Which "Battery Master"? / D+ Needed?

[GrahamPye]

When I was researching my Lithium upgrade and deciding on which gear to use, I noted that several of the B2Bs also included the "battery master" functionality, but when I settled on going blue (i.e. Victron) for everything I forgot to check whether the Orion TR 12/12-30 did that, and of course it doesn't... After a slightly dodgy moment when trying to start the van I checked the engine battery voltage and realised my mistake!
After some agonising, and reading numerous opinions, I decided on the Ablemail AMT12-2 from RoadPro (using the Fun discount, of course) because I thought it was the most flexible, and I'm ex-IT so I'm not scared by complicated programming. However, the Ablemail appears to be in short supply at the moment, and RoadPro didn't receive their promised delivery last week, so I was wondering whether to cancel it and switch to a Van Bitz Battery Master instead. Particularly since I've discovered that the flexibility of the Ablemail requires either a fairly expensive Bluetooth adaptor, or a very expensive USB adaptor and software, the latter really only intended for installers, it appears. What does the Team think?

Meanwhile, I've been topping up my vehicle battery with a mains trickle charger (I'm on EHU at home), however the increased voltage from the charger resulted in my B2B thinking that the engine was running and hence siphoning off the engine battery's charge into the hab battery... I've stopped it doing that by temporarily pulling out the link to turn it off. Is this also going to happen when I wire in the Ablemail or Battery Master? I don't have a smart alternator, so the B2B's voltage sensing option seems to work OK, so I was lazy and didn't try and find a convenient D+ signal - must I/should I do that too?

Thanks, Graham

 

[tonka]

I bought the CBE version. Lots of funsters seemed to recommend it as they did the battery master just that it was much cheaper. . My vans been sat on the drive since last October with no EHU, relying on the solar and all batteries are 100%.

 

[DBK]

The Battery Master doesn't need a D+ signal. Can't speak for the CBE version. I suspect both do a similar job. Solar or EHU charges the leisure batteries and the vehicle battery is kept topped up. It just works though no doubt there are more complicated alternatives.

 

[funflair]

I bought the CBE version. Lots of funsters seemed to recommend it as they did the battery master just that it was much cheaper. . My vans been sat on the drive since last October with no EHU, relying on the solar and all batteries are 100%.

CBE do a Lithium version of their CSN2 battery maintainer, they say the original shouldn’t be used with Lithium.

 

[Barti Ddu]

CBE do a Lithium version of their CSN2 battery maintainer, they say the original shouldn’t be used with Lithium.

Yes. I've noticed this too. Any idea why the original CBE unit shouldn't be used with lithium? After all it is similar to the battery master.

^{_{Subscribers  do not see these advertisements}}

 

[LithiumConvert]

The B2B is always best when activated only by a D+ signal.

As your motorhome does not have a smart alternator, the equirement for a battery maintainer is not so critical as the standard alternator will properly charge the engine battery.

The rest of us have to find some way of making up for the fact that a smart alternator never charges the engine battery properly and lead-acid batteries like to be properly charged.

My prefered solution to that is to use another low power B2B wired to charge the engine battery from the leisure battery, manually switched on, but normally on permanently. Keeps the engine battery properly charged at all times.

Some will say, and have said, "OTT", but it does the job.

 

[tonka]

CBE do a Lithium version of their CSN2 battery maintainer, they say the original shouldn’t be used with Lithium.

Feedback from people i spoke with said they were using one ok and with Lithiums.
The battery master is also not lithium compatible but again quite a few seem to be using them.

I saw the CBE Lithium version but had already ordered and took delivery of the standard unit. So far all has been good.
The van was sat from Early October till Februrary with no charging other than the solar. All has been fine.
The CBE seem's to have been around a long time to have proven itself, i'm aware there was a faulty batch that were recalled but seemed very isolated and they acted on it promptly.

 

[fred_jb]

There is no guarantee that applying a D+ signal to the B2B will prevent this scenario as in some cases it seems to be an either/or situation - voltage sensing remains operational even if D+ is off, so either method can activate the B2B. This seems to be the case with the Renogy B2Bs, and possibly with others.

Apparently Renogy suggest putting a high power relay in the starter battery to B2B line, and switching that with the D+ signal to prevent voltage sensing from working when the engine is not running. I had already done this and it works though I'm not sure how necessary it really is as in my case it is only in rare situations that the B2B operates without the engine running.

