Reply
 
Thread Tools Display Modes
 
Old 01-06-2018, 02:59 PM   #1
New Member
 
Join Date: May 2016
Location: Texas
Posts: 16
Default Integrating Sterling B2B charger in RV w/Intellitec battery isolation setup

I have a 2017 Sprinter based motorhome built on the cutaway chassis.
I'm considering switching out the Intellitec components (Intellitec Isolator relay and relay delay) for a Sterling battery to battery charger in order to better tailor alternator charging for the house lithium bank, which I am going to increase to 400 AH so I can run more power hungry appliances, esp the microwave.
With the voltage drop coming via wiring from the alternator, the lithium bank does not see an appropriate bulk/absorption voltage and I'm concerned about how the alternator will fare if it is faced with a heavily depleted battery bank and the rapid charging profile of the lithium chemistry. It appears that many/most Sprinter RV manufacturers seem to be disregarding Mercedes recommendations for auxiliary battery bank size (100 AH), even with the stock Interstate batteries.
From a post on another forum where the Intellitec Isolator relay was replaced with a Blue Sea component, this relay is under the passenger seat. Not sure where the isolator relay delay is, but wonder if it is in the chassis battery compartment.

I'm still learning about DC to DC chargers like the Sterling units that allow separation and tailored charging profiles for the house bank. I read the instructions for a Sterling battery to battery charger, but I am far from clear how to integrate it in my system that has the Intellitec stuff. In integrating a Sterling in my system, it appears that the Sterling replaces the functions of these stock units.


Any thoughts?
__________________

woundedpig is offline   Reply With Quote
Old 01-06-2018, 03:10 PM   #2
Platinum Member
 
Join Date: Aug 2010
Location: Minnesota
Posts: 7,517
Default

I haven't dug deep into all the Sterling stuff, but have looked at them several times. I think all of them are setup to drag down the alternator as far as possible so they can supply the most charging current possible.

From what we have heard of the MB systems, the biggest issue may be that the MB electronics might not like the high output that it doesn't know where it is going. A lithium battery pack of 400AH will accept much more than the stock alternator can put out, so it will be maxed out all the time, and stock alternators don't like that. High temp compensation or shutoff would be absolutely necessary, I think.

Essentially all the high charge rate systems on Sprinters use standalone secondary alternators to charge the batteries, controlled by a remote regulator to get charge profile.
__________________

booster is online now   Reply With Quote
Old 01-06-2018, 03:31 PM   #3
New Member
 
Join Date: May 2016
Location: Texas
Posts: 16
Default

My understanding is that the amp draw is limited by the Sterling units, so that even if the batteries could pull at 100 amps, a 60 amp BB1260 would limit at 60 amps, thus protecting the alternator from being overdrawn.
From their product data sheet:

"This unit will increase the vehicle’s voltage to the auxiliary battery when it is low and reduce the vehicles voltage to the auxiliary battery when it is high. It will also NOT permit high current inrush beyond the rating of the product (even under high demand loads) and so delivers the auxiliary battery system the correct voltage for different battery types (programmable) regardless off the main system voltage swings, thus, protecting the auxiliary batteries from unnecessary damage. It ensures a constant, safer and much faster charge from the system."

"As the ProBatt C current limits you do not need to rate this product to the size of your charging source - for example, the 120A model can work with a 200A alternator without causing any damage."

Still learning.........
woundedpig is offline   Reply With Quote
Old 01-06-2018, 03:54 PM   #4
Platinum Member
 
Join Date: Aug 2010
Location: Minnesota
Posts: 7,517
Default

Quote:
Originally Posted by woundedpig View Post
My understanding is that the amp draw is limited by the Sterling units, so that even if the batteries could pull at 100 amps, a 60 amp BB1260 would limit at 60 amps, thus protecting the alternator from being overdrawn.
From their product data sheet:

"This unit will increase the vehicle’s voltage to the auxiliary battery when it is low and reduce the vehicles voltage to the auxiliary battery when it is high. It will also NOT permit high current inrush beyond the rating of the product (even under high demand loads) and so delivers the auxiliary battery system the correct voltage for different battery types (programmable) regardless off the main system voltage swings, thus, protecting the auxiliary batteries from unnecessary damage. It ensures a constant, safer and much faster charge from the system."

"As the ProBatt C current limits you do not need to rate this product to the size of your charging source - for example, the 120A model can work with a 200A alternator without causing any damage."

Still learning.........
Yes, the Sterling will stop at its max output, but if you are going to do only 60 amps, why use it. You don't need a fancy profile for lithium, just constant voltage (if it can hold it at the alternator) until you hit a voltage level, and then shut off. Normally, the low-mid 14's voltage of the stock alternator would be OK for lithium. My bet is that the Sterling would limit current if that is what you want to do, but I seriously doubt it would be able to hold voltage on a lithium pack, unless they are doing a PWM type current reduction, which in many cases just makes the voltage look like it is holding, it appears.

