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Batteries - AGM, LFP, and Flooded Cell

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Pax

Batteries - AGM, LFP, and Flooded Cell
« on: April 17, 2016, 02:34:49 am »
There has been a lot of discussion about batteries, but I haven't heard about LFP type batteries until recently.  Here is an excerpt from RV'ers magazine:

Flooded cell — This is the common wet cell battery that everybody loves and hates. It’s cheap, messy, widely available. They have to be mounted in a well-ventilated area and must be kept right-side-up at all times. They can accept up to about 20 percent of their rated capacity when charging. High discharge rates will quickly drain them and shorten battery life. Normal life span is about 4-5 years or 500-1000 charging cycles.

AGM — About 50 percent more expensive than wet cell, there’s never an acid mess or need to replenish water. They can be mounted in a closed compartment and in any orientation. Charge acceptance, discharge, and life span are like wet cell.

LFP — Nearly four times the cost of wet cell, but life span makes up for it: easily 8-10 years and 3000-5000 charging cycles. Fully sealed, any orientation, and about 1/3 the weight of wet cell or AGM. Perhaps most importantly for RV/solar applications, LFP will accept 3X its capacity in charge rate, which allows use of full solar capacity at all charge levels. They also can be discharged at very high rates without any penalty (I run my microwave on battery power). LFP batteries have been full-custom applications until recently, but there are now drop-in replacement LFP products for lead-acid batteries.

    - Mike

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Ron Dittmer

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Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #1 on: April 18, 2016, 03:47:36 am »
Interesting!

I wonder what two LFP batteries would cost?  I also wonder if they are available in 6V?  I paid ~$200 for our last pair of 12V lead acid batteries, and ~$400 for our most recent pair of 6V AGM batteries.  My hope is that our 6V AGMs will perform better and last longer.  Time will tell.  I didn't learn much from one 4 week trip with brand new 6V batteries.....of coarse they worked great being brand new.  My hope is to get better performance in year 3 & 4 & beyond, hoping there is a "beyond".
« Last Edit: April 18, 2016, 06:56:38 am by ron.dittmer »
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Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #2 on: April 18, 2016, 08:13:31 am »
Mike,
I see from your comment that you run your microwave off the battery through the inverter. Does that mean you have LFP batteries?  If so I would be interested in the amp hour capacity of the batteries and any other changes that were required to safely charge and discharge them.

I had considered having the ability to run the microwave off the inverter for very short periods of time (1-4 minutes) instead of starting the generator but the discharge capability of the two 6 volt batteries to supply the needed amperage became a concern. I know the amp hour draw and Peukert effects are huge even if they could supply the needed amperage and the batteries would be quickly discharged if used for longer periods.   If you do not have the LFP units could you elaborate if there was a discharge rate issue and how you handled it.

The newer technology LFP systems certainly looks interesting and I would like to learn more about them.

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Pax

Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #3 on: April 18, 2016, 08:54:26 am »
I don't own these batteries, but just quoted the author of the article.
A quick search online showed there aren't an overwhelming number available yet apparently, but run in the range of $300-$400 or so each.  I don't know anything more about the batteries (positive or negative, no pun intended) than what I posted.  Just thought I'd share that in case others were thinking about replacements and/or possible better alternatives for their solar systems.  They do seem interesting.

  - Mike



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Chihuly

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Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #4 on: April 19, 2016, 12:23:35 am »
Just to answer a few questions. I have Lithium LiPo batteries. I installed a 400 amp hour  battery. Cost is generally around a $1000 per 100 amps hr. of battery installed. Keep in mind a 100 amp LiPo is equivalent to around 200 amps of lead acid batteries because of there low discharge abilities. They will still read above 12.8 volts at 98% discharge. There is no harm in discharging to 98%.
I installed a little larger Inverter than came with the PC and I even use the Convection oven for  thirty min. and barely use 10% of my total cap. Cost seems outrageous at first but when you compare over time LiPo should beat lead acid or AGM batteries if they perform to what the manufacture says they should. They have not been out long enough yet to see the real deal.
   I should warn you about some companies out of Florida selling drop in replacements, they should be avoided. It took me letters to the BBB in Tampa and finally I had to contact the Attorney general before getting my refund. Look for companies with good reputations and willing to stand behind their products. I finally purchased mine from a company called Starlite Solar out of Yuma. They installed them for me which I had originally planned on doing myself. With what I learned from them I am glad I had them installed and walk me thru it.  I was going to make some mistakes I would have regretted later. Add a little Solar and you can go and go and go.  I put 130 hours on my Gen before getting my Bats and Solar. I haven't put an hour on it since. I have even contemplated taking it out.
   I am not on my computer much these days but I will try to check in for follow up questions if any. Please be patient I just got home from 5 months on the road and now I am trying to catch up.

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Ron Dittmer

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Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #5 on: April 19, 2016, 10:39:13 am »
I have Lithium LiPo batteries. I installed a 400 amp hour  battery. Cost is generally around a $1000 per 100 amps hr. of battery installed.
Are you saying the battery cost you $4000?
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Chihuly

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Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #6 on: April 19, 2016, 02:06:33 pm »
Yes. Sounds crazy up front and it is not for everybody but so far I couldn't be happier. I do admit I could have gotten by with 200 amps of battery just fine because I have yet to ever drop below 68% of my capacity and I don't conserve in anyway like I used to with my lead acid 6 volts. That's also running in the cold with the heater running all night, Watching the big sceen, microwaving popcorn, what ever. The other BIG seller for me was the weight reduction. I had 4, 6 volt batteries I think they weighed 240 lbs. My new batteries weigh right around 100 lbs and have almost twice the usable capacity of my 6 volt batteries. I would have had to have around 360 lbs, of lead acid batteries to equal what I have now.
One last Kudos to PC with a little anti freeze in my shower drain and ran some thru the mercerator pump along with a some in the grey and Black I was able to hang out in temps to -6 F with no problems. The only thing that you have to watch is the propane isn't  very efficient at those temps and if your tank falls below 1/4 you will run out of propane.