 

[LithiumConvert]

Alternatively, buy a good B2B.

 

[fred_jb]

Alternatively, buy a good B2B.

Not necessarily a matter of good or bad. It is a design choice to cater for both standard and smart alternators. However I would agree that Renogy could have done better with this by ensuring that, when present, D+ control overrides voltage sensing.

^{_{Subscribers  do not see these advertisements}}

 

[LithiumConvert]

It is a design choice ......

It is still a purchase choice.

 

[fred_jb]

It is still a purchase choice.

Yes, assuming that this level of detail is available in the specs or manuals pre-purchase to help inform your choice. I don't think this was the case for the Renogy kit which is why I try to alert people to this issue.

However, I have no idea whether other brands have similar minor operational issues. I don't really see this particular quirk with the Renogy kit as a big deal and so far have been pleased with its performance.

 

[AshVanBitz]

Feedback from people i spoke with said they were using one ok and with Lithiums.
The battery master is also not lithium compatible but again quite a few seem to be using them.

I saw the CBE Lithium version but had already ordered and took delivery of the standard unit. So far all has been good.
The van was sat from Early October till Februrary with no charging other than the solar. All has been fine.
The CBE seem's to have been around a long time to have proven itself, i'm aware there was a faulty batch that were recalled but seemed very isolated and they acted on it promptly.

Hi tonka

Just to interject, I would like to clarify that the Battery Master is fully suitable/compatible for use with a lithium battery.

As long as both battery banks are 12V (engine and leisure), then the Battery Master can be installed to maintain the engine battery. It only transfers the power when there is a voltage difference over 0.75V (engine battery being the lower of the two). It transfers power (it does not charge) from the leisure battery to the engine battery to maintain this 0.75V difference.

So with the lithium batteries voltage resting at around 13.5V (on average), the engine battery will in turn maintain a resting voltage of around 12.6V-12.7V.

Kindest regards

Ash

 

[fred_jb]

I believe that the Battery Master simply uses a diode between the two batteries, with a resistor to limit the amount of current that can flow.

Assuming it is connected correctly, the diode prevents current flowing in the wrong direction - from starter battery to leisure battery - as a diode is effectively an electronic one way valve.

The other characteristic of diodes is that they only allow current to flow if there is sufficient voltage difference between the anode and cathode terminals. This will vary depending on the diode type, with a standard silicon diode requiring about 0.7V difference and a Schottky type requiring only around 0.3V. The BM makes use of this to ensure that the source battery has to be at a level at least 0.7V above the destination battery, though you have no control over the actual voltage levels it operates at.

Because of this the Battery Master is a very simple device with no user control or adjustability of voltage thresholds, so in my opinion is rather overpriced for what it is.

I use an Ablemail device which is fully configurable but only if you buy the rather overpriced Bluetooth dongle to allow it to interface to a smartphone app.

 

[eddie]

I believe that the Battery Master simply uses a diode between the two batteries, with a resistor to limit the amount of current that can flow.

Assuming it is connected correctly, the diode prevents current flowing in the wrong direction - from starter battery to leisure battery - as a diode is effectively an electronic one way valve.

The other characteristic of diodes is that they only allow current to flow if there is sufficient voltage difference between the anode and cathode terminals. This will vary depending on the diode type, with a standard silicon diode requiring about 0.7V difference and a Schottky type requiring only around 0.3V. The BM makes use of this to ensure that the source battery has to be at a level at least 0.7V above the destination battery, though you have no control over the actual voltage levels it operates at.

Because of this the Battery Master is a very simple device with no user control or adjustability of voltage thresholds, so in my opinion is rather overpriced for what it is.

I use an Ablemail device which is fully configurable but only if you buy the rather overpriced Bluetooth dongle to allow it to interface to a smartphone app.

I believe you’re wrong, I hand made everyone originally in the evenings after finishing the day’s installations and I have said on MHF time and time again, I didn’t produce them to sell, and, I produced them to solve an issue, an issue that still exists some 30 years on.

Lots of alternatives on the market, some cheaper some more expensive but Battery Master is simple to fit, (Three wires) isn’t complicated to set up (it works straight away) and there are tens of thousands of them out there keeping peoples engine batteries topped up 24/7 365 without the need for a Smartphone, Bluetooth connection, a Dongle, a Raspberry Pie connection

I all I want it to do is trickle charge the engine battery and not everyone wants 52 charging options and profiles!

