No Solar yet but would like to keep batteries topped up in storage

[FrankNicklin]

We dont have solar yet but would like to keep the batteries topped up whilst in storage. Been reading a lot about Windscreen solar chargers at 20 to 30w connected to the vehicle battery but would also like to top up the leisure as well if possible.

I'm no expert in vehicle electrics although I have installed bits and pieces over the years in cars. The MH is a 2002 Ducato base with a 94ah engine battery and a 150ah leisure battery.

Behind the drivers seat there was some poorly maintained wiring that comes from under the drivers seat in to the seating area where the water tank is located. There is also a 20AMP inline fuse located here. I've wrapped the cables in loom tape and housed the connection in a choc block box for now with the 20amp fuse alongside (not in the box) and easily accessible from the drivers door.

In the wardrobe behind the EHU socket is the charger and a relay. The relay is mount directly to the back of the wardrobe wall. Not sure if this is the split charge relay.

Any thoughts about how I could install a suitable panel. Lots of cheap rubbish out there. Any recommendations on a suitable setup for this. We are new to Motor Homing and I don't want to be throwing lots of money at solar just yet as we are likely going to be on EHU when we can.

 

[MisterB]

you could pick up a second hand panel cheaply enough. even a folding panel placed on the roof (so no one walks off with it whilst in storage) might come in handy. your intent to only stay where ehu is available might stop you attending rallies, or temp holiday sites .....?

vanbitz do a very good battery maintainer (also available through motorhome fun) ?

 

[FrankNicklin]

you could pick up a second hand panel cheaply enough. even a folding panel placed on the roof (so no one walks off with it whilst in storage) might come in handy. your intent to only stay where ehu is available might stop you attending rallies, or temp holiday sites .....?

vanbitz do a very good battery maintainer (also available through motorhome fun) ?

We have a couple of events planned next year which will not have EHU so likely will have solar by then but looking for a temporary solution. Don't particularly want an external panel just yet, but hoping that I can get something set up that would suffice for the next 3 or 4 months. The MH will be used occasionally through the winter purely as a means of transport to keep the wheels moving and the brakes active for the odd days out. The storage is only a few miles from home so quite convenient in that sense.

 

[FrankNicklin]

The VanBitz battery maintainer you refer too, is that their Battery Master device.
[Broken Link Removed]

 

[Petroleumblownapart]

The VanBitz battery maintainer you refer too, is that their Battery Master device.
[Broken Link Removed]

What brilliant bit of kit it is and dead simple to fit.

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[rosalan]

Some time ago I had a small solar panel to keep my van battery topped up, it sat behind the windscreen. Coincidence or not, during the time I used it, the engine battery failed on two occasions. The little panel had no control and it was suggested to me that it could be the cause of battery failure.

 

[FrankNicklin]

Some time ago I had a small solar panel to keep my van battery topped up, it sat behind the windscreen. Coincidence or not, during the time I used it, the engine battery failed on two occasions. The little panel had no control and it was suggested to me that it could be the cause of battery failure.

Yes Ive heard this. Without a controller PWM or MPPT the panel will draw power from the battery when there is no sun sufficient to create voltage and therefore flatten the battery.

 

[Tombola]

Solar panel to the leisure via contoller...battery master to the starter.

Sorted

Or remove the batts and keep them topped up at home

 

[FrankNicklin]

Thats what I would like to do. My leisure battery is under a seat in the MH and the consumer unit, fuses and EHU charger are in the wardrobe next to it.

Not sure how to get a feed from the LB to the VB. Not clear from the wiring in the wardrobe where I can attach the relevant feeds back to the VB.

 

[Jev88]

Wire solar direct to battery via a good quality MPPT controller. I suggest you add a vent pipe to the leisure batteries to vent down and outside any gases it produces. When new the battery probably had a couple of plastic plugs at either end. You can get little plastic pipes that fit and then run fish tank airline to outside.
Solar below 60watts is almost useless in UK winter.

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[FrankNicklin]

Wire solar direct to battery via a good quality MPPT controller. I suggest you add a vent pipe to the leisure batteries to vent down and outside any gases it produces. When new the battery probably had a couple of plastic plugs at either end. You can get little plastic pipes that fit and then run fish tank airline to outside.
Solar below 60watts is almost useless in UK winter.

I Have a Numax fully sealed battery. As far as I know there is no option to fit a vent tube. Was thinking of at least 120w foldable solar panels with MPPT controller at the moment. Fit an Anderson connector for hookup but I need to work out how to get the Battery Master feed to the VB.

 

[Coastal Cruiser.]

If it was easy access to the battery I would buy a cheap battery and just keep one charged at home and swop over every few weeks…

 

[Tombola]

I Have a Numax fully sealed battery. As far as I know there is no option to fit a vent tube. Was thinking of at least 120w foldable solar panels with MPPT controller at the moment. Fit an Anderson connector for hookup but I need to work out how to get the Battery Master feed to the VB.

