# Mixing amps ? (Batteries)



## moblee (Dec 31, 2006)

I know this has been done to death but I have searched & not found the real Answer  

I have been offered a 85A Two year old Leisure battery (From a caravan).

Right my Question CAN I connect this to a equal quality 110A to create (basically) one big battery.

Are there any conflict issue's with charge cycle's,one bringing the other one done or anything like that ?

I like a Answer from the Experts please  

Thanks


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## DABurleigh (May 9, 2005)

Moblee,

You CAN do.

The penalty is you will curtail the life of both batteries to some extent.

http://www.motorhomefacts.com/ftopicp-82120.html#82120
http://www.motorhomefacts.com/ftopicp-386443.html#386443
http://www.motorhomefacts.com/ftopicp-1007264.html#1007264

Dave


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## rayc (Jun 3, 2008)

*Re: Mixing amps ?*



moblee said:


> I know this has been done to death but I have searched & not found the real Answer
> 
> I have been offered a 85A Two year old Leisure battery (From a caravan).
> 
> ...


The answers you may get from the experts may be so detailed, contradictory and confusing that you may be better off asking a layman.
They may tell you that you shouldn't do it as both batteries should be the same age, capacity and general state otherwise al sort of things could happen. The first may be that you lower the capacity off the 110ah one.
When I saw the topic title I thought we were going to have a great discussion on studio amplifiers.
Ray


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## Zebedee (Oct 3, 2007)

From a non-expert, but pragmatic standpoint . . . . .

. . . . how cheap are they Phil?

That's the deciding factor as far as I can see.

There are no safety issues, so if they are cheap enough in the first place who cares if their life is shortened a bit! :wink: 

Dave


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## clive1821 (Mar 27, 2010)

Yes Ray I see your point thourght it was going to be on amplifiers studio, stage etc... still I now see the point..... just as a matter of interest I have mixed batteries 90Ah 70Ah and 110Ah and they still work, but if I were asked in my working capicity I would always advise same type and same capacity as I would on this site, mind you the van is a power hungry van and I can have flat batteries in a day or so.... its better when we get the sun in the summer and then all is better with the pannels doing something like work... looking forward to Romsey soon.....


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## MiketheWelshman (May 1, 2005)

Simple answer, if you do, the larger battery probably wont fully charge,and, if the smaller battery is on its last legs,it will effect the other, in short, you could end up with less capacity than you already have. All this assumes that you couple the two batteries to the same charge source. You could charge one from the mains via a seperate unit and just use it for the telly,say.
Mike


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## andrewball1000 (Oct 16, 2009)

Why link them? Others may prove to you that two batteries in parallel will give you longer duration, however this may be outweighed by the imbalance of amps and the risk of one duff cell in one battery pulling down the other. 

You don't have matched batteries and the cost of the gizmos to combine the two might be better put into buying matched batteries.

You do have a freebee so if you want to use it, why not keep it separate but use the low tech battery1 battery 2 switch to use/charge one then the other. You may not get the duration but you will always have a full spare when the other is flat.


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## Daedalas (Nov 12, 2009)

I did what AndrewBall1000 suggested and I have an older 85 AH lead acid which came with the Medallion and a new 110 AH gel which I had recently bought - so I went the switcheable route. Either one or the other is in circuit at any one time but never both together. 

The marine switch I used for the job does have the capability of switching both on together but I avoid doing that for all the reasons mentioned.

When one battery is getting low I have the security of knowing the other is available: I just need to remember to switch over and charge the flat one as and when we find an EHU or on the next move.

Works grand so far.


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