Reply
 
Thread Tools Display Modes
 
Old 11-09-2018, 03:25 AM   #1
Bronze Member
 
Join Date: Jul 2018
Location: Texas
Posts: 29
Default Could this be a battery isolator problem, or???

I recently replaced my stock Magnatek 6332 converter/charger in my 1998 Xplorer 230 XLW with Progressive Dynamic's PD 4635 unit. The conversion was painless and has proven to be a major and needed upgrade; not only do my house batteries charge much more quickly, and the converted 12VDC is now super clean, enabling problem free DC power to all devices including my TV, but I suspect that the life of my batteries will be greatly extended as a result as well.
However, when removing all power sources to the RV in order to install the new converter after unplugging from 120VAC, I then disconnected my house battery and (wisely) double checked for DC voltage before proceeding with the exchange, and found that I still had 11.8 volts showing on the DC side. The start/engine battery was still connected at this point, and thinking that as this RV is equipped with a battery isolator I had not disconnected it. I then checked the voltage of this battery before disconnecting it, and at the battery terminals it showed 12.8 volts, but after disconnection the house voltage dropped to zero and I proceeded with the converter swap. (one volt difference between the terminals of the battery and the house circuit voltage before disconnect).
Before I made this converter swap, the original house charger only charged the house batteries and not the start/engine battery and that is still the case with the new unit. So as before I planned to reinstalled a small (1 amp) smart trickle charger on the start/engine battery, but only after checking that the PD charger was operating correctly by going through bulk (14.4V) and acceptance (13.6V) cycles before hitting a final float stage (13.2V) after approximately 34 hours, and it did so. After confirming that it was indeed operating correctly in this regard, I hooked up the trickle charger to the start/engine battery, and after around three hours I was registering 13.5-13.6V on the house battery circuit, and 12.9 on the start/engine battery (up from 12.6 before charging it). When I disconnected it, the house battery circuit after a couple of hours returned to 13.2V.
So, although the PD 4635 is not charging the start/engine battery, the voltage from it is definitely affecting the house battery circuit and in fact the reverse is true! I'm thinking that the isolator is malfunctioning; however, this RV also has an emergency start feature that with a dash button press a solenoid is activated that connects the house batteries to the start battery if it has been inadvertently discharged (headlights left on, etc.) and I had recently used that feature, so I suppose that could be playing a part in this issue as well.
Any ideas, anyone?
__________________

nicaland is offline   Reply With Quote
Old 11-09-2018, 11:09 AM   #2
Platinum Member
 
markopolo's Avatar
 
Join Date: Oct 2006
Location: New Brunswick, Canada
Posts: 7,733
Default

Sounds like you're on the right track and have a good understanding of what is happening.


These two pdf's have isolator troubleshooting steps and should be helpful:


Battery_Isolator_Trouble.pdf


isolator sp1.pdf
__________________

__________________
Two bikes on sliding cargo box: https://www.classbforum.com/forums/m...icture206.html & 1997 GMC Savana 6.5L Turbo Diesel Custom Camper Van Specifications: https://www.classbforum.com/forums/f...vana-5864.html
markopolo is offline   Reply With Quote
Old 11-09-2018, 02:51 PM   #3
Bronze Member
 
Join Date: Jul 2018
Location: Texas
Posts: 29
Default

Thanks Marcopolo! This indeed is very useful information. Based on my initial read of these two documents my first guess is that diode 1 has shorted. I forgot to mention that the alternator is successfully charging the house bank, but I have yet to check the relative voltages of each bank while charging with it. I'm going to disconnect shore power, discharge both banks a bit, and test relative voltages per these instructions at the isolator. I'll report my findings after doing so. BTW, my Xplorer manual, which actually is a wonderfully complete, detailed, and well organized one, states that the converter/charger when in use charges only the house bank. Why is this the case, and is there a way to get around this condition and have it charge the engine battery also? As I had mentioned before, I do hook up a trickle charger for the start/engine battery during storage, but it sure would be nice to have my new charger sned the same charging protocol to it as well.
nicaland is offline   Reply With Quote
Old 11-09-2018, 05:04 PM   #4
Platinum Member
 
markopolo's Avatar
 
Join Date: Oct 2006
Location: New Brunswick, Canada
Posts: 7,733
Default

A battery isolator is unidirectional. Charge current flows in one direction. A battery separator can be bidirectional.

Some battery separators use more current than others so some research before purchase is beneficial.

This Automatic charge relay -> https://www.bluesea.com/products/761...12_24V_DC_120A - looks to have good specs.

Quote:
Q: How does an ACR differ from a battery isolator?
A: Battery isolators use one-way electrical check valves called diodes that allow current to flow to, but not from, the battery. ACRs use a relay combined with a circuit that senses when a charging source is being applied to either battery. ACRs are more efficient than battery isolators because they create little heat and consume minimal charging energy.
__________________
Two bikes on sliding cargo box: https://www.classbforum.com/forums/m...icture206.html & 1997 GMC Savana 6.5L Turbo Diesel Custom Camper Van Specifications: https://www.classbforum.com/forums/f...vana-5864.html
markopolo is offline   Reply With Quote
Old 11-09-2018, 05:38 PM   #5
Bronze Member
 
Join Date: Jul 2018
Location: Texas
Posts: 29
Default

Well it certainly looks like a battery separator, or an Automatic Charge Relay, as Blue Sky is calling this one, would be a better solution than an isolator in all respects, unless there are major efficiency differences involved. Are these typically found in more recently designed/built two battery bank applications in lieu of using an isolator?

