Valence U27-12XP Lifepo4 Lithium Battery -
what do i need to run these ?
These batteries are normally part of a large array in trucks and come with a master BMS controller and sperate isolator relay . . .
This is what they look like in their natural habitat . .
this is the OEM Master BMS . . .
and these are the main Contactor Relays . .
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These are very popular in the solar storage and Leisure application on the second hand market . . .
but there are some things that you need to know about how to get the best out of these batteries . .
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1: there is no internal "Low Voltage disconnect", this is because in the OEM setup the disconnect relay is separate in inline with a block of four batteries . . . what this means is that you can damage the battery if you run it too low (below 10v) . . . The manual states the OEM low volt cut off will kick in at 10v, but in our application we have to fit our own. there are many "battery protect" devices about . . . . My preferred unit is the Victron Smart Battery Protect. - Note that the internal BMS will track the voltage and show a green, yellow, red status LED.
you set the low volt trigger and at that point the loads are disconnected saving your battery . . . note all charge sources need to be behind it, ie dont back charge through it !
so you can either just use a battery monitor and isolator and switch off the battery when it runs low . . . or if like me your forgetful then fit the automatic version.
here is an example of the Victron 65A
Victron Energy Smart BatteryProtect 12/24V 65A - BPR065022000: Amazon.co.uk: Car & Motorbike
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and the 100A version:
Victron Energy Smart Battery Protect 12/24V 100A - BPR110022000: Amazon.co.uk: Car & Motorbike
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2: Like most batteries there is no internal fuse or circuit breaker, we need to fit a safety fuse next to the battery. the fuse needs to be able to protect the cabling and installation. the size and rating of the fuse depends of the total system, the current drawn and the size of cables., ,. each cable or circuit needs to be protected by its own fuse. . . but the master battery fuse needs to be first inline and capable to carry to total system current . . . which is why the main battery cables are always the thickest.
you can use MIDI & MAXI fuses and fuse holders . . . you can also use thermal trip switches . . . . but from testing i have found to get hot in operation so prefer to use MIDI fuses now.
MIDI fuse holder example . .
Buy All Trade Direct 1 X Strip Link & Midi Fuse Holder For Striplink & Midi Fuses Fuseholder Fits All at Amazon UK. Free delivery on eligible orders.
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and MIDI fuses . . .
Buy Carviya 5 Pack Mini ANL Fuses 30 Amp 40Amp 60Amp 80 Amp 100 Amp (30/40/60/80/100 Amp Combine) at Amazon UK. Free delivery on eligible orders.
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3: Isolator switch . . . This is optional.
If you want a master ON/OFF switch for the battery bank you can fit one of these . . . You can also use the Victron smart protect as a virtual on/off switch . . . or just remove the MIDI fuse as mentioned above . . . you might want to use this when the van is parked up for an extended period . . . oe while doing work on the van?
Buy Master Switch Battery 12V/24V - Battery Cut Off Switch - Master Battery Isolator Disconnect Switch Car Battery Kill Switch Accessories For RV Yacht Boat Truck Bus Motorcycle Car at Amazon UK. Free delivery on eligible orders.
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4: battery monitor . . . . This is optional. . . . being Lifepo4 a Shunt style of monitor is required . . . this will give you a gauged view of the SOC "state of charge" of the battery . . .
That will give you an idea of when to recharge etc and how much run time you have left . . . most will also show you how much power you are drawing or charging .
more can be seen over here >
Battery Monitoring -- How I Done It --
My preferred shunt monitor is the Victron Smart Shunt, . . or the BMV712. . . . There are others now from Renogy and other suppliers.
Victron Energy SmartShunt Battery Monitor 500A Bluetooth Inside - SHU050150050: Amazon.co.uk: Business, Industry & Science
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and
Victron Energy Battery Monitor Digital Watt Voltage Current Power Meter (Battery Monitor BMV-712 Smart): Amazon.co.uk: Business, Industry & Science
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The awesome BM2 is also a worthy investment for overall data logging (free APP on your phone, Bluetooth) . . with it you can see the over trend of the voltage in your system and see how and when the battery is being drained or charged. . .
Auto Battery Monitor BM2 Bluetooth 4.0 12V Device Car: Amazon.co.uk: Electronics
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5: A Proper charge source . . . "Charger" . . . There is no inbuilt charge protection, so its important that you use a charger fit for purpose. most modern smart charger are suitable if they have a lithium profile . .
Remember "charge Sources" are EHU charger, DC-DC charger, Solar charger etc etc etc . . . basically any source that will feed to power to the battery. - s o you need to make sure that all your charge sources are suitable
more can be seen here >
EHU -
Battery Chargers - How I Did It -
DC-DC -
DC-DC Charger (for leisure battery) -- How I Done It --
Solar -
Solar PWM & MPPT Controllers - How I Done It -
my preferred charger is now Victron because of the excellent data monitoring, configuration and usability of the free Blutooth APP.
heres two examples of the ones i have:
15A blue smart charger . . .
Buy Victron Energy BPC120531064R Battery Chargers with Built-in Bluetooth Module at Amazon UK. Free delivery on eligible orders.
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30A blue smart 12/30/1 charger
Victron Energy Blue Smart IP22 Charger 12: Amazon.co.uk: Electronics
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6: Low temperature protection . . . . . These batteries can be used down to -10degc which is great . . . . BUT the only issue is charging !!
like most Lifpo4 batterys they should not be charged below 0dec . . . or 5degC if you add a margin... . one option is to fit a temp monitor and APP to get some real data on the batteries temp . . . . just because its freezing outside it doesn't mean the battery inside the van is also freezing . . . so start with a temp monitor.
like one of these . . .
Fridges & Cold Beer -- How I Done It --
Shop ORIA Wireless Thermometer Hygrometer, Mini Bluetooth 5.0 Humidity Temperature Sensor with Data Export and Notification Alerts Push for iOS Android for House, Wine Cigar, Baby Room. Free delivery on eligible orders of £20 or more.
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if you are in a situation where you need to charge at very cold temps then look at some of the options over here >
Lithium LifePo4 12v Batteries - Time For An Upgrade?
or get yourself some 12v heat pads and thermostat . . . but remember is only CHARGING where this is important . . . . you may find that just running some loads for a few mins is enough to raise the battery temp.
7: BMS comms cable and software . . . optional . . . the internal BMS in the OEM setting is running 24/7 as as such data logs all the battery metrics . . . like SOC and WH discharged etc etc . . . BUT when the battery is separated from the master BMS the data logging is switched OFF after a few mins. . .
that is until you get/make your own cable and run you own software . . so when the battery is running stand alone . . . as in our vans the data logging is disabled . .
its been suggested to have the cable and software . . . because when plugged in and connected the internal BMS starts logging data and activates the top balancer circuit. . . the suggestion is that with daily use (charge /discharge cycles) that the battery should be fully charged with the cable and software connected to that a fully top balance of the internal cells is carried out ( every 1-3months if battery is used daily) . - note that most users of these batteries don't do this and just charge and discharge as normal with no ill effects provided the charging and discharge limits are not exceeded. (im doing tests to see if the internal balancer kicks in without the software connected)
..
www.t6forum.com
diysolarforum.com
github.com
got it sussed now .
