Lithium battery for starting in an gasoline car - in cold weather
Our tests of a LP12V/60AH battery in a Chrysler Voyager. The battery was installed in 9/2012. Now it has two winters usage and about 20000 km of driving. We do not see any change in performace. The car was able to start car in -20*C last year (about 1 week of cold waether) and in -13*C this year.
The test diagram shows the performace in cold weather (around 0*C). In cold weather the voltage during the start impulse will drop as low as 8.4V. After the engine starts working, the charge voltage will increase as high as 14.6V.
Can the automotive 12V battery charger be used for LiFePO4?
Some chargers can be used, some cannot. There are two things that need to be considered:
1) Full charge voltage. The LiFePO4 batteries need to be charged at least to 14.6V. However, some automotive 12V battery chargers charge only to 13.8V or even less. This is not sufficient. Only chargers with higher charge voltage may be used. Note: some chargers support higher voltage by manual selection of something like „a boost mode“.
2) Trickle charge not supported. The LiFePO4 batteries will be damaged when left on charge with the trickle mode charging. Most automotive 12V battery chargers have the trickle mode as a default setting. With LiFePO4 batteries, the charging must be stopped and the charger needs to be disconnected after the charge cycle is finished. If the charge disconnect after full charge, it may be used for LiFePO4. It is a must to avoid the trickling charge mode.
How to connect LP12V90AH+ batteries together to get a 24V pack?
A simple solution to make a 24V 90AH battery pack. When positioned next to each other (as shown at the picture) CALB180 terminal connectors are compatible and make a cheap solution!
Please note that you need to charge both of the 12V batteries to full foltage to get them balanced before using the two batteries as 24V pack.
CALB180 terminal connectors - http://www.ev-power.eu/_d2796.html
LP12V90AH battery - http://www.ev-power.eu/_d1873.html
FAQ: How to open the top cover of the LP12V battery?
Answer: First, please check this link:
The monolithic Winston batteries were not originally made to be opened, therefore small damage of the plastic case can be expected even if you are careful. All the batteries at the link above were opened simply by knife and hammer. The lid is little bit bigger then the battery case and it can be taken down with small knife or nailfile. You can use hammer to knock a little bit to the opposite side of the knife/file, it can help you. Slow and careful approach is the way. Do not forget to screw out the sleeve nut at the terminals first before opening the battery case itself!
As soon as the battery will be opened, it is wise to assemble balancing connector to the case itself to have it accessible for the future.
FAQ: Refreshing a LP12V battery
Question: I have a 12V battery that was damaged by deep discharge. Now the performance of the battery is poor. What can I do?
Answer: Our tests show that usually one of the cells is affected in the 12V pack when the battery is damaged by deep discharge or other improper usage. Very often it is enough to replace just one of the cells inside the 12V battery pack to refresh the function of the battery.
The individual cells of the LP12V 40AH, 60AH and 90AH batteries are identical with the single cells.
Steps for the replacement:
- Open the TOP cover of the battery to get access to the cells.
- Check the cells to see their voltage level. You may wish to put the battery under load to see the performance of the cells.
- Replace the defective cell with a new cell.
- Charge all of the cells one-by-one to the full level to have all the cells inside the battery balanced.
- Make the final test of the battery to confirm the proper function after replacement.
The photos show the idea of the replacement. A defective cell is “black”.
FAQ: The LP12V batteries consist of 4 finely balanced cells. Is there really no need to balance each internal cell during the whole battery lifetime? Can you confirm, please, that managing this model as a single monolithic 12V block is really enough forever?
Answer: The block batteries with 4 internal cells are offered from 2009. There are users who have been using these batteries for 5 years without any internal balancing and they keep using them on and on. This gives the evidence that this technology solution is stable and reliable.
We confirm that when the battery is used properly without overcharging and without deep discharge, it will last many years. Additionally it is possible to add external monitoring of the internal cells. Some users open the top cover of the battery pack to get access to the internal cells for regular check-ups. You can check more details about the LP12V technology at our GWL/Blog.
FAQ: Charging modes for the MPPT Tracer series
Question: Which battery type setting should be used for the LiFePO4 cells/batteries with the MPPT Tracer Solar Charge controllers?
Answer: The voltage levels are shown at the table. Changing the battery type will change the maximal voltage level between 14.2V, 14.6V and 14.8V. All of these levels are pretty OK for the LiFePO4 cells.
Note: check the details on the LiFePO4 battery charging levels (14.4V vs 16V) and study details why to avoid keeping the battery at full charge voltage level.
Additional note: please keep in mind that the voltage levels for the MPPT chargers (Tracer series) are at 25*C nominal. With the temperature decreasing, the voltage levels will increase as indicated in the manual: -30mV/*C. This means that for temperature 15*C (of the MPPT temperature sensor) the voltage levels will increase by +0.3V
Summary: for cold temperatures (15*C and less) you may wish to have the setting for GEL and/or SEALED battery to stay bellow the safe charge voltage of 14.6V per battery.
There are single cells in the 12V LP battery too!
Check this tip: sometimes it may be smarter to choose the 12V LP monolithic LiFePO4 batteries instead of individual 3.2V rated cells. The reason is simple – the 12V LP batteries contain a pack of four completely identical 3.2V cells integrated inside of the plastic case.
If individual cells are not on stock, purchasing the 12V LP batteries instead of separate cells is quite advantageous. When buying the 12V batteries your will not only get the finely balanced 4 cells, but there are stainless steel bolts and copper terminal connectors included with the battery as well. With the 12V LP batteries you get these for free!
As the photos show, it is quite easy and simple to open the 12V battery to get access to the individual cells.
Check our offer for Winston 12V 90Ah (http://www.ev-power.eu/_d1873.html), Winston 12V 60Ah (http://www.ev-power.eu/_d1872.html) and Winston 12V 40Ah (http://www.ev-power.eu/_d1871.html) models, that can be modified to access the single cells.
The original Winston LP12V80AH battery - after 3 years at 98AH!
The photo shows the LP12V 80AH battery produced by Winston (ThunderSky) in 2010. After 3 years of continueous use it gives 98 AH (!) of real capacity. After the warranty period, the battery was modified by the user to get access to each cell and to monitor the voltage of the cells, using the CellLog8.
What can be said? It seems better than “ideal dream”. But it is not a dream, it is the reality of the LFP technology. With LFP cells energy storage is possible!
Connecting LP12V batteries - serial and parallel
We always recomend to make paralel connection first before making the serial connection. With parallel connection the two (or more) batteries are managed (monitored) as one block.
The LP12V20AH battery with improved terminal connectors
For starting applications you can improve the performance of the LP12V20AH battery by using more robust copper terminals.
Replacing OPTIMA Yellow 65AH with 60Ah Winston LP12V60AH
The Chrysler Voyager (now Lancia Voyager) has the Optima Yellow 65AH starting battery. We have made replacement with Winston LP12V 60AH model. The Optimal lead-acid has 28 kg. The Winston lithium battery has 12 kg. In cold weather, you can see the difference in starting the car immediatelly.
Example of discharge of 20Ah cells at 360A (18C)
The graph shows discharge characteristics of 12V batteries using 20Ah cells at 360A.
Building a LiFePO4 battery - charging and initiation
Check a useful article published by one of our customers.
An electric car using the LFP batteries for the traction.