Any strange behaviour, crashing issues etc, post them here! Problems compiling the firmware should go in the General support section rather than here
#42797
PSIG wrote: Tue May 12, 2020 6:45 am I would say your voltage drop is far too high and may be causing some corrections issues. There are many references online, but for high-amp connections we aim for 0.1V drop, with 0.2V maximum in the race cars and trucks. We have exception for high-amp starter circuits (drop through the relay) of 0.3V while cranking. Typical generic automotive standard for alternator-to-battery drop is 0.4V maximum under running load (lights, fan, etc) at cruise-range rpm, but we like to see much less. I would look for connection or cable issues (positive and ground), and test the battery for condition or damage. Your battery should be acting as a large stabilizing capacitor (a good thing), with little voltage difference from the alternator.

To carry it a step further, we use a separate voltage-sense wire from the main power junction to the voltage regulator. It is minimum 18AWG even though it carries no current, for minimal effect on voltage. This allows the regulator to respond quicker to system loads and to adjust regulated voltage to compensate for any increased voltage drop. If the drop increases 0.1V, then the regulator outputs 0.1V more so the system is maintained at full voltage.

Look at it this way - with a 1.2V drop, your alternator isn't even charging the battery until it is nearly 14V output. :shock: You might want to look into adding something similar in your system after fixing any issues you find. Good luck!




Thanks David.

I can see now I left out an important part of this.

The Battery will get with in 2/10 but takes a while. and the battery is dropping volts with each ancillary turned on but will get back to near charging voltage but over time. With the alt connection the recovery is minimal time.

The battery is like a big capacitor, it takes time to discharge and takes time to charge.

Any knowledge on this latest craze of large supper capacitor banks for main battery?
Looks promising and they charge/recover much quicker. Yes there are faults with the cap main battery idea.

Also the problem is much less with higher RPM.

I tried large jumper cables as a temp bypass, tried a known good battery, hooked up my good 25 amp charger and two different alts.
Yes voltage drop will create issues with voltage correction and temporarily with tune a little.

Now that it is hooked up to the alt out put the issue is gone from the ECU. Probably a compromise work around, but it worked.

This is a very minor issue but I enjoy finding these little things that make over all tuning better.

Tuning is now hitting target AFR just with auto tune with road tune and MLV agrees with the data.

I can now see timing and afr faults with the O2 and EGT and I just change the timing and or the target AFR until it all looks good.

I think perhaps what I am working on and what you just posted can help others here to first look to see if the ecu voltage is good and help them fix it as it will make a difference with your tune.



It was only a minor issue but they all matter.


Thanks David.

Always good to get your input.


Black Knight
#42802
PSIG wrote: Tue May 12, 2020 6:45 am
To carry it a step further, we use a separate voltage-sense wire from the main power junction to the voltage regulator. It is minimum 18AWG even though it carries no current, for minimal effect on voltage. This allows the regulator to respond quicker to system loads and to adjust regulated voltage to compensate for any increased voltage drop. If the drop increases 0.1V, then the regulator outputs 0.1V more so the system is maintained at full voltage.

Look at it this way - with a 1.2V drop, your alternator isn't even charging the battery until it is nearly 14V output. :shock: You might want to look into adding something similar in your system after fixing any issues you find. Good luck!
This part of your response is very interesting to me. As I've now found a really good 12v supply for the ECU I was considering something similar to what you stated above. Find the best location for the alt sensing wire to help it maintain the correct voltage. Also, your idea about using a larger wire makes sense. I'd also considered using an inverted op amp sensor circuit to force it by a very small percentage to overdrive the charging so it charges more aggressively sooner. Yes, it will need a max voltage cutout or it could run away and overcharge. Or I could place a simple minor voltage drop in the sensor wire. Those two options are good if I don't find the right location to control the alt charging response to get the desired charging voltage.

Due to a couple of work-arounds I did on this issue, the injector volt correction when battery is fully charged is seeing less than 3/10 volt drop. So overall my work-arounds have come to what you stated was a good voltage range.

But like you, I'd like to see how close I can get the voltages so that volt correction could be only used shortly after cranking volts drop.

At this point it's kind of a minor issue but I like all things fixed and done right.

Once again David, thanks for the input.

Black Knight
[/quote]
By JHolland
#42826
Black Knight wrote: Tue May 12, 2020 8:53 am Any knowledge on this latest craze of large supper capacitor banks for main battery?
Looks promising and they charge/recover much quicker. Yes there are faults with the cap main battery idea.
Black Knight
The supper caps are OK - the breakfast caps tend to go 'snap crackle and pop' *

With supercaps you need to ensure that you don't exceed either the inrush current or the maximum load current.

Another thing to consider is lag in the system, if you have a lot of filtering then the voltage you will be reading will be behind the actual voltage. Have you looked around with a scope to see how noisy your system is? How stable is your battery voltage? do you get much fluctuation on the injector supply, any ground shift on the injectors? Mostly how well does the voltage at the injectors follow what you are reading with Speeduino.

