Lithium LifePo4 12v Batteries - Time For An Upgrade?
- Thread starter Dellmassive
- Start date
Essentially yes but it's Bulk until 14.2V (default) not Float.
I also have the BMV 712. It's a flexible beastie and depends on what you want to use it for. Info as @Dellmassive has already posted.
Victron Energy › ...PDF
Manual - Victron Energy
With SLA its 3 stages Bulk, Absorb, Float.
with Lithium's is only two stages . . . But the (Bulk + Absorb) is the 1st stage. Then Float/storage as 2nd stage (very basic explanation).
So the Lithium battery will draw the MAX current from the charger until the Voltage rises to the set value (normally 14.2 - 14.6v)
then the charger will move to Float. - float is used as a power supply to keep the battery at 100% while powering your loads.
+++
the more advanced explanations is the charger goes through stages. . . to get to the float stage.
using metrics like max absorb time, restart bulk etc etc etc .
that's all part of the profile.
+++
have a look at these history charts from my Victron 30A charger on a 100ah lithium.
you can see it done :
Bulk for 57mins charging 29.2ah (raised the battery to set voltage, in Constant Current mode 30A max the charger could deliver.)
then moved to Absorb, but timed out after 2hrs charging 56.9ah (constant voltage mode - reducing current)
But. . . .
The battery still took 27.4ah until it was 100%, you can see that in the storage section. - that took an additional 13hours !!!!
so the bulk + 2hr Absorb wasn't enough time to fully charge the battery. (100ah lifepo4 battery flat down to 5% soc and FULL recharge to 100%)
if you restart the cycle it will start charging faster again.
my solution was to create a pre-set with a longer Absorb time to allow the SOC to rise higher before moving into float/storage mode.
+
Last edited:
mrdanielmh
Member
This is amazing information thank you! I'll stick with defaults and then keep an eye on things too see what needs adjusting
mrdanielmh
Member
The mains charger shows Ah..
And the mppt shows %....?
Not sure why?
Ill have a think ..
Take a look at the Demo files in the App.
And the mppt shows %....?
Not sure why?
Ill have a think ..
Take a look at the Demo files in the App.
Anyone tried these guys?
www.ksenergy.co.uk
5): KS-LT200B 12v 200AH Super Series Bluetooth High Power lithium leisure battery
<h1 style="text-align: center;"><span class="wysiwyg-font-size-large"><b><b>KS-LT200B</b><b> 200AH SUPER SERIES 12V High Power/High Capacity </b><b>- </b><b>with integral Low</b><b> Temperature Protection and Bluetooth Remote Monitoring</b></b></span><span class="wysiwyg-font-size-smaller"><b>...
No knowledge of KS, but have a look at @RoamerBatteries. They seem to be a better deal. Steve has been helpful in answering questions etc.Anyone tried these guys?
5): KS-LT200B 12v 200AH Super Series Bluetooth High Power lithium leisure battery
<h1 style="text-align: center;"><span class="wysiwyg-font-size-large"><b><b>KS-LT200B</b><b> 200AH SUPER SERIES 12V High Power/High Capacity </b><b>- </b><b>with integral Low</b><b> Temperature Protection and Bluetooth Remote Monitoring</b></b></span><span class="wysiwyg-font-size-smaller"><b>...
Upto 400ah in a single unit
They look interesting . . .No knowledge of KS, but have a look at @RoamerBatteries. They seem to be a better deal. Steve has been helpful in answering questions etc.
Upto 400ah in a single unit
Product Selection Super Series
Select you lithium motorhome leisure battery or your camper, caravane, marine and boat LiFePo battery
Has anyone actually received anything from Roamer yet? The 400ah battery has my attention but no feedback.No knowledge of KS, but have a look at @RoamerBatteries. They seem to be a better deal. Steve has been helpful in answering questions etc.
Upto 400ah in a single unit
Ordered a 400max. Will update when it all arrives. Steve at Roamer has been amazing.
Lithium leisure Batterys and PWM solar controllers - Not Advised. (But fine on any of the SLA chemistry battery types) - IMHO
Im doing some testing and come across some interesting data that leads me to advise that PWM solar controllers may not be the best thing to use with a Lifepo4 battery charging.
My advice would be to upgrade to a MPPT solar controller that has a proper Lifepo4 battery charge Profile.
