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explain battery isolator and battery relay

RootBreaker

RootBreaker

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Ok so I just worked some OT and going to get my truck registered... since I fixed the leak so next is my final issue.... I have a electrical drain that keeps on killing my batteries..


I currently have
63a alternator - new
90a battery isolator
2x duralast gold 1000ca batteries in parallel on A of isolator
2 x 1300ca dump truck batteries in parallel on B of isolator

now I am thinking that I need to fix this battery drain (but cant figure out where it is coming from)

anyway.. im also thinking of looking at doing the pontiac transport 140a upgrade... I tried it a few years ago and couldnt get it to work...

so I have both connectors... that delco one that is 2 wires into 3 and I also have the 3 wire plug.

So if I put a 140a alt in I need a bigger isolator.... thus looking on ebay.. I found 200A isolators for about $100
http://cgi.ebay.com/ebaymotors/200-...024QQitemZ370051350786QQrdZ1QQsspagenameZWDVW

and a relay for about $50-$60
http://cgi.ebay.com/Stinger-200-Amp...ryZ14932QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/Stinger-200-Amp...ryZ33574QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/PAC-200-PAC200-...ryZ33574QQssPageNameZWDVWQQrdZ1QQcmdZViewItem



so what are the differences?
I was told that there is still a small drain on the isolators but not on the relays...

I know someone is going to chime in and say to get a ford relay.. if that is true.. tell me what i need and how to hook it up...

I can simply replace the isolator I have with another isolator in a few minutes.....


I know someone is going to say to find my drain...
put a meter between ground and battery and see what amp draw there is but when I did that last time I did not have a draw... I dont have to go with a bigger alt but figured it would be nice....


also I was told isolators dont fully charge max volts.. they are usually a bit lower... as relays are full voltage....
 
I figure im gonna get my charging system upgraded before I bother with the isolator so still gonna need to know the difference..

just bought me a pontiac trans sport 140a alt with 30 day warranty shipped for $40!!!!!!!!!!!!!!!!!!!1

so more to come....
 
RootBreaker said:
Ok so I just worked some OT and going to get my truck registered... since I fixed the leak so next is my final issue.... I have a electrical drain that keeps on killing my batteries..


I currently have
63a alternator - new
90a battery isolator
2x duralast gold 1000ca batteries in parallel on A of isolator
2 x 1300ca dump truck batteries in parallel on B of isolator

now I am thinking that I need to fix this battery drain (but cant figure out where it is coming from)

anyway.. im also thinking of looking at doing the pontiac transport 140a upgrade... I tried it a few years ago and couldnt get it to work...

so I have both connectors... that delco one that is 2 wires into 3 and I also have the 3 wire plug.

So if I put a 140a alt in I need a bigger isolator.... thus looking on ebay.. I found 200A isolators for about $100
http://cgi.ebay.com/ebaymotors/200-...024QQitemZ370051350786QQrdZ1QQsspagenameZWDVW

and a relay for about $50-$60
http://cgi.ebay.com/Stinger-200-Amp...ryZ14932QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/Stinger-200-Amp...ryZ33574QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/PAC-200-PAC200-...ryZ33574QQssPageNameZWDVWQQrdZ1QQcmdZViewItem



so what are the differences?
I was told that there is still a small drain on the isolators but not on the relays...

I know someone is going to chime in and say to get a ford relay.. if that is true.. tell me what i need and how to hook it up...

I can simply replace the isolator I have with another isolator in a few minutes.....


I know someone is going to say to find my drain...
put a meter between ground and battery and see what amp draw there is but when I did that last time I did not have a draw... I dont have to go with a bigger alt but figured it would be nice....


also I was told isolators dont fully charge max volts.. they are usually a bit lower... as relays are full voltage....
Click to expand...


The isolators are basically big diodes, so they'll drop about a half a volt from one end to the other. The diode functions as a one-way valve, so to speak, so that while the alternator charges both batteries, loads on one battery (or in your case, battery bank) don't carry through to the other side.

A relay would just connect the two batteries together and charge both ... you wire it with the key so the relay is ON while the alternator is presumably charging, and OFF when not. This is simple, old school, low-tech ... and what I do, 'cuz it's what I had when I set up my batteries. There is no appreciable voltage drop across the relay.

Now, if you have a drain on any of the batteries, it's nothing to do with the isolator or relay or whatever. That's on the load side, and you need to fix it (or put up with it, if it's your radio or whatever.) The isolator doesn't load the batteries any, and if the drain were the alternator, the diode function of the isolator would prevent it from loading the battery anyway.

I can draw up a quickie picture if none of this makes sense.

I would definitely put an ammeter on the batteries to check drain (remember not to start the motor, or run the winch, or anything else with a giant draw). You can pull fuses for the radio, ECM or whatever, etc and see when the drain changes. Maybe your ignition is hooked to an always-on or something? I would think that a radio memory would take 100-200mA, so if your drain is more than that, I'd be suspicious.

You definitely need an alternator with more than 63A output, 'cuz your batteries will only run your lights/winches/whatever once ... and then take FOREVER to charge on that tiny thing. Ideally your alternator can cover whatever load exists on the electrical system, and the batteries are only there to take up the slack, i.e. start the motor or run the winch for a brief period of time.

As for the Transport alternator, I've done it on two trucks, and found the biggest PITA was mounting the thing to my BBC, where I had to weld up a custom bracket. On my SBC it bolted up in place of the old one.

Wiring it was easy; using the correct plugs, I just matched wire colors, and it worked. I can dig up pix for you of the adapter harness I made if you like.

-- A
 
thanks for the reply...

well I just bought the relay style....
before reading your post..

now on the relay style.. am I going to have problems with the fact I am using 2 differnt batteries in each bank? or is that ok?

so I have my pontiac transport alt on its way (in about a week)
just bought the relay isolator
own both style plugs... for the conversion..

here is the relay I just bought
http://cgi.ebay.com/STINGER-SR200-S...ryZ50552QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


now I know I have a drain.. and know it isnt the batteries.....
I replaced the alt thinking it was that but that didnt fix it... and yes 63a is not nearly enough....

I will get out there and charge up the batteries and then let you know what kind of amps I show on the draw side....:crazy:
 
can you dig up some pics?

also which plug did you use?
was it the cheap $6 from autozone where it has 3 wires or did you use the delco one that you just plug in the 2 plug on 1 side and the 3 side on the other?

I have both plugs so yeah I can try both......

I just remember last time I tried this I couldnt get it to work... eventually I got it to work but was putting like 18v out!!!!!
 
RootBreaker said:
can you dig up some pics?

also which plug did you use?
was it the cheap $6 from autozone where it has 3 wires or did you use the delco one that you just plug in the 2 plug on 1 side and the 3 side on the other?

I have both plugs so yeah I can try both......

I just remember last time I tried this I couldnt get it to work... eventually I got it to work but was putting like 18v out!!!!!
Click to expand...

Well, the 18V thing could be 'cuz the regulator on that particular alternator was fried, could be due to wiring issues, or could be due to the isolator.

When you put the new one in, I would initially just hook it to one battery bank directly (put the charge wire that would go on the center terminal on the isolator directly onto one of the battery bank terminals instead, bypassing the isolator). Once you know it's charging properly, THEN mess with the isolator setup -- one piece at a time, ya know.

I bought the plugs separate; one was a two-pin thing that fits into the factory wiring harness, i.e. is the same gender as on the old-style alternators. The other was the funny new round style that fits into the new-style alternator. The ends of each were just bare wires.

http://www.slosh.com/ck5/subbiebuild...ternator-2.jpg

Old-school on the left, new style in the alternator. Brown wire doesn't go anywhere, red to red, black to black. Solder, heatshrink, voila. (And yes, it's heatshrunk ... clear heatshrink.)

