Battery Isolators,Separators, and Switches?

[daveb]

At least on my build the radio switch doesn't divert all power draw of the stereo to the house battery system when switched on. Also the separator will open at 12.8v when either of the battery systems drop to 12.8 provided the separator is in an automatic mode and is working correctly. Seems yours is working correctly because you state the fridge was still operating. I'm also not saying it was just the radio that caused the starting battery system to go dead but stereos with amplifiers can pull a substantial amount of power if (as in my case) they're wired into the vehicles stock fuse block. A voltage monitor (even the cheap plug in types) can go a long way when you're off shore power. The 12vDC power plugs on the dash run off the starting battery system where the outlets in the living areas typically are powered off the house battery system. You might have something else going on but my guess is it was the radio or something else you left on.
[edit] I think Greg's examples explained about the Surepower separator SMB installed years back. For several years SMB had the separator set to automatically jump start the vehicle every time the key was turned to start the vehicle. Many times it would mask a bad (or weak) starting battery. If the starting battery drops too low (completely dead) the separator would not engage to help jump the vehicle. That's a pretty rare situation but might be worth looking into. Pulling the ground wire off the separator is one way to test the starting battery. If you have that setup, pull the ground to the separator and let the van sit with no charging and see if it labors to start. In later years SMB disabled the auto jump feature and added a push button switch at the dash so the owner would have to manually force the separator to help jump start the vehicle.

Hope this helps
Dave

[coyotearms]

Originally Posted by awiggin2

I am a new sportsmobile owner and know very little about electrical systems. That said, I'm hoping the answer to my question does not leave me asking more questions.

I recently went camping and left my van parked for about 48 hours; fridge running the whole time and using the stereo occasionally (maybe 2 hrs/day). This amount power consumption concerned me, but I knew I had cables and a friend's diesel truck, so I viewed it more as an experiment. I left the 'radio switch' on the external/house battery the entire time, thinking if anything ran down it would be the house battery, not the van battery. To my surprise the van battery was dead, yet the fridge (the biggest power hog) was still going strong.

I've read most of the initial post, but I'm still confused as to why this happened and how to fix it. Apparently the refrigerator chewed through the van battery first and then moved onto the house battery. Why? (what good is a house battery if it is second in line to the van battery?)

Assuming this is your first post of this problem, I found scant info on the layout of your electrical system. I basically agree with daveb that you should be suspicious of the "radio" switch and how it is actually wired. Is there an added amp that was not installed through that switch? A problem there and a not-so-great engine battery bank could easily explain what happened. A "radio switch" can also make it more difficult when getting service from a vehicle dealer if they get suspicious that an electrical problem is in the house system and not the van system.

If your van is new, call SMB up and discuss the problem with them. Unfortunately, it is typical that you now are a long way from there, so that in itself is a problem. I had quite a few electrical things wrong with my build. I had a "start" button on the dash that had contacts dangerously close to other wiring, a dead-on-arrival Surepower battery switch and the second one too hot to touch when it connected the batteries together (used 60 Watts!), I dumped it for a much better Blue Sea unit. Even the way the solar was wired was wrong. Lastly, there was no fuse between the house battery bank and battery separator that would save the day in case of some kind of disaster in the engine battery bank such as a short, so when one tried to jump start the van with the house batteries (button on dash?) an even bigger problem would be created without it! So the lesson is spend some time with a volt/ammeter crawling around making sure you understand how things are wired. Went something goes wrong on the road you will be glad you have a better idea of how things work. If you end up having an accurate electrical schematic based on you sniffing so much the better!

[DonnyMeek]

After reading that post I'm going to have to rethink my simple second battery wiring solution.
I hadn't factored in the possibility of my starting battery going bad and trying to draw current from my winch battery to run the starter motor.
The 10 gauge wiring used in the install is kind of whimpy for that kind of draw.

[Dirk Mitchell]

Scal that is the best write up I have seen about how to set up a battery isolator, thanks for taking the time to write that up. You did mention cost being a deciding factor I am looking at that as I am looking at my build.
I tracked down the items on your diagrams to compare prices and they are a bit spread out for sure.

