How to troubleshoot aux battery charging - Sprinter-Forum

ellisja · 10-06-2010, 08:21 PM

Greetings,

I am the happy owner of a 2006 Roadtrek Adventurous. I seem to be having a problem and could use some guidance. Seems that when I am driving the vehicle, I am not charging my auxillary batteries. When I run my generator or connect to shore power, the batteries are charged. Obviously, something is amiss. Where should I start looking (other than the owner's manual)?

Thanks, in advance, for your help. Have a great day!!!

v/r
John

aljimenez · 10-06-2010, 09:39 PM

How are you concluding the house batteries are not being charged while driving?

If you think the house batteries should completely charge from a deep discharged state while driving, be prepared to drive for a very long time. Deeply discharged batteries need many hours of driving to charge. Basically, driving typically injects a few amps each hour into the batteries, while being connected to shore power injects tens of amps each hour depending on the type of converter you have... Al

ellisja · 10-06-2010, 11:13 PM

Thanks for the feedback, but my last drive was 6.5 hours of driving and with apparently little, or no, charging. I am doing a similar trip this weekend and am looking to troubleshoot while out.

aljimenez · 10-07-2010, 02:03 AM

Quote:

Originally Posted by ellisja

Thanks for the feedback, but my last drive was 6.5 hours of driving and with apparently little, or no, charging. I am doing a similar trip this weekend and am looking to troubleshoot while out.

Did you have some appliance on battery, like the refrigerator, on while you were driving? If the answer is yes, then most of the amps from the engine will go to feed that appliance while you are driving and you will get very liitle charge of the batteries... Al

NBB · 10-07-2010, 02:19 AM

Unless he's running an overhead A/C, there should be plenty of amps going to the batteries. Even a propane fridge in DC mode hardly uses anything in the context of a running alternator. My guess is the isolator is either damaged, or was never installed. A lot of people don't like hooking AGM's up to a "bulk charger" like the alternator. Read the manual, and/or head to the repair shop. It's a simple thing, but if you have to ask here about it, it's unlikely you'll be able to fix it. It could be something as simple as a fuse. The alternator isn't current limited except by it's max capacity -at least 65 amps or so for a Sprinter. Many have 220 amp alternators. That thing will give the batteries all they can take - possibly more than a "shore" charger. A few amps an hour per the above post is not correct, unless the battery was already fully charged.

Trekker · 10-07-2010, 02:31 AM

Amen to NBB. I agree 100% with your assessment. Automotive alternators put out a minimum of 55 amps at full power, Sprinter probably even more. Perhaps it might be a simple problem of the isolator not being grounded, or a lead came off (?). Check the wiring at the isolator. Thanks for correcting the mis-information NBB.

ellisja · 10-07-2010, 03:22 PM

All,

I assume the issue is the battery isolator as well (and have since I found the issue). BTW, nothing is running/operating while I am driving, typically.

While on this trip, me and the trusty multi-meter will conduct some tests and replace the isolator/secure the ground/etc. if needed. Not a big deal, but looking to the experience and knowledge of the forum for any obvious issues peculiar to Sprinter based platforms that could cause the problem. Thanks to all.

v/r
John

ellisja · 10-13-2010, 01:45 AM

All,

Was a simple fuse (on the battery power splitter). The 70 amp in-line fuse for the aux battery was the culprit, but was not evident from looking at it. The trusty multi-meter did the trick. Picked up 2 replacements and all was well.

Thanks,
John

NBB · 10-13-2010, 03:44 AM

Might want to do some figuring on why the fuse blew in the first place. Also, 70 amps sounds a little on the low side. Might verify that is the correct fuse, not just the wrong one someone else put in there. Good luck,

carrothers · 10-25-2010, 03:28 PM

I noticed on the long trip this past week that RT put in a "battery disconnect" switch just above the sliding door. I thought it was strange that regardless of which way the switch was toggled the light stayed on. It's a little bit confusing; but the only time you want that switch to be on is when you are going to be in deep storage for some period of time. Otherwise, if the switch is "on" the altnernator can't charge the house batteries. It needs to be wired so that the light is only on when the disconnect is engaged. IMHO.