-- A
 
dremu said:
I bought the plugs separate; one was a two-pin thing that fits into the factory wiring harness, i.e. is the same gender as on the old-style alternators. The other was the funny new round style that fits into the new-style alternator. The ends of each were just bare wires.

http://www.slosh.com/ck5/subbiebuild...ternator-2.jpg

Old-school on the left, new style in the alternator. Brown wire doesn't go anywhere, red to red, black to black. Solder, heatshrink, voila. (And yes, it's heatshrunk ... clear heatshrink.)

-- A
Click to expand...

gotcha... yeah I tried that method too... but I was told to hook the 2 wires up to the existing wires... but take the brown (exciter) and link it to the red!!!!!....

I will get the alt in and do that... disconnect isolator (I was planning on that ta boot) then hook it up and see what happens...
 
dremu said:
A relay would just connect the two batteries together and charge both ... you wire it with the key so the relay is ON while the alternator is presumably charging, and OFF when not. This is simple, old school, low-tech ... and what I do, 'cuz it's what I had when I set up my batteries. There is no appreciable voltage drop across the relay.

-- A
Click to expand...


does it matter if the batteries are a different size? are all of your batteries the same?

since it just recharges them.... I have bank 1 of the same and bank 2 of the same.... am I going to experience an issue where the 1300ca batteries may not charge as good as the 1000ca?


now that brings up another question...

I currently have a 10 gauge charging wire.... is that good enough for the charge to the bed bank?

also does that mean I will try and draw from the rear battery banks if the fronts are dead when trying to start? if so I dont think 10gauge will do for starting.... unless it will only be a charge wire.... then huh?
 
RootBreaker said:
does it matter if the batteries are a different size? are all of your batteries the same?

since it just recharges them.... I have bank 1 of the same and bank 2 of the same.... am I going to experience an issue where the 1300ca batteries may not charge as good as the 1000ca?


now that brings up another question...

I currently have a 10 gauge charging wire.... is that good enough for the charge to the bed bank?

also does that mean I will try and draw from the rear battery banks if the fronts are dead when trying to start? if so I dont think 10gauge will do for starting.... unless it will only be a charge wire.... then huh?
Click to expand...


I see no issue in having different banks. Directly paralleling different type batteries can give you headaches, but you're not doing that.

The rear (aux) batteries would only feed juice up front to start if your isolator is configured to do that ... generally the whole point of an isolator is that it (duh) isolates the aux batteries from the starting ones.

At best, 10AWG is only good for relatively low current over a short length, like two or three feet. I think the charge wires on mine are #10, but then it only goes from the alternator to the closest battery, which is about what, two feet or so. Especially on the 140A alternator I shoulda used #8.

For longer runs, like eight or ten feet, I think #8 is good for 75A, and #4 can do 150A or so... so for the bed batteries, I'd do #6, maybe #4 if it's not much more $$. In theory you'd only have half the alternator charge current going to either battery bank at any given time, but if one set is nearly dead then more juice would go to them.

If you're gonna be starting from your aux batteries, then yeah, you need #4.

-- A
 
well I know what an isolator does... :crazy:

I was saying I have a 200a stinger relay and curious as it is not an isolator if it is ok to have different types of batteries...

also I dont want to charge from the back set....

also I was told 10 gauge was good enough for charging... so guess we will see when I get the new alt in.... :wink1:
 
RootBreaker said:
well I know what an isolator does... :crazy:

I was saying I have a 200a stinger relay

also I dont want to charge from the back set....

also I was told 10 gauge was good enough for charging... so guess we will see when I get the new alt in.... :wink1:
Click to expand...

The relay IS an isolator, just a simpler one than the solid state.

The amount of current a wire can carry is a function of its size and the length, so one can't categorically say that #10 is good for a charge wire. For a short run and for, say, 100A tops, you should be okay... but more than a coupla feet, get something bigger. (Jeez, if you're using triple-ought for your winch, why aren't you using #4 for your alternator? :haha: )

-- A
 
dremu said:
The relay IS an isolator, just a simpler one than the solid state.

