Copper bars

Nov 26, 2008
1,966
Endeavour 42 Cruisin


This showed up on Facebook. Copper bars instead of wire. I would think the jerky motion of the boat under weigh could damage the battery posts unless the batteries are TOTALLY confined with zero movement. No?
 
Nov 14, 2013
200
Catalina 50 Seattle
That looks like a pretty solid installation to me. There's virtually no wiggle room between the batteries themselves or between the batteries and the walls of the compartment. Also, every single terminal is rigidly connected, distributing any forces over a large number of anchor points. It does look like it would be tough to get to some of the watering openings and they're using a Xantrex charger but nobody's perfect.
 
Feb 14, 2014
7,400
Hunter 430 Waveland, MS
I would think the copper bar thickness is the key to stability.

In structural engineering, they would be called "struts" or "cross members" which actually distribute loads more evenly.:thumbup:

Wire is designed to flex and relieve forces.o_O

Your picture looks better for sailing in high seas.
Jim...
 
Oct 26, 2010
1,883
Hunter 40.5 Beaufort, SC
Not sure I like the tread engagement on the battery post nuts though. Looks like only a few threads engaged and I'd be a little worried about them working their way loose since there is not as much "frictional force" with only a few threads involved in the holding. (I don't see any lock washer or other device to ensure it doesn't back off). On the other hand, it is not a structural connection so maybe its not a problem. I'm a nuc and we were always concerned about proper thread engagement. It doesn't have anything at all to do with the buss bars though (other than they are thick which has reduced the available stud length to thread into the nut). I'd have the same problem if it was wires and the stud didn't engage fully with the threads.
 
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Jun 11, 2011
1,243
Hunter 41 Lewes
I think that the exposed sections and nuts would disqualify it from a proper installation.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME


This showed up on Facebook. Copper bars instead of wire. I would think the jerky motion of the boat under weigh could damage the battery posts unless the batteries are TOTALLY confined with zero movement. No?

For a shore based installation copper bar stock is fine, and stationary and off grid systems use them regularly. However on a moving boat they are not a good idea unless the bank can not move one iota of a mm under any and all circumstances. I have seen terminal studs broken due to wire jumpers being too tight and not enough of a gentle curve between batteries. I also saw a Northstar battery that used a solid jumper break the terminal free of the case. These jumpers are supplied only for shore based installations (UPS etc.) yet the owner used them on his boat...

A couple of other concerns in that photo are;

  • No space between batteries for optimal cooling
  • The copper bar stock is too thick for the T105 low profile stud terminals making thread engagement difficult at best..
  • Each nut should have a locking washer or be a nyloc that engages the nyloc portion with stud threads. Trojan has shortened the height of threaded terminals because people were ignoring torque specs too often. T105's can be ordered with taller terminals or the RE style terminals which I prefer when starting from scratch.
  • There are no visible ties downs to hold the battery bank in place other than what appears to be some thin fiberglass walls. What keeps the batts in that compartment in a knock down?
  • Can that compartment hold acid? With flooded batteries we need to provide for acid containment and with a gaping cut out in the right wall for hoses....
  • The cut out in the box for the hoses disqualifies the installation from being considered a battery specific compartment, because it is not a battery specific compartment or enclosure the terminals need terminal boots.
  • Does the compartment have a cover?
  • Spilled liquid and debris covering tops of batteries can lead to ruined batteries from contamination when you open them to service them..
 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Wow. That's at least 1125 Ah at 12V. What kind of boat?
 
Nov 26, 2008
1,966
Endeavour 42 Cruisin
Thank you RC! That is what I was thinking, nice to hear you have seen the evidence of what can happen.
 
Oct 29, 2016
1,915
Hunter 41 DS Port Huron
Shouldn't the temperature connection be under the bar? otherwise it won't be reading correctly.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
Shouldn't the temperature connection be under the bar? otherwise it won't be reading correctly.

Ideally a temp sensor should be on the side of a battery but there are rarely provisions made for this. That sensor however is best where it is, in that install, and like most things battery temp related, it's a compromise. The temp changes will have a slight delay but arguably better than creating a high resistance connection by stacking on top of it. Highest current carrying wire, in this case copper bar stock, goes on the bottom with successively lighter loads on top.
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
Trojan has shortened the height of threaded terminals because people were ignoring torque specs too often.
I just had to ask .................... how does this affect applied torque ? Either too much or too little ?
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
I just had to ask .................... how does this affect applied torque ? Either too much or too little ?
According to Trojan too much and snapping the longer studs off. They "claim" they see less broken studs with shorter studs than longer. Course both the tall version and short version are 5/16"... Perhaps just a way for them to shave .0002 cents off each battery. It has been a real PITA because special ordering T105's with different terminals is more expensive and I can't just grab them out of standard stock...
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
They "claim" they see less broken studs with shorter studs than longer.
Makes sense to me :doh: .................... shorter studs, only half the thread on the nut is engaged, thread strips, and excessive torque is avoided. Maybe a bit of a problem with stripped threads on the studs, but no more broken studs.
 
