Car battery remote disconnect / saver?

[JOEPRO]

For weekend use cars or second cars that can sit for weeks between uses I am looking for a remote disconnect solution so not having to pop the bonnet each time.

Something like this maybe or has anyone got a recommendation please?

https://amzn.eu/d/8jtQG5I

 

[sako243]

I assume there's a timer involved but it does state in the description that when it drops below 11.8V it kills it automatically. There's a mention of 120s one would hope that means it's got to be below 11.8V for 2 minutes for that to happen?!

 

[Ubique]

A rating of 240 (Chinesium) Amps is barely the rating of a small petrol engine starter current draw.

 

[JOEPRO]

A rating of 240 (Chinesium) Amps is barely the rating of a small petrol engine starter current draw.

Any suggestions then?

 

[qwakers]

12V Battery Protect Relay 500A

The 12V Battery Protect Relay 500A is a smart high-current magnetic latching contactor, that can handle continuous DC currents of up to 500Amps. The contactor can easily be installed in an engine room or battery compartment while being controlled from a more convenient location by a small...

merlin-power.com

 

[JOEPRO]

12V Battery Protect Relay 500A

The 12V Battery Protect Relay 500A is a smart high-current magnetic latching contactor, that can handle continuous DC currents of up to 500Amps. The contactor can easily be installed in an engine room or battery compartment while being controlled from a more convenient location by a small...

merlin-power.com

One that's not nearly £300

I *think* the ratings of 250 or 500A etc are meaning continuous rating loads.

For short term startup currents I am seeing reference to being suitable on other 250a battery disconnect relays but granted its not clear in the description exactly what are the max startup current recommendations.

It's for my Dad's car and I ordered one. I will fit at the weekend and see how it performs. Its easy to fit and to remove again so no harm done if it doesn't work as intended or fails.

I have a few other cars that would benefit from this type of device too so curious how this works out.

 

[qwakers]

Battery Protect Relay (500A) - TBS Electronics EN

The DC Modular Battery Protect Relay (TBP) is a smart high current magnetic latching contactor, that can handle continuous DC currents of up to 500Amps. The TBP has a number of additional features over our RBS. Most importantly, it can protect your battery without the need of an external...

tbs-electronics.com

the bumpf.

 

[Ubique]

Any suggestions then?

A Ctek charger with an external charge port. What you want to do isn't for the 'cost conscious' if you want to do it properly and electrically safely.
The new(ish) Ctek One is a good bit of kit but possibly over-budget with suitable connectors.

 

[JOEPRO]

A Ctek charger with an external charge port. What you want to do isn't for the 'cost conscious' if you want to do it properly and electrically safely.
The new(ish) Ctek One is a good bit of kit but possibly over-budget with suitable connectors.

It's for my Dad's car he has a Ctek charger already but only used when battery drains down which is not ideal.

Looking for a way to remotely disconnect the battery with a fob so he is likely to use it more often.

The one I linked says the following amp ratings-



600amp cranking should be OK so worth a try I think.

 

[Ubique]

Don't take this the wrong way but I'd try education / repetition to get the Ctek used regularly, I wouldn't trust that box any more than I would Putin. Any battery will self-discharge when disconnected so you're only really removing ~30mA of current drain, it'll still need charging. If the Ctek is a bridge too far, then how about a decent solar panel?

 

[JOEPRO]

Don't take this the wrong way but I'd try education / repetition to get the Ctek used regularly, I wouldn't trust that box any more than I would Putin. Any battery will self-discharge when disconnected so you're only really removing ~30mA of current drain, it'll still need charging. If the Ctek is a bridge too far, then how about a decent solar panel?

Its a 2005 SC420 Lexus. I measured and the car has 60ma parasitic draw when locked and sitting.

Is that too high? Not sure. My Mercedes generally have more like 30 - 40ma draw.

The main issue is this car is a second car of my Dad's so sits unused for weeks at a time.

Education etc yes I hear ya!!

