We just got our 2018 Serenity two weeks ago. My husband and I are completely new to this whole adventure. We have been learning everything about it until we take it out in January on our first planned trip.
As we tested everything and studied all the details, while plugged into land power, we played music on the radio of our entertainment system. Later that evening, we decided to take it out to fill it up (diesel). The battery was DEAD! We have 96 miles on it and the battery was DEAD! How is the entertainment system (Jensen) running off of the chassis battery? That system has the DVD Player for the TV, music, etc ... Shouldn't that be running on the house batteries? If that isn't what killed the battery, we don't know what did!
We scoured the manuals and can't even find which source of power the entertainment system is running on!
Any ideas?
Slinkblot
G'day! Oh Dear!!!! What a way to start your ownership..... OK, lets see if we can help. Not a Serenity owner.... but, about 99% of the modern RVs use similar strategies for battery charging and use.
1. There are two battery systems: chassis (starts van & runs dash radios, GPS, etc.); coach system (runs all the other 'stuff' in the coach).
2. The coach has a 'MASTER ELECTRICAL' switch. ON when using the coach amenities, fridge, water heater, water pump.... everything in the coach. OFF when not using the stuff in the coach!!! Generally, you can charge the coach battery bank with MASTER OFF.
3. The Sprinter (chassis) system runs everything Sprinter... nothing in the coach. Key should be OFF & OUT when parked. IDK about Serenity, but Views and Navions have two switches on the dash. One allows you to run the radio/entertainment/gps from the COACH batteries OR the chassis battery. The chassis selection is key controlled by the ignition key. So switch to Chassis ... unless you want to use the chassis battery for entertaining or programming GPS. If you leave the ignition ON (or key in ignition) AND the the radio switch ON, it will run the chassis battery down. Confused yet???
OK... Ignition OFF, dash switch to Chassis, and COACH MASTER OFF... when leaving the coach/van.
Charging strategies:
Shore power or generator will only the charge the coach battery! It provides 110V AC to those things needing it (HVAC, WH, fridge) AND 12V DC for those other things in the coach (LED lights, water pump, furnace motor, etc..)
Shore power or generator WILL NOT CHARGE the chassis battery!!! EVER....!!!
The Sprinter's alternator will charge BOTH battery sets when the engine is running. It also provides 12V DC for the Sprinter's amenities AND the coach's 12V DC 'stuff.'
Possible reason for dead battery: it' is bad; or, you left the ignition on, key in, or entertainment 'switch' to chassis rather than coach. Also, batteries are not "Harry Potter" devices. You don't wave a wand and instantly charge them. It takes a few hours, usually, to bring them up to full charge. It aint' 'magic'!! So you could have had a battery that was not fully charged to start with. So... first we need to check the charge in the batteries.
Your Serenity probably has a panel that shows you the levels of fluids in the various tanks AND the charge on the batteries. Our View will show battery voltage (state of charge) for both battery sets. Without starting up anything and shore off*, first thing to do is turn on the MASTER COACH (no other draws except maybe an LED light to see what you are doing)..... Go directly to your panel and check the SoC. You may be reading volts directly or it may be several LED lights (F, 3/4, 1/2, 1/4) or something like that. That's your reference....
* if on shore power... disconnect and wait about 5 minutes & turn on an over head LED light to take off the surface charge on the battery. That will give you a bit of a truer reading.
STARTING STRATEGIES: Obviously, a dead/low chassis battery won't start the van. There maybe a switch on the dash that allows you to 'slave' the coach battery to the 'low/dead' chassis battery. On a View/Navion you hold the 'slave' switch ON whilst turning the key to start. Once started, the Sprinter will run and charge batteries on it's own.
If the coach battery is also low.... start the genny, if you can. You may be able to MacGuyver as start by 'reverse slaving' the batteries. Get someone to hold the salve switch ON while someone else starts the genny. Once running, the genny will provide 110V and charge the chassis.
Last, I'd not fret over running the battery down..... once or twice is probably no big deal in the long term. Just charge it up and double check what you are doing to avoid running it down.
SoC Chart: Print out and tape near your control panel....
https://drive.google.com/open?id=1dSBhn-zwWUwmgC0JPd5NzNPq3JA8l8J6