Hello Everyone!
This spring I will be installing 8 Lishen 270ah cells 2p4s into my MotorHome giving me a 12v 540ah battery (Hopefully useable of 500ah) . My batteries are ordered and I already have most of the other accessories I will need. I have a Batrium bms and it will be controlling a Kilovac EV200AAANA contractor. My biggest question right now is the bus bars on the battery. Please double check my thinking... I have a tenancy to overthink a lot of things (a lot!).
The two largest draws on the battery will be a first, a Victron 12/3000 inverter/charger. This should have a max draw of 250ah (maybe more if in surge mode). Second, I am also wanting to keep the emergency boost ability of the MotorHome. There will be a 400a Class T fuse protecting the battery - so hopefully if I ever need the boost, the starter will use less than 400a (or there goes a $35 class T fuse). Like most RVer's I don't expect to use the full power of the inverter or boost very often - if at all.
So to the bus bars... As part of my design both the positive bar & the negative bar coming off the battery will have a 90 degree bend in them. (Shunt & fuse will be mounted vertically on the outside of battery box). So I will have to heat and bend over the bus bar.
I have 2 choices of bars:
First, I was thinking of using copper bars from onlinemetals .125 x 1" (1/8" x 1"). The charts I found says that will handle 270amps @ 30C rise (and 360a at 50C rise and 415a at 65C rise). Since anything around 250amps will be very short-lived, I think that will be OK. Stainless Steel Studs into the aluminum battery post (with red permatex or purple loctite) and a nord-lock washer & ss nut on top and it is ready. Issue - different metals & corrosion.
Second I was thinking of Aluminum bus bars .250 x 1" (1/4" x 1"). The charts say this will handle 300a @ 30C rise. I like this idea, of aluminum post, busbar and fastener, except I cannot find any M6 aluminum posts - so I would probably put the stainless nut all the way up the aluminum bolt, add the nord-lock washer, then through the aluminum bars and into the aluminum posts (w/ red permatex or purple loctite). The bolt head will stick up over everything else, with the nut that holds everything down a bit lower. I like this method because everything is aluminum (except the lock washer and nut), so hopefully there will be no corrosion issues and if so it is a replaceable bolt probably 3/8"+ away from the battery posts.
I have read several posts about using the copper bus bar and no one seems to be really concerned about the dis-similar metals.
So am I overthinking it again...
Does anyone see any other issues with these plans???
Which would you choose - aluminum or copper bus bars?
Thanks for your ideas
Rocketman
This spring I will be installing 8 Lishen 270ah cells 2p4s into my MotorHome giving me a 12v 540ah battery (Hopefully useable of 500ah) . My batteries are ordered and I already have most of the other accessories I will need. I have a Batrium bms and it will be controlling a Kilovac EV200AAANA contractor. My biggest question right now is the bus bars on the battery. Please double check my thinking... I have a tenancy to overthink a lot of things (a lot!).
The two largest draws on the battery will be a first, a Victron 12/3000 inverter/charger. This should have a max draw of 250ah (maybe more if in surge mode). Second, I am also wanting to keep the emergency boost ability of the MotorHome. There will be a 400a Class T fuse protecting the battery - so hopefully if I ever need the boost, the starter will use less than 400a (or there goes a $35 class T fuse). Like most RVer's I don't expect to use the full power of the inverter or boost very often - if at all.
So to the bus bars... As part of my design both the positive bar & the negative bar coming off the battery will have a 90 degree bend in them. (Shunt & fuse will be mounted vertically on the outside of battery box). So I will have to heat and bend over the bus bar.
I have 2 choices of bars:
First, I was thinking of using copper bars from onlinemetals .125 x 1" (1/8" x 1"). The charts I found says that will handle 270amps @ 30C rise (and 360a at 50C rise and 415a at 65C rise). Since anything around 250amps will be very short-lived, I think that will be OK. Stainless Steel Studs into the aluminum battery post (with red permatex or purple loctite) and a nord-lock washer & ss nut on top and it is ready. Issue - different metals & corrosion.
Second I was thinking of Aluminum bus bars .250 x 1" (1/4" x 1"). The charts say this will handle 300a @ 30C rise. I like this idea, of aluminum post, busbar and fastener, except I cannot find any M6 aluminum posts - so I would probably put the stainless nut all the way up the aluminum bolt, add the nord-lock washer, then through the aluminum bars and into the aluminum posts (w/ red permatex or purple loctite). The bolt head will stick up over everything else, with the nut that holds everything down a bit lower. I like this method because everything is aluminum (except the lock washer and nut), so hopefully there will be no corrosion issues and if so it is a replaceable bolt probably 3/8"+ away from the battery posts.
I have read several posts about using the copper bus bar and no one seems to be really concerned about the dis-similar metals.
So am I overthinking it again...
Does anyone see any other issues with these plans???
Which would you choose - aluminum or copper bus bars?
Thanks for your ideas
Rocketman