battery isolator replacement

[mkguitar]

Seems that my Sure Power 16023A is done.

I am now working in EU, before leaving home the other day with coach battery switched "off", I disconnected my chassis battery and...the underhood light stayed on! ...running off the shore power.


When i get back home I'll get into it but first suspect is the battery isolator.


the 2006 Pleasure-Way Lexor ( Chev) has a stock electrical system- nothing special or added ( like solar or extra batteries).

another SP16023A would be easy in terms of cabling and mounting- a direct easy swap.

What is a suggested battery isolator- anything better come up in the 10 years since my van was built?



Thanks, Mike

[markopolo]

Other members here will know what the latest & best units available are. My understanding is that those traditional isolators tend to cause a significant voltage drop at the house battery.

I'll chime in with the low cost Aopec unit I installed: http://www.classbforum.com/forums/f8...lled-3409.html

The advantages would be insignificant voltage drop if any, bi-directional so both the house and chassis batteries charge when plugged in or on solar etc. With my clamp-on ammeter, I measured 0.25A to 0.28A current draw when engaged (cut in 13.3v / cut out 12.8v). You can use a switch to break/make the tiny gauge ground wire to manually disengage the house and chassis batteries if/when desired. (that's contrary to what Aopec told me in an email - but I clearly hear the "clunk" sound caused by the unit engaging/disengaging when I use the switch I installed)

It's rated 140A so only good for appropriate capacity systems.

I didn't know much about the brand before I bought it or even now but it is still working and price was pretty nice for the feature set.

[booster]

I have two of these sitting on my shelf used, but now unused:

https://www.bluesea.com/products/761...12_24V_DC_120A

They use a bit of power when combined at 175ma but only 15 when open. 120 amp continuous rated. They are nice because they have an input that will force them open to disconnect the coach if the batteries are full. You just use a switch and put 12v on the input.

$20 apiece plus shipping? or whatever

[mkguitar]

Thanks but the BlueSea are under-rated for my alternator

Mike

[booster]

Originally Posted by mkguitar

Thanks but the BlueSea are under-rated for my alternator

Mike

I don't know Pleasure-way wiring, but many B's have 80 amp breakers in the coach to engine cable, which would be 4 gauge. That would limit what you put through the separator to the 80 amps. That is how our Roadtrek was wired and breakered.

[jumpshowhigh]

Very simply, MOSFET based isolator from Perfect Switch is what's in my Sprinter. Seen them on Newell Coaches too. Far better than mechanical switches and not like the old diode style isolators....these have essentially no voltage drop. www.perfectswitch.com

[mkguitar]

This needs further investigation.

Pulling the terminals shows signal between the A and batteries 1 and 2 and signal between E and A- so that all checks out.

Reconnecting everything as of today shows normal operation ( No power to chassis with chassis battery disconnected)- so no underhood light on by itself

As expected power at #2 terminal from aux battery ( switched off) when shore power is connected.

I will be looking further.

Mike

[peteco]

Originally Posted by booster

I have two of these sitting on my shelf used, but now unused:

https://www.bluesea.com/products/761...12_24V_DC_120A

They use a bit of power when combined at 175ma but only 15 when open. 120 amp continuous rated. They are nice because they have an input that will force them open to disconnect the coach if the batteries are full. You just use a switch and put 12v on the input.

$20 apiece plus shipping? or whatever

Hey booster I am interested in these. I tried to send a PM but it is not showing it sent. PM me. Thanks.

[mkguitar]

Found the cause of the initial under hood light on with battery disconnected!

I had a battery trickle charger on my chassis battery- and shore power connected- even though the battery negative was disconnected...the battery was "seeing" chassis ground through the 2 extension cords plugged into my house...

I put a grey ground lift on my trickle charger and the underhood light and chassis have no power to them anymore.

So there is/was no problem with my isolator

duh!

Mike

[booster]

Originally Posted by mkguitar

Found the cause of the initial under hood light on with battery disconnected!

I had a battery trickle charger on my chassis battery- and shore power connected- even though the battery negative was disconnected...the battery was "seeing" chassis ground through the 2 extension cords plugged into my house...

I put a grey ground lift on my trickle charger and the underhood light and chassis have no power to them anymore.

So there is/was no problem with my isolator

duh!

Mike

I have never checked to see if a charger has the 12v negative tied to the safety ground. It never occurred to me that it even might be. I wonder is most/all chargers do that.

[markopolo]

deleted my other post

What is the second extension cord connected to? Was it another trickle charger or the coach AC panel?

[mkguitar]

There is shore power.

and the trickle charger extension cord

both are connected to outlets at the house..

the circuit is completed through the grounding of the house outlets.

lifting the ground of either of the cords breaks the circuit


what this really points to is my initial concern ( underhood light & chassis energized) is that I had the trickle charger in place and didn;t think to remove it...
Considering I work with electronics- this is shameful- and I got hung up on assuming an isolator problem- where one didn;t exist.

The good news is that I have gone through some wiring and cleaned up the connections.

Mike

[booster]

That is the part I don't get. The AC ground is on the neutral by code at the box in your house, so both grounds, and neutrals are the same. The DC side is separate, or so I thought, so how would the ground of the chassis battery get connected to the frame of the vehicle unless the negative of the trickle charger is connected to the AC safety ground? I need to go out and check a couple of chargers and see if they are electrically connected between DC negative and AC safety ground.

[avanti]

Originally Posted by booster

The DC side is separate, or so I thought, so how would the ground of the chassis battery get connected to the frame of the vehicle

???
My understanding is that the DC battery ground is almost always connected to the chassis. Mine certainly is.

For one thing, this would HAVE to be the case if you are using your engine alternator as a charging source.

[booster]

Originally Posted by avanti

???
My understanding is that the DC battery ground is almost always connected to the chassis. Mine certainly is.

For one thing, this would HAVE to be the case if you are using your engine alternator as a charging source.

I probably wasn't clear on that. He has his chassis battery negative cable off, positive still on, and the battery is still connected to the chassis through the trickle charger and shore charger. The only way that could happen, I think is if the trickle charger 12v negative is connected to trickle charger AC safety ground.

[avanti]

Originally Posted by booster

I probably wasn't clear on that. He has his chassis battery negative cable off, positive still on, and the battery is still connected to the chassis through the trickle charger and shore charger. The only way that could happen, I think is if the trickle charger 12v negative is connected to trickle charger AC safety ground.

Ah, now I see what you were saying. Sorry.

[booster]

I just checked the 3 standalone chargers that I have available. The Ctek is two wire, so doesn't apply.

The old sears fixed voltage unit shows megaohms between 12v negative and AC safety ground.

The Blue Sea marine charger that I use as a bench charger showed megaohms and then open, so must have charged a capacitor.

The trickle charger mkguitar has must be wired differently than regular chargers.