Jump to content
Do Not Sell My Personal Information


12v battery maintenance


FROSTYBALLS
 Share

Recommended Posts

22 minutes ago, Dala said:

I have it wired the same way.
Directly to the battery terminals.
I recharge with a solar panel or a smart charger set to AGM.
They installed the connection cable for me directly at Toyota.

 

What Solar panel did you get and where do you position it ‘in the car’?

Link to comment
Share on other sites

I have a 2019 Rav4 hybrid and have had issues with the 12v Battery in the winter. I want to self install a Defa 1203x Battery maintainer in the engine compartment as it'll work with the installed block heater through a single exterior port and Toyota dealers sell these with rav4s hybrids. The instructions say to screw the eyelet to the Battery (not desirable as it's in the trunk) or to the positive power connection of the underhood fuse panal. The only positive power connection I can find is the jump start point, but that seems to be meant for clamps and not eyelets. Any ideas on how to do this?

Link to comment
Share on other sites


11 hours ago, IanML said:

I haven't seen the jump start point, but could you attach a bolt-on clamp which has provision for an eyelet attachment point?

On the blade connection I doubt it.  The blade is in a fuse box, in a plastic fence and covered by a hinged red gate.  To add a bolt at this point would risk compromising the insulation. 

There will be somewhere else where access to a positive feed is possible but you would need to isolate the hybrid Battery first.  Not something I would want to consider. 

 

Link to comment
Share on other sites

  • 2 weeks later...

After a decent journey on Sunday, yesterday was the first time I used the car since then. Checked the Battery voltage before start up and it was 10.9v (albeit in ACC) put it in IGN and it dropped to 10.1v. Over to Ready and it goes up to 14.4v as expected.

Car went into Ready absolutely fine so no real issue but these voltages do seem very low after just 3/4 days.

Incidentally, I did the same process when leaving the office and the initial ACC voltage was 11.9v

Link to comment
Share on other sites

Because the Battery load (which lowers the voltage) is unknown and possibly a variable, the way to get a valid view of Battery state is with the car's systems as shut down as is possible.  The car should be switched off, with the bonnet (or other access to the Battery, where applicable) open, and the measurement should be taken after a good pause since unlocking and opening up (say 30 min), to allow circuits which were woken up to go back to sleep.  In that state, a healthy battery which is well-charged should be about 12.4V, or more.

You can then switch to ACC with switchable services (eg radio, lights) off, and get a comparative reading to work with in the future.

However, if the two values (10.4 and 11.4) were obtained under the same load conditions, there does seem to be an excessive loss of charge.

  • Thanks 1
Link to comment
Share on other sites

2 hours ago, IanML said:

Because the battery load (which lowers the voltage) is unknown and possibly a variable, the way to get a valid view of battery state is with the car's systems as shut down as is possible.  The car should be switched off, with the bonnet (or other access to the battery, where applicable) open, and the measurement should be taken after a good pause since unlocking and opening up (say 30 min), to allow circuits which were woken up to go back to sleep.  In that state, a healthy battery which is well-charged should be about 12.4V, or more.

You can then switch to ACC with switchable services (eg radio, lights) off, and get a comparative reading to work with in the future.

However, if the two values (10.4 and 11.4) were obtained under the same load conditions, there does seem to be an excessive loss of charge.

I think the two comparable figures are the two after turning on ACC. After 3/4 days of no use 10.9v versus after 8 hours of no use 11.9v.

Link to comment
Share on other sites

  • 2 weeks later...

Coming back to this thread as the other drifted. I read somewhere yesterday that another car, Nissan Leaf I think, automatically charges the 12v Battery from the traction Battery 60 mins after it is shut off then every 4 days if it hasn't been started. Although there were some complaints that this is inhibited if it is left plugged in.

So it's quite possible to implement, presumably through software, so it's a shame Toyota haven't picked up on this yet as it seems to make sense.

  • Like 2
Link to comment
Share on other sites

So I installed the Battery monitor I bought last night.

First some pre-install observations. I started the car to leave work last night and voltage on the cigar lighter went to 14.4v. This was in EV, heaters running, lights on wipers on. After about 4/5 mins, the voltage dropped back to 12.6v. I make the assumption the Battery is fully charged so the investor has switched to maintenance voltage.

