll have drawn out 100ah. There are different "X hour" rates. Batteries used for power backup, might be rated at the 5 hour rate, or the 10 hour rate (actually, they are mostly rated at the 6 hour rate).

The reason is the Peukert effect. Say a battery is rated 100ah at the 20 hour rate. 5a load draws it down in 20 hours, total drawn out 100ah. But that same battery with a 10a load on it will NOT last 10 hours. It will fully drained in say 8 hours. So that same battery would be rated "100ah @ 20hr rate" OR "80ah @ 10hr rate". Then again, if you cut the load in half to 2.5a, that same battery will last MORE than 40 hours. So that same battery might ALSO have a rating of "120ah @ 40hr rate".

The 20 hour rate is commonly used in automotive, marine, RV and solar applications.


The alternator's "300a" rating is the max it can put out. If it is actually run at that rate, it will deliver 300a in one hour, or 300ah. The gotcha is that when it's hot, it'll put out less. So a 100a rating usually actually means something like, "100a @ up to 200 degrees F, 80a above 200 degrees F".

All bets are off with custom alternators. You'll have to ask them about their unit's ratings at different temps.

3) I know people say that batteries should be topped up to 100% every so often to ensure longevity. How often is it recommended batteries be topped up? If I cycled, theoretically, between 50% and 85% discharge for long periods of time, and only hit 100%, say, once every month, would that be bad?

EVERY MINUTE that a lead-acid battery spends with its electrolyte less than fully saturated, sulfation of the plates will be occurring. The further below fully saturated it is, the faster that happens. For longevity (like a big expensive battery bank on a solar powered off-grid house) it is recommended that the battery reach full charge EVERY DAY.

When designing solar system for off-grid buildings, you figure out your loads and that gives you your daily energy budget. Double that to determine the required battery bank size (to stay above 50% drain on the batteries). Then you figure out how much solar you need to get that battery bank back to 100% every day.

On a truck - it's often not possible or practical. In that case, expect the batteries to have a shorter life-span.

4) Will a side effect of this setup be enhanced power for my winch? E.g., if I am using my winch, can I flick the switch on the blue sea acr to shift power from my house batteries to my truck batteries, causing basically unlimited winching power?

Unlimited? No. Longer run-time until you have to shut down and let the alternator recharge the batteries? Yes.

Unless...the alternator can supply all the winch needs - then the batteries won't be drained at all to run the winch and you would have unlimited as long as the engine is running.

But electric winches have a "duty cycle" rating anyway, and you have to allow them to regularly have a "cool down period". As long as you do that, the alternator will be "bulking up" the batteries during the winch's cool down.

And yes, you can force tie the batteries during winching with the large Blue Sea ACR, which is one of the nice things about that unit.

5) Any suggestions on a good monitoring solution to have hooked up to the house batteries to manage all of this, and to see the charging rate in real-time?

Bogart Tri-Metric or Xantrex LinkPro would be the most commonly used. Both have amp counters and will require a shunt. SmartGauge is also good, but is not an amp counter (it's algorithmic) and doesn't require a shunt.

 

[adam88]

EVERY MINUTE that a lead-acid battery spends with its electrolyte less than fully saturated, sulfation of the plates will be occurring. The further below fully saturated it is, the faster that happens. For longevity (like a big expensive battery bank on a solar powered off-grid house) it is recommended that the battery reach full charge EVERY DAY.



When designing solar system for off-grid buildings, you figure out your loads and that gives you your daily energy budget. Double that to determine the required battery bank size (to stay above 50% drain on the batteries). Then you figure out how much solar you need to get that battery bank back to 100% every day.



On a truck - it's often not possible or practical. In that case, expect the batteries to have a shorter life-span.

Hi dwh. Thanks for the answers. You mention lead-acid specifically. What about the lifeline AGM batteries I am using? Obviously even AGM batteries will have a shorter life span if they are abused (e.g., not fully charged or overly discharged), but do the AGM's handle it better than lead acid?

