Lithium batteries make me happy

viento1 · November 08, 2011, 09:10:28 AM

Sorry for hijacking the heater thread.

OK, I am running my bus with a couple of old batteries from my friends farm truck. I fried my 8 trojans last year and proved to myself again that I am not quite responsible enough to care for these things. I just do not feel love for these heavy, acid filled, nasty blocks that require me to brush toxic fuz off the terminals and check gravity and fill with water and PREVENT from freezing.

I just found out from the other thread that a company is selling Lithiums for $650 for 100 amp hr. That equates to $3100 for 500 at 12V or for me $3100 for 250 at 24Volt.

that seems like a great deal to me...

The other quote I got was almost double...

technomadia · November 08, 2011, 09:48:33 AM

Yes... we think the price is becoming into the realm of possibility, and even potentially cheaper than a AGM setup of similar usage amperage over time.

But we are not yet to a point of recommending them for those not tech / electrical / battery savvy.

Be very very aware that Lithium Ion for a house battery bank is still considered on the 'bleeding edge' and pretty advanced technology.

It's unproven for this application, there are very few RV house systems running off of them and we're still tweaking our own system.

There's a lot of things to be very aware of, and a lot of caution that has to be used. If you dislike maintenance, we do not consider LiFePO4 to be maintenance free yet - especially when doing a DIY build like we did (and for which those quotes were for). For instance, for the past several weeks we have been fighting with our bank to get all of the cells properly balanced. And there are still firmware tweaks to our electronics that need to be made to shut them off at the proper times when charging/discharging for a house system (this chemistry is mainly used in electric vehicles right now, which is a different need... Elite Power is currently working with us to tweak things for this application)

Some of the caveats are:

1) There are no inverters, yet, on the market with charging profiles for LiFePO4. You must be in tune with how to properly program yours to deal with LiFePO4.
2) Draining below zero or overcharging - even once - can permanently kill the battery bank, with no recourse. It could be a very costly mistake (much more than frying 8 trojans), and does take some care and feeding and proper setup. If you're not familiar with things like BMS/EMS systems, etc - be sure to over-educate yourself on the topic.

This is still pretty uncharted territory. And we do NOT recommend them yet for those not willing to take some potentially costly arrows in the back, and aren't willing to be pioneers into a new technology. We currently consider LiFePO4, especially when doing it DIY, to be a couple more years off before being considered mainstream.

Here's a link to our articles on our LiFePO4 experiments:

http://www.technomadia.com/category/life-on-the-road/technology/lithium-ion/

Highly recommend anyone considering this to follow along, and stay tuned for our upcoming updates on the costs (not just for the batteries, but all the other components needed to build a proper bank, not to mention the hundreds of hours we have invested in research, building & tweaking) and the challenges we've encountered.

- Cherie

viento1 · November 08, 2011, 10:48:28 AM

Hi Techno,

Great response, my only experience with Lithium is a 20amphr 36volt dirt surfer with marginal success and of course a few RC planes burnt to a crisp.

I just cant help myself, I want to build an electric car too. I used to be a weekend warrior auto sport guy and I think this is a great way to spend my kids money.

Mex-Busnut · November 08, 2011, 12:56:58 PM

With proper maintenance, are a pair of truck batteries usable? The only deep cycle batteries I can get here are golf cart 6-volt, 35 ampere-hour size.

pvcces · November 08, 2011, 10:50:08 PM

I doubt that the golf carts that you mentioned are 35 amp hours; you might check the specs. The ones that I am aware of run over 200 amp hours.

Tom Caffrey

Mex-Busnut · November 12, 2011, 12:14:02 PM

Quote from: pvcces on November 08, 2011, 10:50:08 PM
I doubt that the golf carts that you mentioned are 35 amp hours; you might check the specs. The ones that I am aware of run over 200 amp hours.

Tom Caffrey

Tom:

Thanks for your reply.

Please remember I am 600 miles South of the border. The only "deep-cycle"-type batteries I can find here are these. These are 12-volts, and pretty small in size. They are at the local Sam's Club. They would run me almost $100 U.S. each. A brand new truck battery is only $125.

pvcces · November 12, 2011, 08:49:05 PM

I stand corrected.

Lots of the time, things seem to cost less in Mexico. That's not always the case, however.

35 amp hours times 6 volts comes to 210 watt hours. It wouldn't take long a refrigerator or furnace to deplete those, would it?

Take care.