Why?
we as we may know a PWM (Pulse Width Modulation) solar controller is just a fancy switch (in its basic form)
it will switch the panel voltage over to the battery on/off/on/off/on with varying pulse widths (all very fast, multiple times a second).
the issue seems to be that the solar panels can generate high voltages like 16,17,18,19,20,22v - which is too high for the standard Lifepo4 batty internal BMS.
these high voltage spikes can trigger the BMS to shut down or trigger Over Voltage alarms.
lets look at todays test . .
here is a 50w foldable panel connected to a PWM controller (set to Lifepo4 profile) .
the setup is connected to the Poweroad Lifepo4 battery box for some testing. (which has a Victron smart shunt and various other monitors)
being only 50W, we could expect a max of 3A charge current ( and a OCV of 18.5v - this is the important bit) . . (i got about 2.7A which was good)
but take a look at these 18.5v voltage spikes on the scope. . . . measured direct at the battery terminals !!!!
moving over to the Victron Smart Shunt we can see what's going on.
we can see that the battery is full and the internal BMS has shut-off the charge current going into the battery (the RED trace on the left of the right tablet).
now the PWM controller has no effective load or battery to sink the power into we can see the high voltage spikes. (the BLUE trace on the right of the right tablet)
The chart is showing 18.5v spikes across the battery as the PWM controller is trying to charge the battery. -this is the direct panel voltage being switch to the battery terminals.
here you can see the PWM controller showing a warning as its detecting the blocked current flow to the battery . . b01 error (check battery)
this has also triggered the "cell overvoltage" warning from the battery BMS.
the BMS is dealing with the situation by blocking any incoming charge current,
but it cant do anything about the high voltage spikes coming from the solar controller.
we can see the spikes as a ripple in the Bm2 monitor . .
but the spikes / pulses are to fast to be plotted on the 24hr plot.
so it seems that PWM may not be best suited for Lifepo4 batterys that have internal BMS.?
in comparison look at yesterdays charging trace . . when a MPPT controller was used.
the charge plot is flat and smooth.
MPPT solar controllers use the same charging stage / profile as a regular mains charger.
The output is controlled and regulated.
there are no high voltage spikes and the charge current is delivered in a controlled manor.
all the way up to the point when the battery 100% fully charged . .
So my advice to myself and anyone interested is to use MPPT solar controllers for Lifepo4 battery's.
Notes:
This effect will be seen when the battery is 100% fully charged and the internal BMS shuts off the incoming charge current. (revealing the voltage spikes from the controller)
these spikes are absorbed by the battery 0-99% SOC and are not seen as the current flow and low internal battery resistance cause a volt drop - masking the spikes.
The Victron Smart shunt has higher resolution so the spike can be seen and plotted on the graph.
The BM2 has a lower resolution so the spikes are not so evident.
the spikes can be verified with a scope or potting multimeter.
A Renogy Voyager 20A PWM was used in this test.
A Victron 12/30 240v charger was used in this test.
A Victron 75/15 MPPT was used in this test.
A Poweroad 100Ah Lifepo4 was used in this test.
++++
Edit:
it seems that a major battery manufacture agrees with these findings, i received this the following day . .
--
Hi Dellmassive,
Thanks for the effort.
You are correct, the MPPT is more suitable for our batteries.
The interval and peak current of PWM charger is hard to control.
In addition, the big peak charging current is also not good for our battery.
Best regards,
Poweroad Tech
POWEROAD (XIAMEN) RENEWABLE ENERGY TECHNOLOGY CO., LTD.
7/F Haiyun Building, No. 16, Haishan Road, Xiamen 361013, Fujian, China
Lithium-ion Battery: www.poweroad.com
Energy Storage System: www.poweroad-ess.com
Advanced Lead-acid Battery: www.yucell.com
--
++++
Im doing some testing and come across some interesting data that leads me to advise that PWM solar controllers may not be the best thing to use with a Lifepo4 battery charging.
My advice would be to upgrade to a MPPT solar controller that has a proper Lifepo4 battery charge Profile.
Why?
we as we may know a PWM (Pulse Width Modulation) solar controller is just a fancy switch (in its basic form)
it will switch the panel voltage over to the battery on/off/on/off/on with varying pulse widths (all very fast, multiple times a second).
the issue seems to be that the solar panels can generate high voltages like 16,17,18,19,20,22v - which is too high for the standard Lifepo4 batty internal BMS.
these high voltage spikes can trigger the BMS to shut down or trigger Over Voltage alarms.
lets look at todays test . .
here is a 50w foldable panel connected to a PWM controller (set to Lifepo4 profile) .
the setup is connected to the Poweroad Lifepo4 battery box for some testing. (which has a Victron smart shunt and various other monitors)
being only 50W, we could expect a max of 3A charge current ( and a OCV of 18.5v - this is the important bit) . . (i got about 2.7A which was good)
but take a look at these 18.5v voltage spikes on the scope. . . . measured direct at the battery terminals !!!!
moving over to the Victron Smart Shunt we can see what's going on.
we can see that the battery is full and the internal BMS has shut-off the charge current going into the battery (the RED trace on the left of the right tablet).