After arriving home and a bit of faffing and wiring a CTek plug to the Battery monitor, it's about 45 mins after arriving home. I open the car, plug the monitor in pair it to the phone and it instantly pings an alert to say battery is 0%!! Voltage is 11.98v. I close the boot and lock the car (boot was open max 2 mins). It starts to climb until it settles about 12.14v. I get lots of alerts through the evening saying battery level 4%, 3%, 2%, etc. The voltage gradually falls to 11.94v by midnight.

Now it gets interesting. The scheduled charge starts at 00:30 (schedule set on charge point). The voltage increases at the same time, suggesting the traction battery is "charging" the auxiliary battery. However, the voltage is only 12.64v so it's only at a maintenance charge level. It was 6C outside so I assume the battery heater was running.

The charge finishes around 02:00. The voltage drops to 12.3v then continues to fall fairly quickly before settling to a gradual fall of around 0.02v per hour. This morning (without touching the car) is 11.95v and 0%.

Screenshot_20221102-071713.thumb.png.86fb0603534d8bbf2fde52c9d84a4eaf.png

Screenshot_20221102-074317.thumb.png.b0f2e46eba9d5178a2754f1af269e1e6.png

  • Like 2
  • Thanks 1
Link to comment
Share on other sites

I think that either the car's charging function is misbehaving and not fully charging the Battery, or the Battery is not capable of accepting or retaining much charge.

I'd start with the latter, and see whether Toyota will replace the Battery under warranty.

Link to comment
Share on other sites

3 hours ago, nlee said:

So I installed the battery monitor I bought last night.

First some pre-install observations. I started the car to leave work last night and voltage on the cigar lighter went to 14.4v. This was in EV, heaters running, lights on wipers on. After about 4/5 mins, the voltage dropped back to 12.6v. I make the assumption the battery is fully charged so the investor has switched to maintenance voltage.

After arriving home and a bit of faffing and wiring a CTek plug to the battery monitor, it's about 45 mins after arriving home. I open the car, plug the monitor in pair it to the phone and it instantly pings an alert to say battery is 0%!! Voltage is 11.98v. I close the boot and lock the car (boot was open max 2 mins). It starts to climb until it settles about 12.14v. I get lots of alerts through the evening saying battery level 4%, 3%, 2%, etc. The voltage gradually falls to 11.94v by midnight.

Now it gets interesting. The scheduled charge starts at 00:30 (schedule set on charge point). The voltage increases at the same time, suggesting the traction battery is "charging" the auxiliary battery. However, the voltage is only 12.64v so it's only at a maintenance charge level. It was 6C outside so I assume the battery heater was running.

The charge finishes around 02:00. The voltage drops to 12.3v then continues to fall fairly quickly before settling to a gradual fall of around 0.02v per hour. This morning (without touching the car) is 11.95v and 0%.

Screenshot_20221102-071713.thumb.png.86fb0603534d8bbf2fde52c9d84a4eaf.png

Screenshot_20221102-074317.thumb.png.b0f2e46eba9d5178a2754f1af269e1e6.png

Any more observations would be welcome.

  • Like 1
Link to comment
Share on other sites


3 hours ago, nlee said:

So I installed the battery monitor I bought last night.

After arriving home and a bit of faffing and wiring a CTek plug to the battery monitor, 

Screenshot_20221102-071713.thumb.png.86fb0603534d8bbf2fde52c9d84a4eaf.png

Screenshot_20221102-074317.thumb.png.b0f2e46eba9d5178a2754f1af269e1e6.png

This bit really interests me.  I have a CTEK lead hard wired to the Battery and would love to use that for a Battery monitor. 

I presume you have wired a CTEK male plug to your Battery monitor.  If so, where did you get one? 

As Ernie said, more observations please. The voltage display looks good so what is the % figure I wonder. 

Link to comment
Share on other sites

12 minutes ago, Roy124 said:

This bit really interests me.  I have a CTEK lead hard wired to the battery and would love to use that for a battery monitor. 

I presume you have wired a CTEK male plug to your battery monitor.  If so, where did you get one? 

As Ernie said, more observations please. The voltage display looks good so what is the % figure I wonder. 

I couldn't find any male plugs as such so I bought a ctek 56-689 adapter cut the other end off and connected the Battery monitor with a 2 pole inline spring lever connector I had lying around.

In hindsight, I could have connected a more standard socket to the other end and plug on the Battery monitor then I could potentially have used more standard plugs to connect other things if I wanted in future.

