dewilso Posted August 6, 2019 Report Share Posted August 6, 2019 I’m putting 4x Battle Born batteries in my RV. The batteries will be end to end, parallel wired. I'll use 2/0 cable from the batteries to the inverter. Now.... one end of the bank along with cables will be 50" longer than the other, is this a problem ? What gauge cable should be used between the batteries ? Thanks Quote Dave W. KE5GOH Stuck in the 70's --- In E. Texas Link to comment Share on other sites More sharing options...
jcussen Posted August 6, 2019 Report Share Posted August 6, 2019 For my 6 BB's used 2 AWG from each battery to positive and negative bus bars, and 3/0 from each bus bar to inverter. https://www.wiringproducts.com/battery-cable Quote Foretravel 40ft tag 500hp Cummins ISM 1455 watts on the roof, 600 a/h's lithium in the basement. Link to comment Share on other sites More sharing options...
oldjohnt Posted August 7, 2019 Report Share Posted August 7, 2019 If you mean say the final cable from the POS to Inverter is 50" longer then the final cable from the NEG, that's no major concern. Of course, the bigger the cable the less line voltage drop, so size your cables to limit voltage drop to whatever you find acceptable. The absolute MINIMUM wire size I suggest is 125% of the maximum continuous current AND THEN UPGRADE AS NECESSARY TO REDUCE VOLTAGE DROP...…... Sorry, I cant suggest your cable sizes sitting here not knowing the current and wire length...….. HOWEVER and most don't realize this, to insure EACH battery receives equal charging and EACH battery supplies an equal amount of load current, its best if you do as the Smartgauge suggests (iffffffff THEIR results, not mine, are accurate???). They have four examples (with detailed test results) of different methods to connect multiple batteries in parallel ranging from better to best BUT this takes more cables and connections mind you. Its NOT for everybody except those sticklers who want each of their batteries to last and function the same and not let a couple do most of the heavy lifting. Take a look at their test results versus different connection methods ITS QUITE SURPRISING !! SURE a simple old straight ladder parallel connection will "work" there are likely hundreds of such out there and all "working". But if better battery load and charging balance is important and in order to protect such a huge investment in Lithium batteries, one might want to consider a connection method to achieve more equal charge and load balance (be it their own method or as Smartgauge suggests) among multiple batteries. NOTE I support any RV owners to wire as they wish, its their RV their money and their choice NOT ANY OF OURS so wire as you see fit. http://www.smartgauge.co.uk/batt_con.html Take a look, don't take my word for it (those are NOT my tests or results, no warranty mind you), then make an informed decision that's best for YOU. John T Quote Link to comment Share on other sites More sharing options...
jcussen Posted August 7, 2019 Report Share Posted August 7, 2019 The smartgauge method #3 Is the same method I used. Using an amprobe on each battery cable shows loads pretty equal. I still have a smartgauge wired in, worked on my lead acids, but not on my lithiums. Still makes a good voltmeter though. Quote Foretravel 40ft tag 500hp Cummins ISM 1455 watts on the roof, 600 a/h's lithium in the basement. Link to comment Share on other sites More sharing options...
oldjohnt Posted August 7, 2019 Report Share Posted August 7, 2019 JC, With my small 29Ft Class C and modest energy requirements I only have three AGM batteries in parallel (520 Amp Hours) so am currently configured with the SmartGauge Method 2, but am considering the improved Method 3 like you used. It just takes more cable and connections. If I was investing several thousand in batteries I would for sure want them connected so each shares the load equally. Our local Interstate Battery shop makes up great looking cables including crimped soldered then heat shrink terminations in all sizes and colors. Of course, any simple ladder method (ton of them out there) still "works". To each their own. Nice chatting with you John T Quote Link to comment Share on other sites More sharing options...
dewilso Posted August 7, 2019 Author Report Share Posted August 7, 2019 I’ll be using the #2 method, as I have in the past with good results. This install will be in my class B so space constraints are the biggest concern. Thanks Quote Dave W. KE5GOH Stuck in the 70's --- In E. Texas Link to comment Share on other sites More sharing options...
hemsteadc Posted August 8, 2019 Report Share Posted August 8, 2019 Parallel batteries each supply 1/4 of the amps. You can size cable accordingly. Quote Link to comment Share on other sites More sharing options...
Kirk W Posted August 8, 2019 Report Share Posted August 8, 2019 On 8/6/2019 at 5:21 PM, dewilso said: Now.... one end of the bank along with cables will be 50" longer than the other, is this a problem ? You could attach the battery cables into the center of the bank in order to minimize the distance differential. Quote Good travelin !...............KirkFull-time 11+ years...... Now seasonal travelers.Kirk & Pam's Great RV Adventure Link to comment Share on other sites More sharing options...
