Lithium-ion batteries as replacement for lead-acid

[PDBreske]

I started a thread on house battery capacity and it turned into a discussion on lithium-ion batteries. This thread will focus solely on li-ion batteries and their use as starting and/or house batteries for a skoolie.

Let me start by saying I hate lead-acid batteries. Just about everything about them pisses me off. They're heavy. They take up lots of space. They vent poisonous, corrosive, and sometimes explosive gases. They require periodic maintenance. They don't last very long relative to other chemistries. You can use only a fraction of their capacity before they need to be recharged. They must be charged slowly to prevent damage. Higher discharge rates lead to reduced capacity. Did I mention they're heavy?

A relatively new alternative to lead-acid is lithium-ion. These batteries are better than lead-acid in almost every way. They weigh less than half for the same amp-hour capacity, and that capacity is fully available for use without negative effect on the battery. They are truly zero-maintenance. They don't vent gases of any kind. They can be charged very quickly, up to a current equal to the battery's capacity (a 100AH battery can be charged at 100 amps). They are very efficient, with input-output efficiencies over 99 percent, meaning you get out almost everything you put in. Due to their typical construction, individual cells can be easily replaced by the manufacturer, leading to low repair cost and better warranties. Li-ion batteries can also be used as both house batteries and starting batteries. One manufacturer claims 2000 cold-cranking amps from a single 150AH li-ion battery.

Just about the only drawback is cost; they are very expensive. Depending on the level of included electronic control, a single li-ion battery can cost ten times what a comparably-rated lead-acid battery costs. Notice I said comparably-rated, not comparably-useful. Since a li-ion battery can be deep discharged down to 100 percent depth-of-discharge (DoD), a 100 amp-hour li-ion battery gives twice the useful capacity of a 100AH lead-acid battery that can be safely discharged only to about 50 percent DoD (if you want the battery to last more than a couple years, that is). Using this information, the cost suddenly drops to fives times that of lead-acid. Now we're making progress.

Li-ion batteries last much longer, with lifetimes between 2,000 and 5,000 cycles. Compare that to the typical lead-acid lifetime of 500-1,000 cycles. When you factor in the cost of replacing lead-acid batteries two to three times, the price of li-ion drops even more.

Something else about li-ion batteries: There are several different chemistry types available, but the two that you may have heard about are lithium-cobalt and lithium-iron-phosphate. Cobalt-based batteries are the ones that you find in cell phones and laptop computers. These batteries also have gained a bad reputation for causing fires on aircraft and there are now restrictions on how they may be packaged and shipped. Lithium-iron-phosphate batteries, due to their chemical composition, cannot catch fire due to a thermal runaway. They are safe. Lithium-iron-phosphate batteries are referred to as LiFEPO4 or LFP (Lithum FerroPhosphate).

Most of what I know about li-ion batteries is general information or what I've learned from the manufacturer of Smart Battery products, based in Tampa, FL. I don't want to say they are the best or cheapest li-ion batteries available (definitely not the cheapest), but they do have some features that I like. I'm hoping this thread will encourage other skoolie members to research and share what they learn here so we can all find out more about this technology.

Over the past week, I've exchanged emails with one of the company sales representatives. I had many questions that weren't answered on the website and I would like to share them here so we can all compare the Smart Batteries to other battery brands.

Where are the batteries manufactured?

Phil,

Thanks for your inquiry on Smart Battery,

To answer your question the actual building and assembling happens in China. The batteries are all designed in Tampa Florida and then the manufactor makes them to our specs and standards. So its not "China junk" like the majority of Chinese made products are.

Are you looking for a certain battery in particular? Is there any questions i can help you out with that could help? Feel free to ask. Thanks,

What is the warranty on the batteries?

Ok so as far as the warranty goes, there is 5 year manufacturer warranty that covers everything. Out side of the 5 yrs we can rebuild these batteries. Since they are made up of a internal bolted construction we can fix any battery for $100 flat rate. We are currently working on a lifetime warranty but have not released it on the website yet.

The site says they can safely be used to 100% depth-of-discharge (DoD). What is the expected number of cycles at that DoD?