^{_{Subscribers  do not see these advertisements}}

 

[fred_jb]

I believe you’re wrong, I hand made everyone originally in the evenings after finishing the day’s installations and I have said on MHF time and time again, I didn’t produce them to sell, and, I produced them to solve an issue, an issue that still exists some 30 years on.

Lots of alternatives on the market, some cheaper some more expensive but Battery Master is simple to fit, (Three wires) isn’t complicated to set up (it works straight away) and there are tens of thousands of them out there keeping peoples engine batteries topped up 24/7 365 without the need for a Smartphone, Bluetooth connection, a Dongle, a Raspberry Pie connection

I all I want it to do is trickle charge the engine battery and not everyone wants 52 charging options and profiles!

I was not meaning to criticise the Battery Master as a device. It does the job well and is all most people will need. My only criticism, given that it is a fairly simple passive device containing just a few cheap components, is the price, which typically seems to be £69.95. As a result I think some people think it is a more sophisticated intelligent battery management type device, which I'm pretty sure it isn't.

 

[eddie]

I don't expect Coca Cola's secret ingredients aren't that expensive

Yet using the same components no one has replicated the same satisfaction

 

[Richard n Ann]

I don't expect Coca Cola's secret ingredients are that expensive

Yet using the same components no one has replicated the same satisfaction

Try Freeway cola from Spanish Lidls,

Beware though, The French Freeway is full of aspertane and is revolting

 

[fred_jb]

Try Freeway cola from Spanish Lidls,

Beware though, The French Freeway is full of aspertane and is revolting

Well as far as cola is concerned even the "Real Thing" is pretty revolting to me! Other opinions are available!

 

[Abacist]

I was not meaning to criticise the Battery Master as a device. It does the job well and is all most people will need. My only criticism, given that it is a fairly simple passive device containing just a few cheap components, is the price, which typically seems to be £69.95. As a result I think some people think it is a more sophisticated intelligent battery management type device, which I'm pretty sure it isn't.

Most of us haven’t got a clue let alone wonder how intelligent it is! It does the job which is all I was interested in and the price struck me as eminently affordable for the convenience it provides and potential for a saving a Cab battery from becoming flat.

It was suggested that it was not right for Lithium so I bought an Ablemail. The instructions are crap and the supplier then sent different instructions. Neither enabled me to get it to work so it was a complete waste of money as far as I was concerned.

You connect the Batterymaster and it just works. If you don’t like the price, don’t buy it!

^{_{Subscribers  do not see these advertisements}}

 

[fred_jb]

Most of us haven’t got a clue let alone wonder how intelligent it is! It does the job which is all I was interested in and the price struck me as eminently affordable for the convenience it provides and potential for a saving a Cab battery from becoming flat.

It was suggested that it was not right for Lithium so I bought an Ablemail. The instructions are crap and the supplier then sent different instructions. Neither enabled me to get it to work so it was a complete waste of money as far as I was concerned.

You connect the Batterymaster and it just works. If you don’t like the price, don’t buy it!

That kind of confirms what I was saying about people thinking it is a more sophisticated device than it is. When people suggest that it is not lithium compatible, or ask if it has a lithium profile, it is obvious that they don't understand that it is a fairly simple device.

In any case, as it is a device which is only designed to charge the starter battery, and as far as I know all motorhome base vehicles use lead acid starter batteries, whether it caters for charging lithium is irrelevant. Of course it will take power from the leisure battery which may well be lithium but the only effect of that is the higher voltage of lithium batteries make them a better source for charging a lower voltage lead acid battery.

The Ablemail device is tricky to set up especially using the Bluetooth interface due to the fact that by default it is set in power saving mode so the Bluetooth shuts off after a few seconds, disconnecting the phone app. The trick is to connect and very quickly go into the settings and turn off power saving before it turns off. It took me several attempts, but since I did that it has been completely reliable.

 

[eddie]

Van Bitz Battery Master

>>CLICK HERE TO BUY

www.motorhomefun.co.uk

Best value of the internet

 

[autorouter]

but when I settled on going blue (i.e. Victron) for everything I forgot to check whether the Orion TR 12/12-30 did that, and of course it doesn't... After a slightly dodgy moment when trying to start the van I checked the engine battery voltage and realised my mistake!

If you have the Victron Orion 12-12 30, it is definitely possible to set it up so it triggers only on the D+, not on any voltages. But you have to go into the settings and change it, I think its default settings are voltage sensitive. As I recall, it's the opposite way round to what you'd expect. The voltage sensitive settings are termed 'engine running detection' or something. You have to override that, so that it triggers only on the D+ signal from the alternator. So you want to turn the 'Engine Running Detection Override' setting to 'ON'.

