Author Topic: Tie deep-cycle batteries together?  (Read 21041 times)

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force9BOAT

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Tie deep-cycle batteries together?
« on: December 03, 2005, 08:03:30 AM »
Hello,


If I want to double or triple my storage capacity can I do that by connecting two or three deep-cycle batteries together connecting all the positive terminals to each other and all the negative terminals to each other?  I'm thinking that would have the effect of turning two or three (or more) batteries into a single large battery.  I just want to ask if that is a "safe" thing to do.  Don't want an explosion.


Thank you,

Rob

« Last Edit: December 03, 2005, 08:03:30 AM by (unknown) »

wpowokal

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Re: Tie deep-cycle batteries together?
« Reply #1 on: December 03, 2005, 03:53:33 AM »
Basically yes with limitations. It is best if the batteries are of the same age.


It is concidered not advisable to paralell more than two, because you run into issues of sharing charge current and discharge current. Having said that I run nine banks in paralell.


It is IMHO very advisable to fuse each battery, posotive and negative, now many will argue that positive is enough.


allan down under

« Last Edit: December 03, 2005, 03:53:33 AM by wpowokal »
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Zix

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Re: Tie deep-cycle batteries together?
« Reply #2 on: December 03, 2005, 07:15:51 AM »
Allan,

Why do you fuse the neg. side?


(I may learn something here).


Zix----------

« Last Edit: December 03, 2005, 07:15:51 AM by Zix »

Nando

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Re: Tie deep-cycle batteries together?
« Reply #3 on: December 03, 2005, 10:31:08 AM »
Paralleling batteries is quite OK, make sure that all batteries are the same voltage.


The idea of fusing each battery is OK and good idea, in this case fuse JUST the Positive Bornes, Not need to have the negative.


Make sure that the fuses are of the same value and the connections to all batteries are the same length and same wire thickness ( as heavy as possible ).


With several fuses, it is best to add fuse blown detectors -- which add the complexity of the set up but if you need such capability.


The fuse detector is made by two PNP transistors, 3 resistors and ONE LED, the circuit does not use any current except when the fuse is NOT present lighting the LED ( 12  Milliamps or so).


I drew the circuit in two forms JPG and GIF, Named: BLOWN FUSE INDIC.


I inserted both to see which one shows best.


Nando







« Last Edit: December 03, 2005, 10:31:08 AM by Nando »

Jerry

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Re: Tie deep-cycle batteries together?
« Reply #4 on: December 03, 2005, 11:07:35 AM »
Hi Nando.


Nice circut. This might help though. Being in the car audio biz we have all kinds of very nice, gold plated and very heavy duty parts for high amperage DC power distrobution.


I sell a gold AGU fuse in 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70 and 80 sizes

with an led blown fuse indicator inside the glass fuse body.


I sell the fuses for $1.25 each. These fuses can be perelelled for higher  amperage use.


I also sell a varity of fuse blocks and holders. Also gold plated and up to a 4 gange for indevidual distrobution or perelelling.


Also have the large bolt down ANL fuses  up to 300 amps each also in gold plate at $5 each. These can also be perelelled for higher amperage.


Also have watter tight marine fuse holders for the above large fuses at $10 agu and $20 ANL.


The AGU fuse holder accepts up to 4 GA. wire. The ANL up to 0 ga. I use 4/0 GA. on the open type ANL holder. These holders are $10 each.


Much, much more hardware of all kinds is in stock.


                          JK TAS Jerry    

« Last Edit: December 03, 2005, 11:07:35 AM by Jerry »

nothing to lose

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Re: Tie deep-cycle batteries together?
« Reply #5 on: December 03, 2005, 02:12:34 PM »
One thought comes to mind for me real quick, say if a Neg wire comes loose or a wrench falls  and you get a short between the end of the neg wire and the postive post you blow a negative fuse, if no fuse then something else lets loose.


Probably rare tht would happen, but in such a case the positive wire may be fused, but the post itself is not, so if the negative wire is shorted directly to the positve post as I mention above then a fuse in the positive line does no good as the short is actually BEFORE the fuse. Course if a wrench falls acrossed both posts themselfs then no fuse in either line would help. Be carefull of large steel wrenches floating loose around batteries :)


I think of this somewhat because I just shorted a NEG wire to a positive post in a car a few minutes ago. Lucky nothing bad happend, just LOTS of sparks for a split second, the Positive fuse of course did not blow, it was not in the circuit shorted by the negative wire touching the positive post.

