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Old 03-02-2017, 21:27   #5536
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Sorry, are you talking about first charging to 3.6, then cutting back at some point to 3.45? I haven't seen that, is it supposed to buy you a shorter charge cycle to get to 100% - which is bad for the bank?

I'm not talking about it I'm discussing the points Jack made in the video. He charged this specific cell just to learn the limits of it if you had watched the video which I know I did years ago before I even owned a battery bank. He is only relating to his viewers how quickly these particular cells uptake the energy they are fed and his recommendation is then later in the video that a normal user should simply set to 3.45 and forget about the rest with these cells. Admittedly Jack is over the .3C suggested charge rating of one cell (54amps) by using 100amp charge rate but for Jack it does not matter he is only demonstrating the benefits or shortcomings of the cell. I never did find the one video where he proposed to cold soak the cell and then test.

Then after the acceptance charge is completed he plainly states that he had to physically turn down his automatic power supply to maintain the constant voltage at the end of the charge. So then I conclude that perhaps an automated system for these cells is not a great idea.
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Old 03-02-2017, 21:35   #5537
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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So with this particular cell would it be wise to have something automated looking after the top end of a charge? I submit that no it would not and that such a charge should only occur with the security detail present - namely the all knowing and learned owner and master of the vessel.
With any LFP-scale investment, this ignorant "master of none" noob - not to mention early-onset demented, ADHD distracted, substance abusing, forgetful and bone lazy - there is NO way I wouldn't have fully automated control over the actual charging process.

Flip a switch, go relax until the cut-off signal sounds, ok maybe actually power down the genset and check the logs every once in a while, that's my style.

Scheduled maintenance checklist routines performed under my full attention, ok, but certainly not routine recharging cycles.

Margins of error that close, costs of error that high? If has to be manual, I'd stick to buying Sam's GCs every few years forever.
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Old 03-02-2017, 21:56   #5538
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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With any LFP-scale investment, this ignorant "master of none" noob - not to mention early-onset demented, ADHD distracted, substance abusing, forgetful and bone lazy - there is NO way I wouldn't have fully automated control over the actual charging process.
Okay and as I'm sure many others are aware as well this kind of trolling or language for whatever reason really isn't tolerated here. Also if you flat out calling me or others these things I ask for retraction immediately. I'm sure there are a great many individuals here that don't hesitate to pull out their volt meter to do sixteen simple voltage checks if and when needed to do a full acceptance charge on their cells to the upper knee.

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Flip a switch, go relax until the cut-off signal sounds, ok maybe actually power down the genset and check the logs every once in a while, that's my style.
Certainly and your allowed to have your style but then is it prudent or is it more akin to making sure everyone in Paris knows you have expensive diamonds and wonder why you have been relieved of them?


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Scheduled maintenance checklist routines performed under my full attention, ok, but certainly not routine recharging cycles.
To be clear there is nothing routine about taking cells up to or close to 3.6 volts and that is explicitly what I was referencing.


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It is just as easy when doing a full charge for a balance or whatever reason to take the bank that high to be that person

Margins of error that close, costs of error that high? If has to be manual, I'd stick to buying Sam's GCs every few years forever.
I believe we are saying the same thing here I just don't know where you went at the start of this post like way off topic.
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Old 03-02-2017, 22:08   #5539
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

There was a time when I planned for alternator charging of my lithium bank. I studied alternators some and found that sure in fact I could charge quite fast with them but for my solution it just did not pan out. Still didn't change the fact that I had spent considerable time weighing the merits of the genie or other small compact generators to provide DC charging at 48volts.

Then when I examine http://www.balmar.net/wp-content/upl...S-MC-614-H.pdf I'm not sure I would ever let this anywhere near my lithium bank from my brief reading of the document. If I ever charged my lithium bank with an alternator I would only ever charge to a certain voltage and then simply disconnect. This thing seems to have endless cycles from float to absorption to float. Truly lead acid technology.

Charge to certain voltage -> Stop
Detect low voltage setting -> Start

I mean how hard is that for pseudo code and yet manufacturers can't get their head around it two variables?