Let's assume that I cycle DAILY between 50% and 85%. That is, in the morning I wake up and the batteries are 85%. Then they get discharged to 50% by the end of the night, and so on. Once a month they get fully charged for a few days to 100%. In this scenario, are we talking major decreased lifespan, or just maybe 5-10%?

 

[dwh]

AGMs are lead-acid batteries. So are GELs.

AGMs are a.k.a., "starved electrolyte" - but they are still use lead, acid and water to store power. They just happen to have fiberglass fabric sandwiched between the plates which absorbs the electrolyte (Absorbed Glass Mat), and which also leaves less room inside for electrolyte, hence "starved".

So yes, the lead and sulfur will react with each other to create lead-sulfate - just as iron and oxygen will react with each other and create iron-oxide.


In that scenario, I'd take a WAG (wild-assed guess) that you're looking at a 1/4 -1/3 lifespan reduction. But I could be way off and it could be 1/2.

 

[DiploStrat]

Some Real World Numbers

Ndeke Luka has a 600Ah bank, made up of four 6v, 300w Lifeline AGM batteries.

The 2013 Chevrolet pickup has two 125A Bosch alternators and two Delco Lead/Calcium starter batteries.

The starter batteries are coupled to the camper batteries (about 20 feet, one way) with a pair of 1/0 AWG cables.

I use a Magnum SBC to control a 200A Blue Sea. (Doing it again, I would simply use a Blue Sea ACR)

There are 5x100w panels on the roof, running through a Blue Sky MPPT controller.

Background loads are a 4.5 cu ft Nova Cool refrigerator, a Webasto Dual Top, and a Nature's Head composting toilet.

The big loads are an induction cooktop, a Sharp 6k BTU A/C, and a Sharp convection/grill/microwave.

Our normal overnight power consumption averages 100Ah, up to 150Ah if we cook a full breakfast. We have the heat on at night, make cappuccino, charger computers, etc. In two years, the only thing I have not really tested is the air conditioner, but it can draw up to 60A per hour.

We typically drive two hours before noon and typically reach full charge (recovering up to 150A) between noon and one PM.

At engine start, with the batteries down over 100 Ah, I will see engine charge rates well over 100A. If the batteries are down and the sun is out, I can approach 30A from the solar panels.

The simple fact is with a 600Ah battery bank, typical use rarely draws the batteries lower than 85%, so most of the charging is in the absorb, vice bulk, stage.

Of course, your mileage will differ, but I hope this helps.

Remember, you want to get those AGMs recharged everyday. You can violate the 50% rule, but only if you will immediately recharge them. Discharging and then leaving the batteries discharged is the kiss of death. As my contact at Lifeline stressed to me, most people kill their batteries because they don't charge them LONG enough. Small variations in voltage, wiring size, etc., are much less important than a long, long charge. Hence my constant suggestion of solar.

For example. This morning we were 115 Ah down. We had chores to do, so we were late starting. No matter, we were charging at over 12A from the solar. We then drove an hour before stopping to shop. At this point we had recovered all by about 15Ah. A hour's shopping and we were at 100%

News you can use:

-- Uber high charge rates often don't happen. A good 150A alternator is probably all you need. Big cables help.

-- Slap on all the solar you can afford.

-- Don't neglect your shore power charger. I am very happy with our Magnum inverter/charger. It can produce about 125A and allows you to tweak to your heart's content.

-- If all else fails, charge longer and lower.

None of this is hard, just a little complex. Come to Overland Expo next weekend and you can attend my session and examine Ndeke Luka for yourself.

 

[4x4junkie]

Let's assume that I cycle DAILY between 50% and 85%. That is, in the morning I wake up and the batteries are 85%. Then they get discharged to 50% by the end of the night, and so on. Once a month they get fully charged for a few days to 100%. In this scenario, are we talking major decreased lifespan, or just maybe 5-10%?

I think that as long as you can hit 100% charge on your batteries at least every couple weeks, they should last a good long while (I do have batteries over 10 years old that often don't get a 100% charge for a month or more that are still working fine).

