Battery question please

[dg0603]

Apologies if this sets a new record for dumb questions, but I need some clarification. 2022 Tellaro w/ Lithium system

Is there a separate 12V battery for the house side, Or does the same battery that starts the vehicle also serve as the house 12V.

I would hope it's not one 12V battery, right? But I'm confused the "Emergency Start" documentation talks about the starter battery being too drained and taking from the house side. Is this the separate house 12V? Or the Lithium?

And why would the started battery be drained if it is not used as the house battery.

Thank you!

[DavidEM]

Your lithium batteries are separate from your coach's starting battery.

The emergency start switch is kind of an anachronism. It is for the rare case when you leave your driving lights on or something drains your starting battery. Pushing the switch temporarily connects the two systems and lets the house batteries boost the starting battery.

With lithium house batteries I would hold down that switch for a while before trying to start to let the starting battery build up a charge. Otherwise the internal lithium BM might trip due to the high starting current.

David

[Chateau_Nomad]

Yes... you have two separate batteries... generally referred to as a "house" battery, and a "chassis" battery. The chassis batter is under your hood close to the engine. Your house battery (or batteries) are located elsewhere - depending on the type (lead-acid vs lithium).

Let's say you leave your parking lights on - which could drain your CHASSIS battery. Now your coach engine won't start. Enter the "emergency start" button/switch. When you push it, the chassis battery is bypassed and the starter draws power from your "house" battery to start the engine. Once the engine is started, BOTH batteries will begin charging.

That's pretty simplified, but it's a pretty clever life saver.

[dg0603]

Thank you

Just to be crystal clear.

There is NO separate lead-acid battery for the house side. The battery that powers the 12V items is the same one that starts the vehicle. right?

There is one lead-acid battery on board.

[EA37TS]

Originally Posted by dg0603

Thank you

Just to be crystal clear.

There is NO separate lead-acid battery for the house side. The battery that powers the 12V items is the same one that starts the vehicle. right?

There is one lead-acid battery on board.

You have 2 batteries.

[dg0603]

I have the Lithium system to replace the generator.

I'm not talking about those coach batteries. I'm wondering if I have two lead-acid batteries. One under the hood, and one for 12V house applications

Then the Lithium would be separate.

[16ACE27]

Originally Posted by dg0603

I have the Lithium system to replace the generator.

I'm not talking about those coach batteries. I'm wondering if I have two lead-acid batteries. One under the hood, and one for 12V house applications

Then the Lithium would be separate.

The lithium IS the house battery that powers all 12 VDC house applications. There is no LA battery on the house side of an RV with a lithium house system.

Clear enough?

[dg0603]

yes, ok thank you.

[Chance]

Originally Posted by dg0603

I have the Lithium system to replace the generator.

I'm not talking about those coach batteries. I'm wondering if I have two lead-acid batteries. One under the hood, and one for 12V house applications

Then the Lithium would be separate.

It’s a great question, and I don’t think you have provided enough information to rule it out completely — as in 100% not possible.

It’s unlikely but theoretically possible because Thor reserves the right to make design changes if they want, and I’m not certain whether you have the standard lithium or optional lithium system which may make a difference. The standard system has TWO 100 Amp-hour lithium batteries for the coach. Add the chassis lead-based starting battery and that makes three batteries in total.

If you have the “OPTIONAL” 800-Ah Re(Li)able Renewable Battery System, then I’m not certain if it operates on 12 Volts or 48 Volts. Initially I recall they were 12V, but other Thor (company) products have recently started using 48V systems in vans (probably only from Volta, but that may have changed). It’s also possible Thor can supply Volta system since they reserve right to do so (though unlikely) due to supply chain shortages.

Anyway, these 48V battery systems normally have a DC-to-DC converter that maintain an additional small 12V house battery charged. That 12V battery powers small loads that require 12 Volts like lights, fans, water pump etc.

If you have standard 200 Ah Lithium system, you can rule out 48V and thus extra 12V lead battery for coach.

If you have optional 800 Ah Lithium system, it is possible that it’s 48V, and “may” have an extra 12V battery for coach. Or not. I don’t see how it can be ruled out completely without additional information.

I would look at owners manual, or electrical drawings if you have them first. If not sure, then I’d call Thor and ask if any Tellaro are now manufactured with 48V system. And if so, whether they use a third coach battery for 12V loads.

These new “generatorless” battery systems can be different than traditional motorhomes, particularly if not based on 12V electrical for primary battery energy storage.