Any experience charging a lithium battery off a truck alternator

[rrliljedahl]

Does anybody have any experience, recommendations or precautions about charging 12 volt lithium batteries off of a truck alternator?

Dry camping and want to be able to use 12volt /120 volt refrigerator (Danfoss 4.4 amp compressor) and microwave/convection oven (15 amp) liberally.

Current set up is
Duramax LBZ diesel powering a single 250 amp 12 volt alternator (manufacturer estimates it will out out 120 amps at idle).
4 gauge wire from alternator with 250 amp fuse to truck batteries
2 AGM starter batteries in truck
Solenoid between truck batteries and camper activated only when truck is running
2/0 wire pulled to camper
250 amp Anderson plugs with voltage measurement of 14.6 at camper
330 watts of solar on the roof (estimating generation of 100 amp/hours on a sunny day) with programmable MTTP controller.
Present plan 200 - 300 amp 12 volt lithium camper batteries (still estimating daily electrical needs) and a Magnum Energy MS 2000 invertor.
No generator in set up.
Thought was to idle the truck to help recharge the batteries if the solar is not keeping up.

No debate that the lithium batteries are costly.

Specs show lithiums are significantly lighter and can be discharged by 80-90% routinely.

I just read that lithiums can be charged much faster than lead acid or AGMs as lithiums do not need a slower "float"but voltage should be no more than 14. Does anyone know if that is true? If so, how do I insure that I would not destroy a lithium battery with there being 14.6 volts at my camper?

Thanks.

Ron

 

[AndrewP]

You have an endless amount of power here, so I'm sure something will work.

Did you read up on the Lithiums? I'll bet most of us here, and especially me, familiar with Lead-Acid batteries know next to nothing about large lithium batteries. They are likely to require a different charging voltage/plan than lead acid, so I would ask the manufacturer of the batteries if 14.6 is OK. They are too expensive to take any chances.

Your power hog here is going to be the microwave. Is that 15 amps at 12 volts (which sounds too low)or 15 amps at 120 volts? Big difference in power use. You need to estimate your daily amp-hour or watt-hour use before you can decide what and how many batteries you need, and whether your power input to those batteries is sufficient for your needs. "liberal" use of a microwave/convection will be a challenge for any mobile electrical system.

 

[DiploStrat]

Ron,

I have a similar system in AGM and it works very well. (You can read more at my site.) I am very interested in lithium batteries, but have be put off a bit by some of the experiences of these folk: http://www.technomadia.com/2015/02/living-the-lithium-lifestyle-3-5-year-lithium-rv-battery-update/

Normally, I suggest an intelligent relay for use with a modern engine like yours, but for lithium it might be worth looking at this new B2B which would offer you a range of programs, including voltage reduction: http://www.sterling-power-usa.com/BBW12120-120amp-sterling-power-probattc-batterytobatterycharger12vto12v.aspx

FWIW - Your alternator is most useful at the START of the charge cycle, when the AGM batteries will take a lot of current (bulk charge), rather than at the end when the solar panels tend to produce more current than the batteries will take.

N.B. Your GM truck will routinely charge at 15.5v when the temperatures drop below freezing. Factor this in your planning.

AM Solar are starting to sell lithium batteries installed at their shop. I tend to trust them: http://www.amsolar.com/home/amr/smartlist_131/lithium_batteries.html

 

[rrliljedahl]

My mistake. 10 amps at 120 volts but is 115 amps at 12 volts when being ant they an inverter for the microwave convection oven.

Nuking hot water or left overs would not take that long. It would be trying to make brownies in the convection oven that is the challenge. I was hoping that I could just start up the truck to solve that problem.

So far lithium manufacturers have had no experience using a high amp truck alternator for charging purposes. They just say they do not know if it would work.

 

[rrliljedahl]

Ron,

I have a similar system in AGM and it works very well. (You can read more at my site.) I am very interested in lithium batteries, but have be put off a bit by some of the experiences of these folk: http://www.technomadia.com/2015/02/living-the-lithium-lifestyle-3-5-year-lithium-rv-battery-update/

Normally, I suggest an intelligent relay for use with a modern engine like yours, but for lithium it might be worth looking at this new B2B which would offer you a range of programs, including voltage reduction: http://www.sterling-power-usa.com/BBW12120-120amp-sterling-power-probattc-batterytobatterycharger12vto12v.aspx

FWIW - Your alternator is most useful at the START of the charge cycle, when the AGM batteries will take a lot of current (bulk charge), rather than at the end when the solar panels tend to produce more current than the batteries will take.

