[Guide] Battery Maintainer (for Starter battery) -- How I Done It --

[ginkster]

I will reread this to understand.

The van DOES have dash button to switch off stop start (so annoying) so I guess swapping scr for dc to dc (or getting someone to do it) makes sense.

I aim to sort Solar soon (if I can find someone to install, it’s the wiring side (where it goes etc etc that concerns me on that one).

Does a dc to dc obviate the need for a amt12-2, eg will it keep both batteries in good health etc?

Yep, DC-DC if it’s a smart alternator. Some DC-DC will also trickle charge the SB (so no Ablemail needed) but check the specs and logic. Doing the wiring isn’t particularly difficult and will give you a greater understanding of the van and also the knowledge it’s done how you want it, but does require lots of research. If you’ve the time and inclination it’s well worth doing.

Another good resource is climbingvan.co.uk.

 

[Sib]

Thanks for this @Dellmassive! I see some folk that have EHU point plugging an EHU lead into the Powerbank and then out of side window and into the van EHU point which does similar for charging batteries.

Apart from being more stealth (assuming EHU plug on side of van) Is the method you are doing here via smart charger more efficient / less losses etc than using EHU cable?

I could do either option with my van so wondering which is best (stealth issue of cable outside van aside)?

 

[roadtripper]

The EHU route will only work to maintain the starter battery if it is configured to do so, either with a dedicated mains charger or by some form of battery to battery charged (DC-DC capability or separate trickle charger)

If you want to get as much useful energy from your power bank into just the starter then doing that directly with just a maintenance charger plugged into the bank and the 12v socket will be most efficient.

If you power up the EHU then all the 240v electrics in the van will be on, which could consume power that would otherwise go to the starter battery, but also generally the charging from EHU will top up the leisure battery and the starter, which may mean most of the power bank energy doesn't reach the starter battery.

 

[Sib]

Thanks @roadtripper On mine the vehicle battery will charge when plugged in EHU, but good point about all other electrics being on so less efficient.

I've got a Ctek MX5.0 charger and two spare direct to battery connecters with the eyelets to will probably connect one to the vehicle battery and one to the leisure battery and can then charge either battery directly as I choose.

 

[BoroBoy]

Update2:

the follwing morning. . . the ECOFLOW is flat and offline.

View attachment 182934

looking at the BM2 data we can see it lasted till around 4am, at which point the charger switched off and the starter battery voltage started to drop back drown from the float 13.0v charge to normal rest voltage 12.3v.

View attachment 182935View attachment 182936


bringing the ECOFLOW back in and giving it a recharge. . . 7:51am 0% SOC

View attachment 182938

to 100% SOC . . . 9:21am

so about 1.5hrs to recharge.

View attachment 182939

View attachment 182940



we drop it back in the van and reconnect the charger. . . .


View attachment 182941


we can see the charger ramps up and starts to charge the battery again . . . drawing 83w.

View attachment 182942

++++

edit 1300hrs :


things are settling down nicely now,

the ECOFLOW is showing 3W output and 82% SOC, - so just ticking over.

View attachment 182960

the charger in the van is showing pulsing green light . . . so float mode / almost charged.

View attachment 182961

and the BM2 plot is showing starter healthy 13.0v


View attachment 182962

.

+++

edit2: 1700hrs . . .

been out to the shops, and come back - i noticed the NOCO 5A charger was off?

checking the APP we can see the unit is ON,

View attachment 182983

but the AC is OFF . . . ????

View attachment 182984


checking the settings we can see why,

there is a setting for "switching off the AC after a set amount of hours" . . . if not used!

but what point is "Not Used"?

we was drawing 18W earlier. . . .


View attachment 182985



i changed the settings to allways ON for the SYSTEM & AC . . .


View attachment 182986



then re powered ON the AC. . .

this maybe why - we are only drawing 4W from the unit. . .

maybe the AUTO OFF feature was 10w or so? - i had a look at the manual, but that data wasn't mentioned.

( so ill assume 10W is the threshold?)

View attachment 182988





the charger moved to Float almost instantly drawing 4W . .



so lets see how we get on now. =]


the ECOFLOW estimated run time is 99Hrs ?


i doubt that will be the case . . . . .




++++

TBC . . . . . .


.

@Dellmassive - Is this the Ecoflow app?

 

[Dellmassive]

@Dellmassive - Is this the Ecoflow app?

