LiFePo4 battery users

[Ticklebelly]

...... how fast can Lifepo4 be fully charged, even though it need not be fully charged?

I think the whole lead acid 50% rule is a bit whack ....

Regarding weight, in my own system, I have no additional battery. 

I have the 18Ah mightymax '600 watt' stereo battery (ub12180) for jumpstarting when that becomes necessary. 

My approach to the fully charged issue is to charge my Li to 14.1 and stop. My EV focused friend charges to 14.6.    At 14.1, I figure I am only charging to 90% or so, and do not have to resolve any arguments about Li not liking to be held at full charge.

I have a set up that puts 30 Amps to the battery when the alternator is running. Solar gives me what ever is available at the state of the day. Sunny afternoon to sunny morning, I typically draw around 15Ah from battery storage. Having an idea of how depleted the battery is, I can pretty accurately predict how long it will take to recharge.

One Facebook site I visit is infested with a couple of Donald Trump types (I know more about technology than anyone) who insist that no damage occurs if only 50% is drawn down and Armageddon is just around the corner if deep cycled. For a whole year, I cycled a 120 Ah AGM down to 20% every two days. The battery is now 8 years old and still powering a modest installation in a girlfriend's van.

My exAmbo came with an additional AGM battery installed under the passenger seat. A dash mounted switch connects the batteries through a solenoid for starting and charging purposes. When the starting battery is due for replacement, I will replace with Pb but the smallest capacity I figure I can get away with. I will stay with Pb in that position because that is what the vehicle came with and the semi-smart alternator expects a Pb battery.    I figure I will save another 10 Kg. I do have a Li Ion jump starter for redundancy should the start and under seat battery combination not be able to start the vehicle.

[RoamingKat]

The beauty of LiFePo4 is that it will take everything you can throw at it until it is full. So, the speed that you can recharge them is the speed at which your charging system can deliver.

So....no float. I routinely draw 50 amps over night. Then another 50-80 amps in the morning running electric heat. These days...close to the equinox....my 650 watts of solar bring me back to full before noon on the sunny days (delivering about 25-30 amp) and full before evening on overcast days. That is because the max output of the panels is going into the battery...not left unused because of slow trickle used in float.

Last summer I ran a small 5000btu AC unit. About 120 amps (12v). I would run that for a couple hours at dusk. Plus the usual 50 amps over night use. The next day I had an additional 600 watts on my awning...so a total of about 55 -60 amps in total panels. On a sunny day...I was back to full by mid afternoon. I was limping along with damaged panels on top....so I wasn’t getting more than about 15-20 off from them....the awning was carrying most of the load. This year I expect to do better with the new panels.

It was this property of lithium that caused me to select it to start with. No generator or gasoline needed. I do not need to charge from the alternator, I have enough solar to do the whole job.

I charge to 13.8. Per manufacturers spec. The manufacturer has upper and lower drop-dead limits at 14.6 and 11.8. The batteries in electric cars seem to have a greater tolerance for charging voltage. I would be worried if the charging got up that high. The renogy charger is set to 14.0 ... but I almost never have shore power anyway.

[Tom_M]

Here's a good YouTube video explaining different options available for lithium:

If you are considering a drop-in solution, you might want to take a look at Renogy. Amazon and Walmart are selling a 170ah Renogy for $980.84.

Amazon Renogy battery
Walmart Renogy battery

[sternwake]

Sounds like you got quite the capable electrical system Kat. Sometimes I think about having the ability to run a 15 amp table saw from my Van, or other larger power requirment power tools, but am woefully lacking in PSW inverter to do so, and even engine idling the battery would see 50 to 80 amps of load and alternator would get too hot too quick maxed out like that. I'd have to rig up some sort of cold air intake to the back of the alternator to do that with any regulararity. Obviously more battery and a juicepacked Lifepo4 could power more of the load that the alternator cannot.

Yesterday I spliced up another 45 amp anderson powerpole on 10AWG into the 8awg wires already feeding my MPPT solar controller. I had been hooking my 100 watt portable panel directly to any handy 12v powerpole I have located in many convenient places, but once the portable panel itself could make enough amperage on its own to hold absorption voltage, soon it would exceed it ad could overvolt the battery and my system if I was not there to stop that from occurring.

Also direct connecting a panel I would lose some watts from it by not removing it from battery voltage dragging it down, the whole MPPT advantage being bypassed. So it is nice having this extra MPPT input available.

With lead acid I do worry about achieving absorption voltage early enough in the day so that there is enough time in the afternoon to hold absorption voltage, as long as required to get full. and that time has doubled at deep cycle 1000, compared to #400. That is the whole key with getting good life deep cycling lead acid, and it would be nice to not need to worry about achieving full, like one can with Lifepo4. I could likely get away with less solar without the need to achieve absorption voltage before 1pM just to keep lead acid happy enough. I'd only need the portable panel on select occassions, rather than as a necessity just to keep lead acid happy.

