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jddevel

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  • 2 months later...

OK so bought my busbars from  Furneaux Riddall  real meaty ones-never know what I might add. Now battery housing ( using sealed for now until I can try and manage them properly) is in the engine room immediate the other side of the bulkhead of the electric cupboard with inverter, battery charger and 12 volt /240 volt distribution panels etc.. Distance from the furthest battery to the electric cupboard is 800mm. Is there any problem/reason why the busbars can`t be fitted in the electric cupboard please?

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25 minutes ago, jddevel said:

Is there any problem/reason why the busbars can`t be fitted in the electric cupboard please?

None at all. That's where I'd expect them to be :)

Simply ensure that the feed from the batts to the busbars is sufficiently meaty. What's the maximum current demand?

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53 minutes ago, jddevel said:

OK so bought my busbars from  Furneaux Riddall  real meaty ones-never know what I might add. Now battery housing ( using sealed for now until I can try and manage them properly) is in the engine room immediate the other side of the bulkhead of the electric cupboard with inverter, battery charger and 12 volt /240 volt distribution panels etc.. Distance from the furthest battery to the electric cupboard is 800mm. Is there any problem/reason why the busbars can`t be fitted in the electric cupboard please?

Remember to fuse the positive cable as close as to the battery as possible.   I used a terminal fuse as it's less wiring/neater and as close as to the battery as you can get, but they only go upto 300amp.

If your positive terminal is next to the bulkhead then you could use a normal midi fuse/circuit breaker immediately on the other side of the bulkhead, but I would use cable gland like these http://www.screwfix.com/p/tower-male-comp-gland-black-20mm-pack-of-2/80851 so the cable is secure.

Edited by Robbo
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11 hours ago, WotEver said:

What's the maximum current demand?

Put it this way I`ve 650 amp bus bars currently 520 ah battery bank ( cheap sealed until I learn to manage them) and whilst currently a 3600 inverter, washing machine, 240 fridge, 750 watt micro wave (gas cooker) and currently no hairdrier  but a wife!!! so will put in 95mm squared in anticipation of things "growing"

 

11 hours ago, Robbo said:

If your positive terminal is next to the bulkhead then you could use a normal midi fuse/circuit breaker immediately on the other side of the bulkhead, but I would use cable gland like these http://www.screwfix.com/p/tower-male-comp-gland-black-20mm-pack-of-2/80851 so the cable is secure.

Bearing in mind the above assume 300amp fuse will have to go greater?

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47 minutes ago, DHutch said:

Would you not be better with a fuseboard and or set of breakers.

I thought the bus bars were to service batteries,charger, inverter and alternator and link to the distribution board which in my case is fitted with breakers.

 

20 minutes ago, WotEver said:

At the very least, 400A.

What size would you actually recommend then.

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8 hours ago, jddevel said:

What size would you actually recommend then.

Well, the inverter will potentially draw something like 350A at full output but we don't know what your 12V demands are. If they're modest then a 400A fuse might well be appropriate, if they're heavier then maybe 450A. What you don't want to do is to select a fuse that will be running close to its rating, as that would likely prove unreliable. So probably 400A or 450A. 

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22 hours ago, Robbo said:

 

If your positive terminal is next to the bulkhead then you could use a normal midi fuse/circuit breaker immediately on the other side of the bulkhead, but I would use cable gland like these http://www.screwfix.com/p/tower-male-comp-gland-black-20mm-pack-of-2/80851 so the cable is secure.

I used these 20mm cable glands and found that a 50mm2 cable was a very close fit. Not sure bigger would go through without having to modify the gland, which would compromise its water resistance. Bigger glands can be had for larger cables.

Jen

Edited by Jen-in-Wellies
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16 minutes ago, Robbo said:

Just remember to put the lug on after you’ve threaded the cable through!

Remember those 'unbreakable' rubber plugtops where you had to thread the cover onto the cable prior to connecting the terminals...?

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14 minutes ago, WotEver said:

Remember those 'unbreakable' rubber plugtops where you had to thread the cover onto the cable prior to connecting the terminals...?

Designed by a "Engineer" who quite possibly never left their desk!! Including the thread in them that rarely could be used once and did not always stand up to the repeated removal of the plug from the socket.

 

35 minutes ago, Robbo said:

Just remember to put the lug on after you’ve threaded the cable through!

