capping maximum input voltage

i have a 12v circuit board wired into my motorcycle which has an input tolerance of 11v-13v. it is powered directly from the battery which, by nature of the charging system can be upto 14.5v

is there something i can put in line from the battery to the circuit board which will not allow more than 13v to the circuit board?

i thought maybe a resistor in line maybe but i cant let the voltage drop below 11v.
any help would be appreciated, thanks.

Find a proper switch mode / buck boost power supply that runs of 10-15 vdc or so ( to allow for the variation in the motorcycles voltage) and outputs a clean 12 vdc.

Phreak480 wrote:

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Find a proper switch mode / buck boost power supply that runs of 10-15 vdc or so ( to allow for the variation in the motorcycles voltage) and outputs a clean 12 vdc.

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hi, thanks for the reply, so you mean a 12v power supply that is powered by a 12v battery, but the power supply can manage the variation in input voltage but outputs a solid 12v?

can you give me a link to an example of what you are referring to, or shall i just google it?

thankyou

I have no idea what kind of circuit board you are trying to power, but the Astron power supply on my repair bench has variable voltage. It STAYS at 15 volts. I have powered everything that you can put in a vehicle with this 15 volts.

If you are concerned and want to use a regulator of some sort, I need to know the maximum current draw of said circuit board.

What is the load in Amps or Watts?
A simple Zener clamp (regulator) may be all that is required.

the circuit board contains 4 relays which i am using to power a remote start/ignition for my bike. the spec says max draw with all relays energised is 140mA.
i can post a link to the system i am using but i am not sure if i am allowed, does it not say in the forum rules that you cannot post links to stuff? or have i read that wrong?

You can post a link. Some websites such as Ebay, sonicelectronics, are blocked by the server. Post it and I can figure it out if it is a blocked one. If this is designed for automotive/MC use, it will handle the 14. whatever volts you send to it.

this is the unit i am using

https://www.quasaruk.co.uk/acatalog/DS-LEWES4%20Remote%20System-2.pdf

The unit's relays are rated for 5A and they typically have ~30mA coils which aligned with their data. (All relay operating less quiescent = 140mA - 14mA => ~120mA for 4 relays = 30mA per relay.)

The 11V - 13V receiver is obviously not designed for automotive use - ie, typically 8V - 16V operation or tolerance.
And whilst I thought a Zener regulator was fine for capping 140mA to 13V, it doesn't solve the problem of a cranking dip below 11V.


Hence I agree with Master IAAI - get a dc-dc converter that outputs 12V at least 2W (~160mA) with an 8V or lower to 16V or higher input.

Else get a receiver designed for automotive use.

ok, thanks for that advice. can you point me in a direction to such a DC-DC power supply that i would need?
i cant seem to find one, or i am looking at the wrong things.

thanks

You'll need a buck-boost (one that can step up and step down).

Maybe DC 3-35 to 1.2-30V Auto Buck-boost Converter?

that looks great thanks. i will look for something similar here in the UK. i will post up what i find.

i think i found what i need, as links to ebay items cause problems i will just give the item number, it is ebay UK

350769448474

it is very similar to the one you linked to.

Yeah - with the typical Pommie price! (And it's larger, byt it does include convenient screw terminals. Good find.)


Keep in mind that that (or these) unit(s) draw 10mA when idling which is more significant drain on a bike battery as compared to a car etc.

I really do not see a problem powering this unit at 14 volts. If you do use this power supply, you will need to use a relay to only use the supply when the bike is running. Have it run off the battery when the ignition is off.

Ah - but it's for a remote start system....

It will still work, when the Ignition comes on under remote start this will energize the relay and feed power to the unit from the power supply instead of the battery line.

The purpose for this is to not have the extra current from the supply when the bike is at rest.

My understanding is that THIS is the remote start system, but maybe I'm confusing with agemax's Durite thread.

Anyhow, agemax can clarify that. I'll bug out.

I know he is using it as the remote start. If he runs the power supply all the time there will be issues that you have already stated. The relay will power the unit from the battery when the ignition voltage is not present. When the Ignition is powered up, this will then feed the unit with voltage from the power supply, so it does not ever see over 13 volts. It will not matter if it is a remote start condition or if he used the key. Any time the Ignition is on, the unit will get power from the supply.

Power the supply off of ignition, and use a 10,000 or so Mic capacitor to keep power steady at the unit while switching from battery to power supply power.