Battery sulfation is lead sulfate hardening (crystallizing) over time (months, generally). If a battery is repeatedly cycled between say, 50-95%, that last 5% of lead-sulfate never gets dissolved and will eventually harden (crystallize) on the plates until it becomes unavailable to the normal charge-discharge cycle. Continued cycling between 50-95% leads to another 5% hardening over time, and so on (it's a cumulative process) until one day you notice the battery doesn't have near the power it once did.

Bringing the battery to 100% charge dissolves that last bit of lead-sulfate and starts over the time it takes for it to crystallize.

 

[dwh]

Lead-sulfate buildup is one problem. Another is grid corrosion and lead shedding. Another is grid expansion.

There are a few failure modes:

https://www.google.com/search?q=lea......1ac.1.34.heirloom-serp..27.0.0.5ypupKGcI90

 

[adam88]

Ndeke Luka has a 600Ah bank, made up of four 6v, 300w Lifeline AGM batteries.

The 2013 Chevrolet pickup has two 125A Bosch alternators and two Delco Lead/Calcium starter batteries.

The starter batteries are coupled to the camper batteries (about 20 feet, one way) with a pair of 1/0 AWG cables.

I use a Magnum SBC to control a 200A Blue Sea. (Doing it again, I would simply use a Blue Sea ACR)

There are 5x100w panels on the roof, running through a Blue Sky MPPT controller.

Background loads are a 4.5 cu ft Nova Cool refrigerator, a Webasto Dual Top, and a Nature's Head composting toilet.

The big loads are an induction cooktop, a Sharp 6k BTU A/C, and a Sharp convection/grill/microwave.

Our normal overnight power consumption averages 100Ah, up to 150Ah if we cook a full breakfast. We have the heat on at night, make cappuccino, charger computers, etc. In two years, the only thing I have not really tested is the air conditioner, but it can draw up to 60A per hour.

We typically drive two hours before noon and typically reach full charge (recovering up to 150A) between noon and one PM.

At engine start, with the batteries down over 100 Ah, I will see engine charge rates well over 100A. If the batteries are down and the sun is out, I can approach 30A from the solar panels.

The simple fact is with a 600Ah battery bank, typical use rarely draws the batteries lower than 85%, so most of the charging is in the absorb, vice bulk, stage.

Of course, your mileage will differ, but I hope this helps.

Remember, you want to get those AGMs recharged everyday. You can violate the 50% rule, but only if you will immediately recharge them. Discharging and then leaving the batteries discharged is the kiss of death. As my contact at Lifeline stressed to me, most people kill their batteries because they don't charge them LONG enough. Small variations in voltage, wiring size, etc., are much less important than a long, long charge. Hence my constant suggestion of solar.

For example. This morning we were 115 Ah down. We had chores to do, so we were late starting. No matter, we were charging at over 12A from the solar. We then drove an hour before stopping to shop. At this point we had recovered all by about 15Ah. A hour's shopping and we were at 100%

News you can use:

-- Uber high charge rates often don't happen. A good 150A alternator is probably all you need. Big cables help.

-- Slap on all the solar you can afford.

-- Don't neglect your shore power charger. I am very happy with our Magnum inverter/charger. It can produce about 125A and allows you to tweak to your heart's content.

-- If all else fails, charge longer and lower.

None of this is hard, just a little complex. Come to Overland Expo next weekend and you can attend my session and examine Ndeke Luka for yourself.

That's some really great info. I really appreciate you writing all that up. It's actually not all that complex - the way you explain it is simple. In a few days I feel like I've gone from about 0/10 knowledge to maybe a solid 5/10. Still much more to learn, but I totally grasp the concepts.

My loads will very similiar to yours, minus the induction cooktop, but adding A/C. I will probably end up buying/trying one of those 12v A/C's (see other thread I made). The goal is to run the A/C all night long if we have hot nighrs, solely on batteries. Assuming a steady draw of 36 amps, that means overnight it would draw close to 300 amps over 8 hours. The unit may or may not cycle on and off though, so it would likely be less in real world scenarios. But it would definitely be 300 amps if you factor in the load from our fridge and other items. So in the morning, from A/C load and other loads, the 1020 amp battery bank would be down to about 70%.

