How to make a cheap isolated dual-battery setup for $50

[patoz]

I usually check Amazon first for everything, but be careful because there are a bunch of knock-off versions out there at a much cheaper price. They look good and are well built, but the ones I ended up with will not match up to the real Anderson connectors. They're fine for a stand alone system but just won't work with the Anderson brand.

 

[ajmaudio]

Might have been said already but try Mouser and Powerwerx. I used PowerWerx the last couple times and found good prices and prompt shipping. They do have the boots and covers etc.

 

[Hillbilly Heaven]

I use Powerwerx mostly because they have a complete assortment of all Anderson and most of the accessory items. Nice to be able to get it all in one place.

 

[Hillbilly Heaven]

By the way if the SB350 terminals are too large for the wire you are using they make reducing bushings for the terminals. They make them for the SB 175 as well.

 

[luthj]

It is worth noting that the continuous rating of the connectors is much higher than the number in the name would imply.

Running a high power winch for more than a few minutes would normally mean going with a connector that can handle the load at its continuous rating.

So, unless voltage drop is a serious consideration, using a anderson connector at higher than its rating for brief periods is okay. For example, jump starting a car. I have a Anderson connector in my engine compartment for using a front winch. If I use it for jump starting a vehicle, it could see 500A for a second or two. This doesn't mean I need a 500A rating connector. The ~200A version is perfectly fine.

Anderson connectors are self wiping, so they don't need much maintenance. A rain/dust boot is preferred. You need to use adhesive lined heat shrink over the connector though. Water penetration into the wire or the back of the connector will cause corrosion in short order.

A bit of dielectric grease on the connectors from time to time is good maintenance. Also, unplugging/replugging a couple times a month will help keep the contacts clean.

 

[AndrewP]

Actually, the Anderson rating is for "hot plugging" meaning the loads are live when it is plugged in. The continuous rating is actually significantly higher. For instance the SB175 is good for 280A continuous.

 

[luthj]

Actually, the Anderson rating is for "hot plugging" meaning the loads are live when it is plugged in. The continuous rating is actually significantly higher. For instance the SB175 is good for 280A continuous.

Duh, I feel a bit dumb. Thanks for the correction. I guess I got rows the Anderson spec page crossed. Regardless, they are great connectors. :sombrero:

 

[luthj]

post the link for the page/ chart?

I can't find the comparison chart I was looking at the other day. But here is the website with a basic list of maximum amperage ratings and the available PDFs.

http://www.andersonpower.com/us/en/products/sb-sb-boots/index.aspx

 

[53kemper]

Been through this whole thread and plan to install my battery set up this weekend. Lets say I just want my second battery to charge while truck is running and never want to use it to restart my original battery. I need power to the Isolator but not a toggle switch correct? Also the power to the Isolator must be power only when the key is on correct?

 

[dlichterman]

Been through this whole thread and plan to install my battery set up this weekend. Lets say I just want my second battery to charge while truck is running and never want to use it to restart my original battery. I need power to the Isolator but not a toggle switch correct? Also the power to the Isolator must be power only when the key is on correct?

That's correct. That said, being able to override it and self jump is a really handy feature to have...

 

[53kemper]

So if I put the in a toggle switch and turn it to the off position this shuts off the isolator and allows the second battery to jump the first correct?

 

[dlichterman]

So if I put the in a toggle switch and turn it to the off position this shuts off the isolator and allows the second battery to jump the first correct?

No, you need a 3 position switch with On - Off - On or to tie it into something under the hood that would stay on when cranking. The solenoid needs power to join the batteries, not to isolate. I use a timed relay to delay the joining - so one position of the switch is automatic joining 10 minutes after starting the truck, the off position means they aren't joined at all, and the 2nd On position joins the two batteries together immediately.

 

[53kemper]

No, you need a 3 position switch with On - Off - On or to tie it into something under the hood that would stay on when cranking. The solenoid needs power to join the batteries, not to isolate. I use a timed relay to delay the joining - so one position of the switch is automatic joining 10 minutes after starting the truck, the off position means they aren't joined at all, and the 2nd On position joins the two batteries together immediately.

Ok I want to be as basic as possible with out jumping capabilities so No need for toggle switch. Just need second batter to run my cooler fridge at night

 

[dlichterman]

Ok I want to be as basic as possible with out jumping capabilities so No need for toggle switch. Just need second batter to run my cooler fridge at night

If you follow that image and tie into the fuel pump or ignition system circuits, you'd be joining on start already - which might be bad because it could hide when your starting battery is going bad - that's why I did the timed relay.

 

[uhkhu]

Excuse my electrical incompetence, but what determines the size of the solenoid? The original post showed an 80A and it was later changed to 200A for adding a winch. Is that to run a winch while the vehicle is off? I'm just looking to have a small 20Ah battery to power some lights and charge small electronics in my bed. Is 80A necessary or could I drop to 65A (to get the cheaper Blue Sea ACR). I'm running a '13 Tacoma with the 140A alternator, if that changes anything.