183 replies to this topic

[rando]

I expect ten years of battery life because I rarely go below 85% S.O.C However having the amp hours to accomplish this also means that when I do run into days of bad weather I'll have enough power without having to fire up the engine or run a generator to avoid running my batteries too low. I do suffer a weight penalty to accomplish this but since I have a big heavy diesel this isn't an issue. If I were driving a half ton truck I'd definitely want to spend the extra for a lithium phosphate battery. 

 

The 50% number is certainly arbitrary but I think its a reasonable compromise. I really like having a large reserve but if that isn't  a concern you certainly could save some money with a single battery.

 

Wouldn't a longer life span also be a little more environmentally friendly?

 

That is the trick right, to get the longer life cycle, you are typically using about twice the battery, so they do last longer, but there is more of them to recycle.    The total number of amp hours you get out of the battery over its life using either depth of discharge is about the same.

[A.Smith]

My question is; How best to connect different gauges of wire ?

My solar panel has a 2 foot piece of 12 garage. I am running 8 awg from the controller to the solar panel.
How best connect these two different gauges ?

Thanks
Fred
A.Smith

[Vic Harder]

Fred, that's a short piece of 12G.  And it will be on your roof, correct?  You want to keep it out of the elements for sure.  A number of methods come to mind:

 

1) Butt connector - the problem is that 8 to 12 is a big jump and the same connector won't likely work for both.  What i've done in the past is to get an uninsulated butt connector and spread the end that is too small before inserting the wire and crimping it.  Insulating it with weather resistant heat shrink.

 

2) Surface mount box.  Another option is a small surface mount plastic box that you can run the wires into, connect via wire nut and then seal with Dicor or a polyurethane caulk.

[A.Smith]

Fred, that's a short piece of 12G.  And it will be on your roof, correct?  You want to keep it out of the elements for sure.  A number of methods come to mind:
 
1) Butt connector - the problem is that 8 to 12 is a big jump and the same connector won't likely work for both.  What i've done in the past is to get an uninsulated butt connector and spread the end that is too small before inserting the wire and crimping it.  Insulating it with weather resistant heat shrink.
 
2) Surface mount box.  Another option is a small surface mount plastic box that you can run the wires into, connect via wire nut and then seal with Dicor or a polyurethane caulk.

Thanks Vic, much simpler than my over engineered wonders.

[PaulT]

On the smaller wire, strip twice as much insulation as you would normally. Fold the stripped portion in half and twist to create a larger diameter end section and use that in your butt connector. It is not ideal but will likely work fine. 

Another approach is to crimp each wire into an appropriate gauge ring connector and use a screw, washers, and nut to connect the two ring connectors. Cover the connection with electrical tape and seal with liquid tape or self vulcanizing wrap or adhesive heat shrink.

 

Or use a step down butt connector like this: https://prowireusa.c...8-to-12-10.aspx

 

Paul

[JaSAn]

I thought wire nuts were a no-no for mobile applications.

 

I used ring terminals and a 2 stud junction block inside a surface box to connect two AWG 12 solar panels to AWG 4 going to my controller.  

Similar to this only for 4 gauge wire:

https://www.summitra...parts/prf-80112

Edited by JaSAn, 05 February 2021 - 02:18 PM.

[A.Smith]

On the smaller wire, strip twice as much insulation as you would normally. Fold the stripped portion in half and twist to create a larger diameter end section and use that in your butt connector. It is not ideal but will likely work fine. 

Another approach is to crimp each wire into an appropriate gauge ring connector and use a screw, washers, and nut to connect the two ring connectors. Cover the connection with electrical tape and seal with liquid tape or self vulcanizing wrap or adhesive heat shrink.
 

Or use a step down butt connector like this: https://prowireusa.c...8-to-12-10.aspx
 
Paul

Thanks Paul.
Your information and suggestions are another example why this Group is so valuable.

Fred

[Vic Harder]

I thought wire nuts were a no-no for mobile applications.

 

Hmm, good thought.

[anthonym]

Thanks for sharing all of this. I'm new to campers and have been concerned about using systems I don't understand. These resources are great. I'm looking forward to tracing the electrical system with Vic's thread pulled up to get at least a working understanding of what's going on.

 

For the AGM discharge discussion, the chart Rando shared in another thread looks more conservative (and perhaps more accurate) than the one for industrial deep cycles. It's still very helpful to think realistically about number of nights/year and general service age of the battery vs discharge cycles. Even at the more conservative cycle numbers here, discharging past 50% won't be an issue for my frequency of use for a long time (even considering degradation of battery over time and increasing likelihood of deeper discharges to get the same Ah).

 

[steve whiteside]

Good info Vic and you are a talented writer!  Looking forward to the rest.  You should be a technical writer!

 

Steve