Protecting your Starter Battery

[wildebus]

Just about everyone have their Campers and Motorhomes parked up for likely the next 2 months and quite possibly longer. But just like a parked-up car, the Starter Battery will start to flatten when not used.
Various ways to deal with this ...
If you have a VSR split-charge system, this will engage when the Leisure Battery is under a charge, so that will help take care of the starter.
Some Solar Controllers can do a trickle-charge to the Starter when there is PV Harvesting
Some Factory Motorhome Electrical Systems will do a Starter Trickle Charge.
But the majority of campers do not have any of the above, so need an alternative way.
One option - and could be a worthwhile option - is simply to disconnect the Starter Battery. This will prevent it draining as fast (but bear in mind stuff like Central Locking, Vehicle Alarm and those kind of things will no longer operate.
Another option - and one for the longer term - is to fit a Battery Maintainer, and I thought I would do a post to show how simple it can be to fit a Battery Maintainer and it is definately a DIY job you can do while your van is stranded on the driveway.

There are a number of standard Battery Maintainers around, for example Nick of vanbitz on the forum have the Battery Master unit. This following how-to will be done using the Ablemail AMT Battery Maintainer, but the principle of installing one will be pretty much the same no matter which one you get so you can look at this example and apply the steps to whatever you get if you decide to get one.

So for the AMT 12-12 Battery Maintainer, this is what you get

Battery Maintainer by David, on Flickr
There are three connections (and this will be also true of any maintainer) - 0V (Ground) at the back, +V Leisure (so the +ve of the Leisure/Habitation Battery) and + Vehicle (so the +ve of the Starter/Vehicle Battery)

What I recommend you get to go with this Battery Maintainer are some cables and boots. Some Maintainers may have attached cabling pre-wired; others will need cables to be fitted.

Battery Maintainer by David, on Flickr

So installation is dead easy. You connect up the cables to each of the studs on the AMT. I am using Black from the 0V, Red for the +Leisure and White for the +Vehicle. Any colours can be used of course, but I am using those for a specific reason

Battery Maintainer by David, on Flickr

You then slide the cable boots over the studs and they are now nicely protected

Battery Maintainer by David, on Flickr

Now the key thing now is to connect the 0V and the two +V cables to appropriate connections for the Starter and Leisure Battery. Exactly where is the best place in YOUR van will vary from vehicle to vehicle, but I find a good place to use is a B2B (Battery to Battery) Charger if there is one fitted, and this is what I have done here.

I am going to connect all three cables to the corresponding terminals on this Ablemail B2B

Battery Maintainer by David, on Flickr
The fact both the Battery Maintainer and the B2B are both Ablemail products is irrelevant. Just like any Battery Maintainer will have those three terminals I mentioned, every B2B will also have the same +V for Starter and Leisure Batteries and a Ground/0V connection. There is no communication between the two devices, it is just a handy place to piggy-back the cables.

So now simply a case of connecting the cables up. With this B2B, I just undo the nuts and double up the ring terminals

Battery Maintainer by David, on Flickr
You see here why I chose to use Red, Black and White - it corresponds to the B2B wiring (and also the stud boots as well).

And that is all there is to it to have the Battery Maintainer working.
In this example, if you got the cables with the Battery Maintainer the only tool you needed to have for the entire installation was a 10mm socket


OK, so what does it look like working? This particular Battery Maintainer operates on a constant cycle of 3 seconds on, 9 seconds off, with a maximum current of 3A.
This is my own van, looking at the Starter Battery over the last 7 days

As you can see, the voltage has been decaying over the last 7 days and dropped down to 12.2V by around lunchtime today. Now my Starter Battery is pretty new (under a year old) so is holding up well. While I don't have an Alarm, I do have a tachograph that is always ticking away and using power, so keeping an eye on the Starter Battery is pretty important for me.

The sudden spike is when the Trickle Charger was connected. You see the immediate effect of the Solar now able to work on the Starter Battery as well as the Leisure Battery.
Drilling down into more detail, you can see how it is working

Connected just before Noon and the voltage went up and stayed at a fairly constant 12.4V. It is 12.4V as the unit came pre-configured for a vehicle with a SMART alternator, and with those vehicles you do not actually want to fully charge the starter battery due to the way the vehicle electrics work with stuff like regenerative braking.
I then changed the mode from the default "4" to Mode "1". This changes from a SMART Alternator to a basic one like on my 2003 VW. The effect of this on the AMT is to change the maintenance voltage from 12.4V to 12.8V (so keep the Starter Battery pretty well fully charged). Modes 2 and 3 are the same ref SMART/Dumb Alternators, but tuned to Lithium Leisure Batteries rather than Lead Acid technology.