« Last Edit: December 03, 2005, 02:12:34 PM by nothing to lose »

Tom in NH

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Re: Tie deep-cycle batteries together?
« Reply #6 on: December 03, 2005, 07:12:29 PM »
As others have said, it's perfectly ok to parallel two or more batteries together, positive to positive and negative to negative, to make one big battery. There is an adage that if you parallel together a new battery and an old battery, you will soon have two old batteries. Before you connect your batteries together, make sure they all have the same charge state or you will have a massive current flow from the good batteries into the low battery. The size of the wire you will use depends on your current draw. Heavier is better. I have eight batteries configured in parallel for a total of 1000 amp hours. I can have upwards of 150 amps going into my inverter and I use 4/0 multi-strand welding cable between the batteries and to the inverter. --tom
« Last Edit: December 03, 2005, 07:12:29 PM by Tom in NH »

Jerry

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Re: Tie deep-cycle batteries together?
« Reply #7 on: December 03, 2005, 10:27:28 PM »
I use 4/0 ga. also on my 12v battery bank at the store. The battery was a 36 volt lift truck battery. We cut some jumpers and reasigned some conections Now its a 2850LB 12 volt battery.


the 2500 watt inverter is about 2 ft from the batt. and its conected with 4/0 ga. welding cable. Oh yah a large 200 amp ANL blade fuse on the + side.


                         JK TAS Jerry

« Last Edit: December 03, 2005, 10:27:28 PM by Jerry »

wpowokal

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Re: Tie deep-cycle batteries together?
« Reply #8 on: December 05, 2005, 04:40:05 AM »
Zix, I will explain why I fuse both ends of my batteries.


My batteries are 2V so there are many terminals exposed, while technically these should have plastic covers.





For the positive I have fuse holders which connect to a bus bar.





The negative end I bolt in the fuses,




OK why, well if I shorted from one adjacent bank to another battery at a non adjacent battery there would be a voltage difference.

It would be like paralelling a 6V and 12V battery, but in my case the voltage difference could be as little as 2V.


Currents would flow, and their path would be via the negative

connection between the two battery banks.


Now if you are paralelling two 12V batteries that only have their positive and negative terminal exposed,

then negative fusing may be not necessary. Or even two 6V in series paralell,

 because the possibly exposed terminals at mid point would be at the same potential so any accidental short would be a nothing.


Well thats my logic anyway, guess its a result of my background.


allan down under

« Last Edit: December 05, 2005, 04:40:05 AM by wpowokal »
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ghurd

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Re: Tie deep-cycle batteries together?
« Reply #9 on: December 06, 2005, 08:45:07 AM »
This is why I fuse batteries at both ends.



« Last Edit: December 06, 2005, 08:45:07 AM by ghurd »
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TomW

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Re: Tie deep-cycle batteries together?
« Reply #10 on: December 06, 2005, 09:58:35 AM »
G-;


Haha, my rats nest is much less organized.


At least the wiring. My batteries are in a box thats power vented at least.


Cheers.


TomW

« Last Edit: December 06, 2005, 09:58:35 AM by TomW »

hayfarmer

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Re: Tie deep-cycle batteries together?
« Reply #11 on: February 22, 2011, 12:24:46 PM »


G  , say it ain't so. there goes that pedestal image I had. :-[

as long as the skeletians are comming out of closet heres one that is still a work in progress,still scary just not as bad as this.

sleep better knowing its in a block shed building. ::)

this would be a good thread though. "fire traps to avoid"



hayfarmer





zap

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Re: Tie deep-cycle batteries together?
« Reply #12 on: February 22, 2011, 12:42:42 PM »
Nice batteries!
I have a couple SVJ9's dated 07/96... dumpster finds ;D

ghurd

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Re: Tie deep-cycle batteries together?
« Reply #13 on: February 22, 2011, 12:55:55 PM »
Gosh hayfarmer, thanks for bringing that one back!
Pedastals, same as tall turbine towers, do not suit me.  I suffer from acrophobia.
G-
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Madscientist267

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Re: Tie deep-cycle batteries together?
« Reply #14 on: February 22, 2011, 02:19:36 PM »
Wow G -

Just tell me two things - 1, You've since 'organized' this... and 2, if not, it's not anywhere near being considered close to inside your house...

Oh, and that your fuses are not of the 'quantum' variety (cant tell from the pic)... LOL

My wife gets spooked by my system, and it's actually a fairly clean layout:



Fuses everywhere... didn't do the negative side of anything however... guess I never thought it would be of much use.

Then again, I can't exactly 'drop' anything on top of any of them either, it's a fairly tight space in there.