With lithium it doesn't matter if your DOD is 20% or 100% the cycles won't be affected. Maybe in the long run you will see a slight sag in lifespan but as a whole you will still be able to hit the 3000-5000 mark no problem. I have one customer that runs a 200Ah in a ambulance and they 100% discharge it every day and its been working 2 years straight doing this and we had it back and tested it for marketing purposes and it still have 202Ah capacity. I'm not sure what all you are running with it but you will have to use it pretty hard to hit 100% every day in a (RV).

I have a Freedom 2000 inverter/charger. Is there any special settings I need to use with LiFE battery chemistry?

As far as your Freedom inverter goes just hook it up like a normal battery and let it run. The inverter isn't going to know its lithium. Depending on which battery you purchase, if its the 150Ah you can charge it at 150A and have it charged in one hour. Also the voltage curve on the Smart Battery doesn't hardly change from fully charged until its dead. So your inverter will run a lot more efficient because of that. With what you have and are doing i just looked at your website i believe these batteries will fit you guys well. I would like to sell you one and promote it to your group you have going there.

I was looking at the 12V-150AH or 12V-200AH battery for my skoolie conversion motorhome and I’m active on the skoolie.net website. There are other skoolie converters out there who are interested in this type of battery, so I will be passing on this information and—if I do end up buying one—I will share with them my experiences.

The size and boot print these batteries have for the power ratio is amazing. You will find that one battery will run your entire coach and that you will have way less weight and more room for other stuff. Also keep in mind that there is no corrosion to watch for or bad terminals. Zero maintenance is also a plus. Don't have to fill these with water or worry about freezing them. Please let me know if i can get you a sale and start group on Smart Battery.

More questions:

My Freedom inverter/charger has a three-stage charging routine. The BULK CHARGE stage charges the battery at the full charger current until the Bulk Charge voltage limit is reached. The ACCEPTANCE CHARGE stage maintains the voltage constant while gradually ramping down the charge current. This lasts for one hour. The FLOAT CHARGE stage holds the battery voltage at a slightly lower voltage that is safe for long term battery maintenance. I realize these stages are largely irrelevant to the Smart Battery technology, but want to make sure my inverter/charger can’t hurt the Smart Battery. Also, I have an optional controller for the Freedom charger that allows me to change many of the stage settings. Is there any setting that I could change that would be beneficial to the use or longevity of the Smart Battery?

i'm not 100% sure what all the capabilities are for your freedom charger. But if you can adjust stuff just make sure your charge voltage is as high as you can get it. 14.4 to 14.6V DC is where Smart Battery will perform the best. As far as amps go you can't hurt the battery as long as you keep the amps under what the size of the battery is. For example if your battery is the 100Ah Smart Battery you can charge it at up to 100Amps but not over that. Anything less then 100Amps is totally fine. Does that make sense?

You mentioned the possibility of a lifetime warranty in the future. If I buy a battery soon, will it be possible to get the lifetime warranty applied to my battery retroactively or will the new warranty only apply to special batteries not yet in production? If this is not possible, do you have any idea when the new warranty will be available. This factors heavily into my buying decision.

As far as the lifetime warranty goes at this point we don't have a time frame set yet its still coming. But the batteries aren't going to change design or function for the warranty. Just keep in mind that if something was to go bad in your battery, even if you buy it now, we can fix it. And that doesn't cost much at all. $100 will fix any battery.

When my vehicle is complete, I will be traveling the country and using it as a platform for my professional photography business. Is there any possibility of a discount or corporate sponsorship if I agree to badge the outside of the vehicle with Smart Battery advertising for a yet-to-be-determined number of years? Or maybe we can work out some kind of special discount for myself and other members of the skoolie.net community? We are not made of money (else we wouldn’t be buying used school buses) and any consideration would be greatly appreciated.

As far as the advertising goes if you can promise me some sales with your friend group in the future i can work with the price a bit. I'm not real keen on the idea of advertising on the side of your bus without a Smart Battery Representative present.

It was worth a shot.

We have a month lead time right now on some models but if you could round up a few sales at the same time i can make a deal with you. Thanks

If anyone has questions for this manufacturer, I'll be happy to pass them along, or you can use the contact form on the website. The realtime chat feature didn't work for me and the rep says it's flaky to begin with.

Please add to this thread so we can have a single source for info about li-ion batteries.