Yeah. All I'm saying is the 10mA drain when the IGN is not on.

Without the dc-dc converter, a mere Zenor regulator could be used if non-operation below 11V when cranking is tolerable. (11V being its lower voltage spec, but that's not to say it won't work below that - provided lower voltages don't cause "the wrong relays" to trigger!)


I'd think any disconnect relay would be actuated only by the IG Key position (as opposed IGN +12V) to avoid a ride off since agemax didn't see the need for timers etc, so the relay has no impact on dc-dc converter draw.     

Let's hope the dc-dc conv has a low voltage cut-out to protect the battery.


But I will bug out. These are all issues for agemax's design & build. (I did Un-Watch, but I got the notification anyhow.)


PS - the running bike could change the receiver over to a Zenor protection circuit instead of the dc-dc conv (though why bother?), but there are lots of design possibilities.

hi, you are all confusing me a bit now, and i thought i had worked it out lol.
the remote system requires a permanent 12v supply otherwise none of it would work. the only way i can do this is to power the unit straight from the battery.
all i am concerned with is when the bike is running and at high revs, the regulator/ rectifier charges the battery as you ride but the voltage can reach 14.5v at the battery while charging.

will this be enough to damage the remote system and do i need this dc-dc converter to keep the power to the system at a steady 12v?

my other concern is the battery rating is 4.5AMP and the dc-dc converter is only rated at 3AMP max so will that be to much for the dc-dc converter?

thanks

Good - that's as I thought.

By my calcs, assuming you mean a 4.5AH battery and it's in good condition, it will supply 10mA for 90 hours (nearly 4 days) before hitting its 80% SOC (20% discharged) which is the normal limit for a cranking battery for acceptable battery life.
But you may want less discharge to ensure cranking - eg, maybe 2 days.


The receiver claims an 11-13V supply, hence presumably being prone to damage above 13V.
Hence the need/suggestion for a Zener regulator (essentially a voltage limiter), or a dc-dc buck-boost converter for the same >13V protection as well as operation below 11V.   

great, now i think i am with you. so you think i should buy the dc-dc buck-boost i found on ebay and that will do the job?

the battery is a brand new Ballistic 8 cell Lithium battery rated at 4.5amp with 275CCA.

i dont ride the bike every day so would you suggest either disconnecting the buck boost if the bike is left for more than a few days, or i could simply fit an in line switch to disconnect it from the battery power when not in use?

many thanks

No. I think you should buy a suitable module. I don't think you have an understanding of the things required eg, a timer for the remote start, as well as the interlocks that both I and HowieII mentioned.


Failing that, I think you should buy a receiver that suits automotive applications.


BTW - I erred above. I only considered a 10mA drain - ie, the receiver alone.
Include the dc-dc converter's overhead and that doubles to at least 20mA so you can halve my last reply's reserve times.

oldspark wrote:

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No. I think you should buy a suitable module. I don't think you have an understanding of the things required eg, a timer for the remote start, as well as the interlocks that both I and HowieII mentioned.


Failing that, I think you should buy a receiver that suits automotive applications.


BTW - I erred above. I only considered a 10mA drain - ie, the receiver alone.
Include the dc-dc converter's overhead and that doubles to at least 20mA so you can halve my last reply's reserve times.

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i do not understand why you keep saying i should have a timer for the remote start, no ready made kits come with timers?
and i have all the nessecary interlocks in place that are required. the system is the same set up as a unit designed for motorcycle use, except they bump the price but because they say it is designed for a motorcycle, whereas it is not, it is just a off the shelf 12v remote system with a wiring diagram to suit a motorcycle. i am fitting exactly the same thing except i am building ny own system rather than buying a premade set up

I doubt that commercial units would have a 10mA draw, let alone 20mA. And they would be using 12V automotive receivers, not "12V" receivers.

I'd be surprised if they didn't have a timer solely as a timeout for when the key is not inserted. There are other ways of protecting against drive offs, but a timer is one simple method.
Commercial units should also have tilt switches, oil pressure engine stops, etc.

oldspark wrote:

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I doubt that commercial units would have a 10mA draw, let alone 20mA. And they would be using 12V automotive receivers, not "12V" receivers.

I'd be surprised if they didn't have a timer solely as a timeout for when the key is not inserted. There are other ways of protecting against drive offs, but a timer is one simple method.
Commercial units should also have tilt switches, oil pressure engine stops, etc.

