Big Blue

[kramttocs]

...parallel mode to allow jump starting is a nice option.

The factory-style relay can do that, with the addition of the switch shown here:

https://supermotors.net/getfile/905422/thumbnail/battrelayaux.jpg

Don't use the relay with the LED - it's not necessary.

Thanks guys! I find this to be a neat setup - the whole isolation stuff.

Couple questions on those diagrams that may already be answered in those photos but it takes me a while to digest it all (Gary - if this should be a new thread, happy to do so):

1. Diagram A. The harness with the white/purple and the other wire that comes from the firewall.

a. Is this a standalone harness?

b. I get that the wht/ppl comes from the fuse box and to the relay but what does the other wire come from/go to?

2. Diagram A. The relay takes the physical place of the junction point and uses the left terminal for the same purpose, correct?

What is the max alternator amp rating that the relay E5TZ-14677-A can handle? Google didn't show much except a FTE comment about it being at most able to handle 100.

 

[kramttocs]

I'm going to use a Cole Hersee 48530 Smart Isolator on Big Blue, but I have its little brother, the 48525, on our boat. The bigger one is rated at 200a and the little one at 85a continuous, which fits the output capability of the two alternators.

The documentation is here, but my favorite features are:

• Automatic Parallel: The two batteries are paralleled when either battery's voltage is above 13.2V for 2 minutes. So you can pull the auxiliary battery down to zero and it won't connect that one in parallel to the starting battery during starting - like the factory relay does.

• Automatic Disconnect: The two batteries are isolated when both battery voltages are below 12.7V for 1 minute. So if your aux battery dies and it starts taking everything the alternator can put out and still the voltage goes south it'll drop it out of the circuit. However, it doesn't work if the main battery goes south.

  I know that for sure.

• Forced Parallel: One little switch can force it to parallel the two batteries, like if the main has gone south and the aux is up.

• LED: There's an output that tells you when the batteries are in parallel. I check that on the boat frequently.

Showing my ignorance on the 12v minutia but with 12.7 being the resting value, is it expected when the truck isn't running that if the batteries are good with no draw that they would stay in parallel indefinitely?

In real world though is it normal for them to both drop below this and thus isolate pretty quickly?

[Gary Lewis]

Showing my ignorance on the 12v minutia but with 12.7 being the resting value, is it expected when the truck isn't running that if the batteries are good with no draw that they would stay in parallel indefinitely?

In real world though is it normal for them to both drop below this and thus isolate pretty quickly?

I'm going to let Steve address the other questions as those are his wiring diagrams.

On the capability of that relay, the alternators of the day were only capable of ~70a, with one that the F & U series trucks never got being capable of 100a. Since it isn't likely Ford over-spec'd the thing, which would have cost them money, it is probably capable of no more than 100a.

And it is interesting that Cole Hersee has a relay that handles 85a and one that handles 200a. Might those be industry standard specs?

In my experience on the boat, the relay drops out within seconds of the key being turned off. I suspect that the coil current of the relay is enough to drop the voltage to the 12.7.

[kramttocs]

I'm going to let Steve address the other questions as those are his wiring diagrams.

On the capability of that relay, the alternators of the day were only capable of ~70a, with one that the F & U series trucks never got being capable of 100a. Since it isn't likely Ford over-spec'd the thing, which would have cost them money, it is probably capable of no more than 100a.

And it is interesting that Cole Hersee has a relay that handles 85a and one that handles 200a. Might those be industry standard specs?

In my experience on the boat, the relay drops out within seconds of the key being turned off. I suspect that the coil current of the relay is enough to drop the voltage to the 12.7.

Thanks Gary.

Mine is a 150 so looks like that makes the decision for me. Good question on the 85/200. I was looking at one company that offered 75/125 models so not sure how they decide on the limits.

[Steve83]

Diagram A. The harness with the white/purple and the other wire that comes from the firewall.

a. Is this a standalone harness?

If you mean View A in the diagram I posted, and if you mean harness 13A705; yes, it's a separate (optional) section of harness. The main (dash) harness section is 14401.

b. I get that the wht/ppl comes from the fuse box and to the relay but what does the other wire come from/go to?

You'd have to look up 14K067. Maybe trailer brake or battery charge.

The relay takes the physical place of the junction point and uses the left terminal for the same purpose, correct?

Yes.

What is the max alternator amp rating that the relay E5TZ-14677-A can handle?

They're not directly related. It would work with a dinky 60A or a 250A welding alternator, assuming the factory wiring (or better) in good condition.

