Solar + VanBitz Battery Master not holding vehicle battery voltage

[BarumMike]

We have a Roller Team 2021 Zefiro on a Transit chassis. The MH is stored outside in full sun with no easy access to mains hook-up. After the AGM vehicle battery (VB) flattened completely in storage I installed a VanBitz Battery Master. I had hoped this + 100w solar panel would keep the VB fully charged at least in the sunnier months. While we were away for 3 weeks in February the VB completely flattened again (I should have charged up the VB before the trip). This summer the VB voltage has slowly drifted down and required a jump start around 6/7/23 - see battery history chart from Phantom app. Shortly after we did a 200 mile trip to Cornwall with the VB voltage up to 13v but on our return it quickly fell to 12.3 and has drifted slowly down since then. We had the VB checked by the dealer who reported it was fine.
My questions are:
1. Is a 100w solar panel and a Battery Master insufficient to keep VB voltage steady in July? I believe the Battery Master only delivers a 1A trickle charge. Perhaps this is not enough for the current drain in modern vehicle electrics?
2. What VB voltage should I see in summer stored outdoors? It dropped almost immediately to 12.3 on return from our short trip in mid July, which seems low. The leisure battery voltage is maintained at north of 13v by the solar panel.
3. Does all this indicate a problem with excessive current drain from the VB when not in use, or damage to the AGM VB not revealed by the main dealer check?
Thanks in anticipation.

 

[DavidG58]

Sounds like the VB is goosed, I would buy a new one

Unless there is something incorrectly taking power from this battery maybe

 

[David and Sally]

Maybe you need a clamp meter on the VB to see what sort of current is being drawn when all is switched off. You could possibly isolate a draw on the battery.

 

[Kannon Fodda]

The VB voltage of 13V or more is due to charging from alternator or other source. It is not an indication of the battery charge / capacity status.

VB voltage needs to be checked once it has rested for at least 30 minutes, if not an hour. You indicate 12.3V which suggests it is only around 75% full. A full lead acid is around 12.6V / 12.7 V max.

But voltage can also be affected by any load. What is connected to your VB and could be a parasitic draw. Radios are notorious but can also be alarms and even a stuck relay trying to recharge the habitation system (a loop with you battery master trying to trickle the cab). A clamp meter may help you check current flows.

The Vanbitz Battery Master will only trickle charge based on the hab battery voltage being higher than the VB (engine). Solar will put some into the hab and during summer unless your panel is in shade should be more than sufficient. In winter especially on sequence of cloudy days the 100W panel will do very little, mine didn't cope even with no use of van so mains charge top off every fortnight might be desired.

 

[rb62]

I don't think your battery ever recovered from being flattened,there is a special way of trying to recover an AGM battery.I suggest you replace it with a decent lead acid battery.

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[GeoffnDee]

Is the Van bitz battery master behaving as it should ? the light on it changing from red (charge transfer taking place) to green ( voltage approx. equal). The light can remain green if the starter battery has failed or there is a poor connection/fuse blown , The Van bitz web site has a section on how to test that it is operating as it should.

 

[headlight]

A single 100 watt panel and battery master kept my starter battery and 2 x 100AH lead acid leisure batteries topped up over last winter fine.
My van is 2006 and I don't think there is as much parasitic drain when it's parked up as a more modern van.

 

[berni109]

Buy yourself a BM2 battery monitor for the vehicle battery. Bluetooth app will show you what is going on but unfortunately not what might be drawing power. Either removing fuses from the vehicle f/box 1 at a time or a DC clamp meter will be needed to identify the parasitic drain.

 

[Hoovie]

We have a Roller Team 2021 Zefiro on a Transit chassis. The MH is stored outside in full sun with no easy access to mains hook-up. After the AGM vehicle battery (VB) flattened completely in storage I installed a VanBitz Battery Master. I had hoped this + 100w solar panel would keep the VB fully charged at least in the sunnier months. While we were away for 3 weeks in February the VB completely flattened again (I should have charged up the VB before the trip). This summer the VB voltage has slowly drifted down and required a jump start around 6/7/23 - see battery history chart from Phantom app. Shortly after we did a 200 mile trip to Cornwall with the VB voltage up to 13v but on our return it quickly fell to 12.3 and has drifted slowly down since then. We had the VB checked by the dealer who reported it was fine.
My questions are:
1. Is a 100w solar panel and a Battery Master insufficient to keep VB voltage steady in July? I believe the Battery Master only delivers a 1A trickle charge. Perhaps this is not enough for the current drain in modern vehicle electrics?

