HI. I have a 88 BJ74 and I want toinstall a sterio, alarm etc into. I understand how to run the 3rd battery off a converter to run all the accessories, but how do I deal with the truck wiring in regards to the alarm? ie lights, horn, door switches etc. Any ideas for me?
12v Alarm install in 24v BJ74
- Thread starter Phil in BC
- Start date
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Haven't gotten there personally yet but my plan was to tap into the related vehicles subsystems with small 12V relays...
Ron R
Drive a Landruiser, enjoy life
When I installed my 12v alarm/antitheft-system I found that the functions that interrupt/connect things, like fuel-cutoff and ignition disconnect, are switched by relays allready in the unit. These functions typically have an input AND an output. Because they are switched by means of relays they are not connected to the 12V source at all. So there are no external relays needed.
For an input only (i.e door- detect) I had to add an relay parallel to the doorlight.
Some units have their own horn but if your system uses the car-horn I bet it's switched by an internal relay as well and is similar to the fuel/ign cutoff.
With the use of your multimeter you can find it out.
For an input only (i.e door- detect) I had to add an relay parallel to the doorlight.
Some units have their own horn but if your system uses the car-horn I bet it's switched by an internal relay as well and is similar to the fuel/ign cutoff.
With the use of your multimeter you can find it out.
And then wonder why one battery sulphates and one boils...requiring two new batteries a year.
"Never" take a tap off one battery. The charging system "will" overcharge one, and undercharge the other. Use a 24V-12V converter for any 12V needs, or source and install 24V appliances.
Phil, use a converter to a fuse strip, take all your 12V needs off the fuse strip and use relays where you need to. Beamriders in Abbotsford used to have an installer who was on kill and could ensure door lock, lights, and all the bells and whistles on the alarm would function with no issues on a 24V truck.
hth's
gb
I wonder how many times a year this comes up.
And this folks is why 24v systems have a bad name…. not meaning to pick on ya bob, but do you mind editing your post so some unsuspecting green horn doesn’t read it without scrolling down further?
Unfortunately it’s a VERY common misnomer, EVERY car stereo shop in Victoria BC tried to tell me to do the exact same thing when I was price hunting for gear. That is of course after they front desk guy had called over the “guru” from the back, then I go and explain the issue with what they are suggesting and the response from 4 of the 5 shops was “well we do it all the time and its never a problem”… RIGHT…….. HIIIIiii ho hi ho its off to Ebay I go!
Unfortunately it’s a VERY common misnomer, EVERY car stereo shop in Victoria BC tried to tell me to do the exact same thing when I was price hunting for gear. That is of course after they front desk guy had called over the “guru” from the back, then I go and explain the issue with what they are suggesting and the response from 4 of the 5 shops was “well we do it all the time and its never a problem”… RIGHT…….. HIIIIiii ho hi ho its off to Ebay I go!
You will need a converter or something to balance the load on your batteries. The easiest route is just installing a converter but then the load you can pull off of it will be lower. Solar converters work great. Once you have the converter in place buy 24v relays to switch the 12v power to the alarm.
im personally more of a fan of the equalizer idea... get a 30amp unit, then you can pull as much or as little juice out of one of your batteries BUT the equalizer will ensure you don't cook anything... Say you needed so 10 seconds or so a load of 100 amps... the equalizer would pull 30 of those amps from the second bat and the remaining 70 would come from the first bat. After you no longer needed the load the equalizer would continue to run until the voltage between the two bats were within .03Vso say 70 amps for 10 seconds with a supply of 30 amps (70/30)=2.33x 10 seconds then the unit would run for 23 seconds after you were no longer using the load until the cells were equalized (I knows thats a somewhat simplified explanation but it gets the point across.)
Equalizer:
a)same price
b)ensures proper battery balancing ALL the time (IE phantom loads are no issue) 5ma latent draw on average
c)has much better peak power performance vs a converter IE you can pull as much power as you could ever realistically need.
