Ablemail AMT12-2 charging threshold question

[number14]

Been parked up on the drive for a couple of weeks now (off again this weekend BTW) and I have been watching the slow decay on the starter battery and waiting for the Ablemail to kick in. The SB is new, well, 2 months old, and additional parasitic losses are tracker (40mA in sleep mode) and alarm. The SB voltage is now down to 12.29V, measuring the same by both the Victron Smartshunt and a handheld meter. With 200W solar and all this sunshine, the LBs are at float (13.6Vmin).

Now, the Ablemail instructions (programme 4) say that in these conditions it should be charging until the SB is at 12.4V.
However, I have been watching the LED on the Ablemail (yeah, exciting I know) and it only makes one charging pulse every ten minutes or so. The SB then settles for a while at 12.3V then falls to 12.29V. After another long wait there is another charging pulse.

So I am wondering if this is the correct behaviour. Should the Ablemail not start charging once the SB falls to, say, 12.35V to maintain it at 12.4V? Is the unit that I have out of calibration?
I know it's only 0.1V but this represents roughly 10% difference in state of charge.
Or am I being just too fussy!

(As an aside, I purchased from @wildebus via his ebay listing. He includes an excellent instruction sheet which supplements the poorly written Ablemail one as well as a useful wiring harness which allows a switch to be fitted to override the programming modes. I can recommend)

 

[Fisherman]

Been parked up on the drive for a couple of weeks now (off again this weekend BTW) and I have been watching the slow decay on the starter battery and waiting for the Ablemail to kick in. The SB is new, well, 2 months old, and additional parasitic losses are tracker (40mA in sleep mode) and alarm. The SB voltage is now down to 12.29V, measuring the same by both the Victron Smartshunt and a handheld meter. With 200W solar and all this sunshine, the LBs are at float (13.6Vmin).

Now, the Ablemail instructions (programme 4) say that in these conditions it should be charging until the SB is at 12.4V.
However, I have been watching the LED on the Ablemail (yeah, exciting I know) and it only makes one charging pulse every ten minutes or so. The SB then settles for a while at 12.3V then falls to 12.29V. After another long wait there is another charging pulse.

So I am wondering if this is the correct behaviour. Should the Ablemail not start charging once the SB falls to, say, 12.35V to maintain it at 12.4V? Is the unit that I have out of calibration?
I know it's only 0.1V but this represents roughly 10% difference in state of charge.
Or am I being just too fussy!

(As an aside, I purchased from @wildebus via his ebay listing. He includes an excellent instruction sheet which supplements the poorly written Ablemail one as well as a useful wiring harness which allows a switch to be fitted to override the programming modes. I can recommend)

David (wildebus) fitted mine, and he fitted a switch which allows me to manually switch it on and off as required. I see you found this on your aside.
David states in winter he leaves it on for long periods, this would be handy if your van is parked in a secure compound away from home. I have done this and even in winter my solar array manages to keep all of my batteries fully charged with no issues.
If you want me to post a photo of the connections let me know.

 

[number14]

David (wildebus) fitted mine, and he fitted a switch which allows me to manually switch it on and off as required. I see you found this on your aside.
David states in winter he leaves it on for long periods, this would be handy if your van is parked in a secure compound away from home. I have done this and even in winter my solar array manages to keep all of my batteries fully charged with no issues.
If you want me to post a photo of the connections let me know.

Thanks for your reply. I'm quite happy that all is connected properly and, right now, I am making use of David's little harness to override programme mode and give the SB a good boost.

In a nutshell, my concern is that the instructions imply that the SB will be maintained to 12.4V but my unit is only maintaining to 12.3V. Not much, I know, but quite a difference in terms of SOC.

 

[wildebus]

Been parked up on the drive for a couple of weeks now (off again this weekend BTW) and I have been watching the slow decay on the starter battery and waiting for the Ablemail to kick in. The SB is new, well, 2 months old, and additional parasitic losses are tracker (40mA in sleep mode) and alarm. The SB voltage is now down to 12.29V, measuring the same by both the Victron Smartshunt and a handheld meter. With 200W solar and all this sunshine, the LBs are at float (13.6Vmin).

