alternator charging the house battery issues

salim · 05-25-2022, 12:00 PM

Greetings to the collective bank of Sportsmobile wisdom.
I own a 2017 Sprinter Sportsmobile. I switched the lead acid battery to lithium in January. 2x 100watt Battle Born. I had to modify the battery tray to fit the new batteries. Thus I drove the van with the wires tied up and taped to the undercarriage for a few weeks. I have noticed that the house battery is not charging when the van's engine is running. It did with the lead acid battery and would be topped off after a few hours drive. It still gets the trickle from solar but does not get to full when driving for hours. I have consulted the manual and it mentions checking the battery separator fuse. Its a 15 amp, the manual photo shows a 10amp. It is good. It then suggests to check the 12v 150A fuse in the starting battery fuse holder. The manual photo shows its location. The other photo shows the gap where it should be. I am sure one of the other fuses is the right one. But they are all good. I have tried to get in touch with Field Van in Fresno. No effort to return any of my calls yet. I suspect a blown fuse but don't know where to look. I hope the photos are attached. Suggestions? And thanks for any help.

Scalf77 · 05-25-2022, 02:13 PM

I would expect this is the fuse that was added by sportsmobile.

You should just check that 12 volts is on the wire side of the fuse.

It sound like you just dropped Lithium into your existing system. I would suggest at a minimal to change your separator over to a LiFePO4 Battery Isolation Manager (BIM)

-greg

salim · 05-26-2022, 08:28 AM

“Change separator over.” So replace the Battery separator from Sportsmobile with a Battery isolation monitor?
And I had to disconnect the negative and the buss bar from the battery to get to the wire and fuse. How do I test 12v from the wire side?
Thanks for your help.

Scalf77 · 05-26-2022, 09:10 AM

There are a lot of possible pitfalls with just charging directly from the alternator vias the separator. So it is usually a good thing to have something that is designed for Lithium. The BIM will act much like the separator, but will make sure it tries to protect your alternator and not overcharge the Lithium battery.

So to check the 150 amp fuse, measure the on both side of the fuse. The ground probe is connected to a ground and then measure the bus bar side (left) then measure the wire side (right) if they don't measure the same which should be the battery voltage then the fuse is bad.

If it is disconnected from the battery no power or ground connected, you can measure across the fuse with a ohm meter, a blown fuse will be open.

greg

salim · 05-26-2022, 09:34 AM

BIM ordered. Thank you for your time and wisdom.

Tahosrfr · 06-02-2022, 01:35 PM

I am currently doing the same thing with my 2018 smb with agm. You will definitely want to add a dc to dc charger like the one Victron sells. Lithium charges differently than agm so without a smart charging system it will be less efficient and much harder on your Alternator. GL

salim · 06-02-2022, 02:09 PM

Just got the BIM from Battleborn. I have watched a bunch of you-tubes about how to install. It looks like it replaces the battery separator that SMB installed. It is under the drivers seat and the wires needed should be there. I haven't gotten the gumption to attack it yet. It does not come with instructions nor wires or switch. It needs a switch to manually connect the batteries for a engine start with a dead engine battery.
I am wondering what is the difference between a dc-dc charger and a BIM.
And with the zamp solar charger module and the magnum inverter module how can you get a reading of charging from the alternator?
It seems the zamp shows when solar is charging. But I do not know how to get either module to show charging from the alternator.

rvtampa · 06-03-2022, 01:10 PM

Hi Salim

I have been thinking up upgrading 4 6volt Lifeline GPL-4CT AGM Batteries which are under-mounted. Can you share how you modified the battery tray (photo). I am thinking of 4 100AH or a larger 200AH if the tray opening can support a larger battery box. Jason

salim · 06-04-2022, 11:48 AM

I hope these photos help. Sorry I did not respond earlier. The batteries are 100amp Battleborn. They just fit in height. No taller battery could fit.

salim · 06-05-2022, 03:01 PM

Well I am in over my head. There is nothing that looks like the battery separator under the drivers seat. There is a Blue Sea Automatic charging relay ML-ACL deep in a moras by the inverter. Could this be the battery separator? If so I have no idea how I am going to remove and replace with a B.I.M. It feels like this manual was not updated to how SMB west was doing vans at the time.
The 150watt fuse is definitely blown but I am reluctant to change until I can understand why it is blowing.