House Batteries

[jkc306]

Have 2017 Thor ACE, battery dead, jumped started and let run for about an hour. Unplugged from 30amp electrical while in RV barn. Few days later went out to Thor and discovered house batteries are dead...Pretty sure they are "new" still and should be working. Any insights would be helpful (New to RVing)

[jkc306]

curiouser and curiouser...so after a break i stuck the hydrometer on the chassis battery: dead. Pulled it and dropped it off at auto store: dead cell and cannot hold a charge. Purchase suitable comparable battery, check with meter 12.60. i attach negative; upon securing positive, smoke appears and wiring harness is getting hot. disassembled quickly...internet search says the alternator may be bad. I presume the house batt and its systems operate independently of the chassis batt and its' systems??

[pianotuna]

jkc306 wrote:
Well the two batteries could not be recharged. Bar code reader identified old batteries as Exide Nautulis MDP27's. Replaced both; purchased voltmeter, trickle charger and flipped "store" battery option on. Just need to remember to check them regularly...

Thank you everyone for your help, insights and advice!!

Return them. Go golf cart, or go SiO2. That is unless you are a power pole princess.

[jkc306]

Well the two batteries could not be recharged. Bar code reader identified old batteries as Exide Nautulis MDP27's. Replaced both; purchased voltmeter, trickle charger and flipped "store" battery option on. Just need to remember to check them regularly...

Thank you everyone for your help, insights and advice!!

[wa8yxm]

Depending on many things house batteries run down swiftly and it takes several hours to fill 'em back up. Even longer if charging with main engine
I have an 80 amp converter it charges both house (originally 220) and Chassis (73 amp hours) So figure 300 amp hours.. Takes six hours to fully charge from 50% house. I now have over 500 AH of house batteries Takes a bit longer.

[tropical36]

jkc306 wrote:
Thank you all for great advice!! Both house batteries were low on water; filled with distilled. Checked both with hydrometer - both batteries in the red...before buying two new ones i am charging them hopeful they will re-charge.

Both batteries have no labels, info, etc., except for 27 MDP. Appears this means their for either marine/rv use. Also learned you can spend a lot on rv house batteries :E

Thanks for the help, truly learning the RV life!!

Oh, regular battery is fine -

Whatever their condition, you really need pure deep cycle batteries for the house and Golf Cart batteries fit this criteria, if you don't already know that.

[wolfe10]

Yes, checking with a hydrometer until they ARE fully charged will always lead to "bad battery".

Yes, if run very low on water, they are likely bad, but to accurately check, they do need to be fully charged.

And, an equalization charge would be even better.

If doing an equalization charge, I suggest you disconnect them from the coach. Some of your PC boards would not be happy with 15+ VDC.

[jkc306]

Thank you all for great advice!! Both house batteries were low on water; filled with distilled. Checked both with hydrometer - both batteries in the red...before buying two new ones i am charging them hopeful they will re-charge.

Both batteries have no labels, info, etc., except for 27 MDP. Appears this means their for either marine/rv use. Also learned you can spend a lot on rv house batteries :E

Thanks for the help, truly learning the RV life!!

Oh, regular battery is fine -

[tropical36]

jkc306 wrote:
Have 2017 Thor ACE, battery dead, jumped started and let run for about an hour. Unplugged from 30amp electrical while in RV barn. Few days later went out to Thor and discovered house batteries are dead...Pretty sure they are "new" still and should be working. Any insights would be helpful (New to RVing)

After charging disconnect the neg. leads and if they stay charged, then something is pulling them down in storage, which is usually the case and quite common.

[theoldwizard1]

Golden_HVAC wrote:
Maintenance free and coach batteries are not the same.

Most "maintenace free" (engine starting) batteries have caps that can be removed ! I usually clean the outside of my engine starting battery every 1-2 years. At the same time, I pry off the caps and check the fluid level.

[Golden_HVAC]

Have you been adding water to your coach batteries on a regular basis? If the plates are visible, then yes the battery might need replacement. Adding water might restore some of their capacity.

Maintenance free and coach batteries are not the same. A coach battery, you should be able to add water to it every once in a while. depending on how good your battery charger is, you should need to add water about once every 6 months. If the charger is set to high of voltage, then more often. Water is consumed during the charge process.

If the coach was built say middle of the year in 2017, then the battery are at least 3 years old, the chassis might have been assembled as early as September 2016, with a battery that was new in May of 2016? Maybe even older than that. So perhaps 4-5 years old? If you can recharge the battery on a bench or with the RV wiring disconnected from it, then it stays above 12.2 volts without the charger for a week, it should be fine. Yet if it self discharges to say 11.5 volts in a week, it can not be trusted to run anything, it has internