# What Ah Leisure Batteries can I use?



## JayBe (Jul 17, 2010)

Hi everyone

I am seeking some advice concerning the maximum Ah of Leisure Batteries I can fit on a new Rapido. I think the standard battery fitted is either a 100 Ah or 110 Ah Banner Energy Bull.

I want to fit a 135 Watt Monocrystalline Solar Panel and I want to upgrade to two Banner Energy Bull 115/135 leisure batteries (95901). A dual- battery charge controller will be used.

However, I have been told that I cannot fit different Ah batteries because the vehicle (Fiat) alternator is only 100A and any Ah size more than the standard leisure battery fitted, will " mess up" the Rapido Control panel.

I previously had a Rapido, which was fitted with a 120 Watt Solar Panel and I fitted two 125 Ah Elecsol leisure batteries. I never had any trouble.

Perhaps Listerdiesel and Techno100 can give some advice please as I have seen some very helpful advice on similar topics.

John


----------



## Penquin (Oct 15, 2007)

I have never heard of a limit imposed by the vehicle alternator and will also look forward to responses by listerdiesel and Techno100 whose opinions are always useful.

AFAIK the maximum output would be irrelevant as the batteries would never be completely flat and therefore would never require maximum charge, the charge that an alternator gives is dependent on the voltage that it detects I believe and is variable as the batteries are charged, although I believe the vehicle battery takes precedence.

I have fitted 2 x 100ah batteries and there have been no problems that I am aware of.....

I believe that the batteries fitted may require resetting on the habitation control panel, but that may only be the TYPE of battery e.g. gel or wet.....

so, like you, I will look forward to seeing responses.

Dave


----------



## listerdiesel (Aug 3, 2012)

I think that Dave has pretty much said it above, there's no real reason not to fit a second battery, the alternator works with what it sees at its terminals, it has no way of 'knowing' what batteries are fitted.

If you are buying anything bigger than 100W 36-cell solar panels, be careful you don't get a 48-cell panel, most controllers won't work with higher than 36 cells.

Peter


----------



## JayBe (Jul 17, 2010)

> "be careful you don't get a 48-cell panel"
> 
> Peter
> 
> ...


----------



## JayBe (Jul 17, 2010)

Hi Peter

My last was meant for for you ( I am a novice).

I've checked www.cleversolar.co.uk and the 135 Watt panel has 48 cells. Their 100 Watt panel only has 32 cells, does that cause a problem?

We wild/free camp where possible for most of our travels. We don't have a TV, so just LED lights, water pump and water heater fan. Do you consider a 100 Watt solar panel with two 100 or 110 Ah leisure batteries is sufficient?

John


----------



## Penquin (Oct 15, 2007)

To some extent it very much depends on the weather and your location.......

I fitted 2 x 80w panels and they work well keeping the batteries topped up, our consumption is probably heavier than yours as we use a colour TV and satellite dish (or did before they changed the satellites), but of course we are in the South of France so even on cloudy days our intensity is higher than yours would be in the UK.

If however we were using them in the UK in mid-winter (you know, like May last year :lol: ) the intensity is much less so they may not give as much charge, but if you fit one, you can fit a second later if you have the roof space.

Dave


----------



## listerdiesel (Aug 3, 2012)

The reference to the number of cells is significant as a lot of controllers won't take more than 33V input, and shut down if this is exceeded.

They will withstand up to 50V or so, but are not working at that voltage, they are shut off, so 36 cell is the way to go, unless you can find an MPPT controller that is fully functional at the higher voltage.

Peter


----------



## Pudsey_Bear (Sep 25, 2008)

I have a 100w panel, a MPPT controller and 2 x 125ah LBs, we also have TV, and a PVR, fridge fans, inverter, LED and halogen lighting, & a coffee grinder, I don't expect to run out of power when we're wild camping, which is always.

I have a CTEK 5a charger as it's only used on the drive, so no need to charge overnight, the panel gives slightly less than that at about 4a max.

The way I looked at is so long as I am matching or beating my usage over 24 hours the LBs will be fine, as we rarely stay more than 2-3 days anywhere there will a charge from the alternator, which unless you had a massive battery bank will kick in most of the charge, depending on how far you drive of course.

Not sure just how much charge a 50 mile drive would produce, it'll be variable depending on the terrain and speed I suppose, one for Peter I think


----------



## listerdiesel (Aug 3, 2012)

It's a bit of string jobbie.

