Battery charger cable's

[Roger S]

We collected our Carthago van a couple of month ago, I have fitted our Fogstar 230a Lthium battery and it is working well but the installed charger ( CBE CB516 ) is not suitable for Lithium so I ordered a Victron Blue Smart IP22 Charger 12/30 1, & some 16mm2 cable to run from the charger to the Carthago control panel. I have only just thought that the cables from the Carthago control panel to the battery may not be suitable for the possible 30a from the new charger as the original one was a 16a charger. I would appreciate your thoughts please.

 

[DavidG58]

My honest opinion is that if you need to ask you need to get the job done by someone that does know

I don’t have a clue but wouldn’t dream of taking that job on one of my fears of buying a used motorhome is that it will have been ‘worked on’ by someone who didn’t know and didn’t ask

I do hope it goes well for you though, but wonder if the money saved is worth the risk

 

[daveandsan]

That cable should handle 55 amps if it is 16mm2, how long is the run of cable?

 

[tonyidle]

My honest opinion is that if you need to ask you need to get the job done by someone that does know

I don’t have a clue but wouldn’t dream of taking that job on one of my fears of buying a used motorhome is that it will have been ‘worked on’ by someone who didn’t know and didn’t ask

I do hope it goes well for you though, but wonder if the money saved is worth the risk

Like many, many, so-called experts. And in some cases the constructer.

 

[Roger S]

That cable should handle 55 amps if it is 16mm2, how long is the run of cable?

The 16mm cable is from the charger to the Carthago control panel, that will be fine, its the original cable that goes to the battery that I am unsure about.

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[daveandsan]

The 16mm cable is from the charger to the Carthago control panel, that will be fine, its the original cable that goes to the battery that I am unsure about.

I would put 8 awg cable in.

 

[autorouter]

The 16mm cable is from the charger to the Carthago control panel, that will be fine, its the original cable that goes to the battery that I am unsure about.

Does the new cable from the charger go to the B2 terminal of the distribution box? If so, does the cable from the B2 terminal to the leisure battery look as if it is similar in thickness, or thicker? If so, then it is probably OK.

The amps from the alternator/starter battery to the leisure battery goes along that cable, so it should be similar to the 30A from the new mains charger. They are not both supplying amps at the same time, so the cable should be OK.

 

[Hoovie]

another thing to consider is the size of the terminals. I haven't checked but I would be surprised if you could get a 16mm2 cable onto an IP22 terminal? It would be way over the top anyway unless your battery is incredibly far from the charger or has a amazingly convoluted cable run.
6mm2 or 10mm2 would be fine with the likely distance it has to run sending 30A through it.

 

[Roger S]

Does the new cable from the charger go to the B2 terminal of the distribution box? If so, does the cable from the B2 terminal to the leisure battery look as if it is similar in thickness, or thicker? If so, then it is probably OK.

The amps from the alternator/starter battery to the leisure battery goes along that cable, so it should be similar to the 30A from the new mains charger. They are not both supplying amps at the same time, so the cable should be OK.

Thanks for the reply.

1. Yes the cable does go to the B2 terminal and it does look the same size.

2. How could one check if it is operating safely? I imagine the cable would get hot/melt if it had too much current running through it.

3. To Benin the safe side should I connect straight to the battery with the 16mm2 cables and plug the charger into a nearby onboard socket?

Thank you Roger

 

[autorouter]

2. How could one check if it is operating safely? I imagine the cable would get hot/melt if it had too much current running through it.

Cables are normally sized so that the voltage drop when the full current is flowing is less than about 3%. That is to ensure that there is no noticeable drop in performance of the device that the wire is powering. If you do the calculations you will find that if the voltage drop along the cable is 3% or less, the heat generated is well within the specification of the cable. That's why people talk about voltage drop rather than worrying about safe amps limits.

The voltage drop depends on the maximum amps, cable length and the thickness (actually the cross-sectional area in square millimetres). There are a number of online calculators to find the voltage drop, for example this one:

Voltage Drop Calculator | 12 Volt Planet

Use our Voltage Drop Calculator to select the correct Cable for your campervan, motorhome or boat wiring application. Auto and Marine Electrical Components from 12 Volt Planet - Cable Size Calculator

www.12voltplanet.co.uk

As an example, 2m of 16mm sq copper wire in a 12V system will have a voltage drop of 1.26%.

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[Tombola]

To Benin the safe side should I connect straight to the battery with the 16mm2 cables and plug the charger into a nearby onboard socket?

yes, this works, with the added benefit of easy to remove if/when you sell along with the battery.
just take the fuse out or discon the old charger

 

[Lenny HB]

If you are fitting the Victron unit in place of the CBE the cable run will be very short and 10 mm sq cable will be more than large enough it is rated at 70 amps.

 

[Roger S]

If you are fitting the Victron unit in place of the CBE the cable run will be very short and 10 mm sq cable will be more than large enough it is rated at 70 amps.

That was the plan Lenny. However the CBE is in the garage and the battery is in the floor just to the rear of the passenger seat, so the run will be over 5 metres.

 

[Lenny HB]

That was the plan Lenny. However the CBE is in the garage and the battery is in the floor just to the rear of the passenger seat, so the run will be over 5 metres.

But it already has heavy cables to the CBE unit which is where you will be connecting to.

 

[Roger S]

But it already has heavy cables to the CBE unit which is where you will be connecting to.

And that Lenny is why I shouldn't be allowed out on my own

I didn't put 2 and 2 together, so the B2 cable in the control box goes straight to the battery terminal so all is well.

Thank-you

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[GMLS]

yes, this works, with the added benefit of easy to remove if/when you sell along with the battery.
just take the fuse out or discon the old charger

I'm also fitting an IP22 to by pass the CBE.Rather than having a trailing cable I've managed to get a 3x Mate N Lock which I was just going to fit to the Victron cable and connect straight into the power cable that feeds the CBE unit here lower right.Assume that is just as good a solution?