deep cell battery cut-off switch

[Ella1]

Hi,
I haven't been able to get out much, and it appears I probably won't for a while.
I have a deep cell battery that my mechanic says is draining the van battery. I asked about installing a cut off switch so I could turn the connection on or off when I want.
He said no, too complicated/expensive.

Is that right?
Can anyone recommend an rv dealer or service center in Tucson AZ that could do it? Any idea on cost of such a thing?
Or, what can be done instead? I hate to remove the deep cell battery, because I do hope to get out a few more times.

Thanks.

 

[WalkaboutTed]

I've used Big Sky RV mobile rv tech service and was very happy. Shawn will come directly to your home. Ain't super cheap, but what do you want for someone to come to you? He installed an on/off switch between my alternator and the deep cycle battery bank while he ran the cable between the two (I couldn't physically do that). I think that's what you want? The phone # (520) 818-2310

Hope this helps,
Ted

 

[SternWake]

It sounds as if you have not installed an isolation device, such as a solenoid, in between original alternator charging circuit and house battery, and thus house loads are able to discharge engine battery and house battery.

INstalling a  Continuous Duty Solenoid in between engine battery or alternator, and house battery, which allows alternator revcharging of house battery but isolation with engine off, is pretty simple, and thus the 'mechanic' you talked to, well their diagnosis is kind of suspect in my book.

This one does everything automatically it is a voltage sensing solenoisd that only combines the batteries once it sees battery charging voltages:

https://www.amazon.com/Bussmann-RB-...coding=UTF8&psc=1&refRID=9E59G5FJDNNQYNYTCE6A

The following link is a 'dumb' solenoid.  it must be triggered by a switched 12v circuit.  Ideally this circuit would be live only with engine running.  One could also put an illuminated switch to trigger the solenoid manually.


https://www.amazon.com/Cole-Hersee-...86783638&sr=1-6&keywords=cole+hersee+solenoid




There are many dozens of products and methods to allow recharging of house battery while separating engine battery from house loads with engine off.  Above are just 2 of the possible products.

Here is a third which can handle manually  switching a hundred amps on and off:

https://www.amazon.com/dp/B00445KFZ2/ref=twister_B01E53G7QI?_encoding=UTF8&psc=1
  Actually it is rated for 250 amps if the proper cabling is used to carry that much current.
It is about 3 inches square and 2 inches thick.

 

[WalkaboutTed]

I had in hand, a Marinco 701 battery disconnect switch that I had bought from Amazon. When Shawn came, I asked him to put it in. No problem. As far as a solenoid, I didn't need one with the CTEK d250s, but that's a bit pricey for what you want. I wanted to be able to manually turn off the connection, that's why I bought the switch.
Ted

 

[Ella1]

Thanks--I should have said this is a 1995 Chevy Astrovan. I have no idea what the people who installed the deep cell did 15+ years ago.

I don't know how to answer your questions: I haven't driven/used the van much since end of November other than several short trips--10 miles or so one way. (I do not live in the van) Monday the 6th the battery was dead, a neighbor jumped it for me.

That's what I want to do--manually--and easily, turn off the connection. Raising the hood is very difficult for me, so really need an easy way to do it. I don't use the house battery much at all, even when I am out, but I also do not want to take the battery out. I do want it available. Can the switch be put inside the van instead of under the hood without costing a lot more money?

This does sound like what I want, but I don't know car talk well enough. I want to understand better so I can ask for what I want:
SternWake said, "INstalling a Continuous Duty Solenoid in between engine battery or alternator, and house battery, which allows alternator revcharging of house battery but isolation with engine off, is pretty simple, and thus the 'mechanic' you talked to, well their diagnosis is kind of suspect in my book."
SternWake, yes, I think my mechanic is very basic. Fortunately, I haven't had anything beyond that, until now.
Could/SHOULD a mechanic be able to do this? Would the Chevy repair shop be able to?


Ted, thanks for the recommendation.
You said, "As far as a solenoid, I didn't need one with the CTEK d250s, but that's a bit pricey for what you want. I wanted to be able to manually turn off the connection, that's why I bought the switch."

If there is not a solenoid, would it be less expensive to get one and the switch, or just get the switch you have- CTEK d250s?

I can take the van TO the shop, if I have Shawn come here, what parts do I need to have on hand?
Again is this something a good mechanic can do? I asked for a recommendation for an RV repair, because my regular mechanic said no.
I now think he either can't or just doesn't want to do it.