Now, the Ablemail instructions (programme 4) say that in these conditions it should be charging until the SB is at 12.4V.
However, I have been watching the LED on the Ablemail (yeah, exciting I know) and it only makes one charging pulse every ten minutes or so. The SB then settles for a while at 12.3V then falls to 12.29V. After another long wait there is another charging pulse.

There should be a charge pulse approximately every 15 seconds, not 10 minutes (was 'minutes' a typo, or is it really that long a delay?).

So I am wondering if this is the correct behaviour. Should the Ablemail not start charging once the SB falls to, say, 12.35V to maintain it at 12.4V? Is the unit that I have out of calibration?
I know it's only 0.1V but this represents roughly 10% difference in state of charge.
Or am I being just too fussy!

It does sound like the unit is working as it basically should, and it is a question of voltage levels? The unit will operate when the Leisure Battery is ABOVE a certain level AND when the Starter Battery is BELOW a certain level (and BOTH have to be true, it is not an either/or situation). The Voltage of the Leisure Battery is high enough at 13.6V, the voltage of the Starter Battery close to borderline at 12.3V but is enough for it to go on. So best to check what voltage the unit is actually seeing?

When you are checking the voltages, the Smartshunt will be giving the voltage level at the battery terminals I am assuming? You have a multimeter as well? I would put the meter on the same point that the shunt connection is on so you can compare the readings between the two as a calibration check, and then put the multimeter on the AMT12-2 connections and see what that says? Also, should mention that the voltages quoted are rounded. The AMT is microprocessor controlled and the voltage controllers actually have electronic steps of approximately 0.07V (IIRC), so it may not be 12.4V but say 12.38V (I don't know the exact values off-hand, but just illustrating that the working threshold voltage may not be precisely 12.4V).

What I would also be inclined to do change the programme as well. You are using Programme #4.

1. Standard Alternator + Lead Battery; Standard parasitic drain
2. Standard Alternator + Lithium Battery; Standard parasitic drain
3. Smart Alternator + Lithium Battery; Standard parasitic drain
4. Smart Alternator + Lead Battery; Standard parasitic drain
5. Standard Alternator + Lead Battery; Higher parasitic drain
6. Standard Alternator + Lithium Battery; Higher parasitic drain
7. Smart Alternator + Lithium Battery; Higher parasitic drain
8. Smart Alternator + Lead Battery; Higher parasitic drain

I think I would be inclined to change it to Programme #5. This would do two things ...
a ) Change the setting from Smart to Standard Alternator. This will have the effect of having the AMT operating when the SB is below 12.8V instead of 12.4V
b ) Change from Standard to Higher Drain. This will change the duty cycle from staying on for 6 seconds upto staying on for 10 seconds.

You should see quite a difference if you change from #4 to #5.

(As an aside, I purchased from @wildebus via his ebay listing. He includes an excellent instruction sheet which supplements the poorly written Ablemail one as well as a useful wiring harness which allows a switch to be fitted to override the programming modes. I can recommend)

 

[number14]

Thanks for your comprehensive post.
I have checked the voltage at different points in case there were the issues you highlighted but didn't see any differences.

I had thought of changing to programme #8 but your suggestion of going to #5 is even better so I'll definitely try that. Not today though, it's too hot!

 

[Pudsey Bear]

That is all to complicated for my noodle, Merlin's bit of kit is more up my street.

 

[wildebus]

That is all to complicated for my noodle, Merlin's bit of kit is more up my street.

Once setup, you can leave it alone if that is what you want to do. If you want to force it on, you can do. If you change your setup, you can reprogramme. If you want to fine-tune the system, you can do. Or you can buy something that cannot be adapted in anyway. Horses for courses.

Imagine there was only one kind of honey for a bear? if you don't like that honey, you're buggered. Don't you think being able to change the flavour of the honey after you have bought it and brought it home has benefits?