Steve
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How much magic smoke it contains does !

taylorp035

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Re: Tie deep-cycle batteries together?
« Reply #15 on: February 22, 2011, 02:46:40 PM »
The inside of my combat robots are kinda like your set ups.  Rotating motors, gears, parallel and series batteries with no fuses, switches, controllers, and receiver wires all crammed into a space that's not big enough, which is surrounded by aluminum frame members.  To make things worse, everything experiences 10-100 G's when it gets hit by your opponent.  The magic smoke appears often in these fights.  Also, after dumping and average of 1000 watts into the confined space fro 3 minutes, everything was nice and toasty when you opened it back up.

The blue motors are outrunner motors, so the blue shells spin, kinda like rotating cheese graters for wires at ~12k rpm.


That's a bevel gear at the top which rotates at 2,500 rpm.


When we put on the lid, we would have to really push hard so all of the wires would squish down.  We had (11) 8-32 bolts holding the cover down.  We tested one 8-32 bolt in a piece of carbon fiber and it sheared at 7,000 lbs. Thank goodness for 1660 strands of copper per 12 gauge wire   ;D



ghurd

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Re: Tie deep-cycle batteries together?
« Reply #16 on: February 22, 2011, 03:03:44 PM »
Just tell me two things - 1, You've since 'organized' this... and 2, if not, it's not anywhere near being considered close to inside your house...

It really was not as bad as it looked.  Sort of an optical illusion, sort of.
Extra stuff in the pic because of good sun, and "use it while you got it".
The lawn tractor battery being charged from the main bank via an inverter, the DeWalt battery and the camp light too (which may be the bugger that made all the magic smoke in slow motion), add some extra wires that look crazy.
A lot of the rats nest lookig stuff is well organized.  A lot of it is 110VAC wires to the power stips far behind the batteries.  Looks crazy in 2D.  Not so bad in real life.
Black G27 is not even connected, and it and the lawn tractor battery were not usually there.
Bank is up to 880AH now, 990AH sometimes.

It looks better in the dark.
G-
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taylorp035

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Re: Tie deep-cycle batteries together?
« Reply #17 on: February 22, 2011, 03:44:25 PM »
He is me trying to charge a 2s3p pack of 2500mah AA's on top of a ladder on a windy day.  It was hard to tell which wire went where.


tanner0441

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Re: Tie deep-cycle batteries together?
« Reply #18 on: February 22, 2011, 04:48:05 PM »
Hi

 I have three 113AH deep cycle marine batteries paralleled with 35mm sq cables. The charge is put in and taken from the centre battery. I used to fit several batteries to the boats I worked on and as long as the batteries were installed and changed at the same time we never had a problem in parallel or series parallel for 24V. I do have a fuse on my system but on the boats it was always breakers, they were more reliable and quicker acting than fuses especially when you were coming up to 400A, and you only had to flick the lever back up if one tripped.

It is not advisable to mix batteries of different capacities or ages, and the batteries I prefere is AGM or second choice VRLA they stay cleaner on the top.

Brian.

Madscientist267

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Re: Tie deep-cycle batteries together?
« Reply #19 on: February 22, 2011, 05:15:09 PM »
Taylor -

Can't wait to see that in a scaled up version where a 3+ (maybe 4?) digit AH bank is involved...

Anybody got anything that resembles that?

All this reminds me of an email that circulated around a couple years ago... Can't recall the title exactly, but something like "Why code inspectors are necessary". Dozens of pics where people have just 'made it work' regardless of safety...

Should start a new thread... "Most Dangerous Bank" hahaha

Can't say much myself, I've come up with a few pretty bad ones too:



This is one of my SMPS tests a couple years ago. Just before this picture was taken, I had an issue where a couple wires crossed in the wrong spot, and let the magic smoke out of both of them. I didn't know until after this had happened that carpet also contains magic smoke. This was one of the events that taught me that fuses were important, even during development!  :-[

The red arrow points to the 'point of release' that it came from.  ::)

Steve
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taylorp035

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Re: Tie deep-cycle batteries together?
« Reply #20 on: February 22, 2011, 05:33:29 PM »
Here is a video of my hybrid solar charging / running of my laptop with AA's.

http://www.youtube.com/watch?v=o5zID6w7Uf8


Quote
Taylor -

Can't wait to see that in a scaled up version where a 3+ (maybe 4?) digit AH bank is involved...

I was planning on doing a 198 Ah 1.2v pack with my vawt last summer with some 9ah Nimh C cells off ebay, but as usual, I talk more than I actually do...


Once I get all of the items from this drawing under the dash board of the supermileage car, I should have a good photo...




My best photo so far would be the back of the car with all of the electronics.  This isn't everything yet.. it's going to be a tight fit.




