Bluesea issue? - Page 2

achop · 06-25-2017, 04:13 PM

Thanks all for the help understanding this!

achop · 06-25-2017, 05:04 PM

Ok, a couple more (dumb) questions:

I'm sure I'll never have to do this ;-) ;-) but since we're talking about it ...

Assuming the start battery is fully charged and the house battery is completely depleted (and both batteries are otherwise in good shape), if I were to "jump" the isolator as described previously in this thread, ...

1. Would the two batteries essentially come to a steady state of equal voltage? And how long would it take to get there (eg, a few minutes or a couple hours?)

2. Would the "equalizing" process leave both batteries with at least 9.5V? (9.5V is the waterline which, on either battery, will trigger the ACR lockout.)

3. Would the best solution include monitoring the voltage on each battery as the current equalizes, so as to resume engine recharging of house battery as soon as the house meets the 9.5 V constraint?

Thanks!
- anne

**daveb** · 06-25-2017, 10:37 PM

Quote:

Originally Posted by achop

Ok, a couple more (dumb) questions:

I'm sure I'll never have to do this ;-) ;-) but since we're talking about it ...

Assuming the start battery is fully charged and the house battery is completely depleted (and both batteries are otherwise in good shape), if I were to "jump" the isolator as described previously in this thread, ...

1. Would the two batteries essentially come to a steady state of equal voltage? And how long would it take to get there (eg, a few minutes or a couple hours?)

2. Would the "equalizing" process leave both batteries with at least 9.5V? (9.5V is the waterline which, on either battery, will trigger the ACR lockout.)

3. Would the best solution include monitoring the voltage on each battery as the current equalizes, so as to resume engine recharging of house battery as soon as the house meets the 9.5 V constraint?

Thanks!
- anne

When using jumpers you will get a spark if there is a large differential between the batteries or battery banks. How long it takes depends on why the battery system was drained. In some cases in the field you don't know what happened. Maybe a short. In a similar situation I used a jumper with a 30 amp fuse. No sense for a melt down. Most charging is not that high in amps and the fuse is really just to equalize as suggested. I wouldn't try to jump start it though through the separator (Fused Jumpered or not) w/o equalizing the banks for a bit. BTW my connections leads at the separator are long enough to just connect one side to the other...Take the separator out of the system till repairs are made.

achop · 06-26-2017, 02:57 PM

Quote:

Originally Posted by daveb

When using jumpers you will get a spark if there is a large differential between the batteries or battery banks. How long it takes depends on why the battery system was drained. In some cases in the field you don't know what happened. Maybe a short. In a similar situation I used a jumper with a 30 amp fuse. No sense for a melt down. Most charging is not that high in amps and the fuse is really just to equalize as suggested. I wouldn't try to jump start it though through the separator (Fused Jumpered or not) w/o equalizing the banks for a bit. BTW my connections leads at the separator are long enough to just connect one side to the other...Take the separator out of the system till repairs are made.

A very good point, thank you. Were you able to buy a cable with the fuse "housing" already attached? (I found some "fuse loops" that sort of looked like the right idea on a marine website.) What gauge wire do you recommend? It might be nice (or irrelevant) to use a fuse that matches those in the house electrical panel ... I suppose a few extra fuses would be good in an emergency kit ... or have you found they're virtually indestructible and don't generally ever need replacing.

**daveb** · 06-26-2017, 11:01 PM

Yes very good idea about having something like that on board. I drove way down the mountain to get fuse holder for member danhtran (Danh) at one of the Forum group meets in the Sierra’s. Having one would have saved me the trip. They are rated so if it says rated for 30 amps, the pigtail wires will handle that as max current. However you can use smaller fuses if you want.

I doubt your equalizing charge current will be over 30A. I mean I've never seen it, but would keep that in the back of my mind while troubleshooting the issue. Closing in on a dead short is something you want to avoid...believe me!

It wasn't my van and I didn't have a clue why the separator tripped out so the fuse was a safety measure. After we got the separator jumpered, Danh took it back to SMB west where they installed a new separator as his van was under warranty.

MadScience · 02-12-2018, 08:56 PM

I installed a 7610 after my old separator failed open last year. While I was doing some engine work recently I disconnected the starting battery and expected the low power cutout to open the separator. It did not.

I continued to have power on the starting battery side. The status LED also remained on, indicating a connection.

I wonder if I have some other wire bridging the two systems. There shouldn't be, and in fact the old separator had failed open, and the house battery would not charge while driving in the dark. I did no other re-wiring since the separator swap.

There could also be a capacitor holding the engine side high somehow, of course it would continue to be charged. At the time I considered, but did not try turning a load on on that side. Mostly because I wanted to get the work I was doing done before debugging a new issue.

Is a certain level of voltage perhaps high enough to re-close the separator? I'm sure my solar was going strong.

Or do should I consider that my new separator may have an issue?

Scalf77 · 02-12-2018, 09:28 PM

I suspect that it was closed before you disconnected from the battery. At that point it is a closed relay end really nothing to bring it down. If you were plugged in or had solar I suspect it would keep it closed. It does not have to be connected to a battery.

-greg

MadScience · 02-13-2018, 12:10 AM

You're making it sound like I'm actually confused about what it does, which might explain some things.

I suppose 0 volts is not actually the same thing as an open circuit.

So it stays closed if one battery disappears and goes open circuit, but opens only when it goes to low voltage?

If so, then what's the right way to hand a vehicle with one of these to a shop? With the house battery and solar disconnected?

Scalf77 · 02-13-2018, 05:51 AM

So if you followed the installation instructions, there should be a 1 amp fuse going to ground, I suspect pulling the fuse (or just disconnect the wire) should disable it. I am not sure if it's connected that it will disconnect though.

So wiring a switch into the start isolate circuit if you are not using it. That would force it open.

As long as there was no charging source the House side should drop low enough to disconnect., so disconnecting solar, covering panels if you don't have a disconnect method.

You are thinking about how it works correctly. If it was open when you disconnected the battery it should not have connected because the starting side would have been zero, and given you a low voltage lockout. But, if already closed (because of solar power) then disconnecting the battery does not drop that side of the relay to zero because it is already closed. It will be the same voltage as the house side. The voltage would need to drop below 12.75 for it to disconnect. The of course it would not re-close, because of the of the low voltage lockout.

-greg

MadScience · 02-13-2018, 09:36 AM

Thank you!

I'll play with it to fully confirm this behavior, but this is a self consistent view now.

I stuffed the blue sea into the same spot as the old one was, under the degas bottle, which isn't great for access. I did pull out the remote LED, so locating the fuse somewhere, where it can easily be pulled seems sensible.