 

[Pudsey Bear]

Yes, definitely David, but although I like tech as I age I understand it less, hence my happiness with the Gizmott, I does all I need.

 

[trevskoda]

Starter batts should be charging from engine at 14.4v, my solar also takes it to that and then drops back to 13.7 float along with les batts which are old type lead acids.

 

[marchie]

Been parked up on the drive for a couple of weeks now (off again this weekend BTW) and I have been watching the slow decay on the starter battery and waiting for the Ablemail to kick in. The SB is new, well, 2 months old, and additional parasitic losses are tracker (40mA in sleep mode) and alarm. The SB voltage is now down to 12.29V, measuring the same by both the Victron Smartshunt and a handheld meter. With 200W solar and all this sunshine, the LBs are at float (13.6Vmin).

Now, the Ablemail instructions (programme 4) say that in these conditions it should be charging until the SB is at 12.4V.
However, I have been watching the LED on the Ablemail (yeah, exciting I know) and it only makes one charging pulse every ten minutes or so. The SB then settles for a while at 12.3V then falls to 12.29V. After another long wait there is another charging pulse.

So I am wondering if this is the correct behaviour. Should the Ablemail not start charging once the SB falls to, say, 12.35V to maintain it at 12.4V? Is the unit that I have out of calibration?
I know it's only 0.1V but this represents roughly 10% difference in state of charge.
Or am I being just too fussy!

(As an aside, I purchased from @wildebus via his ebay listing. He includes an excellent instruction sheet which supplements the poorly written Ablemail one as well as a useful wiring harness which allows a switch to be fitted to override the programming modes. I can recommend)

David @wildebus wired a switch for me from the manual override selection [since superceded by the firmware of the latest models so selectable via the App]; the manual override transfers power from the LB to the SB for 9 seconds in every 10 [blink and you miss the pause!]. I use this to keep the Yuasa clacium SB at 12.9v-13.2v, especially if we've been off grid for 3-4 days or longer, but balance the time for the manual override against the drain on the LB charging phones and bike batteries via the inverter, especially when solar panel harvesting is struggling

Steve

 

[Thistle]

@number14
Of all the maintainers I’ve found this thing to be the most frustrating it just doesn’t do what one might expect it too without a lot of fiddling about but imho it’s biggest failure it it just doesn’t inspire confidence that’s it’s functioning effectively.

I bought mine from the same person it just didn’t work as expected from day one despite trying all the build in modes I should have sent it back but assumed I was simply unable to get my head around it’s really weird operational quirks.

I eventually wasted even more money on their over priced BT interface and that’s when I discovered mine was all setup a bit weird, Ablemail support suggested the firmware must have been corrupted somehow but would not accept it back for checking even though I had demonstrated internally it was under reading the aux voltage

None of the threshold voltages made sense worse it was (and still does) under read the aux battery voltages further reducing its effectiveness

Via the bt interface and app I was eventually able to set it up with the defaults to get it to do something but there nothing I can do about it’s incorrect source voltage reading so instead I had to adjust other values to compensate

I’ve since defaulted to using the sw2 boost setting which works but having wasted the best side of £150 I could have bought something far better such as the excellent Renogy dcc50s for not a lot more money.

I wouldn’t buy another one especially as a far simpler setup like the much cheaper Voltronic device which afaik contains nothing more complicated than a diode fuse and ptc device such as for a diy one a 12v lightbulb can do a similar job.

 

[Geek]

Should the Ablemail not start charging once the SB falls to, say, 12.35V to maintain it at 12.4V? Is the unit that I have out of calibration?

Any voltage figures like this are approximate, because the correct voltage depends on temperature.
Often there is no external temperature probe so they measure the controller's temperature, so probably have yet another compensation for that.
Depending on the voltage meter, reading them to one hundredth of a voltage is like saying your speedometer is accurate to 1mph. In reality it may be 5mph or more off accurate.