Newbie battery charger questions

[wallport]

Wow - very quick response from them. Yes it's unfortunately normal and they suggest I remove a fuse when it's not in use for long periods.

Fair do's to them on the speed and honesty of the response but I do find it somewhat incredible.

As pulling the fuse is fiddly, any suggestions on how to install a switch? Would have to be simple if I were going to do it myself.

 

[ginkster]

My Autoterm heater has no noticeable effect on the LB when left for a long period. My old lead acid 100ah battery showed no obvious signs of excessive drain when it was left for nearly 6 weeks late last year (6 Nov - 16 Dec). The voltage went from 12.5 to 12.23 over that period which I think is ok, especially as that battery had been flattened totally in the past by the previous owner.

If you do feel the need for a switch it would be easy to put one after the fuse on the positive cable. Doesn’t need to be posh, hide it away in the cupboard. Just make sure the heater has completely finished shutting down before turning the switch off.

 

[AussieMick]

My autoterm heater controller also has a minute effect on the battery.
If you interupt the supply to heater with a switch you will most likely have to reprogram all your preferred parameters on the controller each time.

If I disconnect my battery that supplies the heater I always have to reprogram. It's not hard to do but would get tedious if you have to do it regularly.

Also have you set the controller to go to sleep ie no display when not in use as having display on all the time will use more power from battery than having controller in sleep mode.

 

[wallport]

My Autoterm heater has no noticeable effect on the LB when left for a long period. My old lead acid 100ah battery showed no obvious signs of excessive drain when it was left for nearly 6 weeks late last year (6 Nov - 16 Dec). The voltage went from 12.5 to 12.23 over that period which I think is ok, especially as that battery had been flattened totally in the past by the previous owner.

Do you have the Air-2d model? If so, I wonder if it's a more modern iteration as the company themselves are telling me it will draw up to 50ma.

Of course you may mean that even though yours is drawing this much, your battery (unlike mine) is surviving for many weeks and therefore this power draw shouldn't cause my problem? I'm open to that reasoning but if so I don't understand what is causing it.

Apologies if I'm misunderstanding.

 

[wallport]

If I disconnect my battery that supplies the heater I always have to reprogram. It's not hard to do but would get tedious if you have to do it regularly.

All I reset after testing was the date/time. Am I missing something?

Also have you set the controller to go to sleep ie no display when not in use as having display on all the time will use more power from battery than having controller in sleep mode.

Yes it is setup this way - though I note that autoterm didn't mention this setting so they either forgot or maybe it explains the difference between their max 50ma and my measurements.

 

[Higgidav]

I used to use a Victron smart battery connect device to disable the heater connection via Bluetooth but since I changed to Lithium and the comfort controller I just leave it connected permanently. I don’t have any noticeable draw and the comfort controller reminds me every month to run the heater.

 

[roadtripper]

I think at this stage I'd do what I've been hinting and others have suggested and live with it for a bit to see how it goes. You have the monitoring, you know what to watch out for and if you need to removing a fuse is possible (and free!)

If you want to add a switch then you need to decide if you are happy starting to remove the panels to get to the wiring and also check if you have room to mount things as there is not enough play in the cables to do it from the front by the looks of it.

You'll need something rated for the current draw, I think it's a 25A fuse so you're looking at something like a heavy duty toggle switch and some blade crimp terminals:

ON/OFF Single Pole Toggle Switch With Decal Plate - 30A@12V

ON/OFF single pole toggle switch with optional fitment decal, suitable for panel mounting. Rated 30A@12V DC. Ideal for vehicle & marine wiring applications.

www.12voltplanet.co.uk

As an alternative you could think of it more as a "shut the van down for storage" and fit an isolator type switch. There might be room to do that between your consumer unit and the 12v fuse box. You could then move all the loads you wanted to isolate up from the battery terminal bolt to the isolator switch bolt:

Panel Mount Miniature Battery Isolation Switch - 100A

Miniature panel mount battery isolation / master switch. 100A continuous, 150A intermittent. M6 terminals. Ideal for isolating campervan domestic circuits.

www.12voltplanet.co.uk

 

[AussieMick]

My Autotern controller parameters default back to factory settings when power is disconnected.
Maybe you are using default settings or have a different controller.
I fine tuned mine to the settings I prefer.

 

[ginkster]

Do you have the Air-2d model? If so, I wonder if it's a more modern iteration as the company themselves are telling me it will draw up to 50ma.

Of course you may mean that even though yours is drawing this much, your battery (unlike mine) is surviving for many weeks and therefore this power draw shouldn't cause my problem? I'm open to that reasoning but if so I don't understand what is causing it.

Apologies if I'm misunderstanding.

Yes, it’s a 2d but with the simple controller so maybe that has an impact on the power draw when off. It doesn’t have any lights or settings, just a simple on/off and rotary thermostat. Personally I’d just monitor your LB and when it gets near 12v take the van for a drive (or connect EHU if a drive isn’t possible). It’s good not to leave the van for too long anyhow and an opportunity to give the heater a regular run too.

 

[wallport]

One specific question, any idea why the bm2 says 12.29v is 47%? Surely 50% should be 12.06v (from memory)

Check what battery chemistry the BM2 is set to?

I believe my battery is FLA but that is not an option so I guess ignore the percentages shown from BM2 app and use the suggested voltages instead?

 

[Higgidav]

There was a thread sometime ago on here about setting custom parameters. Below is what my AGM starter battery is set to.

