Lithium LifePo4 12v Batteries - Time For An Upgrade?

[Dellmassive]

Here we go, I've just completed testing on a Victron setup for LTD.

and @Deaky will be happy as its much less "Heath Robinson" solution.


so we have a Victron BMV712 smart battery monitor (monitor power/volt/amp levels in/out of battery) BMV-712 Smart - Victron Energy




Victron Temperature Sensor for BMV702/712 (provides temp/volt data for the BMV) Temperature Sensors [Victron Energy]



and a Victron - SmartSolar MPPT 75/15 (solar mppt charger) SmartSolar MPPT 75/10, 75/15, 100/15 & 100/20 - Victron Energy




The Temp sensor connects to the battery +v post and plugs into the BMV battery monitor. (monitors battery temp and supplies power to the BMV)




Thats about it.

The solar on the roof charges the battery via the MTTP.
The power in/out is monitored via the BMV
you can add your DC-DC as per below.

Now the cleaver bit, you create a VE-Direct bluetooth network via the Victron app, this enables the BMV to report the battery bank voltage and temp to the MPPT wireless via bluetooth..


The solar MPPT has its own setting in the lithium profile that you can now set the LTD point . . . say 5degC, so at that point the MPPT will stop charging the battery. (Solar MPPT LTD done!)


But what about my DC-DC charger? - how do i stop that from charging my batterys when cold? . . . . Well the BMV has a latching relay on the back of the display.
This can be set to do many things, but in out case we are setting it to be a LTD (this is a separate setting/adjustment to the mppt and works independently).

We set the alarm relay to open at below 4degC and to close again above 6degC (you can set whatever limits) we can now use this relay to interrupt the turn on signal for our DC-DC charger.
in our case its a Redarc BCDC charger that requires a ignition/run feed to start working. . . . . so if its to cold the BMV will keep the BCDC off untill the temp rises (by disabling the ignition feed to the dc-dc). (DC-DC LTD Done!)

No external cheap temp PCB`s, no external SCR or contractors, nothing get disconnected and no messing about . . . . . . . just a BMV (with temp), MTTP, DCDC


Now, as for a LBD, thats easy, just buy a victron battery protect unit and set it to 11.5v disconnect then wire between the loads and +v battery terminal - but ill show that a different day.


More detailed look into things below . . . . . . .










what we see below is the BMV now reporting the battery temperature . . . . 18degC




below we can see the temp is being reported to the MPPT . . . 19degC



here we can set the low temp disconnect for the solar mppt.....in this case 10degC for testing.



i set the LTD to below 10degc at this point we are still charging at 45W . . . .



but . . . . . i use brake-clean to freeze the battery terminal to drop the temp . . . when the temp went below 10degC for 10seconds the MPPT charger shut off ( it doesnt say its off, but the PV and solar side drop to 0A and 0W)


as the temp rises again the solar MPPT will restart and start charging again.




Its the same with BMV . . . . you set the relay lower and upper temp ranges and thats-that . . . . just use that relay to shut off your DC-DC charger.


. end.

.

 

[Dellmassive]

cool, thanks. so it would be most useful with a victron MPPT and inventor then? any recommendations on model for my scenario. sorry to ask so many questions. Just love to get the best option on things and i love apps.

depends on your needs . . . but as a guide (if you want to go victron with the app)

300w panel - 12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine
200ah Lifepo4 - Lithium battery 12,8V & 25,6V Smart - Victron Energy
800va inverter - Phoenix Inverter VE.Direct - Victron Energy
75/20 mppt - SmartSolar MPPT 75/10, 75/15, 100/15 & 100/20 - Victron Energy
15A EHU charger - Blue Smart IP22 Charger - Victron Energy
40A DC-DC with MPPT - REDARC BCDC1240D Battery - Battery Charger with MPPT 40A | SplitCharge.co.uk
optional LBD - Battery Protect - Victron Energy
install sundries. -

 

[andys]

Here we go, I've just completed testing on a Victron setup for LTD.

and @Deaky will be happy as its much less "Heath Robinson" solution.


so we have a Victron BMV712 smart battery monitor (monitor power/volt/amp levels in/out of battery) BMV-712 Smart - Victron Energy

View attachment 51536


Victron Temperature Sensor for BMV702/712 (provides temp/volt data for the BMV) Temperature Sensors [Victron Energy]

View attachment 51535

and a Victron - SmartSolar MPPT 75/15 (solar mppt charger) SmartSolar MPPT 75/10, 75/15, 100/15 & 100/20 - Victron Energy

View attachment 51534


The Temp sensor connects to the battery +v post and plugs into the BMV battery monitor. (monitors battery temp and supplies power to the BMV)

View attachment 51537


Thats about it.

