Smartgauge and Adverc battery connections

[plainsman]

I have five domestic batteries, a Smartgauge and an Adverc alternator controller. Currently sensor wires for SG and Adverc Pos and Neg are connected on the same posts as the main 'in and out' terminals respectively on the batteries. This means a number of connections to the same posts. Is there any reason why I should not have these sensor connections made to other batt posts in the bank so as to reduce the number of wires stacked up on one post?

[bottle]

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Edited December 27, 2013 by bottle

[Keeping Up]

I can't comment on the SG connections, but re the Adverc:

 

The Adverc's positive cable is not used in sensing but IIRC it should be as far back towards the alternator output as possible, subject to being on the battery side of any split-charge diodes or relay connection. Its negative connection is (surprisingly) shown in the installation diagram as going directly to the alternator rather than to the battery. Originally the Adverc had only one neg wire but it would tend to go unstable because it was trying to do two things at once so they split the neg connection into two, and I would have expected one to go to the battery neg (for sensing) and one to go to the alternator (for driving the field current), but they made them both black and indistinguishable from each other. I did ask them what would happen if I identified which was which and separated them but I didn't get a sensible answer. I have often wondered whether it would work better if one or both of them was connected directly to the battery negative instead

 

Adverc strangely (I thought) also told me that they advised putting the sensor on one of the battery positive posts, mid-bank, so that half the batteries might be slightly over-charged and half slightly under-charged; my preference on the other hand is to have it at the opposite end of the bank to where you have yours so that the battery furthest from the positive output gets charged to the correct voltage and any voltage-drop in the cables causes a slight over-charge to the others. A slight over-charge can be relatively good for most batteries but can cause a bit of extra gassing, whereas consistent under-charging can lead to sulphation and permanent degradation.

 

Just to add to your woes re the main in/out posts: I assume you have got your batteries balanced by taking the in and out from diagonally opposite corners? If so, did you know you can significantly improve the balance of any bank even further by doubling-up on the two short battery-interconnect cables nearest the in and out corners (ie putting an identical cable in parallel with each one)? For example on a bank of 4, using the diagonal corners reduces the unbalance by a factor of 6, and doubling-up on the two short interconnect cables reduces it by a further factor of 4 (thus achieving a 24-fold improvement over taking them from the same end) but of course it means an extra cable on each of the in and out posts.

[nicknorman]

Provided the battery interconnect wiring is reasonably beefy, it won't make a noticable difference to accuracy if you move the Smartgauge wires to other posts, eg the opposite diagonal.

[plainsman]

I can't comment on the SG connections, but re the Adverc:

 

The Adverc's positive cable is not used in sensing but IIRC it should be as far back towards the alternator output as possible, subject to being on the battery side of any split-charge diodes or relay connection. Its negative connection is (surprisingly) shown in the installation diagram as going directly to the alternator rather than to the battery. Originally the Adverc had only one neg wire but it would tend to go unstable because it was trying to do two things at once so they split the neg connection into two, and I would have expected one to go to the battery neg (for sensing) and one to go to the alternator (for driving the field current), but they made them both black and indistinguishable from each other. I did ask them what would happen if I identified which was which and separated them but I didn't get a sensible answer. I have often wondered whether it would work better if one or both of them was connected directly to the battery negative instead

 

Adverc strangely (I thought) also told me that they advised putting the sensor on one of the battery positive posts, mid-bank, so that half the batteries might be slightly over-charged and half slightly under-charged; my preference on the other hand is to have it at the opposite end of the bank to where you have yours so that the battery furthest from the positive output gets charged to the correct voltage and any voltage-drop in the cables causes a slight over-charge to the others. A slight over-charge can be relatively good for most batteries but can cause a bit of extra gassing, whereas consistent under-charging can lead to sulphation and permanent degradation.

 

Just to add to your woes re the main in/out posts: I assume you have got your batteries balanced by taking the in and out from diagonally opposite corners? If so, did you know you can significantly improve the balance of any bank even further by doubling-up on the two short battery-interconnect cables nearest the in and out corners (ie putting an identical cable in parallel with each one)? For example on a bank of 4, using the diagonal corners reduces the unbalance by a factor of 6, and doubling-up on the two short interconnect cables reduces it by a further factor of 4 (thus achieving a 24-fold improvement over taking them from the same end) but of course it means an extra cable on each of the in and out posts.

 

 

A lot to consider here, as I have five batteries (12345) I have the in/out diagonally opposite but one battery in if that makes sense. That is the pos in/out is on battery No2 and the neg in/out on battery No 4. I think I picked this configuration on the forum or the SG web site. Have I got this right? How does your doubling up suggestion work on my five battery and 'one battery in' connections arrangement? Advice appreciated.

[Keeping Up]

That's a very good setup for 5 batteries. The amount of unbalance would have been twice as bad if you had used the outer diagonal corners or 10 times as bad if you had taken them out of the same end as each other. You could improve it by 25% by paralleling one of the connections to each of the outer batteries (which at least wouldn't increase the number of wires to the in/out posts if you chose the right ones to parallel) or 50% if you paralleled both of each but it's probably not worth the trouble if you've got reasonably thick cables.

 

What you could do is move your Adverc sense wire to the positive end of the same battery as that which has the negative output post, ie move it along by two. That would help you with your original issue of too many cables on the same post while slightly improving the charging, at no cost.

[plainsman]

That's a very good setup for 5 batteries. The amount of unbalance would have been twice as bad if you had used the outer diagonal corners or 10 times as bad if you had taken them out of the same end as each other. You could improve it by 25% by paralleling one of the connections to each of the outer batteries (which at least wouldn't increase the number of wires to the in/out posts if you chose the right ones to parallel) or 50% if you paralleled both of each but it's probably not worth the trouble if you've got reasonably thick cables.

 

What you could do is move your Adverc sense wire to the positive end of the same battery as that which has the negative output post, ie move it along by two. That would help you with your original issue of too many cables on the same post while slightly improving the charging, at no cost.

 

My cables are 70mm, I note you suggest may not be worth the trouble. What I will do though is shift the Adverc sense wire as you suggest. Going back to my original post I'll leave the Smartgauge sense where it is. Thanks for your help