View attachment 239405

Yes

 

[ShooglyStu]

Another interesting solution would be: Cyrix Battery Combiners - Victron Energy
Anyone used one of these?

 

[Dellmassive]

I had one of these before I moved onto DC-DC chargers.

It's not a battery maintainer, it's just a big relay and not to be used with lithium battery's

So not suitable for this application.

 

[whodat]

As a rough guide - I give my battery a top up every so often using the Ecoflow (768wh) using a Noco 5amp plugged into the cigarette lighter/12v.
Topup charging the starter battery (AGM) From 12v to 12.4v and leaving it plugged in for about 24 hours it uses up about 40% of the Ecoflow, so approx 300wh and the Ecoflow does stay 'on' all the time so there is enough power output to keep it interested/awake.

The battery does go upto 12.7v but within a couple of hours, settles back to 12.4v if it is feeling lively.

 

[TallPaul_S]

Just some thoughts on the Ablemail AMT12-2, with a LiFePO4 leisure battery...



If I set the AMT12-2 to mode 3 for lithium, it will only trickle charge the SB if the LB voltage is above 13.5v. Which is 100% capacity with zero load, or actively being charged by solar, EHU etc.

Which, is great if you have solar. But what if you don't?

I probably won't have solar for a few weeks after installing my new 230Ah LiFePO4 battery, and my van can sit not being used for 2 weeks quite often. Which result in the SB gradually going down to 12v - 50% SOC on my 75Ah SB. From the 'fully charged' smart alternator SOC of 80% - meaning a 22.5Ah drop.

Now, I'll have a big old 230Ah battery just sitting there twiddling it's thumbs, while the poor old SB is dwindling away... But as I've got no solar, the Ablemail won't trickle charge as the LiFePO4 voltage won't be above 13.5v.

But, can I simply leave the Ablemail on mode 4, which will kick in the trickle charge when the LB voltage is above 13.0v, which equates to 30% SOC on the LiFePO4 battery? This would mean id be taking from the LB to feed the SB but 20Ah every 2 weeks is completely fine by me, as the LB won't be getting used for anything whilst it's sat on my drive!

Worst case if I left the van for a whole month it would take the LB down to 190Ah, or 82% SOC. Not exactly a huge deal!!

 

[Dellmassive]

i use setting #8 on the VAN.

its worked great. . . but even #8 cant keep up with the drain of those fancy THQ LED rear lights i fitted. !!!

check out the starter battery plummet when i left the hazards on for 3hrs today. . . .lol.

these lamps are super power hungry,






++++++++++++++


but back to the point.

you can use any of the pre-sets. . . 3 & 4 worked ok.

but 7 & 8 worked better. ( and now i just leave mine on #8 )


they call it high power, but the only difference is the ON time is extened, from 3seconds to 6 or 9 seconds.

you can use the BT dongle to tweel all these settings to dial the unit in as you see fit.


ill drop a few screen shots from the BUS,


+++++++++++++

this example from today . . been to work so van been driven and SB and LB are charged.


the Fogstar battery shows resting voltage of 13.4v and SoC 99%.




the SB shows current resting voltage of 12.5v.



so the AMT12-2 is not providing any charge to the SB at the moment as its not needed as SB>12.4v

you can see no power from the shunt.






++++++++++++++

here is an example of the AMT12-2 in action,

looking at the SHUNT on the BUS in realtime.

you see the SB voltage rise as its getting a charging pulse for the 6sec duration, at the same time you see the effective volt drop on the LB caused by the charge pulse,




..


and the same data over a slightly longer time frame, you see the charge pulses.



...


edit,

here is a nice pic from VRM showing the charge pulse over time.. . ( the Calibration is a bit off atm)




and the effect on the starter battery over the same time slot,





....

 

[TallPaul_S]

Perfect, yeah I think I'll just leave it on setting 4 then, my SB drain isn't particularly high:


That's a drop from 12.44 to 12.33v in 6 days. It's worse if I'm working on the van and have the electric doors open.

But it seems silly to have a massive amount of capacity sat there doing literally nothing while the SB voltage is dropping away.

I can also use the MPPT load output battery protect function to set a slightly higher cut off voltage than the 13.0v on the Ablemail, that'll give me more control over how much of the LB capacity is used to charge the SB.

 

[Dellmassive]

looks like the Ablemail APP has been updated. . .

just see a different screen layout that through me.