* You probably need to be British to understand that one.
#42844
JHolland wrote: Wed May 13, 2020 11:13 am
Black Knight wrote: Tue May 12, 2020 8:53 am Any knowledge on this latest craze of large supper capacitor banks for main battery?
Looks promising and they charge/recover much quicker. Yes there are faults with the cap main battery idea.
Black Knight
The supper caps are OK - the breakfast caps tend to go 'snap crackle and pop' *

With supercaps you need to ensure that you don't exceed either the inrush current or the maximum load current.

Another thing to consider is lag in the system, if you have a lot of filtering then the voltage you will be reading will be behind the actual voltage. Have you looked around with a scope to see how noisy your system is? How stable is your battery voltage? do you get much fluctuation on the injector supply, any ground shift on the injectors? Mostly how well does the voltage at the injectors follow what you are reading with Speeduino.

* You probably need to be British to understand that one.
Very good and very well put.

I am British, just living on the other side of the pond.

Yeah, even the cap can be like rice crispies. If you get it wrong the cap will pop and it get will get crispy.

You gave me some good things to think about.

I am thinking that the old antiquated lead acid battery is not compatible with the brilliant ECU.

ECU is dependent on steady voltage and the lead acid battery is good (maybe) for the starter.

I will be finding a way to get this right as I have seen how much the injectors like good steady voltage.


No, there is no noise signal at the ECU. Good clean volts.

The only voltage I see that is off is the voltage shown on the ECU voltage gauge. I am not sure on my next statement but I think it is the ECU circuit creating it's own voltage drop.

The voltage at the injectors is the same as the voltage supplied to the ECU.

MLV shows about a 1/10th volt oscillation. That is good enough.

I will share what crazy ideas I come up when they work.

Sharing iffy ideas is best done after 4 pints at the pub with friends.

I miss that.

Black Knight
By LPG2CV
#42847
Hey BK, love your attitude to four pints and iffy ideas :D

With the world of electronics getting ever more complex (it always was complex for me), one should never forget the basics. And often, the simplest answer is the correct one. Never treat the symptoms, find the root cause.
Nothing wrong with lead-acid batteries and good connections, and, it is what speedy was designed for.

Just starting on my third pint, and waiting for you to catch up. :lol:
By Black Knight
#42850
LPG2CV wrote: Wed May 13, 2020 7:19 pm Hey BK, love your attitude to four pints and iffy ideas :D

With the world of electronics getting ever more complex (it always was complex for me), one should never forget the basics. And often, the simplest answer is the correct one. Never treat the symptoms, find the root cause.
Nothing wrong with lead-acid batteries and good connections, and, it is what speedy was designed for.

Just starting on my third pint, and waiting for you to catch up. :lol:

I was born with a dummy dipped in good British ale. My dad was a good man.

You are correct that the lead acid battery is good enough but the latest tech on supper caps looks good. I may not use them for starting the motor but I may set up a bank of them just for the ECU.
It would require diode isolation and the alt senor wire coming from the ECU maybe. The caps keep the voltage good at the ECU as they charge so fast that volt drop will all but disappear.

Now this is what 4 pints and good friends are all about. After 4 pints no one cares if you are right or wrong. It is just for fun, until it works.

Then we sober up and go build it.

I just started learning electronics 4 months ago and it took more that 4 pints to get through the learning curve. HEHEHEHE

I think now I could build a controller for the super caps. How did that happen????

Always good to hear from you LPG.

Just had my wife's car on a dyno. 1985 subaru rx 2.2 conversion with the hi/low trans turbo blow through impco 225 carb ford dizzy modified to retard for boost and got 180 hp with 6 lbs boost.

As you are an lpg man I thought you would like that one.


Black Knight
By Vordt
#51908
These batteries are good, but aren't they like not lasting for a long time? As I know, the energy storage capacity goes down pretty fast. This is their biggest disadvantage in my opinion, but I hope that soon, in the near future, the engineers will be able to create a new material, or to discover something which will make the batteries with a long lasting life period. I already applied for a dual fuel deal, after reading the information from this guide https://www.simplyswitch.com/energy/guides/understanding-dual-fuel-deals/, because I save a lot of money, first, and second, electrical energy is the future of humanity.
Last edited by Vordt on Wed Jul 21, 2021 2:25 pm, edited 2 times in total.
User avatar
By PSIG
#51912
theonewithin wrote: Mon Jul 19, 2021 9:24 pm If powering the ECU from capacitors you also have to power the injectors from that same power supply.
+1. And the coils also. The issue here is that Speeduino has adjustable voltage compensation for these devices, but it has to see the same voltage as the devices in order to compensate for it. :? If your coil or injector voltage decreases or increases, but the ECM cannot see that happening, then they will not function properly and your tune will suffer.

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