| Author | Message | ||
| Lin
Rating: N/A |
I have just finished installing my five new house batteries. All seems to be well. I have a question that has had me wondering for a while though. I have wired all five bats in parallel. Now can I tap into any terminals I want and still get the same power. Like both pos and neg on one bat at the end of the string, or any combination of pos and neg from any of the batteries. Or must I use, for example the pos in battery #1 and the Neg from battery #5 to get maximum results. I have, maybe mistakenly, believed that, since all the terminals are strung together, it would not matter where I pulled power from. Please correct me if I am wrong. | ||
| BrianMCI Rating: N/A |
With batts tied together in parrallel... You are not wrong. Brian | ||
| Jim Stacy
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It doesn't make a lot of difference. The preferred way would be one cable on # 1 and one on #5. One theory is that hooking both cables to the same battery causes more activity in that battery. Just as easy to hook the preferred way and not worry about it although I think it would be a long time before you would notice a difference no matter how you hooked them up. FWIW Jim Stacy | ||
| Tim Strommen (Tim_strommen)
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Parallel adds current, Series adds voltage. If you're parallel, all positives will have the same voltage potential and all negative posts will be your ground. Tim | ||
| Gary Stadler (Boogiethecat)
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...on the other hand... Jim is correct. If you have a massive load (like a big inverter), you could have issues. Just for arguement's sake (and example) let's say your batteries were spaced ten feet apart, making the entire "string" of them 50 feet long. If you were to NOT use "heavy enough" wire to tie all the batteries together and you hooked the inverter to one end of the string, what would likely happen under full load is that the battery closest to the inverter would supply more current than the battery farthest away, due to the resistance of the wires. Over a period of time, the closest battery would be worked a lot harder and an unbalance in charge could occur between it and the farthest-away battery. The fix would be, as Jim correctly states, to hook the inverter's positive to the (+) of the battery on one end of the string, and the inverter's negative to the (-) of the battery at the other end of the string. If you do this, all the batteries will experience the same loading regardless of the wire resistance and an unbalance in charge will never occur. Practically speaking, this is a real issue with big loads and even closely spaced batteries hooked together with big fat properly gauged wire. If your load is light, it's pretty much a non issue...but it's always a good idea to wire them this way anyway just in case. It's not difficult, and then there is no question. There you are....a different way to look at the same thing... | ||
| Jim (Jim_in_california)
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On the other hand, if you've got three batteries wired up right next to each other with SERIOUS interconnect cables installed correctly, I doubt the issue would be serious. Still, best practices say "each end"... | ||
| TWODOGS (Twodogs)
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interisting question...I went thru the thinking process on my 5 house batteries,when I installed a tiny inverter to hopefully take care of my apt. size refrigerator.. | ||
| captain ron (Captain_ron)
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Two Dogs has an inverter? hmmmm | ||
| Jerry Liebler (Jerry_liebler)
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Lin, For light loads and shallow cycles, as others have said any pair of the terminals will work. But if the load(s) is heavy and you'll be using a significant fraction of the total capacity during each charge/discharge cycle then how you connect will matter. The ideal interconnection will go as far as possible in making each of the batterys experience the same load and charge. In the ideal inter-connection each battery will have the same total wire resistance in the circuit from it's positive terminal to the load and back to it's negative terminal. The matching of circuit resistance will cause equal depth of discharge and recharge for all of the batterys. To match circuit resistance the batterys need to be arranged & connected so the total length of each size of wire used as one traces from any battery's + to the load and back to that batt's - is the same as all the others. Regards Jerry 4107 1120 | ||
| TWODOGS (Twodogs)
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Wish I was as rich as some of you guys....to connect all batteries...I used 3/8 copper tubeing(smashed) & drilled 3/8 hole for the studs on the battery...and ...used #6 wire,salvaged from a dryer cord...  | ||
| TWODOGS (Twodogs)
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my # 2 choice was 3/8 copper tubeing with smashed ends & taped everywhere except the ends...but...didn't have enough copper tubeing | ||
| Lin
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Thanks for the info. I hooked both up off the end battery for now because that is how much cable I had. At some point, if I am seriously loading the batteries dry camping, I will probably buy a couple of feet more and use the far ends. I, like Mr Dogs, look to do things cheaply. It is an extra special bonus when I can just use what I have around (it justifies having saved various pieces of trash for years--priceless!). However, this class A adaption is easy. | ||
| TWODOGS (Twodogs)
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have this saying : "when you are poor....everything ya' pick up will fit somewhere" | ||
| Lin
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I don't know about that. I just finished picking up after the dog in the back yard. | ||
| Gary Stadler (Boogiethecat)
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There's even a place for that stuff.... 5 years ago I started telling my friends that on ebay you could probably sell dog poo if you did the ad right... then two years ago there was a very sucessful auction entitled: (until ebay pulled it  ) "nicely packaged dogshit sent to address you choose" It takes all kinds, but there you have it... a place for everything you can pick up... | ||
| TWODOGS (Twodogs)
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TAY LO -DE HOO (I TOLD YOU SO) | ||
| gusc Rating: N/A |
If you have no corroded terminals and all the cables are the same size any point you pick for neg or pos is exactly the same. | ||
| Gary Stadler (Boogiethecat)
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To paraphrase Kyle in Southpark... No Gusc, you can't. Please read the posts above! If you people don't GET the basic ohm's law stuff that drives the reality of this thread, PLEASE do not post misinformation !! Geez.... | ||
| Sean Welsh (Sean)
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There are two ways to connect batteries in parallel. One, which most here have been discussing, involves connecting the positive terminal of battery 1 to the positive terminal of battery 2, then the positive terminal of battery 2 to the positive terminal of battery 3, and so forth. In this case, Gary and Jim are exactly correct (and Gusc is exactly incorrect). Best performance is extracted when battery 1 (or battery N) has the negative post grounded, and battery N (or battery 1) has the load connected to its positive post. The other way to do this is to run a cable from the negative post of *each* battery to ground, and then a cable from the positive post of *each* battery to an insulated terminal, to which the load is then connected. The first method usually uses less cable and fewer connectors (N jumpers on the negative side, and N-1 jumpers on the positive side, plus the connection to the load), while the second method makes it easier to add or subtract batteries, but uses more cable (2*N jumpers, plus the load connection, plus, to maximize performance, all jumpers must be equal length regardless of physical distance to the load). FWIW. -Sean | ||
| DrDave
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I do it a little different. All cables are the exact same length and ohmmed out first. All negative battery terminals are routed to a single Negative buss bar. Each cable being the same rating and length. All Positive cables (same length) go from each battery positive to a single Positive buss bar. Everything that uses 12 volts runs from the buss bars and not unbalanced from any single battery. Now the big trick is making sure to individually load test each battery so that they are current and voltage stable for a specific load for a specific amount of time. If any battery does not match within 10% I keep trying until I find a set that is pretty well balanced. I use a digital voltmeter, Battery load tester ( modified to only load 50 amps @ 12 volts ) and hydrometer. Of course when I get in a hurry or cheap and use whatever I can find that will carry a reasonable load. These days I am in cheap mode so anything goes.... ( Heheheee ). I will return to my script when I get a bunch of other things done first. My 458 series 3 kw runs for 4 days with my Haier fridge with 3 used and abused Lifeline 4D batteries. I have even fired up the 15K Quick Cool roof air for 15 minutes once with 4 batteries. ( Locates weak cells really fast when they start whistling and blowing steam..!) And YES I am completely NUTZ ! | ||
| Gary Stadler (Boogiethecat)
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YEAY Sean and Dr.Dave! Two more guys who understand! listen up all you other guys.... |