12v Power

[Verteuil Man]

Hello fellow Funsters.

I have read quite a bit about off grid power (we do rallies in fields) and before converting to a motorhome I would have a couple of 110 ah batteries in the caravan with a solar panel. In those days lead acid with factory fitted charging systems. All would be fine until this time of year with shorter day time and less sun to give any meaningful charge. I found that the batteries would last about 3 years. Main power drain being television, lighting, water pump and gadget charging.

Move on now to our motorhome. We have a 2017 Hymer with 2 110 ah Varta sealed lead acid batteries. When we are not on EHU after watching television for a couple of hours on Friday the voltage is down to 13 volts. By Sunday 12.5 volt. I am looking to replace the batteries next year after we return from Spain and the sun drops below the yard arm, but what with?

I am 68 in January and I will have to apply for my C1 in 2 years. There should be no reason not to get it, but you never know. Spending north of a grand on Lithium batteries does not add up as you rarely recover money spent on accessories. Lead acid are a direct swap but I have read a bit about AGM which seem to be a step up? If I fitted 2 AGM batteries will the factory fitted 12 volt charging system work with them? There are also solar panels but I assume they plumb into the moho electronics.

Any thoughts in simple terms would very much be appreciated.

 

[MisterB]

i thnk you will find that lithium batteries have come down a hell of a lot in price - from what i understand (and if im wrong i am sure someone will correct me) a 105ah lithium is about the same in terms of useable capacity as you would get from 2 x 110ah lead batteries.

Fogstar have a 230ah lithium battery for £720 - so a lot further south than your £1000 thinking .... with a 230ah you should get twice as much available power as you currently have (again someone will correct me if i am wrong)

 

[Lenny HB]

I assume your van has the Varta LA batteries as the original AGM's failed, AGM's are pretty useless as leisure batteries.
The Elektroblock charger in a 2017 Hymer will have charging profiles for Gel & AGM. I assume the Varta batteries you are Varta LFD's these are one of limited number of sealed LA that are OK to charge on the Gel settings.

From your voltage reading I would say your batteries are still good for a few years.
If you are going to change them I would change them for Gels.

 

[Verteuil Man]

I assume your van has the Varta LA batteries as the original AGM's failed, AGM's are pretty useless as leisure batteries.
The Elektroblock charger in a 2017 Hymer will have charging profiles for Gel & AGM. I assume the Varta batteries you are Varta LFD's these are one of limited number of sealed LA that are OK to charge on the Gel settings.

From your voltage reading I would say your batteries are still good for a few years.
If you are going to change them I would change them for Gels.

Thank you Lenney HB.

 

[Nedge68]

Unfortunately Varta have stopped making the LFD90 they are now making LED95. AGM batteries do not seem to be suitable as a leisure battery, please read the info a available here…

Battery Technology Advances mean big savings and better batteries for Caravans/Motorhomes

The best Leisure Battery is also one of the cheapest - Powerframe Varta LFD90 and Bosch L5. A Deep cycling and Starter battery in one.

www.aandncaravanservices.co.uk

lots of good info here on chargers battery types, etc

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[pappajohn]

If you still have 12.5v on Sunday from Friday I would leave as is....
12.6v is fully charged at rest.

 

[autorouter]

There are also solar panels but I assume they plumb into the moho electronics.

Not sure what you mean here. Are you saying there are some solar panels on the MH now, or that you are thinking of the possibility of fitting some?

You say the voltage goes from 13V to 12.5V so you have some means of measuring the battery voltage. A battery 'at rest' (ie not loaded and not being charged) will have a voltage of between about 12.7V (full) and about 12.0V (as flat as you should let it go). If it's 13V or more, then something is charging it. That's why I think you might have solar panels.

A charger usually actively charges at about 14.5V, and then drops to about 13.5V when float charging, which keeps the battery topped up without overcharging.

To keep the batteries in top condition, you should get them to 100% state of charge regularly, at least once a month, or every fortnight is better. Regular charging to 100% disperses the sulfation that otherwise gradually accumulates, degrading the battery capacity. If you look after the batteries they will last a lot longer than 3 years.

 

[Verteuil Man]

Not sure what you mean here. Are you saying there are some solar panels on the MH now, or that you are thinking of the possibility of fitting some?

You say the voltage goes from 13V to 12.5V so you have some means of measuring the battery voltage. A battery 'at rest' (ie not loaded and not being charged) will have a voltage of between about 12.7V (full) and about 12.0V (as flat as you should let it go). If it's 13V or more, then something is charging it. That's why I think you might have solar panels.

A charger usually actively charges at about 14.5V, and then drops to about 13.5V when float charging, which keeps the battery topped up without overcharging.

To keep the batteries in top condition, you should get them to 100% state of charge regularly, at least once a month, or every fortnight is better. Regular charging to 100% disperses the sulfation that otherwise gradually accumulates, degrading the battery capacity. If you look after the batteries they will last a lot longer than 3 years.

Thanks for all that. I have 2 100 watt panels fitted. What I was eluding to was that the output from the panels would be connected to a device (not a lot of electrical knowledge) then to the batteries either directly or through the fitted charging system. Would that be compatible with AGM?

The moho is at home and plugged on EHU in winter. The panels keep it topped up in summer.

If we are not in Spainbfor a 90 day trip we are out most weekends and touring around to see friends in the UK. It only stands for 3 months in summer when we areb8n France at our house.

 

[autorouter]

Your Hymer will have an 'Elektroblock' (EBL), which is a box with fuses and electrical gizmos that distributes the 12V power from the leisure batteries to where it is needed. This box also contains a charger powered by EHU, that charges the batteries when EHU is plugged in.

The EHU charger is a 3-stage intelligent charger with an output optimised for the battery type. It continually monitors the battery voltage and amps. It actively charges the battery if it needs it, and when it is 100% full it drops to 'float mode', at about 13.5V, which keeps the battery topped up without overcharging.

Another thing inside the EBL is a relay that automatically connects the leisure batteries to the alternator when the engine is running, and disconnects when the engine stops. So your leisure batteries are being charged while driving. A 'relay' is an electrically operated switch.

Solar panels go through a solar controller box, which makes the solar panel output suitable for charging the batteries, and prevents any overcharging. The solar controller isn't inside the EBL, it will be a separate small box somewhere, with a few blinking LEDs.

 

[Verteuil Man]

Your Hymer will have an 'Elektroblock' (EBL), which is a box with fuses and electrical gizmos that distributes the 12V power from the leisure batteries to where it is needed. This box also contains a charger powered by EHU, that charges the batteries when EHU is plugged in.

The EHU charger is a 3-stage intelligent charger with an output optimised for the battery type. It continually monitors the battery voltage and amps. It actively charges the battery if it needs it, and when it is 100% full it drops to 'float mode', at about 13.5V, which keeps the battery topped up without overcharging.

Another thing inside the EBL is a relay that automatically connects the leisure batteries to the alternator when the engine is running, and disconnects when the engine stops. So your leisure batteries are being charged while driving. A 'relay' is an electrically operated switch.

Solar panels go through a solar controller box, which makes the solar panel output suitable for charging the batteries, and prevents any overcharging. The solar controller isn't inside the EBL, it will be a separate small box somewhere, with a few blinking LEDs.

Well, I understand a lot better now.

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