connecting battery's (1 Viewer)

[freelanderuk]

i have just had a 85amp battery replaced under guarantee, at the moment i have 2 85amp battery's connected each with their own connection lead and a 85watt solar panel , i have another 85amp battery that i took of the boat and have the room to store this and connect it up also to the MH,

question is would i be better connecting them all together and just using 1 lead or connect 2 on 1 lead and the 3rd on the other lead ,
what size cable to use if i connect them all together
thanks

 

[madbluemad]

Have a look at this thread.

Link Removed

Jim

 

[freelanderuk]

thanks, i have had a read of that but it does not really answer my question , would i be better connecting all the 3 battery's in parallel or 2 in parallel on 1 lead and the 3rd on its own lead ?
thanks

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[madbluemad]

Try emailing Clive at: clive@motts.org

Its a bit ott for me
Jim

 

[scotjimland]

thanks, i have had a read of that but it does not really answer my question , would i be better connecting all the 3 battery's in parallel or 2 in parallel on 1 lead and the 3rd on its own lead ?
thanks

Hi

The longer the cable the bigger the volt drop, and if you have two batteries together and one further away there will be a charging imbalance.


You will get the best performance if the are all connected together in parallel with short connecting cables.. or links.

Use the same cable in all links and keep them as short as physically possible.. this will keep the volt drop to a minimum..


hth

jim

 

[Terry]

Hi if you connect all 3 together then they will all charge at the same time ie solar / hook up and engine :thumb:Why would you want to separate one ? unless you think you need a e,emergency stand by That would need a independent charger.
terry
Forgot to say use thick cables ( earth strap size if poss )with fuses and keep them as short as poss
EDIT Jim beat me to it

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[madbluemad]

This diagram gives an idea of what Jim is talking about.
http://www.motts.org/second leisiure battery.htm
Jim

 

[freelanderuk]

Hi

The longer the cable the bigger the volt drop, and if you have two batteries together and one further away there will be a charging imbalance.


You will get the best performance if the are all connected together in parallel with short connecting cables.. or links.

Use the same cable in all links and keep them as short as physically possible.. this will keep the volt drop to a minimum..


hth

jim

thanks Jim
the length of the links will have to be about 24" due to getting the battery's in and out of there storage ( back of an autotrail near where the spare wheel goes) all three battery's will be here so i will have leads from my MH panel to 1st battery 24"links to 2nd battery 24"links to 3rd battery , what size cable please and i understand that there has to be a fuse on each +ve

Hi if you connect all 3 together then they will all charge at the same time ie solar / hook up and engine :thumb:Why would you want to separate one ? unless you think you need a e,emergency stand by That would need a independent charger.
terry
Forgot to say use thick cables ( earth strap size if poss )with fuses and keep them as short as poss
EDIT Jim beat me to it

i have 2 connector leads to the MH panel for 2 separate battery's, so was thinking 1 battery on 1 and 2 on the other
thanks

 

[scotjimland]

thanks Jim
the length of the links will have to be about 24" due to getting the battery's in and out of there storage ( back of an autotrail near where the spare wheel goes) all three battery's will be here so i will have leads from my MH panel to 1st battery 24"links to 2nd battery 24"links to 3rd battery , what size cable please and i understand that there has to be a fuse on each +ve

Yes, they need to be fused at both ends as per the drawing Jim posted.. I would buy fused battery terminals rather than in line fuses.. l

You need 25sq mm flexible automotive battery cable ..

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[madmick1945]

Buy a cheap set of jump leads and use that cable -less loss

 

[scotjimland]

Buy a cheap set of jump leads and use that cable -less loss

less loss ???

cheap jump leads are probably only 16mm , and even cheaper plastic..

this application requires 25sq mm automotive cable

don't skimp on battery cables.. buy the right size and quality for the job , if you have any doubts about size use an on-line cable calculator such as AEI or seek qualified professional advice.

 

[freelanderuk]

i have just been reading about connecting up banks of batteries here http://www.smartgauge.co.uk/batt_con.html seams very informative , was thinking about using method 2 or 4 , whats your thoughts on this
thanks

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[scotjimland]

i have just been reading about connecting up banks of batteries here http://www.smartgauge.co.uk/batt_con.html seams very informative , was thinking about using method 2 or 4 , whats your thoughts on this
thanks

Method two is the better .. it's how my four were connected on the RV

as the author says ...

It is simple to achieve but the difference in the results are truly astounding for such a simple modification.

ps.. good link

 

[pappajohn]

i have just been reading about connecting up banks of batteries here http://www.smartgauge.co.uk/batt_con.html seams very informative , was thinking about using method 2 or 4 , whats your thoughts on this
thanks

looking at the diagrams in your link i would put money on the first one being the most popular and widely used method even though the author says its just laziness or incompetence that would dictate this method.

strikes me the author is a bit of an anorak and the actual difference in connection method wont really be noticeable.

personally I'd connect all three pos to pos, neg to neg and allow your charger/solar to charge all three simultaneously.
as others have said....a fuse at BOTH ends of each pos lead.

 

[scotjimland]

looking at the diagrams in your link i would put money on the first one being the most popular and widely used method even though the author says its just laziness or incompetence that would dictate this method.

It is the better way John, have a look at an electric fork lift battery , golf cart or any other piece of kit with cells / batteries and see how it's done .. check your own RV .. I bet it is connected as Method 2

In Method 1, the batteries will not charge or discharge equally .. they won't give their best.

ok, I grant you may not notice if you never use them to their full capacity, ie always on EHU ... but if you want the maximum performance and battery life .. Method 2 is far better.

In a new install or rewire why would you choose to do it otherwise ?

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[freelanderuk]

i have found where i can get the leads made up but can not find any fuse holders for 25sq mm cable or fused cable clamps, any ideas please
cheers

 

[BobProperty]

i have found where i can get the leads made up but can not find any fuse holders for 25sq mm cable or fused cable clamps, any ideas please
cheers

Proper car audio places e.g. Link Removed
For advice search through the forums on http://www.talkaudio.co.uk/vbb/index.php especially the General Car Audio and the Sound Deadening and Fabrication sections.

 

[olley]

i have found where i can get the leads made up but can not find any fuse holders for 25sq mm cable or fused cable clamps, any ideas please
cheers

Hi you want a "Mega" 40 amp fuse and in-line fuse holder will take up to a 40mm cable, see here. http://shop.ebay.co.uk/?_from=R40&_trksid=p3984.m570.l1313&_nkw=mega+fuses&_sacat=See-All-Categories

Olley

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[BobProperty]

25mm and 40mm cable will take a lot more than 40amp. Need to do some calculating as to fuse sizes. Sorry but busy at present so quick reply.

 

[olley]

The idea of using much smaller fuse's than is necessary to protect the cable, is that it is to protect the battery's from each other. You only need a big enough fuse for the maximum likely habitation loads. For RV's the situation is different as they usually have a relay to allow the habitation batteries start the engine, so much bigger fuses are called for.

Clive in his schematic shows 25amp fuses, but getting large cables sizes to fit in fuse holders of that size is difficult.

Olley