1. Bear in mind the Battery Master is only active on a Lead Acid Leisure Battery system when there is active charging occuring. So in July, that might be 12 hours in a full day? So that 1A trickle straightaway is halved to just 0.5A average (a parasitic drain doesn't care if it is daylight or not).
It is not uncommon to have a parasitic draw of more than than on a vehicle, and especially if a Dash Radio has been upgraded and installed unknowingly incorrectly. Have you changed your in-dash radio for a new unit?
Other parasitic draws can be trackers, alarms, etc. Have you made ANY changes to the 'cab' side of the motorhome. Has it always had this drain issue.
I used to have a 2005 Toyota RAV4 and the starter battery on that would die if unused for more than 2 weeks due to the alarm. (dealer advice. leave the alarm off if not using the vehicle over a longer period! useful!!). Once out of Warranty, I just fitted a bigger battery (50% bigger) to prolong the 'stationary' life.

2. What VB voltage should I see in summer stored outdoors? It dropped almost immediately to 12.3 on return from our short trip in mid July, which seems low. The leisure battery voltage is maintained at north of 13v by the solar panel.
3. Does all this indicate a problem with excessive current drain from the VB when not in use, or damage to the AGM VB not revealed by the main dealer check?
Thanks in anticipation.

View attachment 789073

3. what would "excessive" be? all down to what it fitted. But as I mentioned above, if a radio is installed incorrectly, that can certainly kill a starter battery very easily (as has happened to quite a few people I know and fixed the issue easily once they understood).

 

[RogerIvy]

As others have said - the first that came to mind is the possibility of a parasitic draw on your VB.

But you need more info, so you need a good clamp meter and a smartshunt would help too.
When/if you have proven you have a parasitic draw there are many YouTube’s out there that explain different methods of identifying the parasitic draw … all take some time.

The clamp meter will help to show that the Battery Master is working (or not as the case might be).

If you can afford it a smartshunt with Cerbo GX would enable you to set up an alarm on your VB voltage. The GX would need to be connected to the internet.

My daughter also had a problem with an intermittent parasitic draw on her Sprinter. We tried to find it but because it’s intermittent it became silly season. In the end we installed a ChargeMetrix monitor which uses GSM and has a small monthly subscription fee (a few £). This has saved her VB several times (about four times as I recall). So the ChargeMetrix has paid for itself several times.

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[BarumMike]

Wow! Rapid and very helpful replies. Some responses and questions from me.
GeoffnDee.. The Battery Master looks to be working.
Berni109.. We have the Phantom tracker installed and this has the very useful function of tracking the VB voltage and sending the data to the app on my phone. So a BM2 battery monitor not needed unless the tracker itself is the cause of an excess current drain...
Hoovie.. New installations since leaving the factory are an aerial amplifier, usually switched off when in storage, a Cobra alarm and the Phantom tracker. I have the impression the problem is worse since the Phantom was installed, but they maintain it requires only a miniscule current draw. Scope for problems there, which brings me to..
RogerIvy.. A clamp meter sounds a useful bit of kit but a visit to Amazon.co.uk revealed a mixture of very expensive tools and a bunch of cheaper ones of dubious parentage! Can you or anyone else recommend a clamp meter for DC as well as AC which will not break the bank?
rb62.. You may be right that the AGM VB never recovered from being fully drained. How can I test for this and avoid shelling out £150+ unnecessarily? I gather AGM batteries are more vulnerable to such damage than conventional lead acid batteries. When you say "a decent lead acid battery" do you mean a good brand or a conventional not AGM lead acid battery? What was the advantage of using an AGM battery in the first place?

 

[Jimbohorlicks]

Looks like youneed a new battery if its not holding a charge and you haven't changed it for a new one since it was flat.

 

[Hoovie]

Wow! Rapid and very helpful replies. Some responses and questions from me.
GeoffnDee.. The Battery Master looks to be working.
Berni109.. We have the Phantom tracker installed and this has the very useful function of tracking the VB voltage and sending the data to the app on my phone. So a BM2 battery monitor not needed unless the tracker itself is the cause of an excess current drain...
Hoovie.. New installations since leaving the factory are an aerial amplifier, usually switched off when in storage, a Cobra alarm and the Phantom tracker. I have the impression the problem is worse since the Phantom was installed, but they maintain it requires only a miniscule current draw. Scope for problems there, which brings me to..