It is easier and wiser for the lithium bank owner if he is on the boat anyway to implement these two steps then to rely on dated lead acid technology charging algorithms that are not even the best algorithms from the lead acid age as other chargers from the same era are fully automatic and can complete the pseudo code above or at least part of it. Lestronic chargers for example.
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Old 03-02-2017, 22:28   #5540
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Okay and as I'm sure many others are aware as well this kind of trolling or language for whatever reason really isn't tolerated here. Also if you flat out calling me or others these things I ask for retraction immediately.
Woah nellie, only talking about myself here, no aspersions cast on anyone else or their choices!

Of course I use old school for checking up on things, hydrometers included.

But belt & suspenders oversight only, FOR MYSELF I can't be trusted to manage the routine day to day.

All I'm saying. . .
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Old 03-02-2017, 22:37   #5541
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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http://www.balmar.net/wp-content/upl...S-MC-614-H.pdf I'm not sure I would ever let this anywhere near my lithium bank from my brief reading of the document.
​Yes no float is best. But after hitting your 3.5 a 3.3 float is not known to appreciably shorten lifespan.

Maine Sail uses (used?) the MC-614 for his LFP.


Other way to go is battery-to-battery charger, as I mentioned Sterling (up to 120A now, 180 coming) lets you custom program your setpoints, just don't use their canned LFP profile!

So then you can filter all the dumb charge sources you like through a cheap automotive starter, pull exactly what and how you like to the LFP through the Sterling.
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Old 03-02-2017, 22:48   #5542
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Then after the acceptance charge is completed he plainly states that he had to physically turn down his automatic power supply to maintain the constant voltage at the end of the charge. So then I conclude that perhaps an automated system for these cells is not a great idea.
Just a problem with that unit, good chargers and VRs and solar controllers these days control their voltage very closely, hundreds of times per second.

Really good ones have their remote voltage and temp sensing wires completely separate from the charge output.
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Old 03-02-2017, 23:22   #5543
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

And John I think your none of those things and actually I've rather enjoyed communicating with you here on this thread so you need not be so hard on yourself. If your lithium battery user I certainly appreciate you especially because of your valuable input in this thread which in the long run does serve humanity.

I haven't looking into the sterling much whatever that is and I only looked into the balmer ever so briefly not even five minutes. I know many of these charge and set points can be adjusted but isn't that just the case that happened with a state of the art victron multiplus and Joe's batteries.

I guess I'm feeling a sense of inadequacy right now because I don't charge with CC/CV and thought perhaps I was better for it when in reality I had to use what was available and since I had already purchased two lestronic II 48v that came with electric outboards I put them to use with honestly not much thought as to if they would work to charge my lithiums because I was confident they would.

In some manner they do provide a CC/CV tapering down to 8amps at the end of their charge cycle but wouldn't you know it when I want the exact model number I don't have it documented anywhere on hand. Bottom line is I miss my boat so bad right now. I just ordered my trolling motor for it and now I have to come up with a solution to maintain my small bank of 16 calb 72ah lithium batteries with another lestronic II charger albeit 36 v. I will have to run this charger off the house inverter to keep the smaller bank running the gps anchor all night fully charged. I doubt the trolling motor will draw even 15 amps continuous if that but I'm specking the new charger for 40amps just to be safe.

The other thing on my mind is the condition of this smaller bank. When last the ignored thing sat in a milk crate in the bottom of my port hull at a voltage of 53.3 and I'm nowhere near it to check it's condition so I can't plan for any unforeseen inconsistencies with my implementation of this phase of the project.

I just emailed Lester electrical service to ask them why their chargers do such a nice job with lithium batteries and I'm hoping for a response. I'm also hoping to not be that guy that inadvertently or through ADHD, PTSD, or otherwise destroys or damages his lithium bank because of bad charging choices. I'm not sure I would have been better off with an Elcon charger right now or not. Would I buy one perhaps but still is not the time for it. So far I don't believe my charger choice has hurt my bank.
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Old 03-02-2017, 23:51   #5544
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

With LFP less is more, simplicity.

If the charger can't "wait for amps to taper to X then stop" then "absorb at 3.45 for 30 minutes then stop" gets you there, worst case, drop to 3.2 for float until you get a better charger.