One consideration is that I decided to put the Battery on charge today but wanted to monitor at the same time. Obviously, I couldn't connect both so I've used the crocodile clips on the terminals for the charger today but it's only really a one off where I'd want to monitor and charge at the same time.

  • Thanks 1
Link to comment
Share on other sites

Thanks, i had thought of sacrificing a cable. 

Now the next experiment, if any one is brave, is doing the same with a Lithium Battery pack. 

My pack comes with heavier duty cable but I don't think the hybrid 12v Battery needs that HD cable. 

The alternative would be to connect the jumper cables to the Battery and splice the thinner CTEK cable to that. 

Both cables I have have Croc clips but I would not want to attach more than one. 

Link to comment
Share on other sites

16 minutes ago, Roy124 said:

Thanks, i had thought of sacrificing a cable. 

Now the next experiment, if any one is brave, is doing the same with a Lithium battery pack. 

My pack comes with heavier duty cable but I don't think the hybrid 12v battery needs that HD cable. 

The alternative would be to connect the jumper cables to the battery and splice the thinner CTEK cable to that. 

Both cables I have have Croc clips but I would not want to attach more than one. 

Not sure of any technical issues with doing what you suggest, but from a practical perspective, if the Battery is so flat you need to use the physical key inside the fob, it's probably easier to access under the bonnet than dropping the rear seats and crawling into the boot to get to the cable or the manual tailgate release.

Link to comment
Share on other sites

Nlee, in my case I have planned ahead.  I got the dealer to fit my CTEK cable to the 12v under the back seat (YC).  That sorts the charging aspect. 

For jump starting I would, as you suggest, open the bonnet. 

However if I had put in jump start cabling on the Battery then it would have simply been a question of opening the door and plugging in. 

The best reason for trying this is in bad weather and at night.  No groping around under the bonnet when it's dark, wet, windy, and cold. 

  • Like 2
Link to comment
Share on other sites

On 4/13/2022 at 4:22 PM, TonyHSD said:

Would you reccomend it ? I understand they are good for topping up but not for flat batteries ? 

Link to comment
Share on other sites

3 minutes ago, Richnsoul said:

Would you reccomend it ? I understand they are good for topping up but not for flat batteries ? 

They seems alright, however it’s too big for me and I have returned mine. Yes, they are for maintaining charge not for reconditioning dead Battery. People said they are good indeed. , however if you about regular Battery charging better option is to buy a smart charger and recharge once in a while. 👍 

  • Like 1
Link to comment
Share on other sites

For my purpose, it is ideal.  I use my RAV rarely, and it is parked out of doors.  The panel sits on the dashboard and is plugged into the OBD connector.  Unlike the lighter/power socket, the OBD positive pin is live with the car switched off, so perfect.

I used to have to charge the Battery every 2 to 3 weeks, which was a nuisance, but with the panel, the Battery is always fully charged, and the problem is solved.

  • Like 3
Link to comment
Share on other sites

Going back to basics with this 12v battery:

Why would the manual state

■ To prevent 12-volt Battery discharge
……….
● Turn off any unnecessary electrical components when the vehicle is running at a low speed for an extended period, such as in heavy traffic.   ??

While actually running the car I assumed that the traction Battery would always keep the 12v Battery sufficiently topped up, and the ICE will ensure the traction battery is ok. But the implication of the manual that when we are in very slow moving traffic at night in cold winter (heater, lights, maybe AC, probably radio etc) then we should start turning them off is, shall we say, puzzling. I could live without audio but not without lights or heat.

 

Link to comment
Share on other sites

12 minutes ago, TonyFR said:

Going back to basics with this 12v battery:

Why would the manual state

■ To prevent 12-volt battery discharge
……….
● Turn off any unnecessary electrical components when the vehicle is running at a low speed for an extended period, such as in heavy traffic.   ??

While actually running the car I assumed that the traction battery would always keep the 12v battery sufficiently topped up, and the ICE will ensure the traction battery is ok. But the implication of the manual that when we are in very slow moving traffic at night in cold winter (heater, lights, maybe AC, probably radio etc) then we should start turning them off is, shall we say, puzzling. I could live without audio but not without lights or heat.

 

I would suggest, possibly, because it is wrong? Probably a carry-over from ICE & alternator vehicles ... ?

Link to comment
Share on other sites

13 minutes ago, philip42h said:

I would suggest, possibly, because it is wrong? Probably a carry-over from ICE & alternator vehicles ... ?

Agreed.

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share





×
×
  • Create New...




Forums


News


Membership