In a motorhome there will usually be a convenient D+ signal somewhere, without having to go all the way back to the alternator. It is used for various things, including switching a 3-way fridge to 12V when driving, and the step alarm or auto-retract when the engine starts.

There's almost certainly a D+ to the 12V distribution/fusebox - what make/model is it? Should be easy to tap into that.

 

[Ray-Vic]

I actually went for the Ablemail AMT12-2 for no specific reason other than it appeared to offer a little more for the money. However, after the initial setting it to the right profile without Bluetooth (it is possible but a bit of a faff) it has sat there doing its thing never to be touched again. The only real difference I can see relating to the 'lithium profile' is that it has a 1.0v difference rather than the 0.75v of the Battery Master. Is that likely to make a difference? I doubt it.

I think in hindsight I would have been more than happy with the simple 'plug and play' design of the Battery Master, and the much smaller size and ease of wiring. That's not saying the Ablemail was hard to wire, it's just the finding the wire and adding crimps etc which adds to the installation time.

Both clearly do the job they were designed to do, and both worth every penny (IMO of course).

 

[delia]

I agree D+ is the way to go with BTB not voltage sensing.
As regards the CBE battery maintainers I found that without solar output (here in Scotland) keeping leisure up to voltage it didn't work in fact the constant drain on my smart alternator Mercedes based engine battery left it flat in a couple of weeks. To resolve the issue I fitted an Ablemail AMT12-12-5, 2 years ago. It is fully programable to whatever parameters you want, probabley some what over the top but it has worked well so far... apart from the aformentioned hit and miss bluetooth, but that is only really needed when setting up or making adjustments.

^{_{Subscribers  do not see these advertisements}}

 

[CAB96]

I believe, getting back to the OP's original question :

You don't need to do anything with your B2B.

None of these battery maintainers will raise the voltage above that of the leisure battery (like your battery charger does), they simply allow charge to flow when needed.

So they won't trigger your Victron B2B.

 

[Barti Ddu]

I believe, getting back to the OP's original question :

You don't need to do anything with your B2B.

None of these battery maintainers will raise the voltage above that of the leisure battery (like your battery charger does), they simply allow charge to flow when needed.

So they won't trigger your Victron B2B.

100% agree. Our Victron B2B uses voltage detection rather than the D+ signal, and we've also a CBE CSB2 "battery master". The battery master doesn't raise the starter battery voltage enough to trigger the B2B. Everything works quite happily together.

As I said in an earlier post, I'm not quite sure why the standard CBE CSB2 battery master shouldn't be used with lithium, as it clearly works fine. Not quite sure what the CBE lithium version does differently.

 

[fred_jb]

I believe, getting back to the OP's original question :

You don't need to do anything with your B2B.

None of these battery maintainers will raise the voltage above that of the leisure battery (like your battery charger does), they simply allow charge to flow when needed.

So they won't trigger your Victron B2B.

It is true that a battery maintainer won't raise the starter battery voltage above the leisure battery voltage, but this in itself does not necessarily preclude B2Bs from operating as they are designed to boost a lower starter battery voltage to a level high enough to charge the leisure battery.

It seems that it is possible to disable voltage sensing on a Victron B2B so, as has been said, OP should not have a problem if they do that. However, if a B2B is controlled by voltage sensing rather than D+ signal, then whether it gets triggered depends on the starter battery voltage and what the B2B's voltage sensing threshold is set to.

B2Bs are more or less essential for vehicles with smart alternators which tend to aim to maintain the starter battery voltage at no more than about 12.5V. The B2B then boosts this to over 14V to charge the leisure battery, but normally only when the engine is running, indicated by a D+ signal being present, rather than by sensing the starter battery voltage.

Some people have had a B2B operate for a short time with the engine not running but this only seems to happen with non-smart alternators, when after a run the starter battery is temporarily showing a higher than normal voltage. I have also seen this with my smart alternator system when the starter battery has been fully charged with its mains charger or dedicated solar panel.

In my case this is because I have a Renogy B2B which will trigger on either a D+ signal or by voltage sensing, and unlike the Victron has no facility to disable the latter or change its threshold. This can be fixed by putting a D+ controlled relay in series with the starter battery feed to the B2B.