The problem with solar is that, it just isn't enough. We only have room for 300 watts of solar based on the design of our roof. We might get 100 amps a day from that if we're lucky on nice days, but on cloudy days or winter months we'd be lucky to get 1/3 of that probably. I live in Canada and the camper is going to be used up north half of the year, and so the panels basically become useless. Part of me wants to say "Oh well, throw them on anyways, they are cheap", but it's actually not that cheap. It adds up, and it's also more weight on the roof, more holes, etc. If I could add 500w like you have, or even 1000w (if I had the roof space of a huge RV) then it would make sense. But I can't.

I am not ruling solar out yet, but it probably won't happen right away. I figure I can always add it later. I might just have to accept that my batteries will go a bit quicker. I agree with you though, solar is a logical solution. Solar + ACR is a great combo. It's too bad I don't have the room to go big on solar.

 

[adam88]

I think that as long as you can hit 100% charge on your batteries at least every couple weeks, they should last a good long while (I do have batteries over 10 years old that often don't get a 100% charge for a month or more that are still working fine).

Battery sulfation is lead sulfate hardening (crystallizing) over time (months, generally). If a battery is repeatedly cycled between say, 50-95%, that last 5% of lead-sulfate never gets dissolved and will eventually harden (crystallize) on the plates until it becomes unavailable to the normal charge-discharge cycle. Continued cycling between 50-95% leads to another 5% hardening over time, and so on (it's a cumulative process) until one day you notice the battery doesn't have near the power it once did.

Bringing the battery to 100% charge dissolves that last bit of lead-sulfate and starts over the time it takes for it to crystallize.

Thanks for the good info, I didn't know how it worked. Makes sense. I also think a full charge every 2 weeks would be fine, but I guess only time will tell. Common sense tells me not to be overly anal about this. I've seen some of the stuff people put their AGM batteries through. Worst case scenario my batteries go after 3 or 4 years and then for the next set I will have to add some solar. But I highly doubt that is going to happen.

 

[adam88]

AGMs are lead-acid batteries. So are GELs.

AGMs are a.k.a., "starved electrolyte" - but they are still use lead, acid and water to store power. They just happen to have fiberglass fabric sandwiched between the plates which absorbs the electrolyte (Absorbed Glass Mat), and which also leaves less room inside for electrolyte, hence "starved".

So yes, the lead and sulfur will react with each other to create lead-sulfate - just as iron and oxygen will react with each other and create iron-oxide.


In that scenario, I'd take a WAG (wild-assed guess) that you're looking at a 1/4 -1/3 lifespan reduction. But I could be way off and it could be 1/2.

Ah. Now I know... :Wow1: A 1/4 reduced lifespan would be fine. Assuming these batteries last for around 8 years for instance, I could live with 6 years. But I know it's just a WAG. We shall see. It will be an interesting thing to track either way. Honestly, I am more concerned about the alternator than the batteries at this point. This will be a lot of work for an alternator to keep up with, I may be replacing it every couple of years at that rate.

 

[AndrewP]

Following but late to the party...

Just to state the obvious here, Adam, if you forget the A/C all of your problems go away. It's a huge energy waster. No huge alternator, no giant but undercharged battery bank, small solar, and you're in a much better place. Get some 12v fans(or not even) which use much less power and you won't suffer that much. Honestly, if you're that tied to an A/C unit you should probably just stay in a campground with hook ups.

I think you are focusing way too much on small things, and neglecting the big thing which is getting out there and enjoying yourself.

In fact, that's an expo trait. Focusing on the vehicle and neglecting to go on a trip. Seriously, take what you have now and just go.

 

[adam88]

Following but late to the party...

Just to state the obvious here, Adam, if you forget the A/C all of your problems go away. It's a huge energy waster. No huge alternator, no giant but undercharged battery bank, small solar, and you're in a much better place. Get some 12v fans(or not even) which use much less power and you won't suffer that much. Honestly, if you're that tied to an A/C unit you should probably just stay in a campground with hook ups.

I think you are focusing way too much on small things, and neglecting the big thing which is getting out there and enjoying yourself.