Do you have a vsr spilt charge or anything in place already you can connect to anything that links to the battery as long as its connected when ignition is off.

 

[FrankNicklin]

Do you have a vsr spilt charge or anything in place already you can connect to anything that links to the battery as long as its connected when ignition is off.

To be honest I don’t know. Only had the MH a few weeks so finding my way around the electrics. Dont know where that might be located.

 

[Tombola]

Only needs a small .5 mm fused cable if all else fails you can tuck one away and thread it yourself I guess

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[cyberyacht]

You'd be surprised how little solar is producing at the moment. I came back from a trip away with my lithiums down to 57%. 3x100W in series and it's barely staying ahead of parasitic drains let alone bring the capacity up. We may have climate change but the sun ain't shining any more. My house panels have produced the lowest output for twelve years. AS Chief Brodie said "you're gonna need a bigger boat panel".

 

[autorouter]

If the storage is nearby and you have access to it then there is another option. In the days before lithium power packs were available, I used a spare 12V battery, a small 150W inverter and a small 5A battery charger.

Charge the battery at home, then take everything to the storage and charge one of the batteries. It takes some time, so maybe leave it overnight. Probably only needed every fortnight or so. I already had a spare battery and a small 5A charger so this was a relatively cheap option for me.

 

[headlight]

To be honest I don’t know. Only had the MH a few weeks so finding my way around the electrics. Dont know where that might be located.

You should have a split charge or else your leisure battery won't receive any charge from your alternator.
If you have a multimeter then take the leisure battery voltage at rest with no load on it and engine off, which if the battery is in good condition should be around 12.7v, then start the engine and check the leisure battery voltage again with the engine running.
That will show you if your leisure battery is receiving charge from your alternator.

 

[FrankNicklin]

You should have a split charge or else your leisure battery won't receive any charge from your alternator.
If you have a multimeter then take the leisure battery voltage at rest with no load on it and engine off, which if the battery is in good condition should be around 12.7v, then start the engine and check the leisure battery voltage again with the engine running.
That will show you if your leisure battery is receiving charge from your alternator.

OK will check over the weekend. Thanks.

 

[headlight]

OK will check over the weekend. Thanks.

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[FrankNicklin]

I have a split charger. Engine running and leisure battery charging at 14.47V. Didn't check the standing voltage but it has the green visual indicator which is green when engine is off.

 

[autorouter]

In the wardrobe behind the EHU socket is the charger and a relay. The relay is mount directly to the back of the wardrobe wall. Not sure if this is the split charge relay.

If you have a multimeter you can find out if the relay is the split charge relay or not. The leisure battery and the starter battery will probably have slightly different voltages, so you should be able to tell one from the other. If that is the split charge relay, it would have two thick power wires and two thin coil wires. The two power wires will go directly back to the batteries - one to the starter, one to the leisure. If the voltages at those wires correspond to the two battery voltages then it's the split charge relay. If one of them doesn't show a voltage then it's a relay for a device, not the split charge relay.

The split charge relay is switched on by the D+ signal from the alternator, when the engine starts. The voltage between the two thin wires will be the D+, and it should be about +12V when the engine is running, and about 0V when the engine is stopped.

I need to work out how to get the Battery Master feed to the VB.

At the split charge relay you have a wire to the leisure battery and the starter battery. That's two of the three wires you need for a BatteryMaster trickle charger. The third wire is a negative, to the chassis. One of those thin coil wires will be a negative to the chassis, if you can't find any other suitable point nearby. The BatteryMaster only takes an amp or so, so thin wire is fine.

 

[FrankNicklin]

If you have a multimeter you can find out if the relay is the split charge relay or not. The leisure battery and the starter battery will probably have slightly different voltages, so you should be able to tell one from the other. If that is the split charge relay, it would have two thick power wires and two thin coil wires. The two power wires will go directly back to the batteries - one to the starter, one to the leisure. If the voltages at those wires correspond to the two battery voltages then it's the split charge relay. If one of them doesn't show a voltage then it's a relay for a device,not the split charge relay.

The split charge relay is switched on by the D+ signal from the alternator, when the engine starts. The voltage between the two thin wires will be the D+, and it should be about +12V when the engine is running, and about 0V when the engine is stopped.

At the split charge relay you have a wire to the leisure battery and the starter battery. That's two of the three wires you need for a BatteryMaster trickle charger. The third wire is a negative, to the chassis. One of those thin coil wires will be a negative to the chassis, if you can't find any other suitable point nearby. The BatteryMaster only takes an amp or so, so thin wire is fine.

I tested today and do have a split charger. The leisure battery is under a seat in the MH and with engine running voltage was 14.47. Obviously engine battery in the engine bay. I need to locate the split charger relay.