The solar on the roof charges the battery via the MTTP.
The power in/out is monitored via the BMV
you can add your DC-DC as per below.

Now the cleaver bit, you create a VE-Direct bluetooth network via the Victron app, this enables the BMV to report the battery bank voltage and temp to the MPPT wireless via bluetooth..


The solar MPPT has its own setting in the lithium profile that you can now set the LTD point . . . say 5degC, so at that point the MPPT will stop charging the battery. (Solar MPPT LTD done!)


But what about my DC-DC charger? - how do i stop that from charging my batterys when cold? . . . . Well the BMV has a latching relay on the back of the display.
This can be set to do many things, but in out case we are setting it to be a LTD (this is a separate setting/adjustment to the mppt and works independently).

We set the alarm relay to open at below 4degC and to close again above 6degC (you can set whatever limits) we can now use this relay to interrupt the turn on signal for our DC-DC charger.
in our case its a Redarc BCDC charger that requires a ignition/run feed to start working. . . . . so if its to cold the BMV will keep the BCDC off untill the temp rises (by disabling the ignition feed to the dc-dc). (DC-DC LTD Done!)

No external cheap temp PCB`s, no external SCR or contractors, nothing get disconnected and no messing about . . . . . . . just a BMV (with temp), MTTP, DCDC


Now, as for a LBD, thats easy, just buy a victron battery protect unit and set it to 11.5v disconnect then wire between the loads and +v battery terminal - but ill show that a different day.


More detailed look into things below . . . . . . .







View attachment 51538


what we see below is the BMV now reporting the battery temperature . . . . 18degC

View attachment 51540
View attachment 51541

below we can see the temp is being reported to the MPPT . . . 19degC

View attachment 51542

here we can set the low temp disconnect for the solar mppt.....in this case 10degC for testing.

View attachment 51543

i set the LTD to below 10degc at this point we are still charging at 45W . . . .

View attachment 51544

but . . . . . i use brake-clean to freeze the battery terminal to drop the temp . . . when the temp went below 10degC for 10seconds the MPPT charger shut off ( it doesnt say its off, but the PV and solar side drop to 0A and 0W)
View attachment 51546

as the temp rises again the solar MPPT will restart and start charging again.

View attachment 51545


Its the same with BMV . . . . you set the relay lower and upper temp ranges and thats-that . . . . just use that relay to shut off your DC-DC charger.


. end.

.

Just phenomenal How on earth do you get time to do any work

 

[Dellmassive]

Lifepo4 capacity testing.....

More details soon.

 

[Dellmassive]

Part1 - LBD

LBD (Low Battery disconnect) and Lifepo4 capacity testing . . . .

let me start by saying I've been playing with Lithium batteries for years, from RC LiPo`s to laptop/Vape stick 18650`s and also large scale 12v installs for ICE and large inverters. . . . BUT these large capacity Lifepo4`s are freeking awesome !!!. . . (I love this one so much, I've just sold a kidney and bought a second one - Valence U27-12XP 12.8V @ 138ah)

lets start with the LBD, a simple purchase of, in this case the 100A (max throughput) Victron smart battery disconnect : Smart BatteryProtect - Victron Energy




Its Bluetooth so you can adjust the setting and monitor the battery via the app. in this case i set the shut-off point at 11.25V and reconnect point at 12.5V (you can also use the app to manual disconnect the power (like a virtual switch))

you can see it here below, simply connected inline on the positive cable (plus it has its own ground wire)



Normal operation we have this load output active :



then when the battery drops below the alert point we get an alarm like this:





then 30 seconds later the unit disconnects the power:





Job done, this has now shut off all loads from the battery at 11.1V and saving the battery from deeply discharging . . . . the battery voltage recovered slightly as we were pulling a 50A load but it was still below the reconnect voltage / . . . . . . all that was left now was to recharge the battery.

