Are 'smart' chargers and Battery Masters the same thing?

[Ingwe]

I ask because our van (a Bailey Approach 620 Approach) is kept indoors for storage. Therefore, the 130 watt solar panel that normally would keep both the leisure and the cab battery charged won't work.
So for the leisure battery we hook up to the mains but this apparently won't charge the cab battery. Accordingly, we bought a smart battery from Halfords that is supposed to keep the battery (cab) fully charged and when full, to allow only a small maintenance charge thereby avoiding overcharging the battery.
Today we've learned that the need a new cab battery because the casing's split and the plates are bent. The mechanic said probably due to overcharging. He advised disconnecting the earth lead from the battery when not being used. However the last bit of advice is a pain the neck as the battery is not that easily accessible and, in any event, the smart chargers are supposed to prevent overcharging and specifically state that they can be left on permanently.
I've seen lots of references to Battery Masters on this forum and wonder if this is something that is fundamentally different to the Halfords smart charger?
Also, if I bought a Battery Master, how does it relate to the solar panel,which has a dual feed and charges both batteries?
Sorry if my questions seem daft. Just having forked out £125 for a new cab battery three months after £100 for a new leisure battery, I am anxious to keep the batteries in good health and be able to start the van after three weeks or more in storage.

 

[PhilandMena]

When in storage, connect leisure batteries to smart charger and run a cable from pos on your leisure battery to the pos on your cab battery. This is a cheap method of preventing your cab battery from going flat. However, I would recommend getting it sorted by an expert so your charger maintains all your batteries while in storage. Or, disconnect your cab battery altogether.

 

[Pausim]

Just had a look at the spec for Halfords Smart Charger and I am not so sure it is as smart as it claims to be. All the smart chargers I have previously looked at appear to drop the voltage in the float stage, to control the charging level. If Halfords graphs are to be believed their charger maintains the higher level voltage but just limits the amps, I may be reading this wrong. My concern would be that IF it is maintaining the battery at near 14.4 vots it might be slowly frying it, even though the amps are much reduced. I am no expert in these matters and I expect someone who knows what they are talking about will be along shortly to shoot me down.

However being an old cynic it would not surprise me if someone in an attempt to cut the manufacturing cost had found a cheap way to make something’s look smarter than it really is. After all I doubt that “smart” has ever been properly defined.

 

[Reallyretired]

From past experience, I would take anything Halfords told me with a pinch of salt.

 

[Ingwe]

In relation to PhilandMena's helpful suggestion, would there be any advantage to connecting the leisure battery to the smart charger over the leisure battery being charged by the van's internal charger when on hookup? I can see how the lead from the positive post of the leisure battery to the positive lead to the cab battery would keep the cab battery charged but isn't that in effect what I've been doing? I have the clearly not-so-smart-Halford's charger connected to the cab battery and the leisure battery is charged by EHU.

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[Ingwe]

From past experience, I would take anything Halfords told me with a pinch of salt.

Anything? I've found them generally knowledgable and helpful but I take your point that maybe their "smart charger" is a trifle dumb especially if what Pausim asserts is the case. How is a non-techie like me supposed to choose a product? One reads the bumf and takes one's chances.

 

[DBK]

Do you know what sort of charger is built in to the van? If it is something like a CTEK it will be smart enough not to fry your leisure batteries. I've had our MH plugged in over previous winters without issue although now I just let the solar top things up.

I also have a battery master. This senses if the vehicle battery voltage drops much below the liesure battery voltage and when it does gives it a charge.

The answer to the question in the title of this thread is no. The battery master only looks at the voltage difference between the two sets of batteries. It isn't "smart" in the sense of detecting when to go into float mode but it doesn't need to if the leisure batteries are being properly charged.

 

[Ingwe]

@DBK-thanks for the post.
The Bailey user manual says as follows:
"Your motorhome is fitted with a 12v charger as standard. The charger is capable of charging leisure batteries and will not overcharge."

So, if I understand you correctly, if the battery Master only senses the difference in voltage between the cab battery and the leisure battery, if on hook up ( which charges the leisure battery) the battery master senses the cab battery voltage is lower than the hab battery, it will 'divert' some of the ehu charge going to the leisure battery to the cab battery?
We have no problem at all if the van is outdoor and the solar can get to work.

 

[scotzsue]

Don't know if it helps but we have a battery master our vehicle battery was not charged from the mains, now the levels, vehicle and habitation are fairly even. We do have solar,which is effective even in winter.

 

[Ingwe]

@scotzsue-thanks for this.
Our problem is that our cab battery (or indeed the hab battery) isn't topped up by the solar panel as the van is stored inside and gets insufficient light. So we have the hab charged by hookup and separately had a so-called smart charger keeping the cab battery charged. But doing this has overcharged and killed the cab battery.
I conclude therefore that either the smart charger is unsuitable, hence the question whether a battery master is the same as a smart charger or the smart charger we have is faulty.

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[Pausim]

@Ingwe I may be wrong about the possibility that your Halfords smart battery charger was responsible. It was just that the details they give didn’t specify a lower voltage for the maintenance charge. It should have been fine and perhaps there is something else causing the problem.

