Lithium iron phosphate batteries LiFePO4

[gerrym51]

Davydd-although this is basically lithium versus agm-who the heck draws down their batteries to the lower nether regions unless it's an accident or an emergency.


say an AGM can be drawn down to 20 percent 500 times. who draws their agm's down to 20 percent. I never did on my old rv's and i doubt anybody that posts here does. I f it happens say 5-6 times a year(which is a lot) the batteries will more likely die of old age-which is a lithium issue by the way more than the agm's.

we fixate on how many times max draw down can be done then we never do it anyway unless as i said accident or emergency.

[Davydd]

Gerry,

People run their batteries down all the time but that really is not the issue I don't think. I think the discussion here is not one and two auxiliary battery systems. There is nothing to gain in my mind going to lithium ion for 200ah and sticking with traditional RV practices combining a generator and propane for power sources. I think if you are talking about large battery bank systems and running your van on 120VAC in a boondocking situation, getting rid of your generator, and still also running your air conditioning, then lithium ion starts to make a lot of sense.

Roadtrek's Etrek pushed it as far as they could with AGMs. Most likely they ran out of space and weight. The only option then is to go to lithium ion batteries. Roadtrek could not achieve their 24/7 stated goal for air conditioning with AGM batteries.

In most of my readings it seems it is the full timers that are getting dissatisfied with the AGM and them only lasting a season or two from heavy use. This was kind of the reasoning coming out of Technomadia and I have been trying to follow the boating concerns about the topic as they seem to be way ahead of the RVers and maybe for good reason. They can't plug in out at sea as an option.

The Promaster has its own sets of challenges. It is 3 feet shorter than the two Roadtrek extended body experimental Sprinters we know about. That is 20 cubic feet of under body real estate. The lithium ion batteries they have are probably taking up nearly 7 cubic feet of space. That 20 cubic feet also represents a potential of 140 gallons. I'm just using general numbers here as an example (3' x 7' x 1' rounded off to 20). Both of course lose some of that space to frame and axels and more. But the point is it is a lot of real estate under the floor that RVs use and that is a big difference. Could the Promaster go gargantuan on the amp hours? Maybe not. Will they ever go full Etrek of 800 ah? Maybe not. Does it matter? Maybe not. Arlo pointed out in that other thread he seldom maxed his Etrek batteries. So, will that one Northstar AGM be enough for you? With solar it will perform way better than my Great West Van with 210 ah of lead/acid wet cell and no solar. And I boondocked 5 straight days in Glacier National Park with it. With the right size inverter we already theorized you could get your 90 minutes of mid-day air conditioning and show up at the campground with fully charged battery. That's with the one. Would they or could they put two in if you wanted insurance of mind?

[gerrym51]

we need a survey-who continually runs their batteries down to 20 percent- i only did occasionally and accidently

i'm rephrasing this

how many times a year do your batteries run down to 20 percent-a guess is ok.

then how many times on purpose(for whatever reason does not matter) .

How often accidently?

[markopolo]

Most RV'ers wouldn't know. The battery monitors in a lot of RV's are very basic.

That brings up another point. A typical RV battery monitor won't be much good with LiFePO4 batteries.

[gerrym51]

Originally Posted by markopolo

Most RV'ers wouldn't know. The battery monitors in a lot of RV's are very basic.

That brings up another point. A typical RV battery monitor won't be much good with LiFePO4 batteries.

most probably don't=but they are the least likely to spend extra money on a lithium battery.

[Davydd]

Gerry,

It sounds as if you are trying to rationalize yourself out of lithium ion batteries. Like Marko said most RVs are basic and generally have idiot lights to tell you the status of your batteries. My Great West Van Legend was a little more sophisticated in that it gave a voltage readout. How accurate that was I don't know. Do you know what Roadtrek does with its Etrek's? No one I assume knows what they are doing with their experimental lithium ion Bs.