Updated on
Apr 4, 2024






more detailed info . . .

for @BoroBoy and others that find this info usefull.

+++++++++


previously i must have had v..2.xx

this is an old phone showing. v2.20



and the screen layout showed the battery changing colour with live voltage readings . green for charge pulse.





and yellow for pause. . .



then allowing the APP to update. . . . to V3.11




gives us what i saw on my main phone.

OFF for pause.



and RED arrow showing power flow and TRICKLE CHARGING




so moving back to the main phone. . . .


app start. . .



finding the BT device. . .





main screen with charge OFF.




and with charge ON,




settings tab gives you.




device settings.



device readings.



.

going down the device settings page and clicking the ? gets you the option description.





















.

 

[Dellmassive]

pic limit,

continued. . .

AMT12-2 settings pages shown.





.

 

[ginkster]

Just some thoughts on the Ablemail AMT12-2, with a LiFePO4 leisure battery...

View attachment 245389

If I set the AMT12-2 to mode 3 for lithium, it will only trickle charge the SB if the LB voltage is above 13.5v. Which is 100% capacity with zero load, or actively being charged by solar, EHU etc.

Their instructions are not very clear and contradict themselves depending which version you look at! As far as I can tell the AMT will also charge the SB once it drops to 12.2v (or 12.1v in one document) as long as the LB is 0.2v above the SB. This will stop once the SB gets to 11.5v (and/or, if I read it correctly, the LB gets to 12.5v). This is broadly how mine has been working in setting 3. My SB is pretty tired (and I leave my dashcam and Carista plugged in so have a constant small drain) and as it drops to 12.2v ish the AMT trickle charges from the Lifepo4 LB (105ah Fogstar Drift) which is well below 13.5v keeping the SB at about 12.3v. At some point when the LB gets low it stops the trickle. The plot below shows this in the early part. Ignore the right hand side as I was playing with the system.



Some further info from Ablemail, noting different voltages!

 

[DreamingT6s]

Perfect, yeah I think I'll just leave it on setting 4 then, my SB drain isn't particularly high:

View attachment 245407
That's a drop from 12.44 to 12.33v in 6 days. It's worse if I'm working on the van and have the electric doors open.

But it seems silly to have a massive amount of capacity sat there doing literally nothing while the SB voltage is dropping away.

I can also use the MPPT load output battery protect function to set a slightly higher cut off voltage than the 13.0v on the Ablemail, that'll give me more control over how much of the LB capacity is used to charge the SB.

Reading this thread with interest as I have a Sterling BB1230 DC-DC B2B and just bought an AMT12-2 which I haven't received yet. I have read the fitting instructions and lots of info like this thread on line but I am still not clear how I change the setting to Setting 4 for smart alternator and lead leisure battery. Is it via dip switches or how do I change it?

 

[Chris1983]

Reading this thread with interest as I have a Sterling BB1230 DC-DC B2B and just bought an AMT12-2 which I haven't received yet. I have read the fitting instructions and lots of info like this thread on line but I am still not clear how I change the setting to Setting 4 for smart alternator and lead leisure battery. Is it via dip switches or how do I change it?

This was not clear, I rang the phone number for engineer in bumpf included, he talked me through and said ‘we get a lot of calls’

 

[ginkster]

Reading this thread with interest as I have a Sterling BB1230 DC-DC B2B and just bought an AMT12-2 which I haven't received yet. I have read the fitting instructions and lots of info like this thread on line but I am still not clear how I change the setting to Setting 4 for smart alternator and lead leisure battery. Is it via dip switches or how do I change it?

O, it’s not dip switches. Basically remove both positive leads from the AMT. Touch the pos from the leisure battery against SW1, remove and touch back within 40secs. Keep it attached and LED will cycle through flashing the number of times per setting. When it flashes 4 times (for setting 4) remove the pos. Reattach everything and job done.

 

[DreamingT6s]

O, it’s not dip switches. Basically remove both positive leads from the AMT. Touch the pos from the leisure battery against SW1, remove and touch back within 40secs. Keep it attached and LED will cycle through flashing the number of times per setting. When it flashes 4 times (for setting 4) remove the pos. Reattach everything and job done.

Thank you! This is exactly what I was looking for. Very clear, thank you!

 

[ginkster]

Thank you! This is exactly what I was looking for. Very clear, thank you!

No problem. It’s in the instructions that come with it but they are not very clear. It took longer to read the instructions and work out what they meant than actually coding it!