Lithium ion batteries

Mar 14, 2005
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Anticipating the need for a new leisure battery quite soon, I read the article in the current issue of the magazine (Replace your lead acid batteries with lithium ) with interest
However, after several re readings I a not much the wiser.
Questions :
Are Li-on batteries good with motor movers - article quotes inverter supplied microwaves as high demand loads, quoting an inverter powered microwave as a typical 'heavy load' This may be true off-grid, but for the majority the peak load is likely to be the motor mover. The article also suggests that the internal BMS could be limited at 50 amps 12v.
Motor movers I have used have a supply fuse rated at 100 amps, implying the peak load can be way above 50 amps. 40 amps is quoted as the normal draw for both motors running together.

Are the chargers built in to most current caravans suitable/ safe for charging lithium batteries. So far as i could see, the article indicated that they ' needed consideration' which , frankly, is not very helpful.

Finally, apart from the reduced weight what is the cost/benefit calculation given that the normal life of the lead acid leisure battery is, conservatively, 4 years and the cost in the region of £80 - 100.

I have every confidence that some reader will have the answers but I would not be adverse to saving some battery weight as i now find lead acid 110 amp hour pretty difficult to remove and reposition.
 
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JTQ

May 7, 2005
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The first point needing consideration is "are you normally an off EHU camper"?
If no, then improving on battery storage performance is far less important as you don't really have a storage issue.
Basically motor movers ask very little of a battery, the energy they take is pretty small and given careful selection a much more modest capacity one than a 110 Ah will do what most need of it. Unless you have a very long uphill climb requirement from the battery. If the chosen battery does what the mover needs, then it is up to the job whatever size it is labelled as being.
If a regular demanding off EHU camper the arguments for going Lithium get far easier to make.
 
Nov 6, 2005
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Movers can take 90+amps at start up - an inverter-powered microwave will be higher at over 100 amps and run for longer.
 

JTQ

May 7, 2005
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Movers can take 90+amps at start up - an inverter-powered microwave will be higher at over 100 amps and run for longer.
Yes and even a quite small battery can output 90 Amps easily, and even if the mover sustains that high drain for 5 minutes it only saps 7.5 Ah. In reality the current backs off as the van moves unless hauling uphill or out of the quagmire.

Makes lugging a 110Ah battery for no more than running a mover rather an overkill and questions why the suppliers advise such big batteries.
[I hauled my 1900 kg van with a 70 Ah traction battery, up my drive, it lasted about 9 years doing so]
 
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Mar 14, 2005
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Sorry but my original point stands. The mover may not take many watts /per operation but on start up a mover trying to move a heavy van off a muddy field can take a higher current than 50 amps. Otherwise the makers would not have fitted a 100amp fuse.and used the large section cable they do between battery and control unit. I am not usually ' off grid' but would be happy to save say 1/3 of the weight of the leisure battery because it would make things easier for my 84 year old body to lift.
 
Nov 6, 2005
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Yes and even a quite small battery can output 90 Amps easily, and even if the mover sustains that high drain for 5 minutes it only saps 7.5 Ah. In reality the current backs off as the van moves unless hauling uphill or out of the quagmire.

Makes lugging a 110Ah battery for no more than running a mover rather an overkill and questions why the suppliers advise such big batteries.
[I hauled my 1900 kg van with a 70 Ah traction battery, up my drive, it lasted about 9 years doing so]
Until recently, most leisure batteries were just car batteries with different stickers - so unsuitable for high current drain for more than a few seconds - your traction battery would cope so much better.
 

JTQ

May 7, 2005
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Until recently, most leisure batteries were just car batteries with different stickers - so unsuitable for high current drain for more than a few seconds - your traction battery would cope so much better.
Yes, something I have long been aware of, so purchased appropriate batteries for the tasks required.

In respect to Leisure batteries, IMO the late John Wickersham's Power Players back in 2010 is as true today as it ever was.
 
Mar 14, 2005
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Until recently, most leisure batteries were just car batteries with different stickers - so unsuitable for high current drain for more than a few seconds - your traction battery would cope so much better.
Whilst I can't confirm or deny that caravan batteries may have been car batteries with different labels, I suppose it depends on teh make and model, but the other part of your post about current capacity is misleading.

Car batteries as you suggest are designed to provide short burst of high current for cranking the starter motor. Starters motors usually have very high current demands. It not uncommon to see cold cranking capabilities of batteries rated in hundreds of Amps and continual current ratings in the order of 60 to 100A even on quite small batteries.

Batteries with that capability will have no trouble running a caravan mover, where most models have a peak (stalled) current of about 40A per motor, and when actually turning the current demand will usually fall to less than 50% of the peak load.

Several mover manufacturers have designed soft start control systems to keep the peak currents lower.

Typically a caravan mover is used for about 5mins whilst a caravan is sited, The use is often intermittent and as a result the averaged power needed position a caravan will often only consume 1 to 2 Ah of battery capacity.

If you only use sites with hookup's then a small car battery will probably more than enough for your need for the mover.
 
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May 7, 2012
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We have been using a 70 amp battery to power the motor mover on our caravans and it works over the short distances we have used it. The battery though has failed after about six years and so I am wondering if a bigger one might have done better. The main use has been in the storage site where the gap you have to hit is far smaller than on site.
 
Nov 11, 2009
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I've tended to keep with 100+AH as on a number of occasions I have had to extract the caravan from muddy CL/CS sites and had no alternative but to decouple the car and drive it out on its mover. To make it easier I do reduce the noseweight and one time I rotated the van to reduce the nose wheel digging in, and moved it out in reverse over quite a long distance up a slope until its wheels were on the hard track. Fortunately we had been on EHU so the battery was well charged to cope with the evolution. But if you always use hard standing a smaller battery would be fine.
 

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