car battery

[colin-yorkshire1]

hi all,
I am thinking of changing the 110amp Lumax lesuire battery that has been on the van for the last 5years and is now past it's best, for a car type one, primarily because it will be lighter and better for the mover "it's main use" we allways use EHU so a slow discharge lesuire type seems unessasary it takes 15mins of constant use "with the mover" to get the van in and out of the garage, so I think a change may be benificial,
any thoughts or recommendations welcome,
colin

 

[otherclive]

Just changed a 7 year old Elecsol for the same (100) cost just over £100 inc delivery from Tayna. For my Sorento I bought a Varta fromTayna again and the CCA was around 700-800 if I remember right. Bags of kick on cold days the Sorento sounded like a gas turbine until it fired into life that is!!

 

[waffler]

I am unsure about the technology but know that batteries for movers are different. I think a car battery gives about 300 amps for about 10 seconds. Your mover takes up to 60 amps for 15 minutes. That high current for so long is pertinent. I have today bought a new 100 amp hr for my mover. We also rally so run it down. My trusted dealer advised what to have and asked if there is a mover. I'd take advice. The last battery only lasted 9 years although only used for leisure.

 

[colin-yorkshire1]

hi guys, there are two ways to my thinking one is the present battery will need changing this year as it is past it's best and as the battery box is well forward of the axel and adds to the nose weight which I have to reduce by 30kg for the new car the 110amp is a fair old lump so a ligher one should help a bit, second I am sure I read somewhere that car type batteries are better where a inital high power discharge is needed and then recharged, and is different to a leisure battery that prefers a slow discharge and top up,
all I need is a the right battery that will give 60amps for 15 mins followed by a minimum of 2 hours charge (via the car) before it is used again,

edit.
I know that in the old days before EHU's and vans had ther own batteries and we had to power the van via the blue aux wire off the trailer plug, the van would flatten the car battery in 2 or 3 days if the car was not run in between but with modern electrics this should not be a problem as it would be on constant charge from either the car or the EHU once the mover has been used,

 

[tessandan]

if you look on tayna.co.uk there is a section on motor mover batteries. It needs both amp hours, and a good high current short burst ability.
This one is on my shopping list (although I don't have a motor mover yet - but it will happen!)
http://www.tayna.co.uk/Numax-Caravan-Motor-Mover-Battery-P7706.html

 

[ChrisUK]

This is the battery that we have, I think this typre of battery is sometimes called a "marine" battery as it will provide large cranking current for a boat deisel and also is happy with deep (ish) discharge.
Our Numax also has a pair of wing nut terminals which I find useful to connect the solar panel controller.

 

[JohnGriffiths]

Fully agree with your choice of a car/ traction battery Colin. I've been using a fairly small one now on our 1500kg van without any problems for over 3 years. As some have said, a marine battery may be better, but you will certainly pay a lot more for it.

 

[ProfJohnL]

Leisure vs Starter batteries for movers,

I think there is a lot of misunderstanding regarding the type and capacity of battery required to run a caravan mover.

There are two main factors you need to match. The first is the peak current draw for the mover, The battery must be capable of supplying this current, and then there is the total power used by the mover when in use, which is often far less than you might imagine.

All dc motors have a high stall current when the motor is trying to get going, but as soon as the motor starts to spin the current demand falls quite dramatically to the normal operating current. Unless the motor is jammed, the transition from Stall to operating will take less than a second.

So when the motor is trying to start you get the "Stall" current, and when the motor is moving it will use a lower "operating" current. It is not uncommon to find a 10:1 or bigger ratio for the stall current compared to the operating current of the mover.

Most motor manufacture do not quote "stall" currents but will provide operating currents. So to work out the stall current multiply the quoted current by ten to obtain a rough estimate for the stall current

The battery peak current capacity of the battery needs to match or exceed the stall current. In car battery parlance is the Cold Cranking Amperage (CCA) or Peak Current.

The total current (Ah) used by the mover is less than you may think, because it is generally used for short periods of time. Taking Colin's figure of 15Min and even his quoted current usage of 60A (more on this in a moment) As he is only using it for 15min or a quarter of an hour this means his Ah usage is 60A for 1/4hour = 15Ah Put into context that is one internal 12V fluorescent lamp running for 10 hours

It is more than likely that Colin is over estimating the current he is using, as the 60A is the motor working at full capacity for the whole period which will be the max weight of caravan being driver up a 1:4 or 25% gradient continuously. It if far more likely that much of the time the motors will be drawing much less than the 60 probably more like 15A so the power used now falls to 15A for 1/4hour = 3.75Ah (lets be generous) 4Ah

So you don't need a big battery to run a mover, only one that can meet the motors Stall current. If a battery can supply a peak current of 600A there should be no problems.

 

[colin-yorkshire1]

hi all, thanks for the replies, it's all good stuff. and well aprecieated the trouble with marine batteries and to some extent lesuire batteries is the weight one thing I am trying to reduce, a car battery seemed a sensible option due to using EHU's all the time.and they are a lot lighter.
while the Prof,s explaination is more detailed than I had calculated for my self and yes I think 60amps is a bit of a over estimation, I figured the max load (written on the control box) was a good starting point, I have no idea how but also had arrived at a 600amp figure 60x10 =600 the battery on the meriva is quite small in comparison to the lesiure battery but has 800amp written on the label.
what I think I will try on my next dayoff is using the battery off the car and see if there is enough capacity to get the van out and back in the garage there should be but it will be running the mover for about 25mins (not all the way to the front road,
if all is well I will have at least a good starting point.
I will keep you all posted how it goes and what I decide to do.
thanks again colin