now the PWM controller has no effective load or battery to sink the power into we can see the high voltage spikes. (the BLUE trace on the right of the right tablet)
The chart is showing 18.5v spikes across the battery as the PWM controller is trying to charge the battery. -this is the direct panel voltage being switch to the battery terminals.
here you can see the PWM controller showing a warning as its detecting the blocked current flow to the battery . . b01 error (check battery)
this has also triggered the "cell overvoltage" warning from the battery BMS.
the BMS is dealing with the situation by blocking any incoming charge current,
but it cant do anything about the high voltage spikes coming from the solar controller.
we can see the spikes as a ripple in the Bm2 monitor . .
but the spikes / pulses are to fast to be plotted on the 24hr plot.
so it seems that PWM may not be best suited for Lifepo4 batterys that have internal BMS.?
in comparison look at yesterdays charging trace . . when a MPPT controller was used.
the charge plot is flat and smooth.
MPPT solar controllers use the same charging stage / profile as a regular mains charger.
The output is controlled and regulated.
there are no high voltage spikes and the charge current is delivered in a controlled manor.
all the way up to the point when the battery 100% fully charged . .
So my advice to myself and anyone interested is to use MPPT solar controllers for Lifepo4 battery's.
Notes:
This effect will be seen when the battery is 100% fully charged and the internal BMS shuts off the incoming charge current. (revealing the voltage spikes from the controller)
these spikes are absorbed by the battery 0-99% SOC and are not seen as the current flow and low internal battery resistance cause a volt drop - masking the spikes.
The Victron Smart shunt has higher resolution so the spike can be seen and plotted on the graph.
The BM2 has a lower resolution so the spikes are not so evident.
the spikes can be verified with a scope or potting multimeter.
A Renogy Voyager 20A PWM was used in this test.
A Victron 12/30 240v charger was used in this test.
A Victron 75/15 MPPT was used in this test.
A Poweroad 100Ah Lifepo4 was used in this test.
++++
Edit:
it seems that a major battery manufacture agrees with these findings, i received this the following day . .
--
Hi Dellmassive,
Thanks for the effort.
You are correct, the MPPT is more suitable for our batteries.
The interval and peak current of PWM charger is hard to control.
In addition, the big peak charging current is also not good for our battery.
Best regards,
Poweroad Tech
POWEROAD (XIAMEN) RENEWABLE ENERGY TECHNOLOGY CO., LTD.
7/F Haiyun Building, No. 16, Haishan Road, Xiamen 361013, Fujian, China
Lithium-ion Battery: www.poweroad.com
Energy Storage System: www.poweroad-ess.com
Advanced Lead-acid Battery: www.yucell.com
--
++++
Last edited:
yep, I have the 200ah Seatbase roamer.
Used it for 7 nights running a fridge and charging USB devices. Also 2x football matches on a laptop powered from a 300w inverter.
It’s currently on 41% capacity, (according to the BMS app so not sure how accurate).
I’ve disconnected it from the charger as I wanted to give it a good old test. Pretty incredible so far.
Fridge is top loading on lowest setting so very efficient. Beers have always been cold.
Dunno if this has been covered already, but I'll put it out there just in case it hasn't. I changed to Lithium from AGM last year & it has been a worthwhile upgrade. I recently swapped out the Ctek charger that was originally fitted to the van as part of the conversion & fitted the Victron Orion 12/30 & here's the important bit; The AGM battery would charge at around 15A from the CTEK, a Lithium will take as much charge as you can throw at it, including the full 30A that the Orion can deliver. I subsequently found that the original cable from the van battery was getting warm, it was rated at 30A, so was at its limit. I've now replaced the supply cable with an 8mm2 & a 40A fuse. My point being, if you do go down the Lithium route, it may not be just a case of swapping out the battery & charger.
This offer has popped up: Renogy Battery . Any good? Want for under driver seat install so will fit.
good price. but I just looked at Roamer £450 ? It would be good if they have an option to reduce the height so you can stand the battery under the seat.
Some nice new stored long term trend fearures in the latest Victron beta software: VictronConnect changelog and beta releases [Victron Energy]
Should appear soon in the official release if it does not get rolled back again.
Should appear soon in the official release if it does not get rolled back again.
Some nice new stored long term trend fearures in the latest Victron beta software: VictronConnect changelog and beta releases [Victron Energy]
Should appear soon in the official release if it does not get rolled back again.
ooh, if I read that right you get 45d of history (at half hour resolution) in the BMV 712? That’s awesome if so, it always seemed like a huge missed feature that it didn’t log history.
Oh hang on, have I misunderstood this? Does this apply to a BMV 712 with the VictronConnect app or is it only with some central VictronConnect controller of some sort?
Similar threads