But I can't hold his hand either nor can I say 100% that he will use the CTEK even if I remind him on a regular basis.

So whilst not ideal, given the situation an easy to fit and easy to remove disconnect device like this is worth a try. Not the best approach but quick and should provide the desired function.

If it doesn't work I will get a phone call immediately and I will go remove it! For now it's better than fitting another new car battery and letting it degrade quickly. (Yuasa battery now dead after 2.5 years. I'll try warranting it in Halfrauds tomorrow but expect them to have excuses and reject!)

 

[Ubique]

Never really had much to do with Jap stuff but 60mA 'seems' high by European standards where anything above 40-45mA is an 'investigate' and >50mA is a problem. Maybe look at a decent solar panel on the rear parcel shelf (useless if it's in a garage!) As you say, 30-40mA is the expected range which should give at least three weeks of parking before the charge level is such that the car won't start. We had an A176 parked for three months, waiting for the guy to save up to pay his bill - started well enough, the only problem was the corroded brakes....

 

[JOEPRO]

Never really had much to do with Jap stuff but 60mA 'seems' high by European standards where anything above 40-45mA is an 'investigate' and >50mA is a problem. Maybe look at a decent solar panel on the rear parcel shelf (useless if it's in a garage!) As you say, 30-40mA is the expected range which should give at least three weeks of parking before the charge level is such that the car won't start. We had an A176 parked for three months, waiting for the guy to save up to pay his bill - started well enough, the only problem was the corroded brakes....

Solar maintainers is a good suggestion. I had one years ago that couldn't match a w220 S class drain but admittedly I can't remember the brand and output of that solar charger so it wasn't up to much to begin with.

I see the likes of Ring branded range here -

Solar Battery Chargers - Ring Automotive Shop

Charge your vehicle's battery with the power of solar. Ideal for seasonal vehicles, motorhomes and caravans.

shop.ringautomotive.com

Would it be best to go for a 10w or 20w one rating wise? Even for my W220 and w140 S classes, I am interested on what might actually charge them sitting around in semi decent daylight.

 

[Ubique]

The spec. doesn't mention a regulated output, personally I'd look at one that has a regulated output of 13.6VDC as a minimum, the reason being that gives you >1VDC of forward voltage to maintain existing charge. The regulated panels tend to be more 'spendy' but are actually useful with a high quiescent current drain. 20W @13.6VDC gives you 1.47A which is 1.41A of charge at full output (unlikely given your geographical location), the crucial measurement - once above the quiescent equilibrium point, is the forward voltage - without that, you're not actually charging the battery, just supporting the discharge load.

 

[Ubique]

This looks to be a later version of the one I used on my L322 - https://www.amazon.co.uk/POWOXI-Upg...Motorcycle/dp/B07TY3HGF7?ref_=ast_sto_dp&th=1

 

[keithski122]

Would disconnecting the battery long term cause ecu resetting problems?

 

[JOEPRO]

This looks to be a later version of the one I used on my L322 - https://www.amazon.co.uk/POWOXI-Upg...Motorcycle/dp/B07TY3HGF7?ref_=ast_sto_dp&th=1

Thanks I was looking at that one actually. I have 12 cars here, 11 of which sit around so really keen to test one out. Hence I ordered one of those for myself. I have Bluetooth car battery monitor devices so I can report back how it works out on here in a couple of weeks time for anyone else curious.

 

[JOEPRO]

Would disconnecting the battery long term cause ecu resetting problems?

On this particular Lexus- doesn't seem to bother it. That's not to say "something" is lost such as transmission shift learning etc I'm not sure.

But it doesn't ask for a radio code or anything like that. And for all the miles my Dad does in it around town he is happy and car doesn't seem affected as it's already been sitting around with the battery drained intermittently the past couple of years.

 

[JOEPRO]

This is the older one - NFG

 

[m_c]

@Ubique has beat me to it in recommending a solar panel.

I've had plenty experience with aftermarket battery disconnectors, and experience tells me that they cause more problems than they prevent.