 

[WalkaboutTed]

The Marino on/off switch I have in the cabin. I don't NEED it, but I, too, wanted to be able the cut off completely the connection between the alternator to the battery bank, without opening the hood.

I have the CTEK unit pretty much because it also works as my solar charge controller, too. Way overkill for what you need. I just mentioned it by way of explaining why I don't have a solenoid.

But, if you just cut off the deep cycle battery with no charging at all, you'll kill it with neglect. Then you will have to pull it out. So, if you are going to have the van sitting for any length of time, perhaps you can get a trickle charger, either plug in or solar on your dash.
Ted

 

[SternWake]

Your secondary battery likely has some sort of isolation device on it already.

It could have failed. Continuous duty solenoids do wear out and tend to stay connected when they do, so house loads can draw down engine battery.

Batteries do age and go bad, even if not used. They self discharge and lose capacity. the more discharged they are the faster they lose capacity, and it is mostly permanent.

Also driving for 15 minutes is not neearly enough to properly recharge a battery. A healthy battery that requires a jumpstart needs no less than 5.5 hours of driving/ charging before it can be considered fully charged, and this ideal, will likely take much much longer.

Your issues could be entirely related to an undercharged battery.

All we here can do is guess as to what, if any problem, besides a failed battery or 2, exists.

Diagnoising this issue is quite simple, but some mechanics do not know DC electricity very well, and Very few understand the requirements of a battery to remain healthy in deep cycle service.

I would not recommend acquiring any parts, without knowing and testing what already exists.

 

[WalkaboutTed]

As far as Shawn, I had the switch beforehand because it was something he wouldn't have in stock. You may want to speak to him regarding what you should have ahead of time to make it both easier for him, so he wouldn't have to come out twice, and to make it cheaper for you. I'm sure if you explain that funds are an issue, ß that he will consel you on what you should do. You're not a million dollar Class A owner, and it should be a relatively easy (i.e., inexpensive job, we hope). Just tell him that the chick with with tall white van in Barrio Hollywood referred you to him.
Ted

 

[DannyB1954]

A manual switch would have to be heavy duty like they use on boats. Most people use a electrical solenoid. You can feed the coil of it with a small switch to disable it if you like. This isn't rocket science. If someone says too difficult, find another mechanic. The first guy should only be allowed to pump gas.

 

[John61CT]

You have two issues. 1. keeping the house battery (ideally a separate circuit where "non-essential loads" run) isolated from the starter battery (ideally a separate "vehicle running" circuit).

And 2. keeping the house battery topped up, sounds like only "from shore power" is of concern for now.

Your alternator is no good for #2

If the house battery is "mostly shot" and you're not planning on renewing it, then only deal with #1 for now.

You also should make sure while the van is sitting, only the normal self-discharge is running any battery down, not any devices left on pulling a load. Call this job #3.

#1 a cheap solenoid that joins the two circuits together only while the engine is running is crude but at least automatic, but will need to be re-looked at if you add solar, and you still need manual switching of your shore-power charge source system for #2.

A good manual switch to isolate/combine the two circuits is not much cheaper and can be handy for "self jump starting", but easy to forget to switch back and forth between isolate/combine.

Personally I'd recommend a Xantrex "Echo Charge" device, one-way 15A charging flow to top up your Starter from House, about $100-120. But that would require some thoughtful rewiring, all charge sources should go to House, make sure no accessories run off the Starter.

If you're not using the van for dry camping these days, maybe not worth that sort of "doing it right", but to me having to later re-work things is more wasteful.

Another approach is to keep the two batteries connected to share the House loads, and use a low-voltage disconnect on the Starter/reserve to isolate just that battery from all the House loads based on its voltage.

If your House loads are < ​65A this is only $45! http://www.ebay.com/itm/172237303416 and you likely don't need any other rewiring.

100A and 220A versions are a bit more.

 

[Ella1]

According to my paperwork,
April 08, 2015 a new marine battery was installed. Odometer out reading 67109
Dec. 22, 2015 Van battery and alternator installed. Odometer out reading 70776
Feb 07, 2017 New van battery installed. Odometer out reading 74235


Is it likely that the marine battery is dead, needs recharged? Can I do that via several 40+ miles trips? Or are longer ones needed?
To use a trickle charger, I do have to be able to lift the hood, right? I don't know that I can do that. Last time I tried, I couldn't. Too much hood resistance, not enough strength...

I'm beginning to think the best easiest, least expensive solution, is to drive farther at least twice a month.