 

[wallport]

Thanks for that - I'd missed this option.
Earlier in this thread, @roadtripper posted the following:

I'm wondering which profile best fits my battery as they are very different?

 

[roadtripper]

Your battery is a Flooded Lead Acid (FLA) - what we used to call a normal battery until EFB/AGM became more common.

EFB(Enhanced Flooded Battery) and AGM(Absorbed Glass Matt) have slightly higher voltage per cell due to their construction.

The ideal State of Charge chart would be one from the battery manufacturer as that is likely to be the most correct, I tend to use the one I posted when talking about batteries as it has both FLA and AGM and also shows the regions that can shorten life.

In a more value based monitor like a BM2 suggest setting the curve to one you trust rather than using the provided one that it's not clear what it's doing.

 

[wallport]

I sent an email to Yuasa on the off chance they would provide a state of charge chart. No response.

I guess the really important value is the 50% voltage and I have no way of knowing 12.19 or 12.06 but I will go with @roadtripper for now.

 

[wallport]

Just to keep all my Van electric questions in one place, I have just bought an air fryer which I'm hoping to use when on hookup (I don't have an inverter) to increase the variety of food on trips (and maybe serve up a bit hotter). Its rated at 1350w which, according to my maths, equates to 5.625A - so under the 6A rating of some hookups (I guess higher rated hookups are no issue). I think the distribution system for the 240v power socket in the Van is rated at 10A (think thats what a Gacia C10 means - picture below).

Q1. Is my reasoning sound that this will be OK?
Q2. Will anything else be drawing power to take it over 6A if this appliance is all I have plugged in? (e.g. Leisure battery charging)
Q3. Anybody have practical experience of running this type of appliance on hookup?
Q4. As an aside (and maybe a stupid question), I notice that "Lights, charger, fridge" label on the left - I get the separation of the charger but don't understand lights and particularly, fridge. Does this imply that some setups enable the fridge to be powered off 240v when on hookup and battery when not?? Surely in my setup this is not applicable?

 

[roadtripper]

Q1. The rating on an appliance is going to be the maximum average load, it doesn't account for surge loads. Resistive heating elements are a dead short until they same up and the resistance increases, likewise a still motor until it starts moving. Those can cause surges at switch on 2-4 times the rated load and trip out breakers or inverters.

Q2. Yes your mains leisure charger will be running at the same time so any 12v load will likely also be causing a 240v load. How much depends on what 12v load you have and how depleted your leisure battery is at that point if you've been off grid.

Q3. Not that near the limit no, on the narrowboat we use a slow cooker during the day when the engine is on via the inverter but that's 120w

Q4. The traditional 3 way camping fridge runs off Gas / 240v / 12v - it uses heat to drive the cooling circuit not pressure (sounds strange but works quite well) so static off grid you would heat with a gas flame from the LPG, on EHU you can use a 240v heating coil and when traveling a high current 12v heating could would be enough to maintain temperature but only while engine is running. This tends to be the type of fridge expected by the older all in one systems. Modern camping fridges are tending towards efficient 12v only compressor fridges.

You have a generic label there to split the incoming load. Generally you want to consider what happens if something trips - if they are all on the same circuit you loose everything - so it's common to separate lights from the more likely to trip sockets - but also things like fridges and freezers. In a house you have the space to have lots of breakers, in camping general there are only 2 so having the risky "anyone could plug anything in and trip it" sockets on one and everything else on the other is the way to go.

So just read your breakers as "sockets" and "everything else"

 

[wallport]

As ever, very informative - thanks again @roadtripper.

I think 6A hookups are a worst case. I checked on a few sites we have used and where the say, it tends to be 16A but most don't say.

I have a mains power meter so I will plug it in via that and get some measurements. Its true I may not see instantaneous surges but at least I'll know more about what it draws in practice. In the end though, I think we will have to suck and see.

Presumably, if charging at the same time were an issue, one could simply throw the left hand breaker switch for the duration? Or maybe there is another way to switch off charging?

 

[roadtripper]

1A at 240v is 20A at 12v - so rough rule of thumb assume a worst case that 1A of your 240v EHU "budget" is used by your 12v system.

I don't think unless you have an exceptional 12v load or very depleted leisure battery there is going to be an issue.

Your problem is going to be nuisance tripping due to the surge, the benefit is on EHU it will generally cope with a start up surge better than an inverter as there is plenty of power available it's just on a lower rated MCB for safety.

Generally used MCBs trip electromechanically on a gross overload and thermally on a mild overload. Your surge is unlikely to trip the former and likely will not last long enough to trip the later.

And yes you have a 6A and 10A Type C MCBs - the letter defines how they trip and type C are designed for domestic level use and surge loads, there are different types for protecting very large motor loads or things where the trip must be very fast:

MCB Trip Curves - B, C, D, K and Z trip curves- Made easy

Trip curves of MCB's (B, C, D, K and Z curves) tell us about the trip current rating of Miniature Circuit breakers. MCB trip curves

www.electricalclassroom.com

 

[wallport]

Thanks. Interestingly, my meter says that it draws over 6a and not even on the highest temperature so their published figures seem to be wrong. We won't be trying it out on a 6a hookup.

 

[wallport]

Back on my battery draining issue, today I've had a new symptom which I can't fatham. Suddenly the leisure battery drained at an alarming rate when nothing was turned on and noone had been near the van. I know it was nearing the level when we needed to put it on charge but...

What on earth could have caused this? The heater fuse is still out BTW.