There isn't any other "why" wrt LFP compatibility.

Key is after your full charge cycle, disconnect, at rest for a couple hours, check volts. If ~3.40, you did good, call it "functional 100%" and keep doing that every time.

Keep them cool but don't try to charge them when it's cold, don't draw down below 25%.

What else? seems simple right?


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And I'm not being hard on myself, just realistic about limitations of the old noggin. IMO routines are what silicone is for, saves our wetware bandwidth for the more fun stuff.

And yes PTSD too, how'd you know? 8-)

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Old 04-02-2017, 00:03   #5545
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Running an AC-DC charger off an inverter, really?
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Old 04-02-2017, 07:29   #5546
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

I am not aware of how to "easily" measure cell voltages in a multi-cell bank (which is always the case) with a handheld volt meter without isolating each cell from the others. If that is the case, then you have to remove the bus bars/cables connected it all together to get cell voltage readings.

There are some LFP monitors that have individual cell monitors that report back to either a BMS and or a cell logger. I actually am not sure how they get individual cell voltages but evidently they do.

If you want to use a handheld voltmeter to measure cell voltage, though that is certainly something you want to do on a frequent basis. Lot of potential to short the cells when removing the bus bars too.

If anyone has a better way I would love to hear of it. Even if there is a requirement to take apart a 16 cell battery to measure cell voltages, I am certainly just going to sell my cells and go back to another technology.
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Old 04-02-2017, 10:01   #5547
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Well it seem most modern BMS systems monitor cell voltages all the time. The aspect of placing the two probes on the top of terminals is the same. Not sure why you say you would have to disconnect all the batteries.
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Old 04-02-2017, 10:08   #5548
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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If anyone has a better way I would love to hear of it. Even if there is a requirement to take apart a 16 cell battery to measure cell voltages, I am certainly just going to sell my cells and go back to another technology.
Imho, this discussion is getting into the weeds again.

I just equalized the cells before installation and don't go over 3.45 during charge or below 3.1 on discharge, and I just sit back and enjoy both the boat and home backup power systems.

Both systems have BMS installed which never do anything but provide a blinky blinky light show with their LED's.

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Old 04-02-2017, 10:11   #5549
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Yeah I have no doubt I can run a battery charger off an inverter to another battery bank. I've looked but I can only find power supply units and the odd 48v to 36v dc dc converter that would be acceptable to power the unit. The 36v battery charger is the same principle. I only need to match the input charge amps to the output amps of the motor for a gps anchor that can run all night. I already have a 12v battery charger that I have in the boat from a inverter, another 36v will be no different.
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Old 04-02-2017, 10:31   #5550
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Imho, this discussion is getting into the weeds again.
Thank goodness for weedless propellers!

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I just equalized the cells before installation and don't go over 3.45 during charge or below 3.1 on discharge, and I just sit back and enjoy both the boat and home backup power systems.
I would agree it is as simple as that but on one occasion at least in my case there was need to calibrate a fussy potentiometer on my solar charge controller also the other time I had to go above that was when I want to calibrate my EV display for total pack amp hours. Calibrating total pack amp hours means the bank is fully charged and there are no draws on the pack in or out. Apparently after that based on your variables you have an accurate coulomb counter.

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Both systems have BMS installed which never do anything but provide a blinky blinky light show with their LED's.

Not sure what BMS your running but if the house power BMS then I have the same. The lights are informative for sure but I still have not memorized what all the blinks are supposed to mean. It is a very good system the only downside being if ever one of those little blinky boards fail then are you getting the right picture. So far as I'm concerned if you have a house power BMS as many do there may be a way to get individual cell voltages out of the system via the CAN bus but my reality is simply easier to just check them with a voltmeter. So far the system does a great job.

This does bring up another aspect of the shunting capabilities of the system though. Those little boards will never be able to in the case of wildly misbehaving cell for one reason or another be able to quickly shunt enough current to offset a potential tragedy. I'm simply suggesting that when you find yourself at either end of the charging knee for whatever reason that it is not a bad idea to check the voltage levels of individual cells manually with a voltmeter and base your decisions from there.
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