Should the engine alternator charge the house batteries while under way ?

[ArcticGPS]

There are two 6v batteries for the house hooked up in tandem, is this the preferable setup , or could I replace them with 2 x 12v batteries.

2X6Volt is a better configuration for lead acid batteries. Your house voltage should show 13.x volts or so when your engine is on - that is charging voltage.

 

[Wiley1]

Everybody here is assuming that you have a problem with the battery or charging system, but how can we know for sure? It is possible that your batteries and charging system are working nicely, but just not supplying enough power to run all your 12V devices which might include the inverter (which wastes 15% of all power put into it), fridge, lights, dashboard entertainment system, and maybe even a TV.

You desperately need a shunt-base battery monitor such as a Victron BMV-700. That will allow you to measure the amount of current going into, or out of, your battery bank in real time. Underway, you could have somebody watch the gauge with the fridge on and off. That will tell you exactly how much power the fridge is consuming. Same goes for every other 12V device in the rig including the inverter and everything that runs on AC. Once you have those numbers, you can intelligently determine whether your batteries have reached end-of-life.

If you do decide to buy new batteries, please do not make the mistake of buying anything other than LiFePO4. They will provide significantly more power per cubic inch, weigh half as much, last three times longer, and cost less over their lifetime. This is a no-brainer. You can read my analysis here:

buh bye AGM

After 5.5 years, my 4x 100Ah AGM battery bank is performing like 60ah. I won't replace them with another set of AGMs and here is why: Cost of 4 new AGM batteries, 100Ah each, is about $760. But, to avoid discharging below 50% SoC, only 200Ah is usable. Over 5.5 years, that's a cost of $138...

www.thorforums.com

 

[roborider]

Someone recommended 12v batteries instead of 6v. 6volt batteries are actually preferable (if the total AH is the same) for a few reasons:

• Built specifically for deep-cycle use (golf carts, RVs).
• More robust internal components.
• Longer cycle life and durability.
• Less chance of imbalance (simpler wiring).
• Deep draw down on 6v batteries doesn't cause the same stress as on 12v batteries

Note that if you do go to 12v batteries, you must connect them in parallel (positive to positive, negative to negative) for a 12 v system. If you currently have 6v batteries in a 12 volt system, they are connected in series (negative to positive), and you will need an additional cable to connect two 12v batteries in parallel.

 

[16ACE27]

Someone recommended 12v batteries instead of 6v. 6volt batteries are actually preferable (if the total AH is the same) for a few reasons:

Old news - only applies to Lead-Acid batteries.
12.8 VDC LiFePo4 is the only choice for house batteries these days.

 

[RJ Schubert]

Yes it will; REGARDLESS of the position of the USE/STORE switch.

View attachment 1314182

Hi Ted and others. I’m on the road in Montana with my 2018 Quantum RQ29. The inverter also starts beeping for low battery while I’m driving. From your picture and other threads which I vaguely recall, either the 100 amp or solenoid have a flag that pops out when it needs to be reset. When I’m hooked up to shore the house batteries charge fine. Both of the batter are new AGM.

Any idea on what I can check if I can climb under before we are off on the road home?

Thanks.

 

[PS89]

Hi Ted and others. I’m on the road in Montana with my 2018 Quantum RQ29. The inverter also starts beeping for low battery while I’m driving. From your picture and other threads which I vaguely recall, either the 100 amp or solenoid have a flag that pops out when it needs to be reset. When I’m hooked up to shore the house batteries charge fine. Both of the batter are new AGM.

Any idea on what I can check if I can climb under before we are off on the road home?

Thanks.

On your RV, as is normally the case, coach battery charging from the alternator is handled through the emergency start solenoid. Depending on what and where Thor installed it, you will have either a BIM or a IRD/Trombetta solenoid. It may be in the battery compartment or it may be hidden somewhere under the hood or somewhere else. Can't tell you exactly where to look, but I can point you in the general direction. If you have the BIM, it's likely wired backwards from the factory and won't properly charge the coach batteries from the alternator

If you NEED to run the inverter while driving, you will probably need to run the generator periodically to recharge the coach batteries. If you do not absolutely need to use the inverter, switch it off as much as you can. Usual reasons for keeping it on would be a 120 VAC fridge or you need 120 VAC for plugged in items like a computer.

There is also a Facebook group for Thor Quantum owners. You'll find a concentration of model-specific information among its members.

 

[16ACE27]

Hi Ted and others. I’m on the road in Montana with my 2018 Quantum RQ29. The inverter also starts beeping for low battery while I’m driving. From your picture and other threads which I vaguely recall, either the 100 amp or solenoid have a flag that pops out when it needs to be reset. When I’m hooked up to shore the house batteries charge fine. Both of the batter are new AGM.

Any idea on what I can check if I can climb under before we are off on the road home?

Thanks.

By this user supplied diagram you have a BIRD/IRD under the hood.

Thor Quantum RQ29 Electrical Diagram

My Girl Friend got a new Thor Quantum RQ29. After trying to answer her electrical questions and doing a lot of snooping on her rig, I decided to make her a drawing showing both the DC and AC sides on one drawing. The two of us thought we would share the drawing in hopes if you see any mistakes...

www.thorforums.com

Locate that to see if your RV was even designed to charge the house batteries via the alternator.

 

[RJ Schubert]

Thanks Ted. I’ll take a look today. I appreciate the quick response

 

[RJ Schubert]

On your RV, as is normally the case, coach battery charging from the alternator is handled through the emergency start solenoid. Depending on what and where Thor installed it, you will have either a BIM or a IRD/Trombetta solenoid. It may be in the battery compartment or it may be hidden somewhere under the hood or somewhere else. Can't tell you exactly where to look, but I can point you in the general direction. If you have the BIM, it's likely wired backwards from the factory and won't properly charge the coach batteries from the alternator

If you NEED to run the inverter while driving, you will probably need to run the generator periodically to recharge the coach batteries. If you do not absolutely need to use the inverter, switch it off as much as you can. Usual reasons for keeping it on would be a 120 VAC fridge or you need 120 VAC for plugged in items like a computer.

There is also a Facebook group for Thor Quantum owners. You'll find a concentration of model-specific information among its members.

Thank you

 

[16ACE27]

Thanks Ted. I’ll take a look today. I appreciate the quick response

Hopefully you have a BIRD (you would think with an inverter you would) and you just have a bad Trombetta solenoid (common issue). That would be an easy fix.