Rx400h - Siren alarm location

[Mickscores]

Hello dear owners of these wonderful cars, can somebody help me to locate where is located in my RX400h the siren for the alarm?

as i am another one who has problems with flat Battery after 2 weeks of inactivity, i would like to try to disconnect it hoping it will somehow help. 
thank you in advance and wish you all a great weekend

Micky

[m4rkw]

Welcome to the forum! It looks like the siren is somewhere in the back of the car, no.4 on this diagram:

http://europe.toylexparts.com/lexus/524210/mhu38r-awxgkw/309w/002/4/8424/846928c#box_89040

Possibly tucked away under some of the boot trim.

Mark

[Herbie]

I don't know where the alarm siren is located but believe me, it won't make a difference to the Battery because it doesn't take that much.

Plus, you could get into all sorts of problems with choosing to deactivate the alarm if you then try to make a claim for a stolen car.

Much better to either trickle charge it, or go for a regular run out in it, or just fire it up on the driveway for about 60 minutes per week as per the advice on Toyota's website for keeping the Battery topped up while we were in lockdown.

[Romasato]

Just get a solar charging panel to keep the Battery trickle-charged when going away for longer periods - if I understand correctly, connecting it via OBD port will charge the Battery.
In addition, might want to choose a more expensive (~£170?) AGM type of Battery which is less affected by deep-cycles (full discharges). My regular lead acid (wet) Battery stopped retaining charge after a few complete discharges.

[ColinBarber]

6 hours ago, Romasato said:

In addition, might want to choose a more expensive (~£170?) AGM type of battery which is less affected by deep-cycles (full discharges). My regular lead acid (wet) battery stopped retaining charge after a few complete discharges.

AGM can handle deeper discharges, and there are special deep-cycle AGM batteries to handle this even better, but complete discharges are a no-no for any lead-acid Battery.

A lot of the solar chargers on the market help slow the discharge rate but don't provide enough power to keep the Battery fully charged even in Summer, and as the weather starts to turn they aren't going to be much good in this country.

[Mickscores]

Hello all, 

first of all let me thank you all for the interest and the support.

i have tried few of the suggestion above but more in detail:

@Herbie: i followed you advice this week, but just extended for 2 or 3 extra day. Lexus dealer has replaced few times the Battery with a new Genuine Toyota one and never fixed the issue, after couple of days (never more that 15 days) is always the same story and i have the feeling that doesn’t matter how much i ask then, they never check where this absorption comes from, they check only the computer which tells all good so for them is all good. Unfortunately I don’t have garage or drive way as i live in city center.

@Romasato: i do have a solar collector, don’t recall the brand, but was UK first choice and, as confirmed from @ColinBarber just keeps a bit of charge if it’s a fully sunny day but doesn’t help charging at all, not even to start hybrid system.

this is the reason why i am getting a bit exhausted of this situation especially because i have a little kid and every time i am rushing somewhere because of him, i need to jumpstart the car and you can imagine my wife’s comments about it.

thank you and have a great weekend.

[royoftherovers]

Make sure that the following are always switched off whenever you leave the car;

Interior light switch

Boot light switch

Glovebox light switch

Radio,CD, dashcam

Nothing remaining in a USB or auxiliary input connection.

[Herbie]

If you make sure to do as John says above but it doesn't make any improvement then it would seem that you have a parasitic drain fault.

If you've got the equipment and the skill to do it yourself, this video should help you, but there are plenty of other videos on YouTube.

If you can't, or just don't want to do it yourself then I strongly suggest that you take it to a proper auto electrician for diagnosis. I'm a very firm believer in mechanics for mechanical issues, electricians for electrical issues.

 

 

[ColinBarber]

I'm not sure there is a fault here. The RX400h can hope with 2 weeks of inactivity with a good and fully charged Battery but not much more. It then needs 3+ hours in Ready mode to recharge it. If you are leaving it for 2 weeks, using for an hour and then leaving it for 2 weeks again, at the end of the 4th week you will probably have a flat Battery and you certainly will after 6 weeks. Each time you flatten the Battery it will lose its ability to hold some charge so the duration you can leave it before it goes flat will get shorter and shorter.

You could get a deep-cycle Battery to help, you could try and get a bigger Battery so it lasts longer but at some point you will need to recharge it fully.

Definitely worth making sure there isn't a fault - just get the parasitic load measured at the Battery once the vehicle is locked and all systems have gone into standby (wait at least 20 minutes before measuring). If you are seeing over 60 mA then you potentially have a problem and individual circuits can be tested as shown in the video on Herbie's post.

If there is no fault you don't have too many options here. You can either leave the vehicle in Ready mode for 30 mins every few days, use the vehicle more, or physically disconnect the -ve connection on the Battery when you leave it - but that is almost as inconvenient as having to jump it when you need to use the vehicle in a hurry.

 

As has been stated, the alarm doesn't use much energy so disconnecting it really won't make much of a difference. You could go some way by just not arming it (lock the vehicle with the mechanical key in the door lock rather than the button on the key fob) but it isn't going to really help.