jump leads

[dreadnought]

hi all,is it acceptable to add an extra battery to the existing battery bank via car jump leads,there are three 130 amp battery's in the existing bank now ,asking for a friend,many thanks

 

Just to add a bit of background, there are three batteries in the bank,300 watts of solar,but still having to run engine twice a day to top batts up,so he is going to pop another battery in the bank to get through the summer, tia

Edited June 19, 2022 by dreadnought
More information

[Alan de Enfield]

NO

[Tony Brooks]

4 minutes ago, dreadnought said:

hi all,is it acceptable to add an extra battery to the existing battery bank via car jump leads,there are three 130 amp battery's in the existing bank now ,asking for a friend,many thanks

 

As Alan says NO. However, the question suggest there is a lot going on that you have not told us so if you want better advice please explain the background to the question.

 

The BSS (let alone the RCD/RCR ISOs) require a minimum of 25 sq mm conductor cross-sectional area cabling for batteries and the majority of easily available jump leads are really toys, some that are not much more than wire type ignition leads. That is before the dangers associated with croc clips that van easily jump off and short out, causing a fire.

 

[Tracy D'arth]

Just saying as a friend, NO.

 

Put proper battery connectors on with crimped on lugs on both ends of 25mm positive and negative cables.  Connect to the existing battery connections with leads as short as sensible. Ensure the extra battery can vent its fumes outside. Put an insulated cover over the terminals.

[LadyG]

I would have thought any sensible person would know it's unacceptable, dangerous and totally bonkers, your friend needs help!

[frahkn]

1 hour ago, dreadnought said:

hi all,is it acceptable to add an extra battery to the existing battery bank via car jump leads,there are three 130 amp battery's in the existing bank now ,asking for a friend,many thanks

 

Just to add a bit of background, there are three batteries in the bank,300 watts of solar,but still having to run engine twice a day to top batts up,so he is going to pop another battery in the bank to get through the summer, tia

Unless I've misunderstood you, this would not only be dangerous but futile. If the solar is not topping up 3 batteries it will top up 4 even less.

[MtB]

1 hour ago, dreadnought said:

hi all,is it acceptable to add an extra battery to the existing battery bank via car jump leads,there are three 130 amp battery's in the existing bank now ,asking for a friend,many thanks

 

 

As always, what do you mean by "acceptable", and to whom? 

 

Do you mean will it pass a BSS? Do you mean your insurance will still pay out if there is a fire? RCD? 

 

Acceptable to yourself presumably or you would not be asking the question! 

[Tony Brooks]

2 hours ago, dreadnought said:

Just to add a bit of background, there are three batteries in the bank,300 watts of solar,but still having to run engine twice a day to top batts up,so he is going to pop another battery in the bank to get through the summer,

 

Now you have added that we can see the problem is one of the following:

 

Using more electricity than the installed solar can provide each day

Battery bank not large enough for the amount of electricity being used - but I think is no so likely.

Batteries now beyond their useful life. Either sulphated by long term under charging or now have shorting cells. I think this is the most likely without seeing the boaters power audit. Fitting a new battery in this case will just ensure that he will ruin that one as well.

 

 

Edited June 19, 2022 by Tony Brooks

[ditchcrawler]

2 hours ago, dreadnought said:

hi all,is it acceptable to add an extra battery to the existing battery bank via car jump leads,there are three 130 amp battery's in the existing bank now ,asking for a friend,many thanks

 

Just to add a bit of background, there are three batteries in the bank,300 watts of solar,but still having to run engine twice a day to top batts up,so he is going to pop another battery in the bank to get through the summer, tia

It still wont get him through the day. You only get out what you put in, well a bit less actually.

[Tony Brooks]

39 minutes ago, ditchcrawler said:

It still wont get him through the day. You only get out what you put in, well a bit less actually.

 

And that is  why a power audit is needed and then some rough charging regime calculations to ensure you can actually all but fully recharge the batteries once a week and to over about 80% charged each day.

 

Putting more batteries into a system that is never getting fully charged is a sure fire recipe for rapid battery destruction.

[David Mack]

You should be taking the connections from the diagonally opposite corners of a bank of batteries. So if you are going to increase a bank of 3 to a bank of 4 you need to move the existing takeoff connection at one end to the 4th battery and add new connections between both terminals of the new battery to the corresponding terminals on the adjacent battery.

And adding a new battery to an existing bank of older batteries is almost never a good idea.

[LadyG]

Not an expert, but he probably has old batteries which are needing replaced, all batteries in one bank are likely to be in same state of old age, but is it possible he has been replacing them one at a time, or is it possible he has not been checking water levels, or is it possible one cell has developed a fault?

See Tony Brooks, refer to his website and the battery primer on here.

Edited June 21, 2022 by LadyG

[Tony Brooks]

1 hour ago, LadyG said:

or is it possible one cell has developed a fault?

 

Yes, a shorting cell in one battery connected to others in parallel will discharge all the batteries. Although I think it is probable the whole bank is faulty it could be just one. However, just adding a new battery to a bank with shorting cells will just wreck the new battery as well.

 

Sulphated batteries give a faster charge but an equally fast discharge.

Shorting cells give a slower charge but a faster discharge.

 

This is when it is a good idea to monitor the battery performance daily, so you know what is normal and can recognize when it is not normal. Just a decent voltmeter and ammeter is good enough once you know how to interpret the values.

[George and Dragon]

On 19/06/2022 at 12:10, Tony Brooks said:

Putting more batteries into a system that is never getting fully charged is a sure fire recipe for rapid battery destruction.

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[ditchcrawler]

On 19/06/2022 at 09:18, dreadnought said:

,asking for a friend,many thanks

 

No asking for trouble