In fact, that's an expo trait. Focusing on the vehicle and neglecting to go on a trip. Seriously, take what you have now and just go.

hey Andrew,

Thanks for the comments. I do consider all angles for sure, and always appreciate criticism. Sometimes we do get far gone and off on tangents.

I hear what you're saying. I've given that same advice to others before. We do get out, we've been camping a few times this year already. You're right, it is an expo trait, and it's sort of enjoyable. Deep down some of us are just big nerds. We enjoy planning things almost more than the actual finish line. Ever hear the phrase "The hunt is sweeter than the kill"? Sitting around on the internet planning electrical systems and working out every little detail is fun for some. In the end of course you can't plan everything, and things will change. Heck, I was just reading DiploStrat's website (nice site by the way) and I saw on there he was planning his RV for over 4 years.

I've definitely considered what the AC is costing me. Without it I might be able to avoid a big alternator ($400), two extra batteries ($1300), all the wiring and ACR ($500~), and the AC unit of course ($2000). Plus all the weight. So that's a cost of maybe $4000 to $4500 for AC, plus the added weight. But... that being said, for us, AC is a necessity. It may not be for others, but it's something we want. Truthfully, I think others want it too, but it's been so unattainable that most people just give up because it does take a lot of work. But look at new vehicles... how many people buy a new vehicle without AC? Would you buy a new vehicle without AC? Probably not. Would we be fine without one? Probably... but we might be uncomfortable. I've read lots of blogs, several lately actually, where the authors complain about the heat and humidity in places like Colombia where we plan to visit. It is unbearable to many. In fact, we've seen several bloggers leave those areas and drive into the mountains to get away from the heat. One I was just reading today was Drivenachodrive (great blog), their trip to Burma, the humidity was beating them down big time. Here's a quote from their blog:

That night while we slept in Nacho I drifted in and out of sleep. Suddenly my eyes snapped open and I gasped for air. It felt as though I were being waterboarded in some secret CIA prison camp. I rolled over and pressed my face against the window screen, gasping for a breath of fresh air. It never came, and I dizzily rolled onto my back, breathing belabored, hot breaths of thick water vapor. The mattress and my pillow were soaked with sweat. I laid on my back for what seemed like an eternity, our small oscillating fan pushing the watery air over our bodies. I hoped I would adapt quickly to the heat and humidity.

Of course the keyword at the end there is adapt quickly. One will argue that by using AC at night, you are never going to adapt to the heat, but of course that isn't true. We would only use AC at nights and brave the heat during the day much like many people do in warmer cities. Speaking of which, the last thing to point out is we are Canadian. We are used to cooler temperatures. For me, 70 degrees is HOT outside. That's wear shorts weather, sweat, and run the AC in the car weather. Seriously. At 80 degrees, the news networks up here talk about "heat waves" and records being broken. At 90 degrees the cities start to issue heat warnings. Meanwhile, that's every day in places down south.

And no we won't be staying plugged into a campground

 

[DiploStrat]

Some Comments

We are on the road, so this will be sporadic.

-- Thank you for the kind words on our site, but we started geeking out on this not 4, but 40 years ago, sweating in Cameroon and freezing on the Altiplano. Ndeke Luka represents all we have learned and we are very happy.

-- Remember that while we use the analogies of water and air to describe the charge/discharge processes, it is actually a chemical process and obeys its own, perverse rules.

-- You get a battery bank that is big enough that 300Ah is only 70% and you will find a perverse effect that your batteries may not be discharged enough to achieve that high a charge rate. Most of the bulk charge takes place in the first hour. (One reason why it is best to use a genset for the first part of your charge.) And, going the other direction, your French lesson of the day: "Peukert est un salaud!"

-- Because of the perverse nature of a battery's internal resistance and the benefits of time, 30A of solar is actually huge. And the sun is just as bright in Canada. And simply off scale in Bolivia.

-- Speaking of gensets, it might be tha you would be better off with a smaller battery bank and doing some serious sound insulation on a small Onan. Some Tiger owners have done this with good results. Implicitly, if you are worried about A/C where there is no power, then your noise limits are probably more reasonable. Just a thought.