12v battery maintenance

I use a 20 watt solar panel connected directly to Battery it keeps it at 100% full charged.

I have noted that no charger at this rated wattage is avaiable for connecting via ODB port so mayby MFG Ring know somthink that I dont about pluging into this port.

David,

If you want to sit in the car listening to music it is best to leave the car in Ready Mode.  The hybrid Battery will then charge the 12v Battery if the voltage in that starts to drop.  Then, if the hybrid Battery depletes the engine will start (but only for a short period) to recharge the hybrid battery.  

On 8/4/2022 at 12:37 PM, Tel_man said:

Once again left car for eleven day, with solar panel connected via obd port. Battery at start measured 12.1 volts. After 11 days, measured 11.94 volts. So, lost only 0.16 volts with solar panel connected.

On previous occasions, how much has the Battery drained WITHOUT the solar charger connected ?
 

A further feature of Ready mode is you can open the windows at the press of a button as it is already in Ready mode.

While David learnt about chargers and jumpers it the forum he missed the bit about Ready Mode 🙂

Lesson learned, and thanks for sharing your story. I am sure it will be helpful to many and especially those who are new to a Toyota hybrids. 🪫⚡️👍

21 hours ago, dannyboy413 said:

The result showed the battery at just under 8 volts and a low percentage, (forget what)!

There is some interesting information here... and these are just my thoughts...

Taken at face value and 8 volts is uncharted territory. You will find slightly different values quoted for what constitutes a healthy but full discharged Battery and its in the 11.5 volt region for the Battery chemistries involved. So 8 volts is way beyond just being flat.

21 hours ago, dannyboy413 said:

We drove home, a distance of about 20 miles and I left the car switched on in my driveway for an hour.

So lets say 1.5 to 2 hours in some mode that should charge the Battery.

21 hours ago, dannyboy413 said:

The battery monitor was then showing 100%. On checking this morning, it was still showing 100%.

A 100% of what? That is the big big question here.

As I say, these are my thoughts but I can not see a discharged  and otherwise healthy battery being able to be fully charged in that time. The energy input would be enormous and that battery would get hot. It would also need a managed charge voltage (higher than normal) to force the current into the battery... and so...  

I assume the percentage readout is based on terminal voltage of the battery. That means a 1Ah, 10Ah or 100Ah battery that was fully charged would always show 100% because the terminal voltage is at the level corresponding to a fully charged battery. The percentage readout doesn't know the capacity of the battery, it just looks at voltage and calculates a state of charge from that. Think of a 10 year old laptop or phone battery. It might show 100% and fully charged but only runs the thing for a few minutes. 

So I'm honestly thinking that the battery in this case is way down on capacity. What I would do next is a known discharge test by turning on known consumers and seeing how the battery holds up.

Had I been waiting for my wife I would have run out of Battery and petrol! 🤣

@Mooly

That's getting a bit beyond me, especially for a Sunday evening. 😁

The Battery monitor I referred to is this one -

https://www.amazon.co.uk/gp/product/B08VHMJYXY/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

Once installed, I downloaded the app. I have no idea whether it is any good, or accurate, but it is what I have so it gives me a consistent experience and does send me a warning if the Battery condition goes lower than a set percentage, (but I missed the warning on Friday!).

As regards having the car in 'Ready Mode', I was fully aware of that fact, but not for one minute did I think sat there for 2.5 hours watching videos would deplete the Battery so much. Still, we live and learn.  Incidentally, I have just got in the car - untouched from Friday. It started no problem and I had to press the accelerator to make the petrol engine fire up. Hopefully all is well with the world again. 🙂

Mooly, as it happens, my Battery indicated 8v and failed to start Ready mode after 8 days.  It was certainly no where near this on days 6 and 7.  I don't have the details now and clearly I could not have tried earlier for I would have had to had tests at day 6, wait for 7 days and try again, then finally at day 22.

Talking about the NOCO Boost / charger (sort of) I normally keep mine in the car all the time, but during this hot weather I remove it when the car is not in use due to the extreme heat build up.

9 hours ago, dannyboy413 said:

That's getting a bit beyond me, especially for a Sunday evening. 😁

The battery monitor I referred to is this one -

That type of meter tries to deduce charge level from the voltage but it assumes a healthy Battery for interpretation of the results. In other words if it shows 80% then it assumes 80% of whatever the Battery capacity is supposed to be.

If that Battery is deteriorated (say the capacity has fallen from 35Ah to 8Ah) it will still always show 100% when the voltage across the battery is at the value that corresponds to a fully charged battery. The capacity however is not there. 

An analogy... a 1 litre, 10 litre and 100 litre tank will all show 100% full when they are full and all would show 50% when half full. The 100 litre tank could be thought of as a new battery, the 50 litre as the same battery after a few years and the 1 litre as a failed battery. As the battery deteriorates its capacity falls.

