Triton Low Voltage Alarm

[rc404]

I could use some ideas. I often use my Triton to charge batteries in my car on the way to the field. The problem I have is starting the car drops the car voltage enough to trigger the Triton's very annoying low input voltage warning (10.5 volts). I'm looking for ideas on something I could build to keep the input voltage up enough not to trigger the low input voltage warning for the few seconds while I start the car.

Thoughts?

[gulio]

I can't help with a device, but if you happen to be using nickel battery charge routine there's a small 5 second window every minute that may allow you to start vehicle without dropping input voltage.

If doing lipo this is no help, I'm also curious to a device though. Hope you get an answer. better than mine. lol.

[Chippie]

I could use some ideas. I often use my Triton to charge batteries in my car on the way to the field. The problem I have is starting the car drops the car voltage enough to trigger the Triton's very annoying low input voltage warning (10.5 volts). I'm looking for ideas on something I could build to keep the input voltage up enough not to trigger the low input voltage warning for the few seconds while I start the car.

Thoughts?
How about a very large capacitor....1F strapped across the input...like the audio boys do with their hi power amps to avoid sag..I think you may need a
hefty diode befor the cap too to prevent it discharging back to the car battery when cranking the engine.?
Just a thought.

[rc404]

How about a very large capacitor....1F strapped across the input...like the audio boys do with their hi power amps to avoid sag..I think you may need a
hefty diode befor the cap too to prevent it discharging back to the car battery when cranking the engine.?
Just a thought.

Cippie, thanks.

A capacitor (with a diode) is the first thing I thought of. I figured I've got some electrolytics in my junk box. Then I did a little math. Based on my simple assumptions I am needing at least 1-2 Farads. That's not in my junk box.

Not being an automotive audiophile, I hadn't thought about looking into audio system caps. So I searched a little, they would probably work. They start around 1 F and go up. They're also not cheap (at least not junk box cheap). None of them say they have a diode to prevent discharge back into the car power system, but they all must have - right? A lot of them have a built-in digital volt meter, I presume that's for charging?

OK, one option is to watch ebay and see what pops up.

I was also thinking a diode and a gel-cell battery like you'd use in a field box. But would the battery get charged sufficiently through the diode?

[Chippie]

Cippie, thanks.

But would the battery get charged sufficiently through the diode?


If you use a diode with lo forward voltage drop it ought to...

Most alternators output around 14.4v when charging( check when your engine is running with a dvm across the car battery) and as the SLA battery needs around 13.8v then the drop across the diode should provide around the right level....some measurements will confirm this.:)

[rc404]

If you use a diode with lo forward voltage drop it ought to...

Most alternators output around 14.4v when charging( check when your engine is running with a dvm across the car battery) and as the SLA battery needs around 13.8v then the drop across the diode should provide around the right level....some measurements will confirm this.:)

Thanks, I can make those measurements easily and will do so. But don't I then have to include some kind of regulator or at least resistor to limit charging current? I'm thinking that any linear regulator or resistor I add will drop the voltage even more under charging operation and then aren't I back where I started?

[everydayflyer]

Why not just start the car before the charger?

[gulio]

Also can turn off charge, start car, then restart charge?

I'd be curious as to Hook the Triton up direct to the battery then get the input reading while starting the car. It may not be close to the 10.5 low voltage cut-off and if it's not then rewire some stuff may do the trick.

I may just go do this right now,.lol.

[rc404]

Why not just start the car before the charger?

That's my solution now, or to be more specific: Hook up and start the charger in the back of the van, close the rear door, get in the drivers seat, start the car, curse at the Triton, get out of the drivers seat with the car running, open the back of the van, reset the Triton, close the rear door and go back to the driver's seat.

Or to be even more specific, because I can't seem to remember to start the car first and because I'm lazy.

[Chippie]

Well I've re-read this thread....My thoughts are why charge en route to the field? especially if lipos are involved, I wouldnt do it......

Notwithstanding this, yes some form of regulator ought to be used, but then you start having problems with insufficient headroom for the reg to function properly......

[rc404]

Also can turn off charge, start car, then restart charge?

I'd be curious as to Hook the Triton up direct to the battery then get the input reading while starting the car. It may not be close to the 10.5 low voltage cut-off and if it's not then rewire some stuff may do the trick.

I may just go do this right now,.lol.

Maybe I need to be more specific. I'm charging my airplane in the back of my van. I've put a cigarette lighter plug on the input to the Triton and plug it in to a power jack in the back of the van. I suspect it very well could be line losses to the back of the van that contribute to the low voltage, but I'm not going to rewire the van.

[rc404]

Well I've re-read this thread....My thoughts are why charge en route to the field? especially if lipos are involved, I wouldnt do it......


I charge this way because its convenient for me to leave the airplane in the van and because I travel to remote contests. Its convenient to leave it on charge overnight or while I'm driving or parked at work before going to the field.