Oct 26, 2010
1,883
Hunter 40.5 Beaufort, SC
Makes sense to me :doh: .................... shorter studs, only half the thread on the nut is engaged, thread strips, and excessive torque is avoided. Maybe a bit of a problem with stripped threads on the studs, but no more broken studs.
Doesn't make sense to me at all. Since the battery studs are a more malleable alloy (probably a lead alloy) and the nuts are steel (probably stainless) it would strip the stud first as you said. But then, you still have a battery connect that has to be jury rigged to use somehow since the stud is stripped. You just can't slap on a new nut and call it good. You'd have to re-thread the stud, put on a smaller nut or figure some other way to get a solid connection. However, I can't imagine a competent engineer would design it to intentionally not allow full thread engagement with normal installation. If so, the engineer should go back to school. More likely they are designing with full thread engagement and a short stud trying to limit the number of connections by not giving you enough length to keep stacking lug on lug. Or like Maine said, to save a few pennies. Of course this assumes the installer cares about thread engagement at all anyway, which in the case shown above he obviously does not. I really can't imagine that an engineer would design it so that you can't thread the nut completely on the stud with the correct lug on the battery. Consider the consequences if the nut came off and you lost something critical at a critical point. An expert witness would have a field day with that one in a liability courtroom, not to mention the unhappy customers stripping studs and calling the company. As Maine said, the nut should either have a lock washer under it or be a locking nut. You can use a lock washer with partial thread engagement but you can't use a locking nut that way.
 
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Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
Doesn't make sense to me at all. Since the battery studs are a more malleable alloy (probably a lead alloy) and the nuts are steel (probably stainless) it would strip the stud first as you said. But then, you still have a battery connect that has to be jury rigged to use somehow since the stud is stripped.
I believe the studs are SS or tinned copper. It is possible to cross thread them The stud is set into a lead post, depending on how the post is embedded into the lead, it might be possible to over torque the stud and break or loosen the connection between the stud and the lead post. If the post is stripped then one of these guys can be used to connect to the battery. Ancor Tinned Copper Battery Terminal Set If the clamp on terminal is over torqued it can distort the shape of the lead lug and that causes another set of problems.

More likely they are designing with full thread engagement and a short stud trying to limit the number of connections by not giving you enough length to keep stacking lug on lug.
:plus:
 
Oct 26, 2010
1,883
Hunter 40.5 Beaufort, SC
I believe the studs are SS or tinned copper. It is possible to cross thread them The stud is set into a lead post, depending on how the post is embedded into the lead, it might be possible to over torque the stud and break or loosen the connection between the stud and the lead post. If the post is stripped then one of these guys can be used to connect to the battery. Ancor Tinned Copper Battery Terminal Set If the clamp on terminal is over torqued it can distort the shape of the lead lug and that causes another set of problems.
Thanks for the clarification. I appreciate the information. There is a "fix" that can be done so I guess it makes the fix easier but its still a fix, so an alternate method and would have to be done because the original design was hosed up. As an engineer myself, I've never heard of an engineer intentionally designing a threaded connection with less than full thread engagement (the male threaded stud fully through the nut) after installation in the designed connection (including items to be held by the connection if included in the designed installation.)

Any design has to have an acceptable installation spec and I'd bet dollars to doughnuts that if you ask the battery manufacturer or dig deep into the design the nut is designed to be threaded completely onto the stud. Otherwise, how much thread engagement is enough? How would they state it in the spec? Who would decide, "that's good enough for the government?" How would you decide you had enough - count the threads not engaged? Is one thread engaged enough - probably not? How much "friction" is in play to stop unintentional rotation with how many threads? Way to complicated to allow other than a standard designed threaded connection.
 
Oct 26, 2010
1,883
Hunter 40.5 Beaufort, SC
Back to the main topic, sorry for hijacking the "thread." (See the irony there?)

Maine's first post sums it up very well. This is probably not an ideal installation for marine applications on a number of levels. His points, as always, are a good learning tool for all of us. In addition, I might just buy one of those terminal adapters or two as "emergency spares" just in case I "screw" something up (again note the irony there?)

Thanks Maine Sail
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
Doesn't make sense to me at all. Since the battery studs are a more malleable alloy (probably a lead alloy) and the nuts are steel (probably stainless) it would strip the stud first as you said.
The stud posts on batteries by Trojan, East Penn, US Battery, Superior, Crown, JCI etc. etc. etc. are made of stainless steel embedded into the lead. One of the best best options is what some premium AGM & GEL makers offer and that is a female brass alloy insert embedded into internal the lead grid into which you thread a hex bolt. Enersys/Odyssey, Lifeline, Northstar, Firefly etc. all offer this method..
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
If the post is stripped then one of these guys can be used to connect to the battery. Ancor Tinned Copper Battery Terminal Set
If you look at the T105's in the image they are using the ELPT (embedded low profile terminal), which is the most common post the T105 ships with these days. It does not have a second "lead post" that you can connect to as it is nothing more than a small "nub" & not an actual "lead post".

This is why I prefer the EHPT (embedded high profile terminal) which has both a stud and lead post, or the EUT (embedded universal terminal). In the Northeast these are a bit more difficult to get though...
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
Since the battery studs are a more malleable alloy (probably a lead alloy) and the nuts are steel (probably stainless) it would strip the stud first as you said.
Or like Maine said, to save a few pennies.
The stud posts on batteries by Trojan, East Penn, US Battery, Superior, Crown, JCI etc. etc. etc. are made of stainless steel embedded into the lead. :clap: :clap: :clap:
Darn ! ! !
This was just starting to get interesting :hook2:.
 
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