The amount of current a wire can carry is a function of its size and the length, so one can't categorically say that #10 is good for a charge wire. For a short run and for, say, 100A tops, you should be okay... but more than a coupla feet, get something bigger. (Jeez, if you're using triple-ought for your winch, why aren't you using #4 for your alternator? :haha: )

-- A
Click to expand...

got me there...

thanks... that is what I was blind to see... so the relay is a relay/isolator...

cool... yeah im gonna upgrade and get the items I need to working... but only if I can get the 140a alt working.. I tried once before and it didnt work..... so I didtched the idea...
 
Here is an old fashon way of finding the drain culprit. Get a 6 volt light and socket with pigtails ( two wires ). Disconnect the negative from the battery ( the battery should be recharged first ). Connect one lead of the test light to the negative of the battery . Connect the other test light lead to the negative terminal cable. If there is a battery drain the light should glow ( a 6 volt light is easier to see ). Support the 6 volt test light ( high ) so it will be easy to see. Un plug the alternator regulator. If the light goes out you found the short. If it just gets dimmer leave it unplugged while you check ( pull ) all the fuses one at a time. Reinstall as you go. If you open the door place duct tape on the door switch to shut off the dome light. Check all relays by unplugging and checking the test light. Don't forget the hood , trunk and glove box light. Unplug them and check the test light.
You realise that the alternator regulator, radio memory, and digital clock all take a little power and a battery should handle it. If you have power door locks and/or power windows the relays are located under the front seats. They could be wet. Also if you installed an amplifier, ignition noise filter, or fog lights check for voltage bleed. Lastly pull up on your brake pedel, brake lights may not be very bright in the daylight.
Good luck, this is truely a labor of love.
 
just a little clarification here... I've just glanced here and haven't read thru all the posts, but I just want to point something out that seems a little cloudy...

a solenoid and relay are 2 similar, but different animals... They both act as a triggered switch, but a solenoid is a core/plunger style switch, while a relay is a gate style switch. Both with different strengthes..

Solenoids are the choice for any high draw/ cranking/winching application... relays are lower in amp capacity usually.... And a relay is NOT an isolator, it is a switch... It may be being used to isolate, but I would say to classify it as an isolator is, at the least, misleading... no diodes in a relay....

10g is ok for, yeah, stock charging... But anything beyond that, not a chance, you'll nuke it in short order.. And dangerous, when your talking 10' runs to the bed.. here's one chart...

http://www.powermastermotorsports.com/charge_wires.html
 
ryoken said:
10g is ok for, yeah, stock charging... But anything beyond that, not a chance, you'll nuke it in short order.. And dangerous, when your talking 10' runs to the bed.. here's one chart...

http://www.powermastermotorsports.com/charge_wires.html
Click to expand...


so I need a 6g wire from alt to relay then 2 g wire from solenoid to rear batteries and 6g wire from solenoid to front batteries... boy that is big and alot of wire...

just curious on why the pontiac trans sport alternator wire is not that big... it is like 10g????

but guess I will have to do it then...:crazy:

gonna get the alt in first...
 
cuz stock is charging a single battery, 3' away...
 
I'm sure you know this but if you are putting both 1000cca batteries in parallel and one of them is hurt (bad cell etc.) the good battery will kill itself trying to charge the bad one when the engine is off, and it will get undercharged when the engine is on. In fact that situation is even worse than mixing different batteries. You may want to disconnect all your batteries and check their open circuit voltage. If the voltage is significantly different between a pair of batteries in parallel, that may be your problem.
 
ryoken said:
doh... owe ya a beer for that one! :haha:
Click to expand...

Great minds think alike =))

BGKYK5 has a point, come to think -- a sick battery paralleled with a good one *will* cause issue, and I *think* you mentioned this in one of these threads and said you'd tested them ... but there are so many threads now I'm lost. Point being, unhook all the batteries, and check 'em ... maybe even drag 'em over to the parts place and have them loadtested.

-- A
 
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