This is all NiMH. I never charge lipos this way. Not even when I'm in the van. For charging any lipos I have about 6 feet of cable from the power jack and set the Triton and the battery out on the ground away from the car.

[gulio]

I just tried mine ( I have a venture with cig plug in the back)

While hooked to the battery (my van batt is not good) I used Triton on full power and it went to low voltage alarm when starting van. I then cut the power to about 50 watts and started it again with the voltage maintaining over 10.5 so all was well.

It seems that it would be necessary to use large gage wires and go to the batt, but I don't blame you. I wouldn't do it either.

If you are doing nickel batts then perhaps a stop-watch would suffice to tell you when to start the van during the tiny 5 second window?

[SamD]

Keep in mind that the typical protocol on vehicle starting systems is such that when the starter is engaged, all non-essential devices/electronics are switched "off" to avoid parasitic draw on the battery during a state of heavy draw.

That said, I, too, experienced the low voltage warning woes when using my Triton and had the same complaints. After running a direct line from the battery (Both positive and negative) to a hook-up point in my truck's bed, this hasn't been a problem. A bit of work, yes, but it took care of the problem.

[Comatose]

Why not add a small SLA battery (12v, 7AH or so) back where you do your charging? The car's electrical system will keep it charged, and then you'll have a reserve battery to deal with momentary sags and spikes, all without having to rewire anything.

[rc404]

Why not add a small SLA battery (12v, 7AH or so) back where you do your charging? The car's electrical system will keep it charged, and then you'll have a reserve battery to deal with momentary sags and spikes, all without having to rewire anything.


That was the idea suggested by Chippie and I think it might be made to work. I was thinking a battery with a diode to keep the small battery from trying to help the main battery start the car. The main question was would I need some kind of regulator to keep the car system from overcharging the small battery? The problem then is the voltage head room needed to run a charging regulator isn't readily available. I need a regulator that would pass several amps of current with very low voltage drop, but not allow the car system to overcharge the small battery.

[Chippie]

Ok, how's this for an idea....? a small sla battery used as the primary supply for the charger,then a voltage switched relay that is sensitive to the sla's terminal voltage such that it is charged by the car when its voltage falls to a set level and is disconnetced when it reaches another preset voltage...basically a window detector....then to prevent the car from discharging the battery on start up, another voltge sensing relay only connects the charger circuitry to the battery when the car's alternator is running...Could have an override switch for when the engine is not running....

Is this a doable approach? :) I think so as this how I charge my caravan battery while towing....


Doesnt need a regulator that needs a higher input voltage...only charges when is needed....wont be discharged by starting the car(unless you leave the override switch on...)

[rc404]

Ok, how's this for an idea....? a small sla battery used as the primary supply for the charger,then a voltage switched relay that is sensitive to the sla's terminal voltage such that it is charged by the car when its voltage falls to a set level and is disconnetced when it reaches another preset voltage...basically a window detector....then to prevent the car from discharging the battery on start up, another voltge sensing relay only connects the charger circuitry to the battery when the car's alternator is running...Could have an override switch for when the engine is not running....

Is this a doable approach? :) I think so as this how I charge my caravan battery while towing....


Doesnt need a regulator that needs a higher input voltage...only charges when is needed....wont be discharged by starting the car(unless you leave the override switch on...)

Thanks! Very interesting idea. I need to think about it some.

[SamD]

Sure seems like a lot of messing around vs. simply running an independent line directly from the battery. If you integrate the alternator into the lash-up, you're still running wire from the engine compartment to back of the car... Not sure what you've gained by a set-up such as this- other than complication.:confused:

[rc404]

I've been away from this for a week or so. I was thinking of something along the lines suggested by Chipppie, a relay based device. Then I came up with the approach in the schematic below.

What I really want is:

1) the car to power the Triton when the car is either running or not running

2) the car to charge (but not overcharge) the SLA battery when the car is running

3) the SLA battery to power the Triton when starting the car and keep the input voltage > 10.5

4) the SLA battery does not supply current to help start the car

When the car is not running, the Triton will be powered (at least predominately) from the car because the car system has to drop through D1 but the SLA has to drop through both D3 and D4 diodes.

When the car is running, the Triton runs from the car and the SLA will be charged through D1 and D2. The voltage drop through both diodes will keep the charging voltage below 13.8 (granted the SLA will never get fully charged but will be charged to some intermediate level)

When the car is started, its voltage will drop for a few seconds and the Triton will be powered from the SLA through D3 and D4.

Lastly, D1 prevents the SLA from trying to help start the car.

After making one of these up from regular silicon diodes, it appeared that the voltage drops were too large so I substituted in Schottky diodes (1N5820). These are 3 amp diodes (what I could find locally) so I'm limited on charge current. At first try, it seems to work. I'll try it for a while and see if it continues to work.