$ Spot Posted August 8, 2019 Report Share Posted August 8, 2019 15 minutes ago, Kirk W said: You could attach the battery cables into the center of the bank in order to minimize the distance differential. That's Method #3 in the link mentioned above... http://www.smartgauge.co.uk/batt_con.html Spot Quote Link to comment Share on other sites More sharing options...
Sehc Posted August 9, 2019 Report Share Posted August 9, 2019 I have my 690 ah golf cart batteries connected with 2/0 awg. All the interconnecting cables must be the same. I used method 3. All the positive are the same length. All the negatives are the same length. Negs don't have to be same as pos. I used Blue Sea terminal fuse blocks on the positive battery. These; https://shop.marinehowto.com/products/blue-sea-marine-rated-battery-fuse Quote Link to comment Share on other sites More sharing options...
hemsteadc Posted August 9, 2019 Report Share Posted August 9, 2019 2 hours ago, Sehc said: I have my 690 ah golf cart batteries connected with 2/0 awg. All the interconnecting cables must be the same. For series wiring yes, for parallel, no. Quote Link to comment Share on other sites More sharing options...
Sehc Posted August 9, 2019 Report Share Posted August 9, 2019 method two. All the interconnecting positive cables must should be the same length. All the interconnecting negative cables should be the same length. The positives do not have to be the same length as the negatives. Always use a catastrophic fuse on the positive battery. Quote Link to comment Share on other sites More sharing options...
Ray,IN Posted August 9, 2019 Report Share Posted August 9, 2019 Battery configuration has been addressed. Battery cable terminals are often overlooked, when left open to the air, they can corrode inside where they are crimped to the cable, this is unseen and unnoticed until a problem arises. There are approved methods to seal the terminal connections to prevent corrosion. Quote 2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG retired;Good Sam Life member,FMCA ." And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country. John F. Kennedy 20 Jan 1961 Link to comment Share on other sites More sharing options...
Sehc Posted August 12, 2019 Report Share Posted August 12, 2019 It is always good to review this article from Rod Collins. https://marinehowto.com/making-your-own-battery-cables/ Quote Link to comment Share on other sites More sharing options...
hemsteadc Posted August 12, 2019 Report Share Posted August 12, 2019 (edited) On 8/9/2019 at 2:28 PM, Ray,IN said: There are approved methods to seal the terminal connections to prevent corrosion. It's a non-issue with AGM or Li batteries. Ok, I know someone will say my terminals corroded using AGMs, so I better say "I" never had any corrosion with my AGMs, and certainly not with Lis. Edited August 12, 2019 by hemsteadc Quote Link to comment Share on other sites More sharing options...
oldjohnt Posted August 12, 2019 Report Share Posted August 12, 2019 3 hours ago, hemsteadc said: Ok, I know someone will say my terminals corroded using AGMs, so I better say "I" never had any corrosion with my AGMs, and certainly not with Lis. Likewise, "so far" at least (knock on wood) I've seen NO corrosion or accumulation or any deposits (sure maybe a bit of dust) on my terminals since switching to AGM. FWIW Nothing actually lol John T Quote Link to comment Share on other sites More sharing options...
Ray,IN Posted August 12, 2019 Report Share Posted August 12, 2019 (edited) 4 hours ago, hemsteadc said: It's a non-issue with AGM or Li batteries. Ok, I know someone will say my terminals corroded using AGMs, so I better say "I" never had any corrosion with my AGMs, and certainly not with Lis. I can, and will say the same of my SLA batteries cable terminals, at least for the past 6 years after I installed new batteries.. I was pointing out the need for solid, tight crimps, as SEHC detailed in that link. Edited August 12, 2019 by Ray,IN Quote 2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG retired;Good Sam Life member,FMCA ." And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country. John F. Kennedy 20 Jan 1961 Link to comment Share on other sites More sharing options...
Sehc Posted August 13, 2019 Report Share Posted August 13, 2019 Wire and cable connections don't only corrode from battery fume. The moisture and pollutants present in the atmosphere can cause bad connections. A note; I have no battery caused corrosion on my lead acid batteries, house or starter. Proper charging and other maintenance is the key to happy campers. Quote Link to comment Share on other sites More sharing options...
hemsteadc Posted August 13, 2019 Report Share Posted August 13, 2019 2 hours ago, Sehc said: Proper charging and other maintenance is the key to happy campers. Dusting. Quote Link to comment Share on other sites More sharing options...
Sehc Posted August 14, 2019 Report Share Posted August 14, 2019 vacuuming. wax the linoleum. polish the tires. clean the windshield with brillo. Quote Link to comment Share on other sites More sharing options...
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