Equalizer:
a)same price
b)ensures proper battery balancing ALL the time (IE phantom loads are no issue) 5ma latent draw on average
c)has much better peak power performance vs a converter IE you can pull as much power as you could ever realistically need.
- Thread starter
- #10
Hey everyone. Thanks for all the input on this. It's great having a forum like this to get answers from people who know. This is my first LC and I have never had issues like this with any other vehicle, but no matter, its worth the trouble to have a truck like this!
I think I know what i'm going to do as far as the power supply goes. I'll get one of those solar converters to supply a 3rd battery, as long as I can find room to squeese it under the hood, and then run all my sterio etc off the 12v supply from that. My only issue now is hooking the alarm system to the truck, like the door sensors, horn, ignition etc. As long as we can get relays to go from 12 - 24v, then I think my problem will be solved. I live in the interior and doint make it to the lower mainland too often, so having my sterio stolen here isnt as likely, but I still dont want to take the chance. Better safe than sorry.
Phil
I think I know what i'm going to do as far as the power supply goes. I'll get one of those solar converters to supply a 3rd battery, as long as I can find room to squeese it under the hood, and then run all my sterio etc off the 12v supply from that. My only issue now is hooking the alarm system to the truck, like the door sensors, horn, ignition etc. As long as we can get relays to go from 12 - 24v, then I think my problem will be solved. I live in the interior and doint make it to the lower mainland too often, so having my sterio stolen here isnt as likely, but I still dont want to take the chance. Better safe than sorry.
Phil
If your going the 3rd bat rout you may want to look at getting a 24-12V charger instead... A bit more pricey but it will keep the 3rd bat much more healthy. The converters do one of two things either
a) half the power with which they are supplied with could eventually result in cooking the 3rd bat (bat 3 is full but bat 1&2 are charging thus system voltage is in the 29+ range /2 =14.5V output IE bat 3 will start to cook)
B) Output a fixed 12.something V which is sufficient for running things, but will NEVER be able to charge the 3rd bat anywhere close to full. More likely that 12v bat will spend most of its life somewhere in the 40% capacity area, so it will be perpetually undercharged so expect to have to keep an eye on it.
-equalizer would also work with a 3rd bat just be sure you buy all 3 bats as paired (although at that point unless you have HUGE 12V draw I really see no reason to add a 3rd bat, waste of space and money IMHO)
a) half the power with which they are supplied with could eventually result in cooking the 3rd bat (bat 3 is full but bat 1&2 are charging thus system voltage is in the 29+ range /2 =14.5V output IE bat 3 will start to cook)
B) Output a fixed 12.something V which is sufficient for running things, but will NEVER be able to charge the 3rd bat anywhere close to full. More likely that 12v bat will spend most of its life somewhere in the 40% capacity area, so it will be perpetually undercharged so expect to have to keep an eye on it.
-equalizer would also work with a 3rd bat just be sure you buy all 3 bats as paired (although at that point unless you have HUGE 12V draw I really see no reason to add a 3rd bat, waste of space and money IMHO)
Sorry mate, but I wont be editing my post, and I stand by what I said.
An alarm system has for the most part an incredibly small current draw, and nowhere near enough to cause sulfation/boiling. If some turkey were to wire a 12v Winch in this manner, then that would be an issue, but for the OP's purposes then tapping one battery would be perfectly fine.
I will concede that it isnt an ideal solution for the stereo, however for the alarm it would never cause issues
Sean
Just buy regular 24v relays. These will happily switch your 12v power.
Sorry to deviate from your question Phil, but I just can't help but rise to this bait...
As for tapping one battery with no balancing, that would be foolish in my opinon. Sorry, BoB.
Phil's post asks, "HI. I have a 88 BJ74 and I want toinstall a sterio, alarm etc into." A stereo is not a minor draw on the system. You need to have something to balance your batteries and keep them healthy.
