Battery Master Alternative ??

[Marauder]

I've replaced batteries that are just a year old where people have followed that advice.

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So the calculation I have to make is, which is preferrable:

Replace a battery every year - £80 ?
or
use my time, energy, fuel, tyres, mileage depreciation, etc etc, to drive the thing for 90mins every 2 weeks for 6-8 months of the year when I'm not actually travelling in it ?
(6-8monthsx2=12-16 unneccessary journeys @ 100m ea = 1200-1600miles per year?)
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[Marauder]

don't assume it is ok to connect a potential +20V source to a 12V battery because it isn't very sunny!

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ok
thanks for insight
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[autorouter]

So do you think one of these: https://www.ebay.co.uk/itm/29268267...d=link&campid=5338547443&toolid=20001&mkevt=1 which WOULD fit inside my available sunlight patch,
drive one of these: https://www.ebay.co.uk/itm/25468541...d=link&campid=5338547443&toolid=20001&mkevt=1 and give any meaningful yield ?

This panel is 1.5W. I think it would be inadequate for your purposes. It would be better to get a 10W or even a 20W panel if it will fit behind the window and not have a shadow on it.

A 10W solar panel with an Open Circuit Voltage of 19V is not like a charger or power supply outputting 19V.

For a 12V battery that's not fully charged, if you apply a current of 1A, it will not raise the voltage of the battery very much. It doesn't take much voltage rise to allow a current of 1A into the battery. So the battery will pull down the solar panel voltage to a lot less than the open circuit voltage.

For a large panel capable of outputting much more amps, it's a different matter, the voltage can rise to dangerous levels, especially as the battery becomes nearly full. But a 10W panel on a big leisure battery can't really do much damage, especially in winter.

The voltages seen in the graphs are the input to an MPPT controller, and the controller is manipulating the voltage and current to keep the panel at its maximum power point, so the battery won't be seeing that voltage at all. (MPPT = Maximum Power Point Tracking).

As for feeding it into a solar controller, the problem with very low power panels (10W or 20W) is that the controller takes a small amount of power to run it, and that's 24/7, so the panel might not make much more than the solar controller consumes. So I think either a 10W panel direct to the battery, or a 50W panel through a controller.

 

[Hoovie]

if the battery IS fully charged (which may well be the case at some time) the voltage could sit much higher than is comfortable for the battery.
I prefer a "fit and forget" solution that encompases all possibilities, not one that is relevant or appropriate for one, but bad for another, but whatever.

 

[Marauder]

I prefer a "fit and forget" solution

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Me too, - Thats exactly what I have been trying to achieve - fit it, (a solution) and not have to drive van every 2 weeks.

But sadly, it's not looking likely that I'll find a perfect configuration !
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[autorouter]

A possible but expensive solution is to use a 'portable power station' - a battery pack with built-in inverter and charger. You can take it home and charge it, then leave it connected to the EHU inlet to recharge the leisure and starter batteries. It may have other uses to kind of justify it, like keeping the freezer and gas heating on if there's a power cut.

When I had this problem I used a spare 12V battery that I already had, with a small charger, and bought a small 150W inverter. I ferried this between house and MH when I thought it needed a charge, every couple of weeks or so.

 

[Marauder]

I ferried this between house and MH when I thought it needed a charge, every couple of weeks or so.

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There are stairs to my place, and no adjacent parking. I already lugged existing HabBatts home to test them, but had to buy a 'sack truck' for the job.

However, you sparked an idea: maybe keep a spare batt in boot of everyday car, and charge it during normal driving activity.

Now thats worth some thought . . . .
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[Steve and Denise]

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There are stairs to my place, and no adjacent parking. I already lugged existing HabBatts home to test them, but had to buy a 'sack truck' for the job.

However, you sparked an idea: maybe keep a spare batt in boot of everyday car, and charge it during normal driving activity.

Now thats worth some thought . . . .
_

Maybe get someone to do this for you if you are not familiar with the solar and charging before you do some damage

 

[autorouter]

There are stairs to my place, and no adjacent parking. I already lugged existing HabBatts home to test them, but had to buy a 'sack truck' for the job.

However, you sparked an idea: maybe keep a spare batt in boot of everyday car, and charge it during normal driving activity.

Now thats worth some thought . . . .

If I had that problem now, I'd be thinking about a CTEK CS Free. I came across it in a thread by davida71uk. It will charge a 12V battery directly from another 12V battery.

It will also charge from the mains if you want. The inbuilt battery power pack is maybe OK for starting an engine, but has a very small capacity if you were thinking about transferring sizable chunks of power between home and MH. About 5Ah I think. However the ability to charge a battery from another battery is very useful here, and a rare bit of functionality.

 

[headlight]

Marauder my take on this.
For £550 less fun discount and a free night on Cornish Farm Site Vanbitz will fit a 100 watt panel, Victron smart 75/15 MPPT and battery master.
Leisure batteries kept topped up over winter, starter battery kept topped up and depending on the weather about 40amps solar a day in summer.
Problem solved.
I had the above fitted last May and didn't need to use EHU from having it fitted till October including a 24 consecutive night off EHU trip.
We are light electric users though.
In fact I'm going to Vanbitz on Monday to have a Sterling B2B and Victron smart shunt fitted.
With the way electric prices are going it seems a good investment to me and also opens up more opportunities for using the van.
Just my thoughts.

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[Emmit]

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There are stairs to my place, and no adjacent parking. I already lugged existing HabBatts home to test them, but had to buy a 'sack truck' for the job.

However, you sparked an idea: maybe keep a spare batt in boot of everyday car, and charge it during normal driving activity.

Now thats worth some thought . . . .
_

Long, long ago, I had a battery (it was a car battery) in a box with a 7 pin caravan connector wired to it.
In the boot of the car, attached to a relay were a pair of wires connected to a 7 pin caravan socket.

When connected, the car provided a charge to the battery and when on a caravan site, provided electricity to the caravan without using the cars own battery.
This was in the days when Caravans did not have an on board battery.

 

[davida71uk]

If I had that problem now, I'd be thinking about a CTEK CS Free. I came across it in a thread by davida71uk. It will charge a 12V battery directly from another 12V battery.

I sent the unit back I had bought as it would not AC charge. It was on for 19 hours and still flat. What also fell short on the Free (imo) is the lack of an interchangeable lead between croc clips and eyelets. CTEK claimed this was due to the 20A rating required for the boost feature but NOCO make a 20A rated eyelet lead. Now I take a Bluetti ACMax out to the storage barn and have an AA maintainer wired to the engine battery with eyelet connectors. Via the Sterling B2B this also charges the leisure batteries. The Bluetti is a 2048wh unit so weekly I can have the MH batteries on charge in covered storage for c. 16 hours. Admittedly the Bluetti is a fair wedge in cost and it weighs around 20kg but I've SORN'd the MH and don't have to run it out in horrendous winter weather.