I hope this may have been of some use or interest. At least it would have killed a bit of time for anyone reading it as well as for me typing it up . (I thought I would do this write-up as I was connecting the Battery Maintainer up anyway to do a little pre-check before sending it off to Switzerland).

Cheers and Have Fun!

 

[Allen]

You lost me as soon as it got technical..sorry.
My van hasn't moved for two weeks.
Best I can do is start the engine and spend half an hour cleaning inside whilst hopefully maintaining engine battery life.

 

[jagmanx]

A simple battery charger or plug into EHU
Provided household power is within reach !

 

[cronkle]

A temporary version of clive motts bridging fuse could be useful. A wire with crocodile clips at either end and a 10 amp fuse in the middle. (Insert the fuse after connecting up). http://www.motts.org/BRIDGING FUSE.htm

 

[trevskoda]

You lost me as soon as it got technical..sorry.
My van hasn't moved for two weeks.
Best I can do is start the engine and spend half an hour cleaning inside whilst hopefully maintaining engine battery life.

It would take a 40 mile run to get back in what the starter took out,wast of time.

 

[wildebus]

A simple battery charger or plug into EHU
Provided household power is within reach !

Nope, that is not the case. Many (I would hazard a guess at a large majority) will NOT cause the Starter Battery to charge when EHU is plugged in. I explained that at the beginning of my post.

 

[wildebus]

A temporary version of clive motts bridging fuse could be useful. A wire with crocodile clips at either end and a 10 amp fuse in the middle. (Insert the fuse after connecting up). http://www.motts.org/BRIDGING FUSE.htm

You better remember it is fitted! If you have a memory like mine, after 10 weeks you will have forgotten you connected something down there. I used a similar approach when I was building out my van and needed a temporary solution to maintain the shagged starter battery. Used to do through a fuse a week as I forgot about it and used/moved van
A better option to that is a a 12V to 12V extension lead. One end to living area socket and the other to the cab 12V socket. Available generally on Amazon for under £15.

 

[wildebus]

You lost me as soon as it got technical..sorry.
My van hasn't moved for two weeks.
Best I can do is start the engine and spend half an hour cleaning inside whilst hopefully maintaining engine battery life.

It never really got tchnical. Can you use a spanner? If so, you can fit a battery maintainer.

 

[jagmanx]

Nope, that is not the case. Many (I would hazard a guess at a large majority) will NOT cause the Starter Battery to charge when EHU is plugged in. I explained that at the beginning of my post.

Sorry YEP rather than Nope
It works for my..setup I have the manual for my Calira PMU
It states it clearly that EB will be charged when LB full and observation confirms !
I also suggested a simple battery charger although I did not specify to connect it to the Engine Battery
Surely this will work whatever your setup ?

 

[wildebus]

It works for my..I have the manual for my Calira PMU
It states it clearly and observation confirms !

That's good - for YOU.
How many people here have a Calira PMU?
If you read the beginning of my post I said (and quote) "Some Factory Motorhome Electrical Systems will do a Starter Trickle Charge". I did not say NO, or NONE do.
So YOU don't need a trickle charger or any other mechanism to look after YOUR Starter Battery. Good stuff.

 

[jagmanx]

Ok Calm down..You refuted my statement.
You also do not seem to acknowledge the simple solution of a battery charger.
I fully appreciate you were trying to help the many !
No offence intended !

 

[wildebus]

Ok Calm down..You refuted my statement.
You also do not seem to acknowledge the simple solution of a battery charger.
I fully appreciate you were trying to help the many !
No offence intended !

Perfectly calm, thank you, but I just don't like people making blanket statements based on their own single vehicle. it is misleading and incorrect. Sure, you have a system that does that, but make it clear you are referring to your system and not just say "plug into EHU and that is all you need to do". You could have said "I plug into EHU and ....", but you didn't, you said "A simple battery charger or plug into EHU".
And not that many people have a battery charger lying around to connect to their Starter Battery and plug in either, so would have to buy one - and in the longer term a device like a Battery Maintainer (or who knows, fit a Calira PMU?) would be a more usable flexible option if you are going to buy something anyway.
Also, many people can't plug into mains at home to use either the EHU or a Battery Charger fitted to the starter battery, but might rely on their solar setup to keep things topped up in their van when it is parked up. Not much of a solution for them in that case either, whereas a setup that can harness whatever charging system is around - Solar, Mains, Generator or even an EFOY to give the starter battery some juice when the leisure battery is getting its charge has got to be a handy idea.

End of the day, you can get a bit of old mains cable and duct tape one end to the starter battery and the other to the leisure battery and it will keep it from discharging, but I prefer to do things properly and have solutions that are more than for the right here and right now.

 

[St3v3]

…... or plug into EHU....

Perhaps you should edit this to say "Or plug into EHU if you are lucky enough to have one of the few vans that support charging the VB from EHU.

That would clear up the misleading statement.

 

[Silver sprinter]

Thank you wildbus, for the brain dead,( that's me, ) it's always a new language to me and always love the detail you put into your posts much appreciated keep them coming, gerry

 

[cronkle]

You better remember it is fitted! If you have a memory like mine, after 10 weeks you will have forgotten you connected something down there. I used a similar approach when I was building out my van and needed a temporary solution to maintain the shagged starter battery. Used to do through a fuse a week as I forgot about it and used/moved van
A better option to that is a a 12V to 12V extension lead. One end to living area socket and the other to the cab 12V socket. Available generally on Amazon for under £15.

As said, it's only a temporary measure and as your experience showed, the fuse does it's job. It's little more than a length of wire and a fuse holder but may get someone out of a hole

 

[Allen]

I said previously I got lost with the techy stuff.
Just read the first post again and saw this...
"if you have a VSR split-charge system, this will engage when the Leisure Battery is under a charge, so that will help take care of the starter"

I know that when driving my camper it also charges the leisure battery.
Do I have one these magic gizmos then?
The solar panel, I know, charges the leisure battery.

 

[wildebus]

Turn round the question and that will help tell you the answer
When you plug the camper into the mains, does it charge the starter battery? If no, then you won't have a VSR.

Or more generally, if when you plug into EHU, does your starter battery charge get a charge at the same time the Leisure battery does? If yes, that is great and you are sorted. If no, then you don't have a VSR, and you likely don't have a system similar to Jagmanxs that has that feature built in.

 

[UJ99]

My first motorhome (UK-built in 1996) had no original means of charging the vehicle’s starter-battery using the on-board battery-charger when the motorhome was connected to a 230V electric hook-up (EHU). To provide that facility I installed a Vanguard “Battery Mate” ‘battery balancer’ (no longer available) that was similar in principle to the VanBitz “Battery Master”.

My last two motorhomes - 2005-German built and 2015 French-built - had/have an Italian-made CBE electrical system that - when the motorhome is connected to an EHU - allows the on-board battery-charger to charge the leisure-batery and, while that charging is taking place, to direct a low amperage/reduced voltage charge to the vehicle’s starter-battery. This approach is widespread and it is likely that the electrical system of most motorhomes built in Europe during the last 15 or so years have that capability. (A lack of ‘EHU charging’ of the starter-battery in a reasonably recent motorhome’s original electrical system seems to be most common when the motorhome has been UK-built, possibly as a result of a caravanning mind-set.)

A small point, but the reference number of the Ablemail Electronics Trickle Charger (Battery Maintainer) is AMT 12-2, as shown on this webpage

https://www.ablemail.co.uk/content/...ry-leisure-battery-solar-charger-mains-hookup

(UK asking price around £70)

 

[wildebus]

.....(A lack of ‘EHU charging’ of the starter-battery in a reasonably recent motorhome’s original electrical system seems to be most common when the motorhome has been UK-built, possibly as a result of a caravanning mind-set.) ...

I think your point that I quoted above is right. The systems employed by UK Manufacturers do tend to have the same - or very similar - units fitted in both their Caravans and Motorhomes. The Sargent units are extremely common for example, and if you want to charge the Starter Battery from the charger in the EC155 for example (a very common PDU), you would select Vb from the control panel rather than Lb (think they are the labels from memory). So those do do it - kind of.