I was going to mount the 100 watt sunpower flex panel to my roof, but would have to modify it and my roof to get an acceptable installation, and the panel by itself stores nicely on the shelf over the drivers seat, So I decided against hard mounting it.

I also could not have achieved such good lifespan from lead acid without the ability to plug in or at least deliberatley driving early in the morning, much more often.

My Northstar AGM requires the occassional high amp recharge to full from a well depleted state. Too much low and slow solar only recharges, even to full, have it behaving poorly in as little as 6 deep cycles. I can and do regularly feed my 90Ah agm-27 65 plug in amps and my alternator can go as high as 106. My roof solar can do 12 to 13 june 21 at noon.

If Lifepo4 does not care whether it gets low and slow, or lots of amperage from a capable source, there is yet another advantage of that chemistry over lead acid.

I think Charge rate is well misunderstood huge grey area with lead acid, especially when solar is involved and one wants to second guess the recommended rates provided by manufacturere who are generally assuming an overnight charge via a plug in charging source.

Personal experience says not to worry about exceding the recommended charge rates in vandweller applications emplong lead acid batteries. My previous flooded marine group 31 regularly saw large amperages and behaved better after receiving them. The Nannies will say no more than 10 to 13 amps per 100Ah of lead acid capacity. I say no less than 20 for a plug in charging source and mo is bettah.

I've never seen much in the way of recommended minimum and max charge rate for Lifepo4 and how that affects the total KWH figures one could expect from the battery.

[tx2sturgis]

Amazon Renogy battery
Walmart Renogy battery

The price on Amazon for that 170ah lithium shows (on my end) to be $1499 from some 'other' seller.

The price for the 170ah on Walmart.com shows $980 and change. 

If I didn't already have a 100ah BattleBorn I'd probably be all over that deal, especially with my 10% discount.

So far, I like the BattleBorn but I have only been using it for mainly light and medium duty loads, and it gets replenished soon after, using mainly solar. I ordered a Bioenno 10A wall charger for it...when it arrives I will be hooking that up and seeing what's what. 

I'm impressed with the ability this BattleBorn has to accept whatever charge source is feeding it. 

The new Renogy solar controller with LI settings and the 100watt PV panel loaded to full amperage (5 to 5.5 amps) at about 13.3v finishing off quickly at 14.2-14.4v, bringing it back up to 14.4 (my set point) and then I watch the incoming amps drop essentially to near zero as the PV voltage recovers to around 20-21 or so, as it all should since there is no float mode with LiFePo4.

The new trailer is now equipped with 2 lead-acid house batteries (180ah) on the 'house circuit', and this one 100ah BattleBorn on the 'radio and inverter' circuit. 

I still have some work to do, installing cables and connectors for the radio equipment and antennas, but things are looking good so far.

[RoamingKat]

I have not seen a chart that shows charging rate vs total lifetime, or total kWh over the life of the battery. Be nice to know if higher rates improve, cut, or have no effect on the life.

I bought my batteries 3 years ago from electriccarpartscompany.

It is not plug and play. But, experience and knowledge allow me to run my system without all the built in controls.

A BMS does four things... bottom cell balancing (which my batteries do,have built in), battery balancing (purchased separate devices which wire to each battery and then to each other) LoW/high voltage cut off..which I explained earlier in the thread, and temperature cut off...again explained in this thread.

The whole system (with balancers, relays and switches) cost me $2300 for 400ah. Or just a bit less than $600 per 100ah. At that time battle born wanted about $1000 per 100ah.

I think I have been seeing over the last year or so a drop in prices. Maybe when I need to replace in about 10 years it will be the cheaper choice.

[rvpopeye]

That $2300 is the old price ? Do you have an idea the cost for it today ?
Hopefully that is much less already !
(My 75watt panel cost me $600 in 2001, just paid $90 for a 100watt panel last year.)

10 years ?
Probably have something else as the "standard" by then....maybe super capacitors , or maybe something stolen from Nicola Tesla many years ago....

[tx2sturgis]

The whole system (with balancers, relays and switches) cost me $2300 for 400ah.   Or just a bit less than $600 per 100ah.  At that time battle born wanted about $1000 per 100ah.

This BattleBorn cost me $800 brand new, no shipping, no tax, no core....out the door.

Which is not bad, but I'm sure they will go down in price unless the powers-that-be decide to add a tariff just about the time I need a new one.

Funny. I have a friend who has an energy-efficient home. I told him about buying this BattleBorn 100ah battery for $800.

He went all wide-eyed, and said, "Wow! For $800 I can pay my electric bill on this entire property for a whole YEAR!"

Kinda puts this all in perspective.

[Wayne49]

Perspective? Not really.
His $800 annual cost isn't portable.
The battery lasts more than a year. Lifetime seems yet to be determined.
What were his energy efficiency costs?

[tx2sturgis]

Classic case of: you missed the point.

It costs money, and a fair amount of it, to be your own 'power company'.

Normal on-grid electricity costs are pretty low.

THAT is the perspective I refer to.