Battery issue on 2006 Southwind 32VS

[Old Bounder]

Originally Posted by TQ60

Disconnecting the ground only can still allow a discharge...in a different battery.

If there are more than one batteries in use, and the ground is disconnected on ONE, then that battry is removed from the system a nd this it cannot discharge.

But the other batteries may still have a path.

Further, depending on how things are wired up there could be instances of current flows in the wrong direction that could cause damage, this has been seen on some of the older CAT equipment where the disconnect was on the ground side of a 24 volt system and connections were made mid string at the 12 volt point.

There must be connection to both sides of a battery to have a path for discharge, period.

Disconnecting either side will stop the discharge, but the positive post is the better choice.

An isolator can be added this way, connected to the positive post of the battery, this provides a common connection for a single charging source that can charge all batteries in an isolated configuration even if disconnected via the disconnect.

I fully understand the use of battery isolators (diode and mechanical) and the implementation of multiple batteries in multiple banks. However, your entire post makes no sense in the context of RV battery implementation.

Battery disconnect switches need to be placed (electrically) to disable the entire bank involved. That is only common sense.

If disconnecting a battery ground terminal (as opposed to the positive) causes another battery to discharge, then there was a problem in the system long before disconnecting the first battery.

Disconnecting the negative (as opposed to the positive) is always suggested to prevent sparks. Since either will get the job done electrically, the negative is always recommended.

Your last three statements (except for the recommended positive post disconnect), while true, do nothing to support the statements in the post I initially quoted or your current statements

[bjsheldon]

I had the same problem with the chasis battery discharging while being stored. I installed a "Trick L Start" ($39.95 @ RV Upgrade) and it solved my problem. I'm told many RV's don't charge the chasis battery unless the engine is running. The Trick L Start takes current from your solar or converter and charges the chasis battery. You don't need to mess with a battery disconnect. If you really want a battery disconnect, harbor freight has one that connect directly to the battery for $5.95. The solar pannel will not cause your batteries to discharge if its covered.

[Ottawa]

If you have a phantom draw on your chassis battery the solar panel that comes with the MH will not be enough to keep all the batteries fully charged. I speak from experience on this. However, I never used my Trikle Charger after I found the phantom draw.

[TQ60]

I need to clarify a few statements I made.

The suggestion of an isolator connected with the disconnect switches is a non-standard arrangement, since it is a colection of diodes it allows one war current flow, and if connected directly to the battery positive posts it provides a charging path to the battery even if the battery has a complete disconnect from the system via a large disconnect switch.

This allows a single point connection for a charging source such as a solar panel while still disconnecting all system loads.

The statement regarding the disconnect of the negative post ALLOWING a different battery to discharge is confusing, the statement should read ALLOW, NOT CAUSE, but the concern is with how the MH may be wired or thought to be wired. Some loads may be connected to the starting battery, or there may be wiring issues where via diodes or other components that may have failed one may assume the loads are disconected. When they remove the ground from the cabin battery it is disconnected, but the starting battery may still be connected and still discharge. And dependingon how everything is wired, if the starting battery has a ground not connected, the boost switch is used to connect the cabin battery there could be blown cables from excess current flows due to the missing ground wire from the starting battery to the engine block, this depends on the specific MH.

In short, one should always evaluate the system before doing any changes to determine what is there, how it works and what is needed to achieve the desired result. Then take these findings in consideration to determine what needs to be repaired and changed, after the work is done fully test to insure everything works as designed, if not then something was missed in the evaluation or design.

Yes, removing the ground is always the suggested procedure for servicing the batteries, it is the safe way to avoid welding a tool, not always the best for a fixed switched disconnect arrangement.

[Midniteoyl]

NHRA, and all racing bodies that I know of that require a cuttoff, require the disconnect to be on the POSITIVE. That way, even if two vehicles are touching, or a a part of the metal chassis is touching earth, there still is no way to draw from the batt.

[Old Bounder]

Originally Posted by TQ60

I need to clarify a few statements I made.

The suggestion of an isolator connected with the disconnect switches is a non-standard arrangement, since it is a colection of diodes it allows one war current flow, and if connected directly to the battery positive posts it provides a charging path to the battery even if the battery has a complete disconnect from the system via a large disconnect switch.

This allows a single point connection for a charging source such as a solar panel while still disconnecting all system loads.

The statement regarding the disconnect of the negative post ALLOWING a different battery to discharge is confusing, the statement should read ALLOW, NOT CAUSE, but the concern is with how the MH may be wired or thought to be wired. Some loads may be connected to the starting battery, or there may be wiring issues where via diodes or other components that may have failed one may assume the loads are disconected. When they remove the ground from the cabin battery it is disconnected, but the starting battery may still be connected and still discharge. And dependingon how everything is wired, if the starting battery has a ground not connected, the boost switch is used to connect the cabin battery there could be blown cables from excess current flows due to the missing ground wire from the starting battery to the engine block, this depends on the specific MH.

In short, one should always evaluate the system before doing any changes to determine what is there, how it works and what is needed to achieve the desired result. Then take these findings in consideration to determine what needs to be repaired and changed, after the work is done fully test to insure everything works as designed, if not then something was missed in the evaluation or design.

Yes, removing the ground is always the suggested procedure for servicing the batteries, it is the safe way to avoid welding a tool, not always the best for a fixed switched disconnect arrangement.

If that's a clarification, I certainly missed it. I read your post three times and still can't make heads or tails of your logic. The multiple failures, wiring errors or "unknowns" that you elude to are not mitigated or enhanced by where the disconnect is accomplished.

[Old Bounder]

Originally Posted by Midniteoyl

NHRA, and all racing bodies that I know of that require a cuttoff, require the disconnect to be on the POSITIVE. That way, even if two vehicles are touching, or a a part of the metal chassis is touching earth, there still is no way to draw from the batt.

That may be a "requirement" for standardization purposes, but whether a battery is disconnected at the positive terminal, or the negative terminal, will make NO difference whether any component touches "earth" or any body part of another vehicle. NO current can be drawn from that battery, into or out of, any other vehicle unless some metal part lands directly on the disconnected terminal.

Tell me the odds of probability that it will just happen to an exposed positive v/s negative terminal, and explain how it will make a difference.

[Midniteoyl]

NO current can be drawn from that battery, into or out of, any other vehicle unless some metal part lands directly on the disconnected terminal.

The bodies are grounded... yes, two different batteries, but, with the POS still connected and the two chassis touch, there is a path to the NEG of the other vehicle's BATT and thus a potential discharge path..

[John-n-TX]

I finally got all the batteries tested and they are bad. The coach batteries are 6V deep cycle trojan 105's. Does anyone have a recommendation for a good 6V deep cycle battery? By looking at the trojan website it appears their batteries are sold at industrial type locations that cater to bulk purchases.

[John-n-TX]

Thanks for everyone's suggestions. I finally replaced all the batteries about 6 weeks ago and since then no issue with dead batteries. It even sat 4 weeks w/o being started and still 100% charged!

[JohnRR]

Thank you for the update.

[RTegarini]

Since I'm 'electrically challenged', I won't take issue with those that say my BEP Marine Switch, installed on the positive side, won't solve the parasite drain from the chassis battery. (Step, slide-outs, engine, etc.)

I can tell you that before I installed the switch, without fail, the battery was completely dead at the 3-4 week mark. Since installing it, the motohome has sat for 4-5 weeks at a time, and starts right up. Battery has not gone dead and it's not even slightly sluggish or dragging when starting after a long period of non-use.

Since this was far cheaper than installing a solar panel system to trickle-charge the battery and seems to have solved the problem, I'm glad I made the effort. -RT