Advanced RV installs the Silverleaf total coach controller that interfaces with all the other controllers and battery management systems. There is some custom software but I cannot begin to explain it all. What I know is you can control just about everything through it and even remotely. It will give temperature and voltage of every single 3.2V cell in a battery assembly. It will control discharge and will be set to govern it to 80% draw down. I think at that time you can trigger battery disconnect or you can autogen start your engine to charge batteries. Knowing the temperature of the cells they can trigger or not trigger charging and also can stop charging when it reaches a set maximum. Don't take what I am typing as gospel. I don't have mine yet and will spend two to three days at the factory when I pick it up to orient in on all this. Also, we will test run before we leave in case adjustments have to be made. I believe Advanced RV does their own testing routines before turning it over.

I don't need a survey. I know exactly why I am going with the lithium ion option. And, true, with 800 ah I kind of doubt I will go below 20% draw down most of the time knowing my history unless I get wild and crazy and throw a pizza party and use my 1,500 watt table top Breville Crispy Crust Pizzamaker. I'm thinking of carrying it.

[gerrym51]

i would love lithium if available-the available is the key-on a Roadtrek-i am not interested in advanced rv. sportsmobile refuses to consider the smart battery lithium-i asked

however prior to a week ago i di not know about the existence of tpplagm. they seem like a good middle ground closer to lithium than standard agm.

[Fastpaddler1]

Originally Posted by markopolo

Just adding something I posted on Yahoo.

Re: LiFePO4 cost
They DIY approach to packaging the cells yourself can save you lots of money. All of the Lithium iron phosphate cells are made in China and are not that expensive but it is the combining and packaging of them with the mandatory protection circuitry / battery management sytem that into a useable unit for RV's and boats etc. and that only a few companies do it that allows for the very high retail pricing.

Also, one of the arguments in supporting their value as replacement batteries is that you would need only 70% or so of the ah capacity you previous had with lead acid batteries as they can be deeply discharged repeatedly (80%) whereas most lead acid battery users try to limit the discharge to 50%. LiFePO4 battery voltage doesn't taper off until they are basically discharged. Lead acid batteries discharge voltage drops as capacity is used.

Cycle life (80% discharge): lead acid 200 to 300 cycles, LiFePO4 1,000 to 2,000 cycles.
Do you

You can get considerably more useable battery capacity if you have LiFePO4 batteries rather than AGM batteries.

800ah LiFePO4 E-trek battery bank at 80% discharge equals 640 useable amp hours.
800ah AGM E-trek battery bank at 50% discharge equals 400 useable amp hours.

That's like 60% more useable amp hours!

Of course you can discharge true deep cycle lead acid batteries 80% but their lifespan would be greatly reduced as shown above.

Unless some other technology leap frogs over LiFePO4 adoption I think it will eventually be the RV battery of choice assuming prices come down of course.

Could I swap out my current AGM battery for one of these LiFeP04s or will that confuse my power convertor in my 06 PW Plateau TS. The one battery now only has 90ahs and I have to start my generator to recharge every day when dry camping. Thanks. Of course I intend to swap the RV too next year.
AL

[gerrym51]

Originally Posted by Fastpaddler1

Could I swap out my current AGM battery for one of these LiFeP04s or will that confuse my power convertor in my 06 PW Plateau TS. The one battery now only has 90ahs and I have to start my generator to recharge every day when dry camping. Thanks. Of course I intend to swap the RV too next year.
AL

these are plug and play-have all protection devices built in


http://www.lithiumion-batteries.com/

[Davydd]

Fastpaddler,

It may not be that simple. You charge your battery through a Progressive Dynamics PD 9200 series converter. That has their Charge Wizard 4-stage intelligent charging built in for charging lead-acid batteries. Also if you have a 9100 series you might not have the charge wizard which contributes to your disappoint with battery performance. I thought they switched over in 2006. You would have to ask Progressive Dynamics if it will work because lithium ion batteries charge at a higher voltage that that converter does not put out. Also I don't know how the intelligent charging would work. The only battery that might fit your battery box is the 100 ah battery at $1,299 from the Smart Battery recommendation Gerry gave you. Blocks of individual cells to make anything 100 ah or higher up to probably 180 ah might be too tall for your box and anything other than that Smart Battery would probably need more controllers and wouldn't cost any less. Seriously? For one more year it would be throwing money away. For one year, buy the best lead acid wet cell you can find and not AGM. Your converter might not have the charging profiles even for AGMs. That I know from experience.