I`d never do that now would I! Mmmmm

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2 hours ago, WotEver said:

Remember those 'unbreakable' rubber plugtops where you had to thread the cover onto the cable prior to connecting the terminals...?

Yep, most of mine were cut across the 'bridge' but being flexible easy to get the cable through.  

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7 hours ago, WotEver said:

95mm2 cable is about 18mm diameter (http://www.12voltplanet.co.uk/extra-flexible-pvc-battery-cable-95mm-500a.html) so a 20mm gland should be ok. If not, a 25mm gland would be. 

A 20mm gland won't be enough for an 18mm OD cable. The 20mm refers to the outside diameter of the threaded bit of the gland, not the bore for the cable. The root of the thread takes a couple of mm off that diameter, then there is the thickness of the plastic in the gland itself before you get to the bore through the middle that the cable goes through. There is also a lip that the rubber seal seats against that reduces it further. In practice, as I said, I found 50mm2 cable was the maximum that could fit without modifying and perhaps compromising the gland. A bigger gland would be needed for 95mm2 cable.

Jen

Edited by Jen-in-Wellies
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19 hours ago, jddevel said:

Put it this way I`ve 650 amp bus bars currently 520 ah battery bank ( cheap sealed until I learn to manage them) and whilst currently a 3600 inverter, washing machine, 240 fridge, 750 watt micro wave (gas cooker) and currently no hairdrier  but a wife!!! so will put in 95mm squared in anticipation of things "growing"

 

Bearing in mind the above assume 300amp fuse will have to go greater?

PEDANT ALERT !!!!

 

there's a huge difference between 95mm squared (9,025sq.mm.) and 95sq.mm.

 

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36 minutes ago, Jen-in-Wellies said:

A 20mm gland won't be enough for an 18mm OD cable. The 20mm refers to the outside diameter of the threaded bit of the gland, not the bore for the cable. The root of the thread takes a couple of mm off that diameter, then there is the thickness of the plastic in the gland itself before you get to the bore through the middle that the cable goes through. There is also a lip that the rubber seal seats against that reduces it further. In practice, as I said, I found 50mm2 cable was the maximum that could fit without modifying and perhaps compromising the gland. A bigger gland would be needed for 95mm2 cable.

Jen

Yeah, I just checked the size of a 25mm as I suggested and that'd be ok (just):

https://uk.rs-online.com/mobile/p/cable-glands/0564888/

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9 minutes ago, Chewbacka said:

Depending on the thickness of the cable insulation it may be a bit tight, so you may need a bit of lube :giggles:

Well, the gland says 18mm and the cable I found said 17.8mm Max so...

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  • 2 weeks later...

Back to this subject for me. Using the Smart gauge method three(http://www.smartgauge.co.uk/batt_con.html) of balancing batteries ( I`ve 5 leisure so seems suitable) the batteries "housed"  at 90 degrees to the starboard hull on a horizontal shelf on the starboard side and running from cabin bulkhead to stern in the engine room.  The upstand running along the battery shelf would allow me to fix the two bus bars along this upstand in the middle and bring -neg or +pos cables across the top of the batteries to busbars. I have four questions:

1) Is my idea for the location of the busbars acceptable -they are 650amp and housed.They are from Furneaux Riddall 

2) Going to use a 450A fuse (I`ve a 3000 inverter) so can I fix that immediately adjacent to the +pos busbar on the shelf in the 95mm cable take off to the electric cupboard which is the other side of the bulkhead.

3) What size of cable should be used from the batteries to the busbars. Obviously the cable lengths which will be cut to equal length for each positive or negative terminal will differ. Either -neg or +pos being longer dependent on layout.

4) As the batteries can be placed with either positive or negative closest to the hull side is there a recommended preference.

Sorry for all this so early in the morning and I hope I`ve made myself clear with all the questions.

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Hiya,

As long as the busbars are covered and are not in such a position that physical damage is likely (for instance climbing into the engine bay) your position sounds fine. 

Ideally have the +ve terminals closest to the busbars so that there is less likelihood of any damage to those cables. 

Do not cable tie the +ve and -ve battery cables together. Keep the +ves together and the -ves together. 

Cable size depends on load but as you're using 95mm2 elsewhere then why not use it here too?

Hope that helps. 

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