AM Solar are starting to sell lithium batteries installed at their shop. I tend to trust them: http://www.amsolar.com/home/amr/smartlist_131/lithium_batteries.html

Am solar presently is not shipping lithium and ask that you physically bring the truck to them for the installation. They did not know if it would work to power the convection oven when idling the truck. Theoretically, they thought it should. No practical experience yet.

 

[DiploStrat]

My convection microwave takes about 175A DC when running. Normally, my battery bank handles this easily, although the voltage does drop to as low as 11v, so you have to reset the low voltage cut out on the Magnum.

If the batteries are down, I idle the truck and it provides about 100A; that is, the meter shows the negative flow to be only about 50A.

I am heading out towards Bend this summer and will stop in a discuss things with Greg, but as appealing as much as I would love to lose 200 lb., I suspect that I will stay with the AGM's for a while. The system works and they are paid for! The big issue, as I see it, is voltage, not amperage. Your solar charger can be adjusted. A Sterling B2B isn't cheap or small, but it might do the trick.

Best wishes!

 

[rrliljedahl]

My amps needed for the convection oven are theoretical. Camper construction is to start later this month.

1200 watts/120 volts = 10 amps

10 amps at 120 volts = 100 amps at 12 volts

85 % efficiency of inverter
100 amps x 1.15 = 115 amps

Did I do my math right?

 

[DiploStrat]

Sounds about right by my calculator. My number comes from using my Sharp microwave and casting an eye at the amp meter. 100A, 150A, 200A, a 2000w inverter, especially a big iron Magnum, will be fine.

As I say, you might enjoy my site as I built at right about the same levels you are planning.

-- I would add more solar, especially as you are east of the Mississippi.

-- I use 100m2 of wire to the camper batteries, 2x1/0AWG. (Technically, I still have too much voltage drop at 200A, but it is close enough.) http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=0.3224&voltage=14&phase=dc&noofconductor=2&distance=20&distanceunit=feet&amperes=200&x=32&y=9

Going to be fun!

 

[Maninga]

Might be worth having a chat with LeishaShannon

http://www.expeditionportal.com/forum/threads/83962-NPS-Camper-Build

He's gone full Lithium (even took out his starting batteries), can take power from alternator, solar and shore power.

I'll be looking at it more in around 6 months time, the Sterling units sound good for what I'm after.

 

[Kiomon]

I am full lithium in both my rigs. 400ah in the syncro and 600ah in the Unimog.

First up, your bulk charging from the alternator isn't going to be a problem. You have a couple ways you can approach it. You can go the robust way which is a proper multi stage charging from the alternator. Where the alternator output is regulated for all the stages of charging. The sterling battery to battery chargers can accomplish this. We have one of those. BUT you can go a simpler and easier route and use a smart relay, I like the Blue Sea Systems ACR. It senses when the starting battery has a charging current and then combines the battery. Get the model where you can also manually connect and disconnect the batteries. This will make life easier and also allow you to crank from your house bank or charge a dead starting battery from your lithium house battery. It works very well and is a great feature to have. The relay route isn't going to get you to a 100 percent charge, but many alternators are set around 14v or so charging voltage, that's going to get you to about 80/90% on the batteries, and then solar can polish you off when you have it. In practice this works great. Lithium batteries are pretty forgiving in their charging in some ways, they don't need to be charged back to 100 percent, no equalization, and no float needed. Most manufacturers say 14.2-14.4 volts until the batteries are full. No multistage needed. A lot of the more recent experience is saying to even charge a bit lower, around 14v, and you have better long term life from the cells. The jury is still out and it's still early days, but I error on the side of gentler vs more aggressive.

My biggest concern in your set-up is voltage drop and heat generation if you actually push these higher amps. 4 GA is not very big if you are going to push 100+ amps over a longer distance. I am not sure the size of your rig and the placement of the battery banks, but do check out a voltage drop calculator and see what voltage you will actually get at the end of your wiring runs, and upgrade your wiring accordingly.