 

[Ella1]

So if I drive 40 miles over I-10 with the new battery, not knowing the condition of the marine battery, stop for lunch, and drive back the marine battery should be recharging, and there shouldn't be a problem? Is that right?

 

[Optimistic Paranoid]

There should have been some kind of automatic isolator device installed between the two batteries.  The two commonest ones are a solenoid or a diode isolator.  Either can fail. 
With a solenoid, commonest failure is for the contacts inside to weld themselves together so the two batteries are never separated.  When that happens, loads on the house battery also discharge the engine battery.

With the diode type, if a diode fails, no current from the alternator can pass and the house battery never gets recharged by the engine running.

In addition, if it was done RIGHT, there should have been fuses at either end of the wire between the batteries.  If either fuse is blown, no current can flow between the batteries.

Somebody needs to trace the wire between the two batteries and look for the fuses and or the solenoid or diode isolator.

Somebody with a digital meter needs to check a couple of things.  A fully charged battery should read 12.6 to 12.7 volts when the engine isn't running.  When the engine IS running, the meter should be reading somewhere between 13 and 14.5 or so volts, because voltage is pressure, and the alternator needs to put out more volts than the battery has in order to force current into it.  The meter can also be used to verify voltages into and out of the solenoid or diode isolator.

If you're not seeing the higher voltage on the house battery when the engine is running, then the house battery isn't being charged by the alternator, and either the diode
(if that's what you've got) or a fuse is bad.

 

[Ella1]

Is the more appropriate mechanic then an RV shop?

 

[John61CT]

Is it likely that the marine battery is dead, needs recharged? Can I do that via several 40+ miles trips? Or are longer ones needed?
To use a trickle charger, I do have to be able to lift the hood, right? I don't know that I can do that. Last time I tried, I couldn't. Too much hood resistance, not enough strength...

I'm beginning to think the best easiest, least expensive solution, is to drive farther at least twice a month.

Yes it is likely. Note "marine battery" in itself does not have much meaning, very likely not a true deep-cycling type but just a beefed up starter type.

Some alternator/regulator setups don't fully recharge a battery used for deep-cycling even if you drive for 10 hours.

Some stock setups are fine, and others can be tweaked to deliver full current for a nice long bulk/absorption phase, but using an engine+alt or other fossil-fuel generator setup to do the long-tail low-amp many-hours topping up phase is very wasteful, both in fuel and wear and tear on the engine.

Shore power or solar is best for that latter.

Or you just resign yourself to buying new batteries more frequently.

It should be easy for a competent RV tech or mechanic to rig you a high-amp connection for a charger somewhere outside or in (glovebox, under the dash?) so you don't have to lift the hood.

 

[John61CT]

Is the more appropriate mechanic then an RV shop?

If you do your research, have detailed drawings and the specialized parts ready on hand, any guy competent with auto electric should be OK.

If you are asking them to help with design expertise, selecting the components etc, that's much harder to find.

 

[Ella1]

Yes it is likely. Note "marine battery" in itself does not have much meaning, very likely not a true deep-cycling type but just a beefed up starter type.
This battery: 24X-XHD $179.99


Some alternator/regulator setups don't fully recharge a battery used for deep-cycling even if you drive for 10 hours.

Shore power or solar is best for that latter.
Okay, since it is probably dead, and I won't be camping for a few months, will the dead battery continue to pull a current from the (brand new) van battery? Should I have the trickle charger attached to the marine battery? I don't know if that one is easily available.
Should I have the marine battery removed, and replace it later? There is a 400 watt invertor connected to it, but nothing running from that battery unless I am camping. The inverter is turned off.


Or you just resign yourself to buying new batteries more frequently.
Not something I'd like to do, considering overall cost.

It should be easy for a competent RV tech or mechanic to rig you a high-amp connection for a charger somewhere outside or in (glovebox, under the dash?) so you don't have to lift the hood.

I think you said a mechanic could rig a connection for a trickle charger from the deep cell battery to inside the van.
Or, did you mean to rig a connection for a trickle charger from the van battery to inside the van?
Sorry, my head is spinning...

 

[Trebor English]

Removal of the dead marine battery will not fix the problem of running down the starting battery if the starting battery is still connected.  To run down batteries requires either a load always on or a month or two of self discharge.  You need to find and disconnect what is loading the two systems.  A "turned off" inverter can take quite a bit of power.  The self discharge is fixed with trickle charging.  A good battery with no load should go a month just fine.