.

I

 

[Dellmassive]

Part2 - Capacity testing.

LBD (Low Battery disconnect) and Lifepo4 capacity testing . . . .

let me start by saying I've been playing with Lithium batteries for years, from RC LiPo`s to laptop/Vape stick 18650`s and also large scale 12v installs for ICE and large inverters. . . . BUT these large capacity Lifepo4`s are freeking awesome !!!. . . (I love this one so much, I've just sold a kidney and bought a second one - Valence U27-12XP 12.8V @ 138ah)

Lifepo4 batteries are not cheap on the upfront cost, but are way cheaper over the TCO over a longer period vs lead acid and they are way cooler and have awesome energy density.

So to get one on the cheap i decided to buy a used one . . . . now they were advertised as 400 out of 4000 cycles used. But being realistic and knowing ebay i expected a real life battery to be 20% life used so to have a 80% life capacity left . . . so 80% of 138ah should give me 110Ah, though i would be happy for even 100ah. . . . the results at the end are shocking. !!!

The test procedure was to use a separate current meter to monitor the Ah and wh leaving the battery, next was to draw power from the battery.

i started with a 800va Victron inverter and a few 240v 18V makita battery chargers, a 240v 50W desk lamp and a 240v 360W dehumidifier . . . . these all summed up to around 50Amps being drawn from the battery.


This how its setup. the current monitor is on the left and connected to the meter next to it.





heres the inverter, lamp and one of the chargers:



next was a separate volt meter to double check the settings/readings:



Now it was just a matter of time . . . . i had the LBD connected and would shut down the loads at 11.25v, so all i needed to do was run the loads until the LBD cut out and them read the ah used. . . . simples.


i started at 3.30pm battery voltage was 13.2v and i was drawing 50A continuously . . . .




due to the chargers and dehumidifier cycling the power drawn was fluctuating . . . .

1- But by 4.20pm we had drawn 31.AH and 394WH (1:43hrs runtime)




2- by 5:15pm we had drawn 63.AH and 797WH (2:36hrs runtime)




This is the laptop monitoring the battery, its showing 55amps discharge and still 98% full !!





3- But by 6pm things were starting to get interesting. we had drawn 96.AH and 1212WH (3.21hrs runtime) (still drwaing 50Amps!!!!)




The next check blew my mind . . . .

4 - But by 6.43pm we had drawn 129.AH and 1638WH (4:01hrs runtime)




the battery stats were still good, and we were still at around 12.0V . . . . (still drawing 50Amps !!)




The next check point it finally happened . . . . . . . The Victron LDB had kicked in and disconnected the loads @ 11.1vdc . . . .





so what were the results?



5- by 6.52pm we had drawn 137.AH and 1730WH (4:10hrs runtime)

hold on WHAAAAAAAAAAAAAAAAAAT !!!!


50A draw (cycling)
137ah
1730wh
for 4.10 hours



thats astounding , , , , drawing 50A for hours and hours !!!

and the second hand battery !!! well

137ah/138ah * 100 = 99.27%

so not only is the battery still working as NEW but its also proved that it can deliver its 99% discharge capacity to the 11.2v cutoff point.

im sure if i was drawing less that the 50A load i could easily exceed the 138Ah capacity.



The next step was the recharge . . . . . . but having a 15A victron charger, that was a bit slower.....

back in the office:



with this charger:



and this monitor:





i left it over night . . .

during the test i managed to discharge @ 50A which took 4 hours . . . the battery is rated for 150A continuous !!!

the recharge @ 15A to all night and is still going now . . . . but again is capable of charging at 70A !!!!



Conclusion:

These batteries are freeking awsome.

The available discharge rate is freeking awsome.

The available recharge rate is freeking awsome.

the ability to power large loads with 100% DOD & and very low volt sag is freeking awsome.

The upfront cost of the is NOT freeking awsome.




Notes:
Im using a Victron LBD to protect from Low voltage damage
im using a Victron BMV + MTTP with temp control to protect from LTD low temp charging

Dont use those breaker bimetallic trip type switches for high amp loads !!!! i had a 150A trip switch and was only pulling 50A but it started heating up (long duration loads) , the cable started heating up each side of the trip switch from thermal conductivity . . . . . so use appropriate MIDI style fuses . . . . im now replacing ALL trrip style circuit breakers with MIDI fuses!!!