Thanks all for your ideas.

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[Chippie]

Sure seems like a lot of messing around vs. simply running an independent line directly from the battery. If you integrate the alternator into the lash-up, you're still running wire from the engine compartment to back of the car... Not sure what you've gained by a set-up such as this- other than complication.:confused:


I think you may have missed the point....

1 wire is run from the battery to the voltage sensing relay which in turn feeds the supplementary battery....
When the engine is running the relay is energised and charges the extra battery...conversley, when the engine is off or being cranked the relay is de-energised and the battery just keeps feeding the charger........That' how most 'electronic split charge' relays work..


I dont see the diode arrangement working effectively as the 3 diode array provides a dc path in either direction....

[SamD]

Actually, no- I didn't miss the point. The original issue was the drop in voltage that occurred when starting the vehicle engine and how best to deal with this. A number of suggestions were made ranging from capacitors to the SLA with various charging schemes.

As I noted, there are two items:

1. Vehicle starting systems are such that when the engine is cranked, other systems are locked out preventing parasitic draw on the battery at its point of highest draw (starting).

2. The use of a direct wire, from-the-battery, set-up which eliminates the aforementioned problem and any potential voltage drops incurred in the vehicles wiring.

As I stated, this solved the problem for me; it's simple, doesn't require extra batteries, relays and other various components.

Quite to the contrary- some of the other replies seemed to have missed the point. KISS is a tough adage to argue with.

[Chippie]

Actually, no- I didn't miss the point.

Sam, apologies if I insulted you...
I re-read you first post.. If I read it correctly, you ran a wire from the battery to the rear of your vehicle to power your Triton and experienced no drop out when starting....

I'd agree thats a good place to start,but if the battery is in poor nick(condition) then the volts will drop when loaded..perhaps this is what is being seen in RC404's case?

[rc404]

If I read it correctly, you ran a wire from the battery to the rear of your vehicle to power your Triton and experienced no drop out when starting....

I'd agree thats a good place to start,but if the battery is in poor nick(condition) then the volts will drop when loaded..perhaps this is what is being seen in RC404's case?

While its likely that the battery isn't the best (its the original battery in a minivan that is more than 2 1/2 years old), I had the same problem when the van was new so I doubt its just the battery. Sometimes (perhaps 1 time in 4) starting the car by turning the ignition to the on position and hesitating a few seconds, then starting the car, will start the car without triggering the alarm, so I don't think this circuit is shut out when starting.

It seems most likely to be voltage drop in the lines (probably combined with a weaker battery), so running dedicated new lines direct from the battery to the back may very well work. But I would need to get through the firewall into the passenger compartment then run them somewhere out of the way and preferably not visible (behind interior panels or under carpet?) back to some kind of connector. Unless I'm missing something obvious, it doesn't strike me anywhere near as easy as a small battery (which I already have) and a few components that I can make up in the basement and put in a small compartment in the back.

[SamD]

In my case, I simply ran a wire from the engine compartment down along the frame rails of my truck and through an existing opening (hole) in the bed of the truck (for the taillight wiring). That said, it was a simple exercise. If you need to run it inside the vehicle, drill holes, remove panels, etc, then, yes, it's going to be a bit of work- and maybe the extra battery is the simpler way to go. My impression was such that an extra wire was going to need to be run anyway and as such, adding a battery seemed liked even more work. Sounds like this isn't the case, though...

[rc404]

Why not add a small SLA battery (12v, 7AH or so) back where you do your charging? The car's electrical system will keep it charged, and then you'll have a reserve battery to deal with momentary sags and spikes, all without having to rewire anything.

Over the winter this was forgotten about. I finally got back to it and devised a solution using the SLA battery that Comatose suggests. I came up with the approach in the attached schematic.

What I really want is:

1) the car to power the Triton when the car is either running or not running

2) the car to charge (but not overcharge) the SLA battery when the car is running

3) the SLA battery to power the Triton when starting the car and keep the input voltage > 10.5

4) the SLA battery does not supply current to help start the car

When the car is not running, the Triton will be powered (at least predominately) from the car because the car system has to drop through D1 but the SLA has to drop through both D3 and D4 diodes.

When the car is running, the Triton runs from the car and the SLA will be charged through D1 and D2. The voltage drop through both diodes will keep the charging voltage below 13.8 (granted the SLA will never get fully charged but will be charged to some intermediate level)

When the car is started, its voltage will drop for a few seconds and the Triton will be powered from the SLA through D3 and D4.

Lastly, D1 prevents the SLA from trying to help start the car.

After making one of these up from regular silicon diodes, it appeared that the voltage drops were too large so I substituted in Schottky diodes (1N5820). These are 3 amp diodes (what I could find locally) so I'm limited on charge current. So far, it seems to work.

Thanks all for your ideas.