[bobojay]

Fastpaddler, like David says, your converter, if it's still the one that came with your unit is probably not even capable of charging an AGM correctly let alone a lithium. Each battery type takes a different profile to charge correctly for longest life.
Like he stated, go buy a good wet cell for use for only one more year....

[markopolo]

Gerry's got the right type of product linked for a drop in type replacement. In the FAQ section on the site Gerry linked to it mentions that your charger needs to output 14.4v to 14.6v to fully charge their batteries. I think that Davydd is spot on about the cost not being worth it for one year.

Both bobojay and Davydd pointed out the need for a decent charger so I'll just expand on that a bit. A 9100 Series would need the plug-in Charge Wizard add-on to be able output a proper charging voltage of 14.4 volts. Without the Charge Wizard the output is only 13.6 volts. That's not enough to properly charge a battery. That chronic undercharge reduces the battery's capacity and shortens its life. Charge Wizard: http://www.progressivedyn.com/prod_deta ... _9105.html

A 9200 series charger is OK and would work with AGM batteries. It should also work (maybe not perfectly) with the drop-in pre-packaged lifepo4 batteries but I wouldn't leave the van plugged in when in storage.

[Davydd]

I'm not totally convinced. Back then (2006-2007) you had to specify which set up you wanted for your Charge Wizard add on for the PD 9100 for wet cell or AGM. Maybe since then they have got it all sorted out but if the 2006 Plateau has the original PD 9200 series with the built in Charge Wizard spec I would be suspicious. I don't think it will just automatically charge at 14.4 volts either since it was not designed to do so. In effect, I would not do it until sorting it out directly with Progressive Dynamics and not necessarily Pleasure-way. Well, maybe both by now, but not back then.

You know Pleasure-way has been very adamant about not even adding second batteries to their Plateau. They are very conservative about batteries.

[markopolo]

Good point / good advice about contacting Progressive Dynamics first http://www.progressivedyn.com/contact2.php

[Fastpaddler1]

Originally Posted by Davydd

Fastpaddler,

It may not be that simple. You charge your battery through a Progressive Dynamics PD 9200 series converter. That has their Charge Wizard 4-stage intelligent charging built in for charging lead-acid batteries. Also if you have a 9100 series you might not have the charge wizard which contributes to your disappoint with battery performance. I thought they switched over in 2006. You would have to ask Progressive Dynamics if it will work because lithium ion batteries charge at a higher voltage that that converter does not put out. Also I don't know how the intelligent charging would work. The only battery that might fit your battery box is the 100 ah battery at $1,299 from the Smart Battery recommendation Gerry gave you. Blocks of individual cells to make anything 100 ah or higher up to probably 180 ah might be too tall for your box and anything other than that Smart Battery would probably need more controllers and wouldn't cost any less. Seriously? For one more year it would be throwing money away. For one year, buy the best lead acid wet cell you can find and not AGM. Your converter might not have the charging profiles even for AGMs. That I know from experience.

OK.Thanks Gerry and Davydd. I will get by until I switch units. I hope to do the TransCanada route from Vancouver to Halifax next summer then return via the U.S.

Regards,
AL

[markopolo]

Speaking of Progressive Dynamics ............

New Lithium charger announced: http://progressivedyn.com/lithium_battery_charger.html

PD9100L Series 12- & 24-Volt Lithium Ion Converter/Chargers

The new 9100L Series of Inteli-Power chargers are low cost and designed to meet stringent voltages required for properly charging & maintaining lithium ion batteries.

NOTES: ( or Quotes )

Trying to recharge a lithium ion battery with a standard lead/acid charger will result in a partially charged battery and may REDUCE BATTERY Life!

the battery manufacturer must install electronic balancing circuits inside the battery to prevent overcharging a cell, or discharging too much

So a BMS is still required.