Assuming a 100A alternator and revs of the engine up at 2000+, you'll get a steady 70-80A into the battery if that is what the alternator senses it needs.

So a 10 mile drive at a brisk speed will see 30AH or more into the battery.

Peter


----------



## Pudsey_Bear (Sep 25, 2008)

I think it's a 150a Peter.


----------



## listerdiesel (Aug 3, 2012)

That's pretty high, the Discovery is 130A, but 1998/99, so the increased use of electronics, aircon etc etc propbablt requires an even bigger alternator.

At 150A output it would pretty much charge your 110AH in about an hour's running, longer if two in parallel.

The thing that is missing on short runs is the last 10-15% of charge, which is important. If you start with 110AH and only recharge to say 85% full, then your next evening starts off with 85% of 110AH, which 93.60AH. As long as you keep bringing it back to 85% of full charge with a longer run every couple of days, no problem.

Peter


----------



## JayBe (Jul 17, 2010)

*What Ah leisure batteries*

Thankyou for all the feedback so far.

Whilst the majority of solar panels seem to be 36 cell (correct me if I am assuming wrongly), and 48 cell panels appear to be a No No for motorhomes, are 32 cell solar panels OK to use?

Anyone using cleversolar panels or the Bosch cell solar panels sold by photonic universe? The latter are apparently made in China using Bosch cells, shipped to London and then sold worldwide. A lot cheaper than cleversolar which use cells produced in the U.S.A..

John


----------



## listerdiesel (Aug 3, 2012)

The number of cells in a panel dictates the output voltage of the assembly, and at just over 0.5V per cell it can be reasonably accurately worked out in advance what you will get out.

36-cells give 17 - 19V
48-cells give 23 - 25V
72-cells give 34 - 38V

If the output exceeds the safe 'working' input for the controller, it will shut down to protect itself, so although the panel might be fine on a typical UK sunny day, it may overvolt in very strong sunlight.

The Maximum Solar MPPT controller that many of us use has a maximum working input voltage of around 33V. I have tried two 36-cell panels in series with it and it shut off, so 72 cells is definitely too many.

48-cell panels may well be OK, but I have no information on these in use that I can put forward to confirm that they are OK to use.

Similarly, the use of 'Bosch' branding on products appears to be a little strange as they don't appear to have produced such panels themselves.

Peter


----------



## Pudsey_Bear (Sep 25, 2008)

listerdiesel said:


> That's pretty high, the Discovery is 130A, but 1998/99, so the increased use of electronics, aircon etc etc propbablt requires an even bigger alternator.
> 
> At 150A output it would pretty much charge your 110AH in about an hour's running, longer if two in parallel.
> 
> ...


Oh dear, we're in black art country again, as I have 2 x 125ah LBs, so they'll need longer.

This 85% thing Peter, won't that depend on how much I've discharged them?

Is there a way to measure how many AHs they have in them, not important I suppose I just wondered if you could, I have a switchable LCD volt meter using an old Zig switch panel I got for the lights and pump etc.


----------



## listerdiesel (Aug 3, 2012)

You don't need to know the percentage, just keep an eye on the terminal volts.

Don't let it go below 12V, preferably not below 12.4 or so.

Peter


----------



## JayBe (Jul 17, 2010)

Thanks for your input, Peter, but you do not mention 32 cell (solar) panels. Are they unusual and not normally fitted to motorhomes or even suitable?

By the way, somehow - lack of knowledge..... I started this thread in the Morocco section. My apologies to whom it may concern.

John


----------



## listerdiesel (Aug 3, 2012)

32-cell panels won't have sufficient output for 12V charging.

Peter


----------



## JayBe (Jul 17, 2010)

*What Ah leisure batteries*

That has certainly narrowed the field, but does not take into consideration the numerous users of 2 x 80W and 2 x 100W panels. What do such users have as dual battery charge controllers?

John


----------



## Pudsey_Bear (Sep 25, 2008)

*Re: What Ah leisure batteries*



JayBe said:


> That has certainly narrowed the field, but does not take into consideration the numerous users of 2 x 80W and 2 x 100W panels. What do such users have as dual battery charge controllers?
> 
> John


You just connect them up together in a junction box, so long as the watts/amps do not exceed the controller, there is no problem.


----------

