Batteries in parallel

[Chet0729]

I dont have a chart handy but the info should be readily available.
I will just tell you most people under estimate the current those batteries are capable of in a dead short situation. I have seen a car battery melt a wrench when it got jammed between the + and the - .
I would fuse each battery at a fairly low rate like maybe 5 amps or less. This will keep you safe. They actually make those style batteries with a fuse holder right in them. I have seen them in alarms and power wheels toys.
If you fuse them at a low rate and keep the fuse right at the battery you can use smaller wire. The fuses should be as close to the battery as possible.

 

[Another_David]

I dont have a chart handy but the info should be readily available.
I will just tell you most people under estimate the current those batteries are capable of in a dead short situation. I have seen a car battery melt a wrench when it got jammed between the + and the - .
I would fuse each battery at a fairly low rate like maybe 5 amps or less. This will keep you safe. They actually make those style batteries with a fuse holder right in them. I have seen them in alarms and power wheels toys.
If you fuse them at a low rate and keep the fuse right at the battery you can use smaller wire. The fuses should be as close to the battery as possible.

back in the day I was torquing the valve covers on my 1971 Plymouth with a beam torque wrench, which you have to read while on the move. So as i'm diligently focusing on the needle, which I think the spec was only around 15 lbs., the end of the torque wrench comes in contact with the positive batter terminal. I nearly crapped myself. It does spark something fierce.

 

[ToddDubya]

Are you trying to make something like this: http://stores.amp-3.net/double-battery-pack-complete-kit/?

Since you already have the batteries and (I assume) an enclosure, you might consider adding the BatPac to your batteries.

http://www.portableuniversalpower.com/our-products/batpacs/

or more specifically: http://www.portableuniversalpower.com/batpac-rbc2/

At $45 apiece they're a little steep but they give you a lot of the features you're talking about building yourself just in a nice tidy package.

 

[blindfire]

Are you trying to make something like this: http://stores.amp-3.net/double-battery-pack-complete-kit/?

Since you already have the batteries and (I assume) an enclosure, you might consider adding the BatPac to your batteries.

http://www.portableuniversalpower.com/our-products/batpacs/



or more specifically: http://www.portableuniversalpower.com/batpac-rbc2/

At $45 apiece they're a little steep but they give you a lot of the features you're talking about building yourself just in a nice tidy package.

Damn, that is almost exactly what I was looking for.

THANKS! Wonder if I can use my larger batteries in the kit. Looks like the same exact manufacturer that I have for my 15AH

 

[ToddDubya]

The amp-3 guy has a pretty active YouTube channel that I follow: https://www.youtube.com/user/USNERDOC

They make all sorts of cool bags/packs/etc. for ham and emergency uses. It's a little spendy for me, but the stuff is quality and built for specific uses. Judging by his YouTube name I'm guessing he's a former Navy ER Doc. Last I checked his business was just him and his wife. I believe they have all of the bags/pouches/etc made in the US, too.

 

[blindfire]

The amp-3 guy has a pretty active YouTube channel that I follow: https://www.youtube.com/user/USNERDOC

They make all sorts of cool bags/packs/etc. for ham and emergency uses. It's a little spendy for me, but the stuff is quality and built for specific uses. Judging by his YouTube name I'm guessing he's a former Navy ER Doc. Last I checked his business was just him and his wife. I believe they have all of the bags/pouches/etc made in the US, too.

Yeah...a bit spendy here too. I just talked to the BatPac guy and it sounds like a good starting point for me. He even explained how to run two batteries in parallel with it.

The bag is nice in that it does have all of the connector cables pre-built...but I'd like to learn how to make my own first.

You sir...have saved me! Thank you!

 

[blindfire]

Are you trying to make something like this: http://stores.amp-3.net/double-battery-pack-complete-kit/?

Since you already have the batteries and (I assume) an enclosure, you might consider adding the BatPac to your batteries.

http://www.portableuniversalpower.com/our-products/batpacs/

or more specifically: http://www.portableuniversalpower.com/batpac-rbc2/

At $45 apiece they're a little steep but they give you a lot of the features you're talking about building yourself just in a nice tidy package.

Here is my review:

 

[cockpitbob]

Really nice review, and a nice product.

 

[ToddDubya]

Very nice. Those look like just the ticket for quick and easy setup. I'm sure you could build the whole thing yourself for less, but that's a nicely designed and built package. I look forward to needing one someday.

Just a thought: if you rotate battery two 180 degrees you could use a short cable to connect them together 69 style instead of a long cable that loops around.

My first thought when I saw the cable you made was "somebody get that man some heat shrink" but you even acknowledged it yourself.

