[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.