In my signature is a link to the build details for the syncro, it covers a lot of this in the electrical section. Let me know if you have any questions, there are more and more of us out there with lithium set ups, the benefits are significant!

 

[BigSwede]

I just recently emailed Starkpower about their LiFeP04 batteries and they said they would charge just fine off of an alternator.

http://starkpower.com/

 

[rrliljedahl]

I am full lithium in both my rigs. 400ah in the syncro and 600ah in the Unimog.

First up, your bulk charging from the alternator isn't going to be a problem. You have a couple ways you can approach it. You can go the robust way which is a proper multi stage charging from the alternator. Where the alternator output is regulated for all the stages of charging. The sterling battery to battery chargers can accomplish this. We have one of those. BUT you can go a simpler and easier route and use a smart relay, I like the Blue Sea Systems ACR. It senses when the starting battery has a charging current and then combines the battery. Get the model where you can also manually connect and disconnect the batteries. This will make life easier and also allow you to crank from your house bank or charge a dead starting battery from your lithium house battery. It works very well and is a great feature to have. The relay route isn't going to get you to a 100 percent charge, but many alternators are set around 14v or so charging voltage, that's going to get you to about 80/90% on the batteries, and then solar can polish you off when you have it. In practice this works great. Lithium batteries are pretty forgiving in their charging in some ways, they don't need to be charged back to 100 percent, no equalization, and no float needed. Most manufacturers say 14.2-14.4 volts until the batteries are full. No multistage needed. A lot of the more recent experience is saying to even charge a bit lower, around 14v, and you have better long term life from the cells. The jury is still out and it's still early days, but I error on the side of gentler vs more aggressive.

My biggest concern in your set-up is voltage drop and heat generation if you actually push these higher amps. 4 GA is not very big if you are going to push 100+ amps over a longer distance. I am not sure the size of your rig and the placement of the battery banks, but do check out a voltage drop calculator and see what voltage you will actually get at the end of your wiring runs, and upgrade your wiring accordingly.

In my signature is a link to the build details for the syncro, it covers a lot of this in the electrical section. Let me know if you have any questions, there are more and more of us out there with lithium set ups, the benefits are significant!

Kiomon
The 4 gauge wire is a just short run between the alternator and a 250 amp fuse placed before the truck batteries

Between my truck batteries and my 250 amp Anderson camper plug is a run of about 7 feet of 2/0 wire

Voltage while idling at the level of the camper 250 amp Andersen plug measured 14.6 volts

Does that sound sufficient?

Will I damage my lithium battery with voltage of 14.6?

Ron

 

[dwh]

I just recently emailed Starkpower about their LiFeP04 batteries and they said they would charge just fine off of an alternator.

http://starkpower.com/

That's because they are designed to be drop-in replacements for automotive type batteries. Like other drop-in replacements, they have built-in charge control circuitry.

'StarkPower “ULTRAENERGY” Models have a Battery Management System (BMS). BMS monitors the key operational parameters during charging and discharging such as voltages, currents and internal temperatures.

There are three main objectives common to all Battery Management Systems (BMS) are:

Protect the cells or the battery from damage from overcharging or discharging too low.
Prolong the life of the battery with cell balancing.
Maintain the battery in a safe operating state.'

http://www.starkpower.com/spnews/energystoragebatt/



The last table on that page, listing the "advantages" is largely full of crap. For instance, lead-acid self-discharges at 30%/month? BS. Usable capacity 50%, but life cycles 300? More BS. Average life cycles of a lead-acid deep cycle drained to 50% is 1000 cycles, not "150-300 Cycles". From what I've been reading (thanks to links provided by DiploStrat), that operating temperature range is also almost certainly more BS. 0.2C Fast Charging Performance for lead-acid? A few sure, but certainly not most AGMs. Optima, Odyssey, Lifeline pretty much have NO limit as long as they aren't overheated. Odyssey specs say C*4.