 

[Martist]

You'd be surprised how little solar is producing at the moment. I came back from a trip away with my lithiums down to 57%. 3x100W in series and it's barely staying ahead of parasitic drains let alone bring the capacity up. We may have climate change but the sun ain't shining any more. My house panels have produced the lowest output for twelve years. AS Chief Brodie said "you're gonna need a bigger boat panel".

I've just been recording my leisure battery and engine battery voltages over the past days on my drive. I have a single solar panel 140W, connected via mppt to the leisure battery and then via Battery Master to the engine battery. I have various drains on the engine battery such as alarm and tracking but nothing on the leisure battery except for the feed to the Battery Master. In four days my leisure battery dropped from 12.7v to 12.3v and the vehicle battery dropped from 12.3v to 11.9v . So now I'm considering adding a second solar panel and at what wattage to ensure that the vehicle battery keeps a charge to at least 12.3v in cloudy conditions.

 

[Petroleumblownapart]

I've just been recording my leisure battery and engine battery voltages over the past days on my drive. I have a single solar panel 140W, connected via mppt to the leisure battery and then via Battery Master to the engine battery. I have various drains on the engine battery such as alarm and tracking but nothing on the leisure battery except for the feed to the Battery Master. In four days my leisure battery dropped from 12.7v to 12.3v and the vehicle battery dropped from 12.3v to 11.9v . So now I'm considering adding a second solar panel and at what wattage to ensure that the vehicle battery keeps a charge to at least 12.3v in cloudy conditions.

Battery Masters are brilliant BUT..... because it instigates the transfer from hab to engine battery it will stop transfer when the voltages match. This means that if the solar is insufficient (probably on UK in winter) the BM will start feeding the engine again when the engine battery again drops and this gradually drops the hab battery and you end up with 2 flat batteries.
I can't remember the required voltage difference but I think it's approx ½volt. It looks as though your engine battery may be down below the point of no return.
I would suggest charging your hab by plugging into the mains and letting the system do its stuff. Hopefully you may have caught the engine battery in time.
Some funsters have had airbag warnings if the engine battery gets too low but I'm not sure about the finer points of that.
You could go for drive for a few hours depending on your alternator output.
Hope this helps.... Plus maybe others with more experience might also have input for you.
I doubt that an extra PV would guarantee a solution given how poor the UV is in winter.
I've just checked our MPPT and we've managed zero Amps charge for the last 3 days.

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[Martist]

Battery Masters are brilliant BUT..... ...

Thanks for that. It's back on EHU as of yesterday and the engine battery has climbed to 12.33 which confirms that Battery Master is doing its stuff.

 

[Petroleumblownapart]

Thanks for that. It's back on EHU as of yesterday and the engine battery has climbed to 12.33 which confirms that Battery Master is doing its stuff.

Thinking about it.... Maybe if you had left it a bit longer the BM would have triggered.

 

[Martist]

Thinking about it.... Maybe if you had left it a bit longer the BM would have triggered.

Thanks for your thoughts. The leisure battery had dropped from 12.7 to 12.3 without any drain apart from BM, so I believe that the BM was already supplying some current to the engine battery but not enough to surpass the drain on it. Of course, I may be completely wrong . Whatever, with the engine battery down to 11.93 I didn't want to risk it dropping further.

 

[FrankNicklin]

Battery Masters are brilliant BUT..... because it instigates the transfer from hab to engine battery it will stop transfer when the voltages match. This means that if the solar is insufficient (probably on UK in winter) the BM will start feeding the engine again when the engine battery again drops and this gradually drops the hab battery and you end up with 2 flat batteries.
I can't remember the required voltage difference but I think it's approx ½volt. It looks as though your engine battery may be down below the point of no return.
I would suggest charging your hab by plugging into the mains and letting the system do its stuff. Hopefully you may have caught the engine battery in time.
Some funsters have had airbag warnings if the engine battery gets too low but I'm not sure about the finer points of that.
You could go for drive for a few hours depending on your alternator output.
Hope this helps.... Plus maybe others with more experience might also have input for you.
I doubt that an extra PV would guarantee a solution given how poor the UV is in winter.
I've just checked our MPPT and we've managed zero Amps charge for the last 3 days.

The battery master will only work if discharge is less than one amp. The the vehicle battery is dying they the draw will be greater and the BM will not provide charge so shouldn't kill the leisure battery. That said these should only work where there is charge to the leisure battery, if not then it will not be ideal as it will pull the LB down.

 

[Petroleumblownapart]

The battery master will only work if discharge is less than one amp. The the vehicle battery is dying they the draw will be greater and the BM will not provide charge so shouldn't kill the leisure battery. That said these should only work where there is charge to the leisure battery, if not then it will not be ideal as it will pull the LB down.

Most of that is inaccurate. No power is needed to the hab battery as the unit operates on voltage differential NOT any particular voltage. The transfer rate is 1.1A trickle but I'm not sure of the voltage differential. This link explains most....https://www.vanbitz.com/the-van-bitz-battery-master/

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