Battery Issues

[Khawk]

2021 Sunseeker 2440DS - the coach has two batteries and we like to boondock but are having issues.

Battery 1 - with everything off, except the fridge, this battery will completely die after 24 hrs. I have to start the chassis in order to get enough power to start the generator and the run the generator for two hours to charge.

Battery 2 - this battery stays fully charged.

What is the purpose of battery 2? It would seem to me, the system should pull power for both batteries.

Any wisdom would be appreciated.

[Chuck_S]

Boats and -- I assume -- motorhomes commonly have two batteries.

(1) Starting (for the engine) and (2) House (for the stuff inside). No motorhome experience but lots with boats. The starting battery has to be protected so the engine can be started when it's time to go and a common, simple device is a Off-1-Both-2 battery switch. Is there such a switch in your vehicle, or an electronic device serving the same function?

1 is starting 2 is house. Only in Both for charging underway or for emergency starting or other use if one battery is dead. System should never routinely pull from both batteries unless you want two dead batteries. Seems your system is not pulling from both which is correct.

-- Chuck

[kcmusa]

is your fridge propane, 12 volt or 120 volt?
do you have an inverter? residential fridge running off an inverter wlll draw a lot of power from a single 12 volt battery.

[Duckogram]

A 2440DS is a Classic Series so you have 2 house batteries wired in parallel. That pair makes Battery 1. Since you are using that terminology I assume you are reading it off either a solar charge controller or firefly. So Battery number 2 is your chassis battery. You should have a switch on the base of the drivers seat that will allow you to momentarily connect all 3 batteries together.
Since you have a 12V fridge and using other 12v items then yes, you can drain your house batteries in 24hrs. You will shorten their life significantly if you continually go below 50% charge (12.1V). To boondock with your unit I suggest you consider running your genset and adding significant solar to assist with replacing the amps you burn at night.
YMMV

[newRVer]

Originally Posted by Chuck_S

Boats and -- I assume -- motorhomes commonly have two batteries.

(1) Starting (for the engine) and (2) House (for the stuff inside). No motorhome experience but lots with boats. The starting battery has to be protected so the engine can be started when it's time to go and a common, simple device is a Off-1-Both-2 battery switch. Is there such a switch in your vehicle, or an electronic device serving the same function?

1 is starting 2 is house. Only in Both for charging underway or for emergency starting or other use if one battery is dead. System should never routinely pull from both batteries unless you want two dead batteries. Seems your system is not pulling from both which is correct.

-- Chuck

Just a clarification. Motorhomes generally have (2) Battery applications, Engine and House. The engine application is always a single battery. The "house" can have 1, 2 or more batteries. I am assuming that the original poster meant that he has (2) House batteries which from the factory normally come connected in parallel. If this is the case then it is likely that the battery cabling is faulty (or loose) on the one battery and that he is only pulling current from a single battery which would explain why one is depleted while the other still has a full charge.

[billwww3]

Originally Posted by Khawk

2021 Sunseeker 2440DS - the coach has two batteries and we like to boondock but are having issues.

Battery 1 - with everything off, except the fridge, this battery will completely die after 24 hrs. I have to start the chassis in order to get enough power to start the generator and the run the generator for two hours to charge.

Battery 2 - this battery stays fully charged.

What is the purpose of battery 2? It would seem to me, the system should pull power for both batteries.

Any wisdom would be appreciated.

Speaking strictly coach batteries - i have the dual battery setup, wired in parallel, but my solar controller still "sees" battery 1 and battery 2. It does not see the Ford engine battery (the 3rd battery on my unit). I have no idea how this works yet; there are isolators involved... I'm sure Ducky probably knows. The 2 coach batteries act a little differently in charge and charge rates; but they will both go dead if i leave devices drawing current with no resupply - either solar, shore power, generator, or engine alternator. If only one of yours dies with the fridge there must be some cables failing somewhere. Or some tricky wiring scheme.

[Duckogram]

I think we should wait until the OP can verify that the two batteries in the step well are both deados. That would require a voltmeter and the ground disconnected for at least two hours.

For the solar charge controller reading, with house batteries fully charged and only the solar power on, take a voltage reading on the chassis battery
(12.x). Then turn the headlights on and see if the voltage kicks up to the mid 13v range. That will tell you that; A. The solar is charging your chassis battery (probably through the Battery Isolation Manager aka BIM) and B. Which battery it is on your display.
Food for thought: If two batteries are connected in parallel and the output from same is + on one of them and - on the other, how would a meter know there are two batteries. Keep in mind that when you connect batteries in parallel they will balance themselves and charge at a single rate.

If battery 1 charges at x rate and battery 2 is different, that difference is attributable to battery 1 being a deep cycle/dual purpose and battery 2 being a starting battery.

[Khawk]

Originally Posted by Duckogram

A 2440DS is a Classic Series so you have 2 house batteries wired in parallel. That pair makes Battery 1. Since you are using that terminology I assume you are reading it off either a solar charge controller or firefly. So Battery number 2 is your chassis battery. You should have a switch on the base of the drivers seat that will allow you to momentarily connect all 3 batteries together.
Since you have a 12V fridge and using other 12v items then yes, you can drain your house batteries in 24hrs. You will shorten their life significantly if you continually go below 50% charge (12.1V). To boondock with your unit I suggest you consider running your genset and adding significant solar to assist with replacing the amps you burn at night.
YMMV

Thanks for the response. I’m reading the information off the solar charge controller and didn’t realize battery 2 is the chassis battery.

[Khawk]

Any idea what the coach battery specs are?

[Duckogram]

Originally Posted by Khawk

Any idea what the coach battery specs are?

Specs for? Below is a chart for typical group 27 AGM batteries which I believe is what you have.

[billwww3]

Originally Posted by Duckogram

Food for thought: If two batteries are connected in parallel and the output from same is + on one of them and - on the other, how would a meter know there are two batteries. Keep in mind that when you connect batteries in parallel they will balance themselves and charge at a single rate.

Ducky, THIS has been the great mystery i simply could NOT fathom!! Looking all over for some kind of shunt that could account for the 2 separate readings! The truck battery just did not occur to me - i thought it was kept isolated unless the override switch under the seat was engaged.
THANKS!! moving forward now...

bw