You need a diagnosis first.  How long does it sit without running?  What loads are always on?  For example, do you have a keyless entry thing?  That requires a radio receiver always on to detect when you push the button.  An RV technician might be able to diagnose this.  I know auto and diesel people who would have no clue.  I think your best bet would be an amateur who wired up his own system and actually understands what is there.

 

[John61CT]

What he said


> This battery: 24X-XHD $179.99

Yes just a cranking battery, not deep-cycle. The only latter available through big-box mass retail are 6v golf cart type, x2 = 12v, Sam's Club likely better than Costco, but either better than a starter battery and not much more $$


Okay, since it is probably dead, and I won't be camping for a few months, will the dead battery continue to pull a current from the (brand new) van battery?

Well something is, need to identify what.

Should I have the trickle charger attached to the marine battery? I don't know if that one is easily available.

Should charge both up with a proper powerful charger. Test them under load see if they're any good. Keep them isolated from each other and fully charged while the van's being stored.

Then look at what needs doing, so you have a proper system that works for you and you know what's going on with it.


>There is a 400 watt invertor connected to it, but nothing running from that battery unless I am camping. The inverter is turned off.

Check to make sure, may need to isolate the inverter completely - or better, isolate the battery from all loads while in storage. These days just turning things off doesn't stop them from drawing a load.

>Not something I'd like to do, considering overall cost.

But there are costs in proper infrastructure, including labor, install $$. You have to weigh things up for yourself.

For me, I'd gladly spend $1000+ for good chargers, isolation/combiners, meters/monitors etc, even if my batteries cost less than that. Others think that's silly.

But safe solid clean wiring connections, proper fusing etc, understanding the details on how it all works, none of that is optional IMO.


>I think you said a mechanic could rig a connection for a trickle charger from the deep cell battery to inside the van.
Or, did you mean to rig a connection for a trickle charger from the van battery to inside the van?

An AC charger goes from shore power - home, paid campsite, etc to wherever your batteries are. A good design in your case might be an easily accessible spot to attach the 12V cables from that charger, to a "charging buss" circuit from which the current could be directed to feed either/both batteries.

You could use a manual switch allowing you to select which battery gets the charge current.

Or use an automatic combiner that lets both get charged together (also from the alt while driving), but keeps the two circuits (starter vs house) isolated when there's no charge current active.

Either of these may also have the ability to manually combine if you need to "self-jumpstart" in a pinch, without opening your hood.


Note with big drawn-down batteries, a "trickle charger" is only useful to maintain them after they've been recovered and fully charged, assuming they're OK that is. A good fast charger is not cheap, if you need to test tge batteries as well maybe better to get a trusted garage or auto electric shop to help you.


I see your "big picture" choices as

A. work with us to understand this stuff, we help you come up with a solid drawing and list of hardware to buy, or

B. find a friend to do this with you if you think it's just beyond you alone

C. find a competent RV/solar/auto electric professional, trust them to design and do it all and pay their (likely very high hourly) rate.

The last may well be the most difficult, too easy to pay too much for a guy that doesn't know enough. Doing A/B allows you to closely control the process so just basic auto-electric skills are enough for the install work.

But you do need that sort of help just to figure out what you have already, what can physically fit where, etc.

 

[Ella1]

Removal of the dead marine battery will not fix the problem of running down the starting battery if the starting battery is still connected.  To run down batteries requires either a load always on or a month or two of self discharge.  You need to find and disconnect what is loading the two systems.  A "turned off" inverter can take quite a bit of power.  The self discharge is fixed with trickle charging.  A good battery with no load should go a month just fine.

You need a diagnosis first.  How long does it sit without running?  
Depends on my health and the weather--temps, conditions, etc.
I do "grocery" trips ~ every 10-14 days. Longer trips--Thanksgiving I drove ~214 miles in ~ 14 hours, with a few stops during that time. Last summer, ~100-110 miles at least once a month over I-10.



What loads are always on?  For example, do you have a keyless entry thing?  That requires a radio receiver always on to detect when you push the button.  An RV technician might be able to diagnose this.  
Loads on: as far as I know the only thing that's always on is the clock. This is a 1995 Chevy Astro van. Nope, have to insert and twist the key, roll the windows down myself, rarely use the radio or even lights, (not much driving in the dark) I turn the ac off before stopping the van. Well, there is the marine battery and inverter...

I know auto and diesel people who would have no clue.  
Count me in that group. As if it's not already obvious. :-(

I think your best bet would be an amateur who wired up his own system and actually understands what is there.
I don't know anyone like that.