 

[DBK]

@DBK-thanks for the post.
The Bailey user manual says as follows:
"Your motorhome is fitted with a 12v charger as standard. The charger is capable of charging leisure batteries and will not overcharge."

So, if I understand you correctly, if the battery Master only senses the difference in voltage between the cab battery and the leisure battery, if on hook up ( which charges the leisure battery) the battery master senses the cab battery voltage is lower than the hab battery, it will 'divert' some of the ehu charge going to the leisure battery to the cab battery?
We have no problem at all if the van is outdoor and the solar can get to work.

Yes, that's how it works. I think a battery master is all you need.

 

[Nasher]

If the cab battery has a split casing and the only thing connected to it is the Halfords battery charger the the charger is either faulty or has the wrong settings. A Picture of the charger & old battery would be good.

AFAIA the (Vanbitz) Battery Master is designed to allow a small current (1 amp?) to the cab battery from the leisure battery, if the cab battery loses charge. Obviously if the leisure battery is receiving charge from the on-board charger (Via EHU or Solar) then that will keep the Cab battery charged.

Link here:

https://www.vanbitz.com/product/battery-master/

Edit: DBK's post above beat me too it!

 

[Ingwe]

I'll go out to the van later and see if I can take photos. However, I think it unlikely that I will see the damaged battery as it has been replaced by the garage carrying out the service and MOT (not the place where it is stored).
I will take a photo of the Halfords charger.
From all the useful posts, I think the battery master is what is required. I hope I'll be able to fit it myself but if not, will get an auto electrician to do so. Plenty of posts saying how easy it is but I suspect when I try, nothing will look like others' photos/ descriptions and I'll be scratching my head!

 

[eddie]

Battery Master doesn’t care if the Motorhome is plugged in to mains, or if there is a solar panel fitted, its only job is to ensure the optimum charge of the engine battery.

If there is a difference in voltage of 0.75 VDC between the leisure battery and the engine battery the Battery Master will trickle charge the engine battery. It will not and cannot work the other way and discharge the engine battery into the leisure battery. That is the job of the split charge relay when the engine is running.

If the leisure battery gets charged by a solar panel or mains charger the leisure battery voltage raises, creating a voltage difference greater than 0.75 VDC so Battery Master will trickle charge the engine battery.

People often try to suggest that this can cause conflict with existing equipment “My dealer said! ” but, say for example you have a system that trickle charges the engine battery when the van is plugged in, the the voltage of the engine and leisure batteries are the same, so Battery Master does nothing, there is no need.

Dual solar regulators are the same, when the solar regulator is charging both batteries, it does nothing, but, unlike a dual solar regulator, Battery Master will support the engine battery 24/7 even when there is little or no solar activity, or, as in the OP’s case the Motorhome is parked under cover.

Cheapest place to buy a Van Bitz Battery Master is the Motorhome Fun Shop website (support the club) for £59.99

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[Ingwe]

@eddievanbitz-thank you for this clear explanation. Will get one ordered.

 

[eddie]

@eddievanbitz-thank you for this clear explanation. Will get one ordered.

Your welcome, don’t forget don’t buy from us, we are too expensive Support the Club

http://shop.motorhomefun.co.uk/product/battery-master/

 

[Ingwe]

Thanks Eddie.Ordered from here. Hope you still get something out of it.
Had a look in the van today and cannot see a split charge relay, or anywhere obvious, which would have allow me to use as connection points. So I'll ask an auto-electrician to fit it.
As promised, here are photos of the knackered battery and the Halfords "smart" charger. From the latter's box it states:
"Automatically selects the safest, fastest charge rate based on your battery size.
Can be safely left permanently connected to recharge, recondition, and maintain your battery. Etc." (My emphasis).
With regards to the photograph, not too clear but there is a split where circled and where arrowed are vertical lines (white) which the mechanic said was the deformed plate pushing on the side.
A real shame as the battery has a 5 year warranty and other than that, looks perfect. Incidentally, I put the voltmeter across it and it read 12.75v.

 

[Nasher]

A quick scan of the battery charger instructions shows options for charging the battery. I'm wondering whether you had the wrong option selected. That said, even if you had the wrong option selected, it shouldn't have destroyed the battery.

I suspect a faulty charger - take it back & ask for your money back and a new battery

 

[Ingwe]

Thanks, Nasher. I will be raising the matter with Halfords.

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[Hymie]

Got a battery master on ours but also one of these for longer winter layups, but then our old banger doesn't have all these modern electronic gizmos fitted.

 

[Ingwe]

@Hymie- what does that gizmo do?

 

[Pausim]

The gizmo goes on the negative battery terminal. If you unscrew the green knob a little it disconnects the battery to eliminate any drain. Can also be used as a security device by removing the green knob entirely, if fitted with a small bypass fuse leaves alarms etc running but fuse blows if anyone tries to start the engine.
Can also get a version for batteries with screw type terminals. I use one of these on my leisure battery (without bypass fuse) so that I can isolate it when I leave it in storage. This stops the small drain from some of my kit which is not needed when I am not there. The alarm and tracker are connected to the engine battery which stays live.