LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[OceanSeaSpray]

Originally Posted by hellosailor

"Temperature compensation, on the other hand, is a term that relates to correcting the output voltage according to ambient temperature."
Although, as I've heard the term used, the question is very much not ambient temperature, but the temperature of the battery/bank itself.
...
"Built-in alternator regulators cannot (and do not) do this, as they can't sense ambient in the environment they operate in."
...
If no one is doing it yet--that doesn't mean it can't be done. Just that they haven't felt a need to spend the extra buck on parts yet.

Very interesting that lithiums don't need thermal compensation though. In all the messages and all the propaganda, ergh, ah, DATA sheets I've read, I hadn't seen that mentioned before.

Ambient vs battery temperature, yes, fair comment. But if you operate lithiums at a conservative C-rate and stop charging at the beginning of the upper knee, battery temperature will remain pretty close to ambient due to the extremely low internal resistance.

When it comes to sensing ambient temperature inside an alternator, good luck. The air flow around it is more often at engine room temperature rather than anything else. No go, no matter how clever I am afraid.

The fact LiFePO4 data sheets don't specify temperature corrections for charging voltages means just that: no correction. I did research the matter a bit further however some time ago. It becomes a problem when equipment intended for lead-acid cells is used with lithium cells and this is another reason for staying away from gadgets. Same for solar regulators, many fancy ones compensate for temperature. In fact, the simplest, cheapest switching regulators often provide the best service here.
Lithiums are much easier to charge than lead-acid batteries, especially when the aim is ~90% SOC.

[SV THIRD DAY]

Originally Posted by OceanSeaSpray

the simplest, cheapest switching regulators often provide the best service here.
Lithiums are much easier to charge than lead-acid batteries, especially when the aim is ~90% SOC.

Bingo...the take away of the day!
K.I.S.S. doesn't sell high priced computer controlled gadgets!
I was at the Solar expo in San Francisco and also had all the big name LiFePO4 battery manufacturers there a few weeks ago and saw one BMS with a touch screen computer display, ethernet capable, and they are working on an App for the IPhone and IPad....really...ha ha ha

[CarstenWL]

... am am planning to use a Kilovac relay on my soon to be installed 400Ah Winston house bank.

I see that the EV200 is available with auxiliary contacts (could be an advantage for further signaling):

Product Comparison for High Voltage Relays - TE

Can someone comment on the used terminals (not familiar what a 'Stud terminal' is - Coil Leads vs. Stud Terminal for instance?)

Coil leads = wires coming out of the relay?
Stud terminal = ?

Thanks!

Carsten

[DYMOsupport]

Originally Posted by hellosailor

Y
I've had similar gizmos (Esselte/Dymo) produce labels that literally turn black in the heat, but the Brother apparently is different material, and they make specific cartridges for wire labels, extra durable, extra flexible, extra heat resistant. If you can get that there, a bit pricey but a very nice long term solution.

As an honorary Scotsman, I'll say the Brother P-Touch is worth whatever it costs you.

We (DYMO) make plastic and rubber labels of industrial strength. The ones you mention are meant to be used in office environments.

The industrial Rhino series has rubber, vinyl, polyester and plastic tapes that are extremely durable. The D1 series also has plastic ones. In fact, Geomar (a German company that does ocean research) has let us know that these D1 tapes last for years at depths of 6,000 m and weeks under equatorial sun or -80 degrees in the north (one can only wonder how long the industrial ones can survive).

^CM
DYMOsupport

[transmitterdan]

Originally Posted by CarstenWL

... am am planning to use a Kilovac relay on my soon to be installed 400Ah Winston house bank.

I see that the EV200 is available with auxiliary contacts (could be an advantage for further signaling):

Product Comparison for High Voltage Relays - TE

Can someone comment on the used terminals (not familiar what a 'Stud terminal' is - Coil Leads vs. Stud Terminal for instance?)

Coil leads = wires coming out of the relay?
Stud terminal = ?

Thanks!

Carsten

Stud terminal means there is a threaded rod (stud) that you put a ring lug terminal on and then a nut threads onto the stud to secure the lug. Coil leads just means the coil that activates the relay has a length of wire coming out of the relay. You have to terminate these 2 wires somewhere as there is no termination screw on the relay itself.