 

[Kiomon]

Kiomon
The 4 gauge wire is a just short run between the alternator and a 250 amp fuse placed before the truck batteries

Between my truck batteries and my 250 amp Anderson camper plug is a run of about 7 feet of 2/0 wire

Voltage while idling at the level of the camper 250 amp Andersen plug measured 14.6 volts

Does that sound sufficient?

Will I damage my lithium battery with voltage of 14.6?

Ron

14.6 volts is high. ALL lithium battery installs will need a battery management system for safety. technically you could run one without it, but you risk your entire investment. Basically it protects from under voltage, as if you ever run the battery 100% dead, you won't be able to recover it like you can a lead acid battery. The high voltage limit is there because unlike lead batteries, lithium batteries will permanently change their chemical make-up if they are over charged, and be permanently damaged. In addition, the good BMS systems will also monitor individual cell temperatures, voltages, and other metrics to keep the pack balanced and healthy.

The problem with charging at 14.6 is that none of the BMS systems i know of have any way to regulate down the voltage, they will simply disconnect the battery from the alternator. From everything out there now, i would really limit your voltage to 14.2v or lower. The sterlings DO regulate voltage, and they go up to 60 AMPS. If your alternator is that high (14.6v) at idle, i would go for a sterling battery to battery charger, and have the sterling guys dial in your charging profile based on 14.1/2v for charging. The other option is what we did on the Mog, we put a second aternator in for the lithium pack with a custom voltage regulator dialed in for lithium. Works gorgeously, and no paranoia on damage, and its a welder too.

 

[DiploStrat]

Culture Clash!

With the caveat that I have no/no direct experience with Lithium batteries, there are some things to consider.

-- For years, automotive charging circuits limited their voltage to avoid overcharging open flooded lead acid batteries. (FLA) Call this the 13v era.)

-- New types of batteries began to appear with more calcium in the plates. Also AGM batteries, a form of FLA with sealed vents. All of these batteries wanted higher charging voltages for faster charge and other reasons. This gentleman is not, himself, an expert, he re counts the challenges in the Bosch/Mercedes Benz world. (http://www.landiss.com/battery.htm) Handy Bob and Charles Serling, Sr. are also strong avocets of higher charging voltages. This article on batteries, which specifically mentions the Lead Calcium batteries used by GM vehicles, is informative. (http://www.autoshop101.com/forms/hweb3.pdf)

-- The net result is that we are now, for GM vehicles at least, firmly in the 14-15+ volt era. With proper temperature compensation, etc., this is great, assuming that you use a open FLA or an AGM battery. (Kiss of death for gel, but then there are other reasons not to use gel batteries.) In my case, with a 2013 GM diesel truck, I know that, when the temperature is below freezing, my charging temperatures will exceed 15v. (Because my intelligent relay has a 15v cut out.)

Now enter Lithium cells. Lithium have a lot of advantages, better laid out here: http://www.amsolar.com/home/amr/smartlist_131/lithium_batteries.html The trick is that there is growing, anecdotal evidence that Lithiums are sensitive to charging voltage, that is, they want a voltage back in the 13-14v range and, perhaps, heat. It may also be that they should not be float charged. http://www.technomadia.com/2015/02/living-the-lithium-lifestyle-3-5-year-lithium-rv-battery-update/ The BIG problem with all things battery is that you can't really tell how things are going for a few years.

What to do?

-- Some solar controllers are completely adjustable, so you can set the voltages wherever you want.

-- The same is true of some shore power inverter/chargers, such as those made by Magnum Energy.

The trick is that your vehicle charging system is a bit of a closed system; you don't want to upset the relationship between your alternator, starter battery, and computer(s). With open FLA or AGM you can probably get good results with a relay system, intelligent or key controlled. With Lithium, it is more problematic.

-- Certainly a dual system, with a separate alternator/regulator set for Lithium is ideal.

-- The newest generation of Sterling B2B units, those that specifically have the ability to REDUCE voltage, would probably work very well, within the limits of such units; cost, size, total output, and inability to charge the starter battery. Assuming that they have raised the high voltage cut out to at least 15.5v, so that it will stay connected, this is the only product that I have seen that promises a plug and play integration of a high voltage charging system with Lithium cells.

For me, the Holy Grail will be a BMS that automagically makes a Lithium bank look like an FLA bank and I'm not sure that anyone has such a beast on the market.