[Polarweasel]

Definitely interested in the tech, but not a group buy that happens within a month. Our timeframe is probably closer to fall, if we can swing the cost. I would dearly love to start off our build with a good electrical setup, rather than having to rework and require later on.

I'm curious to know what that ambulance is doing to fully discharge its battery every day. It seems like an exaggeration, but maybe it's abuse? I worked in EMS for several years, and I can't think of a realistic scenario here.

[PDBreske]

Originally Posted by Polarweasel

I'm curious to know what that ambulance is doing to fully discharge its battery every day. It seems like an exaggeration, but maybe it's abuse? I worked in EMS for several years, and I can't think of a realistic scenario here.

I agree, that seems extreme. But even if it's an exaggeration that doubles the battery usage (let's say it's 50% DoD every day for two years), it's still amazing that the battery has retained all of it's original capacity with no maintenance and no special charging/de-sulfating requirements.

If there's a battery for dummies, this is it ... and I'll take it.

[Scooternj]

Originally Posted by Polarweasel

I'm curious to know what that ambulance is doing to fully discharge its battery every day. It seems like an exaggeration, but maybe it's abuse? I worked in EMS for several years, and I can't think of a realistic scenario here.

Critical care bus with a really crappy charger/inverter. One of the critical care rigs at the ambulance company I worked for would be really difficult to restart with everything plugged in and running, unless you left it running

[calmingcrow]

I have been looking into smart batteries myself. I think I am definitely going to use them for my battery bank in my bus. I intend to link them and create more kWh, would that be an issue?

[Polarweasel]

Originally Posted by Scooternj

Critical care bus with a really crappy charger/inverter. One of the critical care rigs at the ambulance company I worked for would be really difficult to restart with everything plugged in and running, unless you left it running

And here I thought the private company I worked for cut lots of corners. That would actually have gotten fixed, and quickly. (Though we generally left the rigs running most of the time anyway...)

[Scooternj]

Originally Posted by Polarweasel

And here I thought the private company I worked for cut lots of corners. That would actually have gotten fixed, and quickly. (Though we generally left the rigs running most of the time anyway...)

I know we're drifting, but...all our boxes were, 9 times out of 10, used; our vans, pretty much brand new. The mechanics, on the other hand, were a mixed bag. A couple knew what they were doing, most didn't. My full-time bus had this weird shimmy at highway speeds, they could never figure out.

[PDBreske]

Originally Posted by calmingcrow

I have been looking into smart batteries myself. I think I am definitely going to use them for my battery bank in my bus. I intend to link them and create more kWh, would that be an issue?

Nope, no issue. No more so than with regular lead-acid batteries. I remember reading somewhere that the Smart Batteries will automatically compensate for differences in battery charge in an a bank of batteries, but I can't find it so take that statement with a grain of salt.

[jawa01]

I remember reading this thread awhile ago and hoping it went somewhere. Bought a van (skoolie seemed a bit too big) and am looking to do full solar. Would be worth my while to shave some weight and let the marginal MPG savings pay for it over time. I have a lot of space under the thing I would love to install a drop down cabinet to house a battery more flat and rectangular like a li-ion rather than conventional batteries. Space is a premium.

[PDBreske]

Originally Posted by jawa01

I remember reading this thread awhile ago and hoping it went somewhere. Bought a van (skoolie seemed a bit too big) and am looking to do full solar. Would be worth my while to shave some weight and let the marginal MPG savings pay for it over time. I have a lot of space under the thing I would love to install a drop down cabinet to house a battery more flat and rectangular like a li-ion rather than conventional batteries. Space is a premium.

I think you'll find the consensus is that shaving a few pounds (or even a few hundred pounds) won't really change your fuel economy as much as simply slowing down a few miles per hour. If you really want to save some money, just drive 55 instead of 65. With vehicles like buses and vans, the drag coefficient is so poor that speed, not weight, makes all the difference in fuel savings.

Unfortunately, if you are looking for a flat(-ish) battery pack, you might have to build it yourself. Most of the commercially-available Li-ion batteries tend to be direct replacements for their lead-acid counterparts, so, not particularly flat. The battery packs that are used by electric cars are all custom-built for their application to fit into the platform of the car they power.

[jawa01]

I'm still interested in keeping weight down. Better ride, suspension lasts longer, not to mention it is a van so it's got a finite amount it can carry.