[hellosailor]

Dymo, it is nice to know you make something better. On the US consumer market, the "Esselte" name is likely to bring about "Huh?" from everyone except graphic artists though, and DYMO still gets instant recognition for those 1960's raised-lettering tapes. I've never noticed any other Esselte/Dymo product on the consumer market, and sadly the "P-touch"-like product doesn't seem to make any warning about "use on cold surfaces only". The warmth generated by my computer, an office-environment product, was enough to turn labels on it black and illegible in a short (18 month? two year?) span.

I'm not sure, but I don't think operating the computer at 6000m below sea level would have really helped. Customer support never suggested that one to me, I'll have to try it.

[DYMOsupport]

Originally Posted by hellosailor

Dymo, it is nice to know you make something better. On the US consumer market, the "Esselte" name is likely to bring about "Huh?" from everyone except graphic artists though, and DYMO still gets instant recognition for those 1960's raised-lettering tapes. I've never noticed any other Esselte/Dymo product on the consumer market, and sadly the "P-touch"-like product doesn't seem to make any warning about "use on cold surfaces only". The warmth generated by my computer, an office-environment product, was enough to turn labels on it black and illegible in a short (18 month? two year?) span.

I'm not sure, but I don't think operating the computer at 6000m below sea level would have really helped. Customer support never suggested that one to me, I'll have to try it.

Thank you for the feedback. It seems that what you had was a LW label. They react to light and heat, this is how text is transferred onto them (it is burned).

What I had in mind were D1 tapes. Since posting commercial links here is not allowed, it is best if you contact us so we can send you a sample and you can give it a go.

^CM
DYMOsupport

[hellosailor]

Dymo, thank you for the offer but I have since given away the Esselte label maker and switched to a Brother. I have no idea if those other tapes would have worked in it, but since it has found a new home, that's a moot point.

[ColdEH]

Hey thread gone quiet?

Well i just received 50 pounds of 4/0 wire , and the Mastech bench power supply/charger should be here today as well, this company was great to deal with, and very fast shipping . Using this for initial balancing of the cells .

Also have braided cell connectors coming from EVworks in Australia , I think I will have to wait a bit for them to get here.

But install is moving ahead.

Mastech Power Supply - Best Deals on Variable Power Supplies (Powered by CubeCart)

home

Regards

[msmith132]

CALB bus bars - are they truly up to the task?

I just received my order of 12 X 180 AH cells and bus bars, and the bars look awfully light to me. Before I install them on my boat in a 12 V 540 AH 3P4S configuration, I am looking for a second opinion and am hoping somebody in this group can help me. The bus bars are copper, 0.5 mm thick X 22 mm wide for a cross section of 11 mm², about the equivalent of 8 AWG wire. Frankly I am quite concerned about passing 300 amps thru these bars. Am I missing something? Thanks all.

As well, the HPBMS has no information regarding the current carrying capacity of the relay and alarm channels so I don't know if I need intermediate relays for the various alarms and solenoids, can anybody enlighten me? Thanks again. I'm getting very anxious to get these installed but can't get past these questions.

[hellosailor]

https://en.wikipedia.org/wiki/American_wire_gauge

The Wiki shows your bus is somewhat thicker than a 7AWG equivalent, and while that is not rated to carry anywhere near that current, it also won't melt from it. Since there's no insulation to catch fire, it probably can do the job but with some significant heat during heavy charging. On the bright side, it would also work as a primary fuse in the event of a crowbar short. :-)

[Dsanduril]

.5mm thick? That's copper foil, not a bus bar

Electrical: Busbar - DC Copper Busbar Ampacities

shows 1/8" (~3mm) at 1" (25.4mm) for your current. [edit]DC likes skin, but still,[/edit] 0.5mm seems awfully light.

There's one second opinion, you can probably get a few more around here.

[hellosailor]

"DC likes skin,"
DC?? I thought that was AC that had a skin effect.

[Dsanduril]

Originally Posted by hellosailor

"DC likes skin,"
DC?? I thought that was AC that had a skin effect.

absolutely correct, my fingers somehow got ahead of my brain, not sure where that came from.

[hellosailor]

"my fingers somehow got ahead of my brain,"
The Skin Effect.(G)
A familiar feeling.