Another aspect that I'm having a hard time fully comprehending involves the fact that I'm dealing with two charging sources, shore/generator and engine alternator. If I were to replace my isolator with a separator, would both charging sources charge both banks, and would there be a conflict or overcharging condition if both are charging at the same time? I apologize for the newbie questions; this is one of those things where a little bit of knowledge can be a dangerous amount to rely on!
nicaland is offline   Reply With Quote
Old 11-09-2018, 06:06 PM   #6
Platinum Member
 
markopolo's Avatar
 
Join Date: Oct 2006
Location: New Brunswick, Canada
Posts: 7,733
Default

The Automatic Charge Relay would be better than an isolator in my opinion.

1. Bidirectional charging - when on shore power or generator both the house and chassis batteries get charged. Both batteries also get charged by the alternator.

2. No voltage drop - typically isolator output to the house battery drops by 0.5V. If you have 14V off the alternator that means only 13.5V at the house battery.

One downside would be if you chose a separator with wasteful current draw and you have solar panels on the van. You don't want to waste 1.5A of solar output on the separator. The solution there is to chose something like the Automatic Charge Relay. The current used is 175mA (combined) 15mA (open). 175mA = 0.175A, huge difference compared to 1.5A for example.
__________________
Two bikes on sliding cargo box: https://www.classbforum.com/forums/m...icture206.html & 1997 GMC Savana 6.5L Turbo Diesel Custom Camper Van Specifications: https://www.classbforum.com/forums/f...vana-5864.html
markopolo is offline   Reply With Quote
Old 11-09-2018, 06:10 PM   #7
Site Team
 
avanti's Avatar
 
Join Date: Jul 2013
Posts: 3,054
Default

Quote:
Originally Posted by markopolo View Post
The Automatic Charge Relay would be better than an isolator in my opinion.

1. Bidirectional charging - when on shore power or generator both the house and chassis batteries get charged. Both batteries also get charged by the alternator.

2. No voltage drop - typically isolator output to the house battery drops by 0.5V. If you have 14V off the alternator that means only 13.5V at the house battery.

One downside would be if you chose a separator with wasteful current draw and you have solar panels on the van. You don't want to waste 1.5A of solar output on the separator. The solution there is to chose something like the Automatic Charge Relay. The current used is 175mA (combined) 15mA (open). 175mA = 0.175A, huge difference compared to 1.5A for example.
Well, the other choice is simply a "dumb" separator that only closes when the engine is running, combined with a Trik-L-Start to permit the solar to keep the chassis battery charged.
__________________
Formerly: 2005 Airstream Interstate (Sprinter 2500 T1N)
Now!: 2014 Great West Vans Legend SE (Sprinter 3500 NCV3 I4)
avanti is offline   Reply With Quote
Old 11-09-2018, 06:38 PM   #8
Platinum Member
 
markopolo's Avatar
 
Join Date: Oct 2006
Location: New Brunswick, Canada
Posts: 7,733
Default

That's an option for sure. The Trik-L-Start does introduce a 0.2V voltage drop and limits current to 5A. Plus you have the cost of buying two devices. The Blue Sea 7610 appears to be around $78 on Amazon https://www.amazon.com/gp/product/B000OTIPDQ/
__________________
Two bikes on sliding cargo box: https://www.classbforum.com/forums/m...icture206.html & 1997 GMC Savana 6.5L Turbo Diesel Custom Camper Van Specifications: https://www.classbforum.com/forums/f...vana-5864.html
markopolo is offline   Reply With Quote
Old 11-09-2018, 06:46 PM   #9
Bronze Member
 
Join Date: Jul 2018
Location: Texas
Posts: 29
Default

Definitely sounds like an ARC is a win-win for me then, especially since I'm not using any solar panels. The Blue Sea (not Blue Sky) ARC is only $50 or so more than a new Surepower 1602 isolator replacement cost as well. I have used other Blue Sea products in the past on boats and find their stuff very well made and engineered. I don't know if I will run into any wiring difficulties but haven't researched it yet, and suspect that should be readily available info and not to complicated. As I had mentioned before I do have a start assist system on this RV that via a manually operated relay couples the house bank with the engine start battery, which sounds like will be redundant after installing an ARC in lieu of an isolator, and I figure it would be prudent to disconnect this system after installing the ARC.
nicaland is offline   Reply With Quote
Old 11-09-2018, 06:49 PM   #10
Bronze Member
 
Join Date: Jul 2018
Location: Texas
Posts: 29
Default

Thanks marcopolo for the Amazon link to the ARC. That makes it almost exactly the same price as the replacement isolator!
__________________

nicaland is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT. The time now is 06:20 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.