************************************************************************

another net effect of this full charge/discharge/charge cycle is that the internal cells are now fully in balance, before they were over 12mV out . . . . now they are 1mV out . . . . which is good.

The internal BMS monitors each cell bank:

1-3358mV
2-3359mV
3-3358mV
4-3358mV

the warning point is any cell bank more than 10mV out . . . . at which point the BMS will attempt to balance the bank.

There is a "TOP Balance" and "BOTTOM balance" which refers to the fully charged and discharged state . . . . so an occasional full charge-discharge-charge can be good for cell balancing . . . . but use your BMS monitoring software to keep an eye on things.


************************************************************************

i was soooo impressed i sold my kidney, sole to the devil, my left arm to science and went and bought a second one off the same ebay seller . . . . . . hopefully the testing will prove that both batteries are 99% fresh and new (plus with a 6mnth warranty....i hope so)

************************************************************************-


over to you lot . . . any other testing you want me to do?

any questions?




end.

 

[andys]

Part2 - Capacity testing.

LBD (Low Battery disconnect) and Lifepo4 capacity testing . . . .

let me start by saying I've been playing with Lithium batteries for years, from RC LiPo`s to laptop/Vape stick 18650`s and also large scale 12v installs for ICE and large inverters. . . . BUT these large capacity Lifepo4`s are freeking awesome !!!. . . (I love this one so much, I've just sold a kidney and bought a second one - Valence U27-12XP 12.8V @ 138ah)

Lifepo4 batteries are not cheap on the upfront cost, but are way cheaper over the TCO over a longer period vs lead acid and they are way cooler and have awesome energy density.

So to get one on the cheap i decided to buy a used one . . . . now they were advertised as 400 out of 4000 cycles used. But being realistic and knowing ebay i expected a real life battery to be 20% life used so to have a 80% life capacity left . . . so 80% of 138ah should give me 110Ah, though i would be happy for even 100ah. . . . the results at the end are shocking. !!!

The test procedure was to use a separate current meter to monitor the Ah and wh leaving the battery, next was to draw power from the battery.

i started with a 800va Victron inverter and a few 240v 18V makita battery chargers, a 240v 50W desk lamp and a 240v 360W dehumidifier . . . . these all summed up to around 50Amps being drawn from the battery.


This how its setup. the current monitor is on the left and connected to the meter next to it.

View attachment 51664



heres the inverter, lamp and one of the chargers:

View attachment 51665

next was a separate volt meter to double check the settings/readings:

View attachment 51666

Now it was just a matter of time . . . . i had the LBD connected and would shut down the loads at 11.25v, so all i needed to do was run the loads until the LBD cut out and them read the ah used. . . . simples.


i started at 3.30pm battery voltage was 13.2v and i was drawing 50A continuously . . . .

View attachment 51667


due to the chargers and dehumidifier cycling the power drawn was fluctuating . . . .

1- But by 4.20pm we had drawn 31.AH and 394WH (1:43hrs runtime)

View attachment 51668


2- by 5:15pm we had drawn 63.AH and 797WH (2:36hrs runtime)


View attachment 51669

This is the laptop monitoring the battery, its showing 55amps discharge and still 98% full !!

View attachment 51670



3- But by 6pm things were starting to get interesting. we had drawn 96.AH and 1212WH (3.21hrs runtime) (still drwaing 50Amps!!!!)

View attachment 51671


The next check blew my mind . . . .

4 - But by 6.43pm we had drawn 129.AH and 1638WH (4:01hrs runtime)

View attachment 51672


the battery stats were still good, and we were still at around 12.0V . . . . (still drawing 50Amps !!)

View attachment 51673


The next check point it finally happened . . . . . . . The Victron LDB had kicked in and disconnected the loads @ 11.1vdc . . . .



View attachment 51674

so what were the results?

View attachment 51675

5- by 6.52pm we had drawn 137.AH and 1730WH (4:10hrs runtime)

hold on WHAAAAAAAAAAAAAAAAAAT !!!!