Tom Caffrey

luvrbus · November 13, 2011, 05:25:01 AM

What a screwed up system 95% of the batteries here in the US are made in Mexico a 200 amp 6v here at Sams cost 57 dollars and a 100 bucks in Mexico for a 35 amp

good luck

rv_safetyman · November 13, 2011, 08:34:29 AM

Clifford, the Sam's price for golf cart is now around $89.

Just had to replace a set of 8

While it hurt to pay that much, I realized that I bought my first set of Sam's golf cart batteries in 07/03. Got about 7 years of service by taking pretty good care of them.

Jim

TomC · November 13, 2011, 08:51:27 AM

I have 2-8D deep cycle batteries for house use. I started with normal wet batteries that I had to check on a monthly basis-weekly during summer. It was pain since there is not much room between the top of the batteries and the bottom of the floor (transit bus). I had to use a mirror to check and took an old Surflo water pump to add distilled water at times, and also clean the terminals. Then I discovered Thermoil-which you remove 1/4" of acid from the battery and add the Thermoil to it. What this does is to cut way down on gassing, and evaporating of the electrolyte. Hence servicing was cut down to once a year with the terminals never getting corrosion. But-there was still maintenance involved. Now I have 2-8D Lifeline AGM batteries (255amp/hr each). They have been in for about 4 years with literally NO maintenance at all. Just had to reset the inverter/charger to AGM setting with the charge setting no higher then 14.1 volts with the resting voltage at 13.2 (per Lifeline). And with the wet batteries I could only charge at 60 amps. With the AGM's I was able to crank the charging rate up to a full 130amps. Personally like the AGM's. Will be using 4-L16 Lifelines (there are made within a few miles of me) that are 400amp/hrs each for a total of 800amp/hrs at 12vdc. I have sort of backed myself into a corner forcing me to use AGM's since the batteries will be mounted in my basement which is technically still inside (the inside of the box is 108" minus the 24" basement and 2.5" mid floor for headroom of 81.5"). Good Luck, TomC

luvrbus · November 13, 2011, 08:52:39 AM

Here the Interstate brand golf cart batteries are 89 bucks the others are 69 bucks at Sams both made by Johnson Controls with the same warranty lol

good luck

Oonrahnjay · November 13, 2011, 09:29:26 AM

Quote from: rv_safetyman on November 13, 2011, 08:34:29 AMClifford, the Sam's price for golf cart is now around $89.

Just had to replace a set of 8 While it hurt to pay that much, I realized that I bought my first set of Sam's golf cart batteries in 07/03. Got about 7 years of service by taking pretty good care of them.

Yeah, you'd never get anyone to rent you a battery for $1 a month. What did you have to do besides the usual checking elec. levels and cleaning the terminals?

rv_safetyman · November 13, 2011, 10:51:37 AM

Well, first of all, you would think and engineer could add and subtract. I got 8 years out of those batteries not the 7 that I mentioned before.

Several folks have said that many batteries don't die a natural death - they are murdered!!! In my case, I am very careful to monitor the state of charge (SOC). The only correct way to do that is with an integrating SOC meter. I use this one:

http://www.bogartengineering.com/products/TriMetric

There are others on the market as well.

That meter has a large shunt that allows the meter to keep track of all of the current flow in and out of the battery bank. I really work to make sure that I don't go below 50% SOC (supposedly the magic number for flooded lead batteries). AGM batteries can go lower.

I also have a full sine wave Trace inverter that has a 3 state charging system that is top notch (good modified sine wave inverters also have this feature)

So, the SOC meter, good charging system and reasonable maintenance got me some pretty good battery life.

Jim

Oonrahnjay · November 13, 2011, 07:11:53 PM

Quote from: rv_safetyman on November 13, 2011, 10:51:37 AMWell, first of all, you would think and engineer could add and subtract. I got 8 years out of those batteries not the 7 that I mentioned before.

I wuddn't gonna say nothin'!

Quote from: rv_safetyman on November 13, 2011, 10:51:37 AM(snip) I am very careful to monitor the state of charge (SOC). The only correct way to do that is with an integrating SOC meter. (snip) I also have a full sine wave Trace inverter that has a 3 state charging system that is top notch (good modified sine wave inverters also have this feature)

So, the SOC meter, good charging system and reasonable maintenance got me some pretty good battery life. Jim

Sure did. I'm gonna check out that SOC meter. Thanks for the info.

technomadia · November 16, 2011, 08:44:18 AM

As a follow up to the original subject of this thread, we just posted the next installment of our Lithium Ion Battery series. This time, evaluating the costs of the system we built, compared against a AGM system.

http://www.technomadia.com/2011/11/lithium-update-3-lithium-battery-cost/

Enjoy!
- Cherie