As you have a new, and expensive, lithium system and van, I think I would be looking at adding the extra alternator and saving headaches, and potential warranty issues. MB can't disallow you from doing the mods you are talking or void the warranty because of them, but they could make it tough to collect a warranty repair to that system if something should fail, as they could claim it was caused by the modifications.
booster is online now   Reply With Quote
Old 01-06-2018, 03:58 PM   #5
Platinum Member
 
Join Date: Aug 2010
Location: Minnesota
Posts: 7,517
Default

I would add that if you only concern is current limiting, then the 12v to 12v charger will do what you want. If you want to increase the amount you can pull out of the factory system, you really won't gain anything, I think.
booster is online now   Reply With Quote
Old 01-06-2018, 04:57 PM   #6
New Member
 
Join Date: May 2016
Location: Texas
Posts: 16
Default

I know it is dangerous for a newbie without a lot of electrical know how to play devil's advocate, but here goes.
I have the lithium bank, but I also have 400 watts of solar and could easily add two more panels, with a little labor and wiring. I have the roof real estate for that. My MPPT controller was sized for an upgrade. So, the alternator is not/won't be my only source of charging.
I can get a 120 amp Sterling waterproof rated (which I don't need) B2B for just over $500. A 2nd alternator - something I wouldn't try to do myself, would cost north of $2000, I'm sure, even more, if I chose the high idle option. The Sterling's have a 4-stage charging profile, even a lithium setting, which can be customized even further. The B2B plus would charge the lithium bank under most any circumstance, and with the current limiting, protect the alternator, so I'm wondering about the expense of the 2nd alternator, even though I know it would work. I've read about the impressive charging available from these units and that many folks have the 2nd alternator only, with little or no solar.

Not trying to discount your guidance at all - very thankful for it, in fact, and you've taught me some things along the way. My mind is not made up on this at all.
woundedpig is offline   Reply With Quote
Old 01-06-2018, 05:21 PM   #7
Platinum Member
 
Join Date: Feb 2016
Location: Portland, Oregon
Posts: 1,388
Default

See this related discussion on another forum, OP ended up selecting the Australian unit. OP reviewed current market offerings in a consize table. The only missing one is from Ctec like this https://www.baintech.com.au/can-i-us...art-alternator .
https://sprinter-source.com/forum/sh...ad.php?t=61720

Without knowing your schematic, I could be wrong but:

- Intellitec relays are most often used for disconnecting batteries from electrical RV system so it could work for disconnecting alternator from house batteries or not. In my case I have the factory relay connecting alternator with house batteries and Intelitec between house batteries and loads.

- Your 2017 Sprinter is most likely limited to 40A draw from the smart alternator, a lot of discussion about this subject.

- Most of B to B chargers are tuned for AGM batteries, for Li batteries the question would be how will the B to B charger know when to disconnect the charge, will BMS be smart enough to terminate the charge.
__________________
George
2013 Sprinter VOILA
https://goo.gl/photos/2NCR3teXLSwNYSwN8
GeorgeRa is offline   Reply With Quote
Old 01-06-2018, 05:45 PM   #8
Platinum Member
 
Join Date: Aug 2010
Location: Minnesota
Posts: 7,517
Default

As George says. It is highly unlikely that the solar controller and shore charger will do a good job of lithium charging, with full cutoff/restart. The solution that is the best, it appears, is for the BMS or Silverleaf type controller to handle all the charging from all the sources, so they can be reliably shut off and on when needed without hurting them or causing voltage spikes. If you have a central controller type system, you would not need to do anything with the alternator charging because the controller will disconnect (though the Intellitech maybe) when the batteries are full, and the MB stuff will still have the starting battery for reference.

Of course with the full shutoff style of control, you lose the ability of the solar to support use when the batteries have shut down after getting full, until the go down enough to start charging again.

What van and system is in place now, so we can get a feel for what you are really dealing with?
booster is online now   Reply With Quote
Old 01-06-2018, 07:01 PM   #9
New Member
 
Join Date: May 2016
Location: Texas
Posts: 16
Default

I hope I've set up Google photos correctly. Link below. I have a 2017 chassis Sprinter 3500 V6 diesel with the stock 220 amp rated alternator. Built in a cutaway chassis, so there are more storage options. Currently 200 AH lithium drop-in's but plan to increase to 400 AH. There is an Intellitec isolator solenoid relay under the passenger seat and the isolator relay delay in the chassis battery area, though I haven't looked for it yet.

https://photos.google.com/share/AF1Q...BQaGtPcm42V0dn
woundedpig is offline   Reply With Quote
Old 01-06-2018, 07:08 PM   #10
Platinum Member
 
Join Date: Aug 2010
Location: Minnesota
Posts: 7,517
Default

Quote:
Originally Posted by woundedpig View Post
I hope I've set up Google photos correctly. Link below. I have a 2017 chassis Sprinter 3500 V6 diesel with the stock 220 amp rated alternator. Built in a cutaway chassis, so there are more storage options. Currently 200 AH lithium drop-in's but plan to increase to 400 AH. There is an Intellitec isolator solenoid relay under the passenger seat and the isolator relay delay in the chassis battery area, though I haven't looked for it yet.

https://photos.google.com/share/AF1Q...BQaGtPcm42V0dn
Whose conversion is it? Looks a lot like the Pleasure-way in that it appears to have drop in lithium batteries in it with no integrating controls.
__________________

booster is online now   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 01:47 AM.


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