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why would you have a timeout for a key, when a key is not used? if i was using a key then the whole concept of the remote start becomes pointless.

what purpose would a tilt switch be used in a remote start application?
as far as oil pressure engine stop, no bike i have ever come across has this facility, whether key or remote ignition, in fact i dont think i have ever seen a car with this facility.
there is an oil pressure switch which illuminates a light in the dash area, if that comes on you stop!

So I can jump on your bike & ride off?
Your bike is on its side & it starts, or I kick it over (maybe because of the steering lock) and it keeps running?
There is no oil pressure and - when remote started - it keeps running?

Geez, they are really good remote start designs aren't they?
Or am I yet again ahead of my time wrt to industrial/commercial/any design?

oldspark wrote:

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So I can jump on your bike & ride off?
Your bike is on its side & it starts, or I kick it over (maybe because of the steering lock) and it keeps running?
There is no oil pressure and - when remote started - it keeps running?

Geez, they are really good remote start designs aren't they?
Or am I yet again ahead of my time wrt to industrial/commercial/any design?

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no, you cant just jump on my bike and ride off, unless you steal my remote fob to start the bike.why would it start if it is on its side? (magic) NO bike specific remote start system on the market has an oil pressure fail safe.
you are obviously not way ahead of your time with design, and way behind with motorcycle electrics.(if in fact you have any knowledge of motorcycle electrics at all!)

i think i will leave this forum and find another that knows what they are talking about when relating to motorcycles. when i first saw this site i thought with such a massive membership there would have been quite a few people on here who knew about motorcycle electrics..how wrong i was.

All "Ready Made" remote start units have timers. None of them are designed to replace a key.

Did I mention earlier that you could use a relay and a capacitor to power the unit from either the battery when the ignition is not powered, (it will be under the worried about 14.X volts). And when the ignition is on, this will power the supply and get power from the supply instead of the battery which MAY be at 14.x volts.

PS - sorry IAAI, I missed your replies. But I'm glad you state what IMO should be obvious. Maybe commercials are worth a look see.
The cap might be a cranking ride thru (allowing for (Shottky) diode drop) with a Zenor once started.
Back to my reply (to agemax)...

Ha ha - yeah right.

Alas commercial units cannot assume your specifics - ie, that you know your bike is upright before starting. It's a bit like cars checking they are in neutral or Park etc (which yours too would have).

And ok, so motorbike remote starts allow the engine to continue to run with zero/low oil pressure. Note that I say "continue to run" and NOT start (I'm not stupid).   

You reckon I have no knowledge of mc electrics etc. Strange then that I have corrected a number of OEM design faults.

And you reckon you start the bike and I can't take it and then ride off? Pray tell, with your fob unable to turn the bike off, how will you stop me? (Or is your fob encoding and receiver selectivity that good?)


But fine, go to another site that does not consider nor discuss these issues. Maybe one will empower you to by the right products instead of needing a dc-dc converter to patch your mistake.

And thanks for the forewarning. I now know not to even bother looking at commercial offerings for my bikes (admittedly one is a round-case with kickstarter only, but unlike its OEM version, I can start it with a flat battery AND charge with lights at idle speeds).


Good riding bro.

oldspark wrote:

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PS - sorry IAAI, I missed your replies. But I'm glad you state what IMO should be obvious. Maybe commercials are worth a look see.
The cap might be a cranking ride thru (allowing for (Shottky) diode drop) with a Zenor once started.
Back to my reply (to agemax)...

Ha ha - yeah right.

Alas commercial units cannot assume your specifics - ie, that you know your bike is upright before starting. It's a bit like cars checking they are in neutral or Park etc (which yours too would have).

And ok, so motorbike remote starts allow the engine to continue to run with zero/low oil pressure. Note that I say "continue to run" and NOT start (I'm not stupid).   

You reckon I have no knowledge of mc electrics etc. Strange then that I have corrected a number of OEM design faults.

And you reckon you start the bike and I can't take it and then ride off? Pray tell, with your fob unable to turn the bike off, how will you stop me? (Or is your fob encoding and receiver selectivity that good?)


But fine, go to another site that does not consider nor discuss these issues. Maybe one will empower you to by the right products instead of needing a dc-dc converter to patch your mistake.

And thanks for the forewarning. I now know not to even bother looking at commercial offerings for my bikes (admittedly one is a round-case with kickstarter only, but unlike its OEM version, I can start it with a flat battery AND charge with lights at idle speeds).