2 questions .....
1) Can you use the radio without putting the ignition on?
2) When the radio is on, do you see the VB voltage drop?

RogerIvy.. A clamp meter sounds a useful bit of kit but a visit to Amazon.co.uk revealed a mixture of very expensive tools and a bunch of cheaper ones of dubious parentage! Can you or anyone else recommend a clamp meter for DC as well as AC which will not break the bank?
rb62.. You may be right that the AGM VB never recovered from being fully drained. How can I test for this and avoid shelling out £150+ unnecessarily? I gather AGM batteries are more vulnerable to such damage than conventional lead acid batteries. When you say "a decent lead acid battery" do you mean a good brand or a conventional not AGM lead acid battery? What was the advantage of using an AGM battery in the first place?

 

[rb62]

Wow! Rapid and very helpful replies. Some responses and questions from me.
GeoffnDee.. The Battery Master looks to be working.
Berni109.. We have the Phantom tracker installed and this has the very useful function of tracking the VB voltage and sending the data to the app on my phone. So a BM2 battery monitor not needed unless the tracker itself is the cause of an excess current drain...
Hoovie.. New installations since leaving the factory are an aerial amplifier, usually switched off when in storage, a Cobra alarm and the Phantom tracker. I have the impression the problem is worse since the Phantom was installed, but they maintain it requires only a miniscule current draw. Scope for problems there, which brings me to..
RogerIvy.. A clamp meter sounds a useful bit of kit but a visit to Amazon.co.uk revealed a mixture of very expensive tools and a bunch of cheaper ones of dubious parentage! Can you or anyone else recommend a clamp meter for DC as well as AC which will not break the bank?
rb62.. You may be right that the AGM VB never recovered from being fully drained. How can I test for this and avoid shelling out £150+ unnecessarily? I gather AGM batteries are more vulnerable to such damage than conventional lead acid batteries. When you say "a decent lead acid battery" do you mean a good brand or a conventional not AGM lead acid battery? What was the advantage of using an AGM battery in the first place?

I would ask Lenny HB what he thinks of AGM batteries but it's no publishable,here is his drop test for batteries. Table is in the attachment

First charge the battery fully and leave it to settle for an hour then:-

Disconnect all charging methods.

For example if it's a 100a/h battery load it with a 5 amp load and run for 5 hours, this will represent a 25% discharge. (adjust load/time to suit the size of the battery)
Disconnect the load and leave to stand for at least 30 min then measure the voltage.
Repeat the test and you will have discharged the battery to 50%.
You can repeat again then it will be 75% discharged.

View attachment 720199

 

[BarumMike]

2 questions .....
1) Can you use the radio without putting the ignition on?
2) When the radio is on, do you see the VB voltage drop?

The MH is parked 30 minutes away, but
1) From memory , no, the ignition needs to be on. The radio is the standard Ford unit.
2) Will need to check that. Do you mean instantly or over a period?

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[ChrisL]

Another thing to check for parasitic draw is your alternator, if a diode fails, current will leak back to earth via the alternator body. If you have access to a thermal imaging device any circuit thats live with everything turned off will show up as hotter than the surrounding area.

 

[berni109]

Ok so what does the power curve look like over a 24hr period?
This could be a starting point :

Leisure Battery draining despite good solar

Hi We have a Baily Autograph 79-4 with a 100w solar panel. We currently have a Fuller 110A 12v lead acid leisure battery. The solar controller is currently set to split the charge as 60% leisure and 40% cab battery and is showing the Cab Battery as charged and the leisure battery as charging...

www.motorhomefun.co.uk

 

[Hoovie]

The MH is parked 30 minutes away, but
1) From memory , no, the ignition needs to be on. The radio is the standard Ford unit.
2) Will need to check that. Do you mean instantly or over a period?

If the ignition needs to be on, then the radio is wired correctly and should be not taken as a culprit.
I did mean instantly for the voltage, to look at the load the radio takes. If it took no load, it would suggest it was wired to the Leisure Battery, otherwise with a load it would be on the starter battery as is standard. (some motorhome manufacturers rewire the radio in various ways. they don't all get it right).

The search continues .....

 

[BarumMike]

I will bring the MH out of storage for the weekend, do the battery capacity test and check for battery drain using my newly purchased clamp multimeter. ChrisL, I have a basic thermal imaging camera (iPhone add on) and will play with that. And then report back.