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Ron Dittmer

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Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #7 on: April 19, 2016, 03:49:09 pm »
Chihuly,

Please PM me with the address where you PC is located so I can fly out from O'Hare, steal the battery while you are sleeping, ship the battery home from your local UPS store, then fly back home.  When you PM me, I would also appreciate the location of your nearest UPS store.

Sorry, I couldn't help myself.

In all seriousness, it is quite interesting to read how battery technology is coming along.  What costs $4000 today will cost $400 once they figure out how to manufacture them cheap enough to be competitive.  Electric cars will be the #1 benefactor.
Ron (& Irene) Dittmer

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Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #8 on: April 19, 2016, 07:14:18 pm »
The only thing that you have to watch is the propane isn't  very efficient at those temps and if your tank falls below 1/4 you will run out of propane.

I'm not sure this is pertinent or works the same but we discovered on Boy Scout outings that the propane froze in the line between our 5 or 10 lb propane tank and camp stove. We started turning the propane off at the tank and leaving the stove or lantern run until it "burned out" from lack of propane. If you are not using your propane heater overnight, you could try that and then open the tank in the morning when you want to cook. If you are running on electric space heaters, this might keep your stove alive during daylight hours.

We also learned to fill a pan with water before bed so that once we got that stove going, we could melt the water and make coffee since the water jugs were all frozen. Ah, the memories. We are sooooo happy we have the Phoenix and have agreed that we don't ever want to camp in a tent in weather that evil again.
John, Holly, and sometimes Chloe.
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keelhauler

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Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #9 on: April 20, 2016, 10:42:16 am »
Many gas cylinders supply Butane rather than Propane. Butane will not have any pressure below 35oF.

Propane still has pressure at -40oF.

If you travel to Mexico, they fill your tank with either pure Butane or a mix of Propane & Butane, they just call it Gas or LPG.

For you technical people here is a graph of bottle pressure vs temperature.


Remember when you are using the propane it cools itself down, since you are evaporating the liquid. So the pressure will drop.



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Chihuly

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Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #10 on: April 21, 2016, 11:30:17 am »
Thanks for the propane graph. I do know I have used propane down to -40 with no problem. When my wife ask me if we had enough propane I told her with confidence we did. It registered almost a third of a tank at the bottle. When she woke me at 6:00 AM to tell me the furnace wasn't lighting I was surprised. We then scrambled to start the truck at get moving. I assumed the bottle was empty but when I went to fill it was reading 1/4 full. I suspect it was icing up from use and the pressure dropped. The furnace may have something on it that does not allow it to run once the pressure drops below a certain point, I really don't know. When I filled it I t only took six gallons in a 12 gallon tank. My last propane purchase was in Bellingham, maybe they slip in a little butane?

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jatrax

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Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #11 on: October 02, 2016, 10:23:06 am »
I know this is a bit of an old thread but I have an interest in the Lithium batteries.  @Chihuly can you answer a couple of questions?

1) You said you had 4 - 6 volt batteries on your coach, where did they put them?  And was that a PC install or did you add them yourself?

2) I have done some research on Lithium and they seem to be temperature sensitive.  One shop stated they would not recommend them if they were installed outside the coach.  So did you put yours in the same battery tray as the lead acid on the PC? 


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Chihuly

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Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #12 on: October 02, 2016, 12:44:15 pm »
I had PC  install he biggest battery tray they had and originally planned for the Batteries to be housed there. That tray held 4 six volt lead acid batteries when I left PC.  In Yuma I had my Lipo batteries installed and they talked me into putting them under the bunk since to put them outside would mean I would have to provide a heat source for times when the air temp dropped below freezing.
So far so good and I have even run the air conditioning unit off of them on several occasions. Our daylight hours in the summer here provide more power than we can use and running the air conditioner for an hour or more is not a problem.   
 I enclosed the outside battery tray with aluminum sheeting and made it weather resistant then installed a weather proof toolbox in the tray that can hold more weight than I can ever put into it.

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Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #13 on: October 02, 2016, 01:43:13 pm »
Thanks!
So they put the Lipo batteries under the passenger bunk?  I had not thought about that space, I assume there is plenty of room?  You have a 400 amp pack now, what was the amp rating on your AGM pack?

And did you have to change out the charger or did you use the PC supplied one?

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Chihuly

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Re: Batteries - AGM, LFP, and Flooded Cell
« Reply #14 on: October 02, 2016, 02:30:09 pm »
I cannot remember exactly what my amp hours were but I believe close to 500 Lead acid. 400 amp hours of lithium seems so much more than that its hard to believe. I had PC install a Lithium charger that I sent them but I wish I had not, its really a piece of crap. The nice thing about lithium is you can throw huge amounts of electricity at it to recharge fast. I put the largest charger in I could, the only trouble is it throws out 40 amps for about 30 secs, then starts heating up and then only throws about 13 amps for awhile and then drops down to 10 amps. I will eventually change it out but so far I have not needed it much. The 500 watt solar keeps them up and if I am moving the truck throws a constant 20 amps at it. Oh and I ordered the largest alternator Ford made for the 450.
They make some great Inverter chargers that are designed for Lithium that would have been great but I already had a GO Power 3000 watt pure sine inverter installed and I just couldn't bite off the change at the time. Starlite Solar out of Yuma can answer most of your questions are really great people to work with. They wont sell you anything you don't need.