But if you want to use the aux.batt. for jump-starting, you must use the "Isolator Switch" diagram, which includes replacing the wire from the main to the junction with a heavier cable.

[kramttocs]

I'm going to use a Cole Hersee 48530 Smart Isolator on Big Blue, but I have its little brother, the 48525, on our boat. The bigger one is rated at 200a and the little one at 85a continuous, which fits the output capability of the two alternators.

The documentation is here, but my favorite features are:

• Automatic Parallel: The two batteries are paralleled when either battery's voltage is above 13.2V for 2 minutes. So you can pull the auxiliary battery down to zero and it won't connect that one in parallel to the starting battery during starting - like the factory relay does.

• Automatic Disconnect: The two batteries are isolated when both battery voltages are below 12.7V for 1 minute. So if your aux battery dies and it starts taking everything the alternator can put out and still the voltage goes south it'll drop it out of the circuit. However, it doesn't work if the main battery goes south.

  I know that for sure.

• Forced Parallel: One little switch can force it to parallel the two batteries, like if the main has gone south and the aux is up.

• LED: There's an output that tells you when the batteries are in parallel. I check that on the boat frequently.

Good visuals for the Cole Hersee

D-617_Smart_Battery_Iso.pdf

[ArdWrknTrk]

Good visuals for the Cole Hersee

D-617_Smart_Battery_Iso.pdf

Have a look at this place: http://www.texasindustrialelectric.com/electrical.asp

No, I'm not shilling.

They seem to have a huge variety of high quality components, and I want to see places like this stay in business under siege of Amazon and the like.

[Gary Lewis]

Have a look at this place: http://www.texasindustrialelectric.com/electrical.asp

No, I'm not shilling.

They seem to have a huge variety of high quality components, and I want to see places like this stay in business under siege of Amazon and the like.

Jim - I like shopping locally or helping people who have helped me by buying from them. But when the price diff is almost 2x it makes it hard. That isolator is $103 on Amazon and $196 on that site.

Scott - That's a good file to have as it explains the different modes better than the other one. But, it also tells me something I didn't know - the switch to parallel the batteries only needs to be a momentary. The isolator parallels the batteries for 1 minute when the switch closes. That's not said on the other sheet.

However, there's something that is said on that sheet that can be an issue. It says "Allows bi-directional charging from alternator or from shore/campground power charger/converter when available." But what it doesn't say is that it will parallel the batteries when the charger gets either battery to 13.2 volts. And, if you are using a small enough charger, like a Battery Tender, the pull-in current of the isolator is more than the output of the charger. So the combined battery voltage starts down until you get to 12.7, at which point it opens again and the batteries start charging.

I didn't like that, so I put a relay in the ground circuit to the isolator. The relay is pulled in by the ignition circuit, so when the engine is off and the chargers are on the isolator is dead.

[kramttocs]

Jim - I like shopping locally or helping people who have helped me by buying from them. But when the price diff is almost 2x it makes it hard. That isolator is $103 on Amazon and $196 on that site.

Scott - That's a good file to have as it explains the different modes better than the other one. But, it also tells me something I didn't know - the switch to parallel the batteries only needs to be a momentary. The isolator parallels the batteries for 1 minute when the switch closes. That's not said on the other sheet.

However, there's something that is said on that sheet that can be an issue. It says "Allows bi-directional charging from alternator or from shore/campground power charger/converter when available." But what it doesn't say is that it will parallel the batteries when the charger gets either battery to 13.2 volts. And, if you are using a small enough charger, like a Battery Tender, the pull-in current of the isolator is more than the output of the charger. So the combined battery voltage starts down until you get to 12.7, at which point it opens again and the batteries start charging.

I didn't like that, so I put a relay in the ground circuit to the isolator. The relay is pulled in by the ignition circuit, so when the engine is off and the chargers are on the isolator is dead.

Gary - I think I get what you are saying and it might be a concern I have an onboard battery tender on Camano.

Do you see the pull-in current specified? I called Littelfuse and they didn't know.

I think my onboard is a 1amp and I checked my Battery Tender Jr's and they are 750mA.

 

[Gary Lewis]

Gary - I think I get what you are saying and it might be a concern I have an onboard battery tender on Camano.

Do you see the pull-in current specified? I called Littelfuse and they didn't know.

I think my onboard is a 1amp and I checked my Battery Tender Jr's and they are 750mA.

I looked and couldn’t find it. But I can measure mine. However, it won’t be until later tomorrow or maybe Saturday.