 

[autorouter]

A clamp meter sounds a useful bit of kit but a visit to Amazon.co.uk revealed a mixture of very expensive tools and a bunch of cheaper ones of dubious parentage! Can you or anyone else recommend a clamp meter for DC as well as AC which will not break the bank?

Many on here, including me, like the Uni-T UT210E clamp meter. As well as the 100A range, it has a 2A range that is very useful for tracing small drain currents. Most DC clamp meters are not very good at showing low currents, but this one is good for that. As you probably know, like many clamp meters it has a couple of sockets for probe cables, and can also measure volts, resistance and continuity, so it is a good all-round meter. It's the one I always keep in the motorhome.
Amazon product ASIN B00O1Q2HOQEdit: sorry, just noticed you've already bought a clamp meter.

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[BarumMike]

Many on here, including me, like the Uni-T UT210E clamp meter. As well as the 100A range, it has a 2A range that is very useful for tracing small drain currents. Most DC clamp meters are not very good at showing low currents, but this one is good for that. As you probably know, like many clamp meters it has a couple of sockets for probe cables, and can also measure volts, resistance and continuity, so it is a good all-round meter. It's the one I always keep in the motorhome.
Amazon product ASIN B00O1Q2HOQEdit: sorry, just noticed you've already bought a clamp meter.

Really helpful. With only a mild twinge of conscience I returned to Amazon my first choice unopened and bought your suggestion. It is a very neat unit.

 

[BarumMike]

Battery discharge test result. Thanks for the advice. I set up a 55w headlamp bulb circuit to test drain the VB. This should give a current of 4.6A. The VB was down to 15% by 7h 20min ie the capacity is 46% of the nominal 80Ah. So the battery is in poor condition and needs replacing. Once installed I will do a quick check of VB drain but will probably see how the new VB behaves in normal use of the MH. Thanks for all the help.

The moral of the story for new MH owners is keep a close eye on the VB voltage if you have an AGM VB and store the MH without trickle charging (even with a solar panel and Battery Master). If you are not used to having to think about lead acid battery condition, its easy to not recognise the significance of apparently small drops in voltage in the low 12V range. A fall from 12.3v to 12.0v indicates a fall in capacity from 50% to 25% with the risk of damage to the battery. Bitter experience for me!

 

[BarumMike]

I would ask Lenny HB what he thinks of AGM batteries but it's no publishable,here is his drop test for batteries. Table is in the attachment

Thanks for the really helpful advice. See below for the outcome - we need a new vehicle battery. BTW I followed up your credit of Lenny HB and ended up at a post by Autorouter on Nov 4, 2018 which has a very clear and detailed explanation of doing a discharge test to check battery condition, again crediting Lenny HB and giving a fuller table of charge and discharge levels v battery voltage.

 

[FrankNicklin]

Does the BM2 in its own right cause a parasitic drain on the VB to run the bluetooth module.

 

[Whizzo]

We have a Roller Team 2021 Zefiro on a Transit chassis. The MH is stored outside in full sun with no easy access to mains hook-up. After the AGM vehicle battery (VB) flattened completely in storage I installed a VanBitz Battery Master. I had hoped this + 100w solar panel would keep the VB fully charged at least in the sunnier months. While we were away for 3 weeks in February the VB completely flattened again (I should have charged up the VB before the trip). This summer the VB voltage has slowly drifted down and required a jump start around 6/7/23 - see battery history chart from Phantom app. Shortly after we did a 200 mile trip to Cornwall with the VB voltage up to 13v but on our return it quickly fell to 12.3 and has drifted slowly down since then. We had the VB checked by the dealer who reported it was fine.
My questions are:
1. Is a 100w solar panel and a Battery Master insufficient to keep VB voltage steady in July? I believe the Battery Master only delivers a 1A trickle charge. Perhaps this is not enough for the current drain in modern vehicle electrics?
2. What VB voltage should I see in summer stored outdoors? It dropped almost immediately to 12.3 on return from our short trip in mid July, which seems low. The leisure battery voltage is maintained at north of 13v by the solar panel.
3. Does all this indicate a problem with excessive current drain from the VB when not in use, or damage to the AGM VB not revealed by the main dealer check?
Thanks in anticipation.

View attachment 789073

I have a 100w solar and Phantom tracker & alarm and battery master. This always keeps things charged even in winter. Rarely have to plug in between trips.

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[headlight]

100 watts of solar and a battery master kept my starter battery and 2 x 100AH leisure batteries fully charged over last winter in sunny (not) South Wales.