Madscientist267

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Re: Tie deep-cycle batteries together?
« Reply #21 on: February 22, 2011, 05:49:41 PM »
Quote
running of my laptop with AA's

Not bad, if you've got it only pulling ~25W, that's pretty decent. Most of mine are in the 35W range in slow-motion mode.

You've got some losses there though, significant ones. The B&D inverter/Thinkpad power brick combination is killing a good chunk of your 'savings'.

I have a setup now where with 60W of panel (rated), I actually get ~40W out (I think some of that is the winter effect, won't know till later spring), and my net current flow is just slightly in the direction of charging the battery.

Rats nest looks good and on par with the course here though. :)

As for the car, looks cool man. Hard to gather from the picture points of view, but guessing this is an inverted trike?

How many 'sources' of power do you have feeding it? ie, ICE, battery, pedal, regen braking?

What kind of mileage are you looking at getting from it?

Steve
The size of the project matters not.
How much magic smoke it contains does !

taylorp035

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Re: Tie deep-cycle batteries together?
« Reply #22 on: February 22, 2011, 06:29:15 PM »
The solar panel was putting out about ~11 watts.  I know the power brick / inverter combo is pointless  12v - 110ac - 12v, but it didn't wan't to destroy my nice laptop.

As for power sources, all of the energy that propels the car must come from the 100 octane gas.  Expected mpg's will be about 1500 mpg with a 9-10% efficient engine.  Last year's car got 776.59 mpg, but it weighed 80lbs more and it's air drag force was 3x higher.

I would love to build a series hybrid so we could run the engine for more than 3 seconds (hybrid = more like 2 minutes) so the efficiency will go up. Of course the generator / motor would only be ~80% efficient at best.  Maybe supercharged engine would be in the works with our allowed 1.4ah accessories battery (for the engine).

Here are the rules is you would like to look at them:
http://students.sae.org/competitions/supermileage/rules/

EDIT:  The engine must be the 3.5 hp Briggs and Stratton engine.  You may modify it so long as you keep the main bearings in the crank case.  Also, the series hybrid is currently illegal, but I asked the governing bodies if they would change it ( they can't measure the energy going into and out of the storage battery ). 
« Last Edit: February 22, 2011, 07:26:28 PM by taylorp035 »

Madscientist267

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Re: Tie deep-cycle batteries together?
« Reply #23 on: February 22, 2011, 07:26:06 PM »
Quote
NOTE: Encapsulating another manufacturer's engine within the Briggs & Stratton cylinder/crankcase
assembly is in violation of these rules.

LOL is this really a problem? hahaha Or even a possibility (that would leave the entrant with a noticeable gain)?

Anyhow, quickly glancing over the rules and based on what you're providing here, this is a pulse-and-glide type vehicle then I presume?

Start the engine, engage, get (back) up to speed, kill engine, coast, lather, rinse, repeat?

Still pretty cool. IMHO they should have a hybrid version too though. Bet the MPGs would go up a fair amount then (braking on the slalom comes to mind).

Steve
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How much magic smoke it contains does !

taylorp035

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Re: Tie deep-cycle batteries together?
« Reply #24 on: February 22, 2011, 07:31:29 PM »
Ummm, my school was the team who tried doing that... and yes it is worth it.  3.5hp is waaaaaay too much power and the L-head design of the Briggs makes it very inefficient.  Option two says you make an overhead cam engine out of it, but that is harder than putting a mini 25cc engine inside the crank case.

As yes, it is pulse and glide.  Here is a thread with some pictures if you are interested:

http://fieldlines.com/board/index.php/topic,144470.0.html

The course is 1.6 mile oval, so braking isn't required.  We do have a slalom test and brake test, but they are only there to make sure your design is somewhat safe ( very hard to achieve .25 g's of braking in one of these cars ! ).


Madscientist267

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Re: Tie deep-cycle batteries together?
« Reply #25 on: February 22, 2011, 08:13:56 PM »
Very nice man... And it's apparent that nobody can accuse you guys of NOT having fun building it either...

Probably should take the responses to the car over there from here at this point... Even though this thread is really old (and the mod's presumably therefore haven't said anything yet), we've jacked the crap out of it...  :-X

Steve
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How much magic smoke it contains does !

Bruce S

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Re: Tie deep-cycle batteries together?
« Reply #26 on: February 25, 2011, 03:32:10 PM »

Probably should take the responses to the car over there from here at this point... Even though this thread is really old (and the mod's presumably therefore haven't said anything yet), we've jacked the crap out of it...  :-X

Steve

Steve;
 Nope, guilty having too much fun reading the posts.
BUT maybe that you brought it up we should head over to his posts for the car stuff.
Let the OP chime back in where necessary.

taylorp035;
 That is some stuff you got going on there!

Bruce S

 
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