19.89 Pico 5575pt Master Batt Isolator Switch
59.37 Trombetta 12 Volt Bear DC Contactor Part No. 114-1211-020
96.60 SurePower 120 Amp Dual Battery Isolator
107.30 Sure Power 1315 Bi-Directional Battery Separator
187.18 Blue Sea 7620 Ml-Series Automatic Charging Relay
202.76 Blue Sea 7622 ML-ACR
72.40 Powerstream PST-SSB2180 (Not available on Amazon)

I was thinking of just going with a solenoid but I am thinking that the SurePower 120Amp may be the way to go now.

[Scalf77]

Dirk,

that post is getting a little dated, but still relevant. I have moved on to a Blue Sea 7622 myself now, while it is expensive, it will provide all the options you need, indicators, diagnostic aids, and minimal power draw while connected.

A lot of making the choice depends on the rest of you're system such as alternator, and loads on you're electrical while driving. If I had a Diesel such as the 6.0 I definitely want the ability for heavy house loads to disconnect while driving. This is where the voltage sensing units are a plus.

My rig has Sportsmobile's Starcool Airconditioning, on high this is a pretty high draw on the 12 volt electrical system, add in a few other things and the total load is two high for the alternator at idle or lower RPM's. When I just had the solenoid I had to be careful to monitor my loads during stop and go traffic or the voltage levels would drop. Good luck with your build.

-greg

[boywonder]

Dirk: I used a Blue Sea ACR...smaller and less current capacity than the 7622, but they are much less $$ and come in a few flavors.

https://www.amazon.com/Blue-Systems-...2XT7NEFMA&th=1

The blue sea ACRs do not have the heating losses that the Surepower separators have since there is no coil/relay/contactor

These are also available as an "add a battery" kit which also includes a manual switch.

https://www.amazon.com/Blue-Sea-Syst.../dp/B01DVOH5W2

[Dirk Mitchell]

Originally Posted by Scalf77

Dirk,

that post is getting a little dated, but still relevant. I have moved on to a Blue Sea 7622 myself now, while it is expensive, it will provide all the options you need, indicators, diagnostic aids, and minimal power draw while connected.

-greg

I agree great info! I have really been looking at the electrical system and set up and since I am using the van while I build it I want to make sure there isnt any safety issues. I ran across this and it isn't the cheapest option but it is kind of a cool idea.
Newport Vessels Trolling Motor Smart Battery Box Power Center black
I like the idea of it being enclosed, and the terminals on the outside. The charge meter and the charging ports are handy as well if your building and using it at the same time. Not sure whether it is worth 65.00 but if I can find a high AH battery that will fit in it, then it may be a nice fit.

[syncrow]

I have a 2006 Sportsmobile with a starter and house battery along with a Sure Power 1315-200 separator.

My issue is the separator continuously cycles every few minutes. My controller reads 12.9 volts increasing in tenths of a volt to 14.3v. When it reaches a reading of 14.3v the separator clunks and the reading goes to 12.9v and the separator clunks and the cycle starts again going to 14.3v.

I am just realizing that I am not sure if this happens while I am driving the van. I have only noticed the clunking noise while it is parked.

My batteries both read at 12.8v when disconnected from the separator. I have had my starter battery tested at two auto parts stores and both say it is good. My house battery is a 2 year old Lifeline AGM and as of now I am assuming it is good. My battery terminals and ground connections are clean and tight.

Any suggestions on how to resolve this issue is appreciated.

[Flux]

The clunking noise is when the van is running right?? Would like to know where that voltage reading comes from, maybe the house side of Sure Power??

Last and biggest question is if your alternator is your only charge source for the house battery? If so it could be cooked.

Sounds to me like the Sure Power is going into protection mode as it's reading a voltage of 12.8 or less on the house side and opening to keep the house from draining the starter.

If you have a voltmeter, test the house battery. If your alternator is your only charge source on the house battery, get an agm charger and try to revive the house battery. Something ain't right....obviously, but either your house is fried or just too deeply discharged that the Surepower is isolating it to protect the starter, or your Surepower is funky, which can happen too.

[rockbender]

Originally Posted by syncrow

I have a 2006 Sportsmobile with a starter and house battery along with a Sure Power 1315-200 separator.

My issue is the separator continuously cycles every few minutes. My controller reads 12.9 volts increasing in tenths of a volt to 14.3v. When it reaches a reading of 14.3v the separator clunks and the reading goes to 12.9v and the separator clunks and the cycle starts again going to 14.3v.

Do you have solar panels?