9 hours ago, Roy124 said:

Mooly, as it happens, my battery indicated 8v and failed to start Ready mode after 8 days.  It was certainly no where near this on days 6 and 7. 

As the battery becomes fully discharged the terminal voltage will start to fall ever more rapidly. So it might have held up for 6 to 7 days at which point it is 'empty' and then after that the terminal voltage drops off a cliff.

Mooly, quite.

Regarding bluetooth monitors, the percentage might be related to its capacity at the time, but I think it also shows the voltage which is actually more important.  

Percentage might suggest the Battery will have sufficient voltage to get the car into Ready mode in a number of days that, as you say, can be a variable, but experience will tell.

Voltage OTOH is likely to warn you that it won't or that it might. 🙂

54 minutes ago, Roy124 said:

the percentage might be related to its capacity at the time,

The percentage is based only on the terminal voltage. The monitor has no knowledge of what the actual capacity really is.

It is like you having a car with an unknown size of fuel tank. Unless you know for sure the actual capacity when full then the gauge percentage reading might not be quite what you expect. If two similar cars are made with one having a 5 litre fuel tank and the other a 50 litre the fuel gauges will always read the same when full.

The Battery capacity reduce like this shown below. The percentage meter always reads the same when based on voltage.

1 hour ago, Roy124 said:

but I think it also shows the voltage which is actually more important.  

That's right, the voltage is the important factor when it comes to 'will it work' or not.

You have no way of knowing whether that Battery is (an analogy again) a 100 litre fuel tank that is full or a 1 litre tank that is full. Back to batteries and the last one would be drained with a few flashes of the headlights. Both however correctly show 13.7 volts (or whatever it is) and 100% based on how the monitors work. 

Molly, basically that's what I meant.  

@Mooly @Roy124  So, basically, if I am understanding you gentlemen correctly,  the percentage shown can be useful, but the voltage reading is more useful - or am I still on Sunday night setting? 😕

19 hours ago, Roy124 said:

Molly, basically that's what I meant.  

OK, that's good.

10 hours ago, dannyboy413 said:

So, basically, if I am understanding you gentlemen correctly,  the percentage shown can be useful, but the voltage reading is more useful - or am I still on Sunday night setting?

They are two separate things. 

The voltage is an absolute in that if the voltage is good the car is going to start but it tells you nothing on the capacity of the Battery. The capacity is an unknown and determines how long it will run various items before running flat.

For example you could not differentiate a common AAA 1.5 volt Battery from a AA or a C or a D type by a simple voltage check. All read the same voltage when new and healthy but they all have vastly different capacities. That is the problem, you have no way of knowing from a simple voltage check what the actual capacity is of the Battery in the car.

One minor point, what is the power draw of the bluetooth on the Battery monitor?

21 minutes ago, Kental said:

One minor point, what is the power draw of the bluetooth on the battery monitor?

The following is pretty close to my thought of 'no idea' 

A typical BLE SoC (i.e. a all-in-one Application + Radio chip) typically consumes: A few hundreds nA while in deep sleep, 2 to 10 µA while a RTC tracks time (needed between radio events while advertising or connected), 10 to 30 mA while CPU or Radio runs (computing data, TX, RX)

A problem with the BT monitors is a potential lack of range.  Now if I could sit in my kitchen, check the condition, and then decide whether it was good to go or I needed to charge/jump it would be ideal. 

I am undecided at the moment and think probably relying on my jumper pack. 

I use this to find out the capacity:

https://www.amazon.com/KONNWEI-100-2000-Automotive-Alternator-Analyzer/dp/B09FFBNG66

for long-term car parking, I recommend a 20W solar panel with a controller
in bad weather - clouds, rain - the next morning the voltage is not less than 12.4V
in good weather - sun - the next morning the voltage is 12.6V-12.7V
after seven days of standing, when I opened the car in the morning, I measured a voltage of 12.7V

Hi.

I own a 2019 Corolla Hybrid. I noticed my 12 volt Battery dropped from 12.6 to 12.1 in a couple of days. I've discovered that this only happens when I set the parking brake to come on automatically when the gear selector is in Park. I now apply the parking brake independently.

I use a CTEK XS 7000 to keep my Battery healthy if I'm not using the car much.

Hope this might be of some help.

David,

how do you connect your charger? I have a touring sport with Battery in the back. With my previous Passat GTE I used to charge the Battery in the boot via the positive terminal in the fuse box under the bonnet.

Hi.

I connect my charger direct to the Battery terminals. The Toyota manual say's to disconnect the Battery first, but I've had no problems leaving the Battery connected using the CTEK charger.

David

My dealer will be wiring the CTEK  cable so I can plug in as required. 

19 hours ago, Roy124 said:

My dealer will be wiring the CTEK  cable so I can plug in as required. 

I am going to ask for the CTEK  auxiliary cable to be connected to the Yaris (12v Battery under rear seat) at the service and I can use the crok clips on the Corolla as the Battery is under the bonnet