10-06-2010, 08:21 PM	#1
ellisja Join Date: Jun 2010 Posts: 12 Thanks: 7 Thanked 0 Times in 0 Posts	How to troubleshoot aux battery charging Greetings, I am the happy owner of a 2006 Roadtrek Adventurous. I seem to be having a problem and could use some guidance. Seems that when I am driving the vehicle, I am not charging my auxillary batteries. When I run my generator or connect to shore power, the batteries are charged. Obviously, something is amiss. Where should I start looking (other than the owner's manual)? Thanks, in advance, for your help. Have a great day!!! v/r John

10-06-2010, 09:39 PM	#2
aljimenez Join Date: Sep 2006 Location: San Luis Obispo, CA Posts: 278 Thanks: 87 Thanked 60 Times in 46 Posts	Re: How to troubleshoot aux battery charging How are you concluding the house batteries are not being charged while driving? If you think the house batteries should completely charge from a deep discharged state while driving, be prepared to drive for a very long time. Deeply discharged batteries need many hours of driving to charge. Basically, driving typically injects a few amps each hour into the batteries, while being connected to shore power injects tens of amps each hour depending on the type of converter you have... Al

10-06-2010, 11:13 PM	#3
ellisja Join Date: Jun 2010 Posts: 12 Thanks: 7 Thanked 0 Times in 0 Posts	Re: How to troubleshoot aux battery charging Thanks for the feedback, but my last drive was 6.5 hours of driving and with apparently little, or no, charging. I am doing a similar trip this weekend and am looking to troubleshoot while out.

10-07-2010, 02:19 AM	#5
NBB Join Date: Sep 2009 Posts: 921 Thanks: 68 Thanked 219 Times in 164 Posts	Re: How to troubleshoot aux battery charging Unless he's running an overhead A/C, there should be plenty of amps going to the batteries. Even a propane fridge in DC mode hardly uses anything in the context of a running alternator. My guess is the isolator is either damaged, or was never installed. A lot of people don't like hooking AGM's up to a "bulk charger" like the alternator. Read the manual, and/or head to the repair shop. It's a simple thing, but if you have to ask here about it, it's unlikely you'll be able to fix it. It could be something as simple as a fuse. The alternator isn't current limited except by it's max capacity -at least 65 amps or so for a Sprinter. Many have 220 amp alternators. That thing will give the batteries all they can take - possibly more than a "shore" charger. A few amps an hour per the above post is not correct, unless the battery was already fully charged. Last edited by NBB; 10-07-2010 at 02:29 AM.

10-07-2010, 02:31 AM	#6
Trekker Join Date: May 2009 Location: Ft. Lauderdale Posts: 219 Thanks: 69 Thanked 74 Times in 50 Posts	Re: How to troubleshoot aux battery charging Amen to NBB. I agree 100% with your assessment. Automotive alternators put out a minimum of 55 amps at full power, Sprinter probably even more. Perhaps it might be a simple problem of the isolator not being grounded, or a lead came off (?). Check the wiring at the isolator. Thanks for correcting the mis-information NBB. __________________ 2008 Dodge 2500, Roadtrek Adventurous RS Last edited by Trekker; 10-07-2010 at 02:31 AM. Reason: Typo

10-07-2010, 03:22 PM	#7
ellisja Join Date: Jun 2010 Posts: 12 Thanks: 7 Thanked 0 Times in 0 Posts	Re: How to troubleshoot aux battery charging All, I assume the issue is the battery isolator as well (and have since I found the issue). BTW, nothing is running/operating while I am driving, typically. While on this trip, me and the trusty multi-meter will conduct some tests and replace the isolator/secure the ground/etc. if needed. Not a big deal, but looking to the experience and knowledge of the forum for any obvious issues peculiar to Sprinter based platforms that could cause the problem. Thanks to all. v/r John

10-13-2010, 01:45 AM	#8
ellisja Join Date: Jun 2010 Posts: 12 Thanks: 7 Thanked 0 Times in 0 Posts	Re: How to troubleshoot aux battery charging All, Was a simple fuse (on the battery power splitter). The 70 amp in-line fuse for the aux battery was the culprit, but was not evident from looking at it. The trusty multi-meter did the trick. Picked up 2 replacements and all was well. Thanks, John

10-13-2010, 03:44 AM	#9
NBB Join Date: Sep 2009 Posts: 921 Thanks: 68 Thanked 219 Times in 164 Posts	Re: How to troubleshoot aux battery charging Might want to do some figuring on why the fuse blew in the first place. Also, 70 amps sounds a little on the low side. Might verify that is the correct fuse, not just the wrong one someone else put in there. Good luck,

10-25-2010, 03:28 PM	#10
carrothers Join Date: May 2009 Posts: 19 Thanks: 9 Thanked 5 Times in 3 Posts	Re: How to troubleshoot aux battery charging I noticed on the long trip this past week that RT put in a "battery disconnect" switch just above the sliding door. I thought it was strange that regardless of which way the switch was toggled the light stayed on. It's a little bit confusing; but the only time you want that switch to be on is when you are going to be in deep storage for some period of time. Otherwise, if the switch is "on" the altnernator can't charge the house batteries. It needs to be wired so that the light is only on when the disconnect is engaged. IMHO.

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