Seriously though, nice review of a nice setup. For being 2.5 months into your ticket you've got a great setup.

 

[blindfire]

Very nice. Those look like just the ticket for quick and easy setup. I'm sure you could build the whole thing yourself for less, but that's a nicely designed and built package. I look forward to needing one someday.

Just a thought: if you rotate battery two 180 degrees you could use a short cable to connect them together 69 style instead of a long cable that loops around.

My first thought when I saw the cable you made was "somebody get that man some heat shrink" but you even acknowledged it yourself.

Seriously though, nice review of a nice setup. For being 2.5 months into your ticket you've got a great setup.

Thanks, sir. I really appreciate the feedback. I was thinking the same thing on the 69 battery idea...but that thought hit me AFTER I built that other cable. Hind sight and all that.

Funny thing is, I don't actually have any trouble making the power pole cables even though the guy at HRO assured me that I'd have trouble on the first few cables. So far, every cable I've made works like a charm. Of course, I've built my own RJ-45 Cat 5 cables..and that is MUCH harder than power poles.

So, on the shrink wrap, what size would you go with for covering two 14 gauge wires together? Would you slide it on the cable BEFORE putting the ends on or can you get the shrink wrap big enough to go over the connectors? What heat gun would you suggest?

 

[cockpitbob]

One little hint/kink with shrink tubing. They sell adhesive lined shrink tubing. It's got a thin lining of hot-melt glue. If you want it really secure or water tight you can use that OR, do it yourself by putting a thin layer of hot-melt glue gun glue on the wire first. The heat from shrinking the tubing will re-melt the glue and really lock things together.

 

[ToddDubya]

You want to put the heat shrink on the wires before terminating them. The general procedure is to slide the heat shrink over the wires, solder or crimp on your terminals and then heat up the heat shrink, covering the end of the terminals. It keeps your wires neat, helps prevent against shorts and offers some strain relief. You can also layer it up if you have multiple wires in a cable (wrap each wire/terminal and then wrap the whole thing).

Here's a pic:

Don't overthink the sizing. You don't want to have to force it over the wires, but it shouldn't be "baggy"; it only shrinks so much. I get it at Radio Shack but I just bought a box of small pieces at Harbor Freight. I think they're about a 2:1 shrinkage factor.

Don't overthink the heat gun either. We have nice Weller heat guns at work, but at home I use either my el cheapo Harbor Freight heat gun or a hair dryer. Some people use lighters but obviously there's some risk of burning or melting. It doesn't take much heat.

 

[cockpitbob]

You want to put the heat shrink on the wires before terminating them.

Well, that takes all the fun out of it. I can't count the number of times I've soldered on a terminal then realized I forgot to slide the shrink on.

 

[ToddDubya]

Well, that takes all the fun out of it. I can't count the number of times I've soldered on a terminal then realized I forgot to slide the shrink on.

Knowing to put it on first and actually doing it are very different things. Blindfire will still forget often enough for it to be comical.

 

[blindfire]

Knowing to put it on first and actually doing it are very different things. Blindfire will still forget often enough for it to be comical.

HEY! That was a shot at me, wasn't it?!?!?

 

[ToddDubya]

HEY! That was a shot at me, wasn't it?!?!?

You and everyone else

It's like connecting up an RS232 port. You have a 50/50 chance of getting Tx and Rx correct, but you get it wrong 100% of the time. I've tested the theory by just guessing and had better results than trying to think about it.

 

[blindfire]

You and everyone else

It's like connecting up an RS232 port. You have a 50/50 chance of getting Tx and Rx correct, but you get it wrong 100% of the time. I've tested the theory by just guessing and had better results than trying to think about it.

Heh...yeah...try dealing with current loop. Even m ore fun.

 

[Goliathan]

You and everyone else

It's like connecting up an RS232 port. You have a 50/50 chance of getting Tx and Rx correct, but you get it wrong 100% of the time. I've tested the theory by just guessing and had better results than trying to think about it.

I, too, suffer from UART dyslexia. And I do these regularly in board design. It's ridiculous. I always add strapping jumpers (resistors) in case I get it wrong.

 

[boatman]

didn't read every post, but I do lots with marine batteries. If you are going to parallel batteries, you need to check the distance from the battery to the load. All wire has resistance, you will get a V drop over this. The thicker the wire the less of a drop. Also, if you should get a short, you want a fuse. The fuse should be rated for the wire, not the load (the wire should be checked for the load). This prevents the wire from catching fire. Important stuff on a boat or RV, don't know what you are using it for so don't know if this pertains.