wyattamdahl
New Member
I am connecting two 200ah lithium batteries. What size wire do i need to connect these two?
Battery connector cables
- Thread starter wyattamdahl
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It depends on how much current you wish to draw from them or put into them. are you connecting in parallel or in series?
wyattamdahl
New Member
They will be in parallel drawing a max of about 250amps
check out this resource. If you have about a 5 foot run it says 4 Awg would give you about a 5% drop in volts. You can plug in numbers as you wish and it will tell you the drop for different wire sizes and lengths.
https://diysolarforum.com/resources/best-wire-size-voltage-drop-calculator.33/
https://diysolarforum.com/resources/best-wire-size-voltage-drop-calculator.33/
Bob142
Build more, learn more.
For battery to battery connections, I'd go bigger. 2/0 between batteries if you're using 90C insulation rated wiring. 1/0 if 105C insulation rated. Based on ampacity standards in ABYC. Bigger is better if you can afford it.
John Frum
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@wyattamdahl
Unless this is on a boat or possibly in some environment that is conducive to corrosion you don't need marine grade wire.
2/0 awg is right on the edge of what you need.
You could go bigger.
How did you determine you require 250 amps?
wyattamdahl
New Member
if i was to be running everything at once it would be around 230 amps. So i rounded up to 250
The very best welding cable has 90 deg c insulation. Using welding cable you have to "size up" from recommended marine cable AWG. Marine cable, from quality supply house, is Coast Guard required for any marine use and is consistent in its quality. We throw the dice when buying welding cable, the actual quality can vary. I am not saying you can't use welding cable. Just that marine grade is better and the same cost or less. 1/0 marine is the exact awg you need. I use 2/0 cable from Genuine Dealz. https://www.genuinedealz.com/products/custom-battery-cable-marine-grade-by-the-foot
I use welding cable for everything. I really have no clue as to it's temp rating but if you get above about 130 F I think you have other problems
John Frum
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105 celcius is not even a premium feature for welding cable.
Electrical - Wire - Welding Cable - Page 1 - TEMCo Industrial
temcoindustrial.com
Bob142
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Behold! Southwire Royal Excelene 1/0 welding cable rated to 105C:105 celcius is not even a premium feature for welding cable.
Electrical - Wire - Welding Cable - Page 1 - TEMCo Industrial
My point is welding cable is fine if the wire you bought from Amazon by some accident was premium wire. Check some of the stuff sold by Bob's Curbside Welding Supply.
I use marine standard as it is the same quality from my 2 or 3 suppliers. The marine grade 105C dry, 75C wet, with a UL stamp. Then I know what is going down the road.
I use marine standard as it is the same quality from my 2 or 3 suppliers. The marine grade 105C dry, 75C wet, with a UL stamp. Then I know what is going down the road.
If you are in US came across welding cable some of which is UL listed and 34AWG strands on this page: https://www.wireandcableyourway.com/welding-cable/.
Also thought it was interesting that the Southwire Royal Excelene non-UL listed cable is rated for 105C but uses 30AWG whereas the UL listed version is 90C and. uses 34AWG.
Also thought it was interesting that the Southwire Royal Excelene non-UL listed cable is rated for 105C but uses 30AWG whereas the UL listed version is 90C and. uses 34AWG.
Samsonite801
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I actually bought 25ft of this same cable from this seller and it was good quality:
What cable strippers should you use with these cables? The one I have has the blade stick out that you adjust to cut the insulation but there is nothing to stop it from cutting the conductor itself unless you have it precisely adjusted. For the stiff cables this doesn't cause an issue but for these cables I'm sure it would cut those thin wires.
John Frum
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For my stationary application I am using these wires with mechanical lugs.
When bent it stays bent.
It also tends to stand off the backing board without assistance.
For 1 awg - 2/0 awg I like https://www.servicewire.com/Products/XH-CT.htm
For <1awg I like stranded thhn which is cheap and readily available at your nearest big box store.
The biggest problem is that 2/0 awg of either is pretty hard to cut.
I strip it with my high leverage cutters without issue.
When bent it stays bent.
It also tends to stand off the backing board without assistance.
For 1 awg - 2/0 awg I like https://www.servicewire.com/Products/XH-CT.htm
For <1awg I like stranded thhn which is cheap and readily available at your nearest big box store.
The biggest problem is that 2/0 awg of either is pretty hard to cut.
I strip it with my high leverage cutters without issue.
Hedges
I See Electromagnetic Fields!
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I score the insulation by gently gripping with wire cutters and swinging them around the cable. Or a razor blade.
Then I bend the cable and watch it split open at the cut.
If you lose a few strands that isn't a huge issue. The remaining copper can carry the current, and after some distance of contact, current will spread into the cut strands so all cross section is used and IR drop is kept low.
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