Good riding bro.

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you wont know if you have oil pressure UNTIL the bike is started, so how can it prevent you from starting it?
so please explain, which OEM design faults have you "corrected"?
you still do not grasp the concept of the remote start system do you? i can power the bikes ignition circuit from the key fob, as well as start the bike. if i start it from a distance, and someone decides to jump on it and ride off before i get there, i simply kill the ignition (with the keyfob), bike stops dead!

oh, and there is nothing wrong with my charging system, even at idle!
a flat battery can be a problem, but it is a simple task to bump start it, unlike a car,especially an automatic

i am an idiot wrote:

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All "Ready Made" remote start units have timers. None of them are designed to replace a key.

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so please explain the whole concept of a "remote" start. i would say it is so you could "remotely" start a car or a bike from a distance.
having to sit in the car, or on a bike and physically put a key in, turn it then start the bike with the keyfob is not exactly very remote is it?

and i still have no idea why you keep mentioning a timer, is that to time how long it takes you to press the button on the keyfob after you run to your vehicle and turn the key?

agemax wrote:

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you wont know if you have oil pressure UNTIL the bike is started, so how can it prevent you from starting it?

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oldspark wrote:

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Note that I say "continue to run" and NOT start...

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Clear?

agemax wrote:

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oh, and there is nothing wrong with my charging system, even at idle!

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I never said there was. I thought "round case" was enough of a hint as to which 1972 bike I referred to. They won't start with a flattery even if you could roll start it, and they don't survive city riding at night, yet I can kick-start mine with a flattery and survive with lights below 3000 RPM (which is over 100kmh/60mph) - the required RPM for their "stator" type alternator to adequately run a 55W headlight etc. But if you don't know that vintage etc you probably won't understand how unique mine was (without spending hundred$).

agemax wrote:

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a flat battery can be a problem, but it is a simple task to bump start it, unlike a car,especially an automatic

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Yes, but your remote-start won't work. You miss my point.

agemax to IAAI wrote:

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so please explain the whole concept of a "remote" start. i would say it is so you could "remotely" start a car or a bike from a distance.
having to sit in the car, or on a bike and physically put a key in, turn it then start the bike with the keyfob is not exactly very remote is it?
and i still have no idea why you keep mentioning a timer...

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agemax to oldspark wrote:

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you still do not grasp the concept of the remote start system do you?

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It is you that does not grasp the DESIGN of a remote-start. You have described its primitive function with none of the inherent detail.

To say that you will always be able to turn the bike off with the fob demonstrates your lack of understanding if not ignorance of required "security" and likely countermeasures, or failures. (I presume your fob & receiver have appropriate rolling encoding etc?)


I strongly suggest you read up on remote-start bike systems. This technology is now decades old and it would simply not survive commercially if it did not have the features we have mentioned (and we are only scraping the surface - cold oil viscosity in a bike often means other sensing - the simplest (but in the "too late" basket) being a tilt switch.

Even if the first remote-start prototype did not have such features, it probably wouldn't take long to realise their necessity. And any commercial generic unit must have such features available.

Bikes used to use car remote-start systems but with additions that were unique to bikes. But maybe car systems are a good starting point - eg wrt timers, oil pressure, etc.   
This forum does have threads that discuss such features and requirements though it's only the occasional hobbyist or amateur that doesn't already understand such details so a concise "all in one" treatise may be hard to find (tip - use google).


And tho I am not an installer of such systems, IAAI is and he seems to confirm what I have been saying.
And as Howie II wrote, this has all been done before...


Over & out.

Timer = Run time timer. They all shut off at a selectable amount of time.

I suspect the penny never dropped.
Strange - there is so much web info on such designs...

oldspark wrote:

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I suspect the penny never dropped.
Strange - there is so much web info on such designs...

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it is all up and working absolutely fine, just as i thought it would.
the remote control system actually runs perfectly well being fed direct from the battery, even with the voltage fluctuation.

thanks anyway for any advice given.

You may still miss the point - I didn't think it wouldn't work.

Get back to us if any "accident" or damage happens, or if it ever gets stolen.

will do, but don't hold your breath waiting!

i dont think there are any points i have missed, the system works flawlessly AFAIAC.

I won't hold my breath - I know it's a case of chance and situation.

Alas I/we only hear of deficient designs when the appropriate problem occurs; we have no way of knowing how many deficient or lacking designs have operated fine (so far).