50A draw (cycling)
137ah
1730wh
for 4.10 hours



thats astounding , , , , drawing 50A for hours and hours !!!

and the second hand battery !!! well

137ah/138ah * 100 = 99.27%

so not only is the battery still working as NEW but its also proved that it can deliver its 99% discharge capacity to the 11.2v cutoff point.

im sure if i was drawing less that the 50A load i could easily exceed the 138Ah capacity.



The next step was the recharge . . . . . . but having a 15A victron charger, that was a bit slower.....

back in the office:

View attachment 51676

with this charger:

View attachment 51677

and this monitor:

View attachment 51678



i left it over night . . .

during the test i managed to discharge @ 50A which took 4 hours . . . the battery is rated for 150A continuous !!!

the recharge @ 15A to all night and is still going now . . . . but again is capable of charging at 70A !!!!



Conclusion:

These batteries are freeking awsome.

The available discharge rate is freeking awsome.

The available recharge rate is freeking awsome.

the ability to power large loads with 100% DOD & and very low volt sag is freeking awsome.

The upfront cost of the is NOT freeking awsome.




Notes:
Im using a Victron LBD to protect from Low voltage damage
im using a Victron BMV + MTTP with temp control to protect from LTD low temp charging

Dont use those breaker bimetallic trip type switches for high amp loads !!!! i had a 150A trip switch and was only pulling 50A but it started heating up (long duration loads) , the cable started heating up each side of the trip switch from thermal conductivity . . . . . so use appropriate MIDI style fuses . . . . im now replacing ALL trrip style circuit breakers with MIDI fuses!!!


************************************************************************

i was soooo impressed i sold my kidney, sole to the devil, my left arm to science and went and bought a second one off the same ebay seller . . . . . . hopefully the testing will prove that both batteries are 99% fresh and new (plus with a 6mnth warranty....i hope so)

************************************************************************-


over to you lot . . . any other testing you want me to do?

any questions?




end.

Looks really good. From what I’ve read and watched though, frequently discharging a LiFePo4 battery below 80% capacity does significantly reduce its life.

 

[Dellmassive]

yes this is true. full DOD will reduce the total amount of cycles and is in proportion to the amount of discharge. . . .

the odd full discharge to ballance cells is ok . . say once a month or when needed.

but in real life you should spec your battery bank so that you never deplete it less than 50% before its recharged . . . less that 80% would give the longest lifetime . . . but that just not practical

>4000 cycles (80% DOD)

here is the DOD discharge curve @ C/2.

U-Charge® XP for 12V, 24V, 36V, 48V up to 1kV Battery




*********************************

SOC Alignment
SOC Alignment occurs at charge complete, after all cell blocks have balanced. To optimize the performance of the battery pack this should be done as often as possible. The minimum recommended is at least once a month.

Capacity Learning
Valence modules continuously learn their own capacity. A periodic discharge to 20% SOC followed by charge complete cycle will optimize this process

**********************************


also include the full manual which i found a fascinating read and has a wealth of information. (pdf attached below)

.

 

[andys]

yes this is true. full DOD will reduce the total amount of cycles and is in proportion to the amount of discharge. . . .

the odd full discharge to ballance cells is ok . . say once a month or when needed.

but in real life you should spec your battery bank so that you never deplete it less than 50% before its recharged . . . less that 80% would give the longest lifetime . . . but that just not practical

>4000 cycles (80% DOD)

here is the DOD discharge curve @ C/2.

U-Charge® XP for 12V, 24V, 36V, 48V up to 1kV Battery


View attachment 51683

*********************************

SOC Alignment
SOC Alignment occurs at charge complete, after all cell blocks have balanced. To optimize the performance of the battery pack this should be done as often as possible. The minimum recommended is at least once a month.

Capacity Learning
Valence modules continuously learn their own capacity. A periodic discharge to 20% SOC followed by charge complete cycle will optimize this process

**********************************


also include the full manual which i found a fascinating read and has a wealth of information. (pdf attached below)

.

Yes that all makes senses. Too often though, I’m seeing lithium batteries marketed as “a 100Ah is equivalent to a 200Ah lead acid battery”, and it’s just not true.