Even with no current draw there can be balance issues in a two 12v series system making 24v. Even two outwardly identical batteries, will have slight differences due to internal resistance, plate thickness, electrolyte dilution and the like. Any additional draw will not cause boiling or immediate sulfation by itself. It is when the batteries are charged by the alternator that they become more unbalanced and subject to these issues. If one battery is weaker than the other, it will become more so and the stronger will become more highly charged. If left unchecked, the higher voltage battery will become overcharged and damaged. The low side battery (almost almost the one that gets charged less) will get weaker and, over time, become sulphated. For this reason, it is recommended that even in a completely stock system, the batteries are periodically removed and charged (spring maintenance is a good time) and rotated (high side to low, and vice versa).
Phil, 24v relays should still operate with a 12v actuation, so if you have circuits that need relays, they will still work. The switching power just operates the little coil in the relay - not much required to do this.
As for your power, I would do the following in the same situation:
Keeping in mind what I said above, run all the goodies off one battery and use the Solar Converter to keep them balanced. If you don't run your unit for a while, you risk running both batteries down because of parasitic loads. I don't know how long it might take, but GregB would know. It happened to him. They will be nicely balanced, but low on voltage. That might not be a good thing.
To combat this situation, you could use a switch to change the SC from balance to 12v supply mode when it is not running, but be sure to watch the connect/disconnect order of the converter when you set it up. Or you could use the switch to disconnect the batteries completely, but that would defeat the purpose of the alarm.
The route I would take for the switch is a bit more complex, but much more user friendly. Instead of a manual switch under the hood or dash, I would use an additional relay and wire it into your ignition switch.
The idea behind this is when you put your key into the ignition and turn your truck on, you get 12v directly from one battery. The SC will balance the batteries to keep em good and happy. When you get home, and turn off your Cruiser, the SC will switch from balance to 12v convert mode. This will give you 12v for your radio presets, clock and alarm electronics.
Its the best of both worlds. Balance batteries when running, and no blowing fuses if you momentarily draw more than the 20-30 amps that the SC will allow in 12v conversion. Also, no dead batteries because of continuous minor current draws and a balancer that works to keep them at the same state of charge.
Stone had a system similar to this on his BJ74 and there are a few write ups on this stuff on here. Well, most everything but using the ignition to switch the SC.
Good luck with your project and let us all know how it goes.
-kevin
Well said, and this is the exact reason why even a small tap like a mem preset, clock or even an alarm will cause issues over time.
Kevin, I've got my load balancer hooked up with a relay so it load balances only when running as well.
hth's
gb
wiring in a converter
Hi Folks; sort of a related question so I hope it is fine to hijack this thread.
I have a 24V BJ70 from Japan with a 24V am radio. I have a 12V Landcruiser am/fm radio from a Canadian vehicle that is a perfect fit for the dash and the wiring harness.
Having purchased a 24 to 12 V converter, there are 2 wires "in" from 24V source (power is fused), and 2 wires 'out' to the 12V device. Any advice on where the 24V power in wire should be connected?
Can I cut the existing power wire to the radio, and splice the 24V power in converter wire to the battery side of the existing wire, and the 12V power out to the radio side of the wire? Should both grounds go to the body, or if the power can be splice into the existing harness, should the grounds be too?
Thoughts? Finding lots of theoretical commentary, but no practical hands on 'how to' when it comes to physical connections.
Thanks....Denis
Hi Folks; sort of a related question so I hope it is fine to hijack this thread.
I have a 24V BJ70 from Japan with a 24V am radio. I have a 12V Landcruiser am/fm radio from a Canadian vehicle that is a perfect fit for the dash and the wiring harness.
Having purchased a 24 to 12 V converter, there are 2 wires "in" from 24V source (power is fused), and 2 wires 'out' to the 12V device. Any advice on where the 24V power in wire should be connected?
Can I cut the existing power wire to the radio, and splice the 24V power in converter wire to the battery side of the existing wire, and the 12V power out to the radio side of the wire? Should both grounds go to the body, or if the power can be splice into the existing harness, should the grounds be too?
Thoughts? Finding lots of theoretical commentary, but no practical hands on 'how to' when it comes to physical connections.
Thanks....Denis