The problem is it is an either/or option, not both (and maintaining a battery should be through a fit & forget solution - people want to enjoy their motorhomes without worry).
Also the built-in chargers on many UK (and continental-built) vans are dumb set voltage units and no longer fit for purpose with the type of batteries people are now fitting. And if you replace/bypass one of these dinosaur battery chargers, you also often remove any rudimentary Starter Battery trickle-charge feature that may have been present. A tricky one... keep the built-in charger that lets you trickle-charge the Starter, but doesn't actually charge the Leisure Battery properly in the first place, or fit a proper SMART battery charger and lose that facility (But of course you can add in back in a better way)

 

[wildebus]

I said previously I got lost with the techy stuff.
Just read the first post again and saw this...
"if you have a VSR split-charge system, this will engage when the Leisure Battery is under a charge, so that will help take care of the starter"

I know that when driving my camper it also charges the leisure battery.
Do I have one these magic gizmos then?
The solar panel, I know, charges the leisure battery.

Just on the point of a VSR, I said if you had one it would look after the Starter as well?
A VSR stands for Voltage Sensing Relay.
A Relay is a device that connects two cables together when it is activated (on) - so in a split charge system in a van, a Relay connects the Starter Battery +Ve to the Leisure Battery +Ve. So when the relay is on, the batteries essentially look like and work like one bigger battery, and any charging system (such as the alternator) will charge them both at the same time.

Some vans are fitted with a relay that is activated by the Ignition, or by the D+ signal on the alternator (this is the same signal that controls the little battery light on the dashboard that tells you if the alternator is not working enough). The VSR has tended to be fitted instead of those relays as although it is more expensive, it is a lot easier to install and doesn't need to connect to the vehicle electrics other than the actual battery.
The Voltage Sensing part of the VSR means that the Relay, is activated by Voltage levels rather than a specific signal like D+ or Ignition. When the voltage reaches a certain value, the relay turns on. When the voltage drops below another value, the relay goes off again. This means that it 'knows' when the engine is running as the alternator puts out a voltage of say 13.8V-14.5V which is above the "on" threshold of the VSR, and so the VSR turns on.
Now as a kind of by-product, the majority of VSRs have bi-directional Voltage Sensing - so if either the Starter Battery OR the Leisure Battery has a voltage over the "on" Voltage Sensing threshold, it will activate on and connect the circuit. What this means is the VSR turns on when the Engine is running, when the EHU is plugged in or when Solar is being harvested, as long as the Voltage reaches the required value. There are downsides to VSRs, but this feature is definately a plus!

If we look at my van again... I have removed the AMT12 Battery Maintainer now, and have my VSR connected. Instead of there being a 3 second charge pulse going into the Starter Battery every 12 seconds like I described in the first post, I get the Starter and Leisure Batteries connected together at any time the Voltage of either is above the threshold to turn on.
The graph below shows the voltages of the Starter Battery (top) and the Leisure Battery (called 'System' - bottom).
You see the sudden spike in the Starter Battery around 8:50,and then after that the two lines follow each other? That is because the Solar Harvesting kicked in around 20 to 7 this morning and as it was providing some harvesting, the Leisure Battery voltage started to increase slowly as charge was going in, and by 8:50 the voltage hit that Voltage Sensing threshold of the VSR, which turned it on and the two batteries connected to each other - and so because they are connected to each other, they show the same voltage.

Now I appreciate most people will not have this kind of info to look at, but a simple voltmeter on the Starter Battery and the Leisure Battery to compare will give a useful "moment in time" reading and reveal useful information.


PS. I have simplified some details in this post where they really don't matter much at all in order to understand the concepts. When connected via VSR,the two batteries WILL have slightly different readings due to voltage drop on cables, but if the SB is at 14.33V and the LB at 14.34V (like mine right now), you can be sure they are connected together. If the SB is at 13V and the LB is at 14.34V, that is a big difference and they are obviously not connected .
As an example, I can look at my Batteries and tell very easily if the VSR is on or not.

VSR is ON


VSR is OFF

Now ANYONE can do the same check with a voltmeter. I am just fortunate that I can check this via the Internet (as an aside, I can also turn the VSR on and off via the web, but that is a different subject )