 

[Dellmassive]

I’m seeing lithium batteries marketed as “a 100Ah is equivalent to a 200Ah lead acid battery”, and it’s just not true

oh, why not true? (am i missing something)

if you can use 100% DOD of lifepo4 (but it will recuce the overall life span) - you can only use 50% DOD on a SLA/AGM before its classed at flat (and at 50% DOD will also greatly reduce the life span)


so if i was camping . . .

i could draw 100ah out of a 100ah-lifepo4 down to 11.1v . . . . . but i would need 2x 100ah SLA to get the same 100ah capacity down to the same 11.1v (below 50% DOD SLA voltage drops drastically below any usable voltage . . .ie 11.1v)

so i would agree that 100ah lifepo4 IS equivient to 2x 100Ah SLA.

but i dont agree with the dodgy advertising of say, LIFOS who will state that there battery is 120ah"equivelent" when its blatantly only 68ah.

https://irp-cdn.multiscreensite.com/231bdcf7/files/uploaded/Lifos 68 V2 - A4 Brochure.pdf


i remeber @ROMANY TAMPIN showing me his 120ah Lifos Lithium battery . . . . i was like "wow, thats the smallest 120ah battery I've ever seen!!!! that dont look right?" and in small print it said 68ah . . . but equivilent to 120ah SLA - thats just not cricket !!!!!!! LIFOS STOP DOING THAT AND RATE YOUR BATTERIES LIKE EVERYONE ELSE, JUST STATE THE AH FOR WHAT IT IS . . . . 68AH!

LIFOS QUOTE FROM DATA SHEET:

Depth of Discharge (DOD) All batteries have a DOD. It’s typical to expect a battery using lead acid and gel compounds to give a 50% DOD. This means if, for example, such a battery is rated at 100Ah, it will only provide usable power of 50Ah. LiFOS has a 90% DOD, providing 61.2Ah of usable power, which means that to replicate the available power provided by LiFOS, a +120Ah lead acid or gel battery would be needed.

 

[andys]

As I say, all of what I’ve read pretty much is of the consensus that LiFePo4 batteries can be drained to 80% on a regular basis without drastically shortening their life, against 50% for lead acid, therefore a more honest marketing comparison would be that it’s 1.6 x the equivalent lead acid, rather than double. But interested to see how your real life experience turns out, it’s a while before I’ll change as I can’t justify spending money to replace my current system that covers all my needs (though mainly from the phenomenal performance of my solar setup that means my battery rarely falls below 85-90%)

 

[Bryn23]

I set my cut off to 70% for my lithium system, as the 70-80% seems to be the optimal DOD for life span.

having said that, even at using it to 100% you would still see at least 500 cycles, most people don’t even get to 500 cycles before moving to a different van.

I do like the full adjustability with the Victron gear, it will be between Victron and using Votronic gear for the Crafter/Sprinter build.

Redarc and Everdrive could also be an option, It depends on what is out on the market in 18 months, I’m also excited to see what range of lithium batteries are available, although I’m tempted to build my own with 400ah CALB cells.

Keep up the testing Dell, it’s good to show everyone the pros of lithium and setting up of a system.

 

[Dellmassive]

Second battery is in...... testing begins..

2nd 138ah lifepo4.



second battery testing complete . . . . same setup as before, but this time a more constant 50A draw.



.
we started at rest voltage of 13.2V (100% charged)




with the loads and laptop connected the test began . . . the screenshot below show the 99% SOC and the 49A being drawn by the loads.




At the end of the test we had these reading . . . . at the point when the Victron LBD shut the loads down at 11.25v (drawing a 50A load) . . . .



127Ah - - out of 138Ah rated
1598wh - - out of 1766wh rated

so if we were drawing less loads, we could achieve more ah as the slight volt sag to the LBD would be later.

what was surprising was how quickly these batteries fall-of-the-ledge when they are 95% depleted. This can be seen in the BM2 screen shot below, and also how the battery recovers slightly once the load was disconnected.



All in all a very successful test and a certified good battery.

Next we move on to the recharge . . . . .

 

[Dellmassive]

The above post has been edited to included the test results . . . next was the recharging.

since the last test we have managed to get a Victron 12/30/1 Blue Smart IP22 Charger - Victron Energy

which is a 12v 30A 1xoutput battery charger with Lithium profile..




this has enabled a faster recharge rate of 30Amps compared to the 15A chargers we already had.

you can see the 30A charge in the battery BMS here>



this is the new charger and Power meter showing the details:



and again the 30A charge current and rising voltage of the battery (13.91v at this point)



The BM2 readout across the battery also shows the rapid voltage increase . . .



this is where the problems started . . . . .

at the 30A charge rate the cables and 40A blade fuse holder started to get hot . . . . =[


so we had to stop the charge and sort out the situation . . .

The 12awg cables from the charger to the first 50A anderson plug were upgraded to 10AWG, they still get warm, but not hot.

The 150A power meter was fine and only got slightly warm . . .

The next link was the main problem, the 50A anderson to battery clamps via a 40A blade fuse on 10AWG cable. (the cable and fuse got HOT, but this come with our NOCO 15A charger so i suppose we were pushing it a bit)

we made up a quick replacement cable: 50A anderson plug, 8AWG or 4mm jumper cable and some 100A battery clamps.... (a 50A midi fuse coukld be added close to the battery)


.





.....

Conclusions:

as we know Therese battery's can charge/discharge fast! . . . and with large currents when available.

you need to ensure your cable, fuses, grounds, connections etc etc etc are capable of the expected Load + 50% margin or even +100% margin

this +50% or +100% (over spec margin) will ensure that you have the best cable for the job and will limit and volt drop due to resistance when charging or pulling a load.

**

ie . . . if your charger can deliver 30A, then chose a cable that will handle 60A or 100A for the length of the run - longer run needs thicker cable . . .

**

Fusing is important too, the fuse need to protect the cable, but needs to over rated for the expected current . . . . but under rated for the cable . . .

so in the victron charger of 30A, it has a 40A internal fuse. . . and the cable can handle 60A. (so it all wont get hot while drawing the max 30A load, but in a fault condition the 40A fuse will blow before the 60A cable starts to heatup or melt)

just think of the water + pipe analogy . . . . a thicker water pipe lets more water through, a thinner pipe will restrict the flow of water (at a set pressure).

**

On these Lifepo4 battery outgoing side . . . you may need 100A fuse and 150A rated cable . . . . . depending on your usage.

**

********************************

in my case the Victron 800VA was drawing 50-60A.

the battery fuse was 100A Midi style

and the cable was rated at 150A

so with the above a full load could be drawn without anything getting hot.

and very little volt drop across the system.

*******************************


The same applies if you are using a DC-DC charger . . . . with a lithium battery it will draw 100% of the available capacity constantly until the SOC rises to 85% or so, the it will gradually start to reduce.

if your DC-DC charger has a max output of 30A, then you need to make sure that your cabling and fusing can handle the CONSTANT 30A draw . . . (without getting hot) !!!

i bet most system/cables wont . . . and will start to heat up. as weve said before these batteries are monsters and charge/discharge as fast as you like.

so before you fit one, fully check over you input charging system . . . via EHU,Solar,DC-DC

and also your output system that will feed your loads. . . .

Dont say i haven't warned you !!!!!

one interesting thing to note is that at no point has either battery or terminals got even slightly warm . . . . which is good =]


below: victron 30A charger delivering the full 30A . . . after 5mins . . . its casing is 46degC with the fan running....!


.

 

[andys]

The above post has been edited to included the test results . . . next was the recharging.

since the last test we have managed to get a Victron 12/30/1 Blue Smart IP22 Charger - Victron Energy

which is a 12v 30A 1xoutput battery charger with Lithium profile..


View attachment 52138

this has enabled a faster recharge rate of 30Amps compared to the 15A chargers we already had.

you can see the 30A charge in the battery BMS here>

View attachment 52139

this is the new charger and Power meter showing the details:

View attachment 52140

and again the 30A charge current and rising voltage of the battery (13.91v at this point)

View attachment 52141

The BM2 readout across the battery also shows the rapid voltage increase . . .

View attachment 52142

this is where the problems started . . . . .

at the 30A charge rate the cables and 40A blade fuse holder started to get hot . . . . =[


so we had to stop the charge and sort out the situation . . .

The 12awg cables from the charger to the first 50A anderson plug were upgraded to 10AWG, they still get warm, but not hot.

The 150A power meter was fine and only got slightly warm . . .

The next link was the main problem, the 50A anderson to battery clamps via a 40A blade fuse on 10AWG cable. (the cable and fuse got HOT, but this come with our NOCO 15A charger so i suppose we were pushing it a bit)

we made up a quick replacement cable: 50A anderson plug, 8AWG or 4mm jumper cable and some 100A battery clamps.... (a 50A midi fuse coukld be added close to the battery)


.

View attachment 52143 View attachment 52144 View attachment 52145 View attachment 52146



.....

Conclusions:

as we know Therese battery's can charge/discharge fast! . . . and with large currents when available.

you need to ensure your cable, fuses, grounds, connections etc etc etc are capable of the expected Load + 50% margin or even +100% margin

this +50% or +100% (over spec margin) will ensure that you have the best cable for the job and will limit and volt drop due to resistance when charging or pulling a load.

**

ie . . . if your charger can deliver 30A, then chose a cable that will handle 60A or 100A for the length of the run - longer run needs thicker cable . . .

**

Fusing is important too, the fuse need to protect the cable, but needs to over rated for the expected current . . . . but under rated for the cable . . .

so in the victron charger of 30A, it has a 40A internal fuse. . . and the cable can handle 60A. (so it all wont get hot while drawing the max 30A load, but in a fault condition the 40A fuse will blow before the 60A cable starts to heatup or melt)

just think of the water + pipe analogy . . . . a thicker water pipe lets more water through, a thinner pipe will restrict the flow of water (at a set pressure).

**

On these Lifepo4 battery outgoing side . . . you may need 100A fuse and 150A rated cable . . . . . depending on your usage.

**

********************************

in my case the Victron 800VA was drawing 50-60A.

the battery fuse was 100A Midi style

and the cable was rated at 150A

so with the above a full load could be drawn without anything getting hot.

and very little volt drop across the system.

*******************************


The same applies if you are using a DC-DC charger . . . . with a lithium battery it will draw 100% of the available capacity constantly until the SOC rises to 85% or so, the it will gradually start to reduce.

if your DC-DC charger has a max output of 30A, then you need to make sure that your cabling and fusing can handle the CONSTANT 30A draw . . . (without getting hot) !!!

i bet most system/cables wont . . . and will start to heat up. as weve said before these batteries are monsters and charge/discharge as fast as you like.

so before you fit one, fully check over you input charging system . . . via EHU,Solar,DC-DC

and also your output system that will feed your loads. . . .

Dont say i haven't warned you !!!!!

one interesting thing to note is that at no point has either battery or terminals got even slightly warm . . . . which is good =]


below: victron 30A charger delivering the full 30A . . . after 5mins . . . its casing is 46degC with the fan running....!

View attachment 52147
.

Again, blown away with the amount of testing and detail you go into, not to mention the expense
Will be a great future resource to many on here

 

[Long tall John]

Would this be job done?

It's expensive but simple. I'm not sure if the temperature sensor is compatible with the Orion dc-dc charger or whether it will only work with the victron bmv 712 battery monitoring system, in which case it would be pointless to buy the smart battery?!

 

[Dellmassive]

Would this be job done?
View attachment 52222 View attachment 52223 View attachment 52224
It's expensive but simple. I'm not sure if the temperature sensor is compatible with the Orion dc-dc charger or whether it will only work with the victron bmv 712 battery monitoring system, in which case it would be pointless to buy the smart battery?!

That black temp sensor is only for the VenusGX... you need the blue one for the bmw712. Or the bluetooth one for a mppt.

So nice setup... but that temp sensor wont work. . . . Would be better if you added a bmv712 with temp sensor and a battery protect.

No temp on the Orion.... waiting to get one to test, to see if it can receive temp signal from bluetooth.

 

[Long tall John]

Oh well..... back to the drawing board! I'm kicking myself cos i knew it was the blue temp sensor (as you posted in table at top of page) but i just googled a picture to grab a screen shot and the black one came up.

Note to self: be more diligent!!!

 

[bullracing]

I am not convinced a Lithium battery will last 10 years even with really good maintenance.

 

[mmi]

I am not convinced a Lithium battery will last 10 years even with really good maintenance.

True, it's still a challenge , e.g. ---> Solving the problem of lithium-ion battery ageing

Googling "calendar aging of lithium-ion batteries" surfaces quite a lot of work and studies to understand the challenge.
E.g.
--> https://uwspace.uwaterloo.ca/bitstream/handle/10012/12177/Catton_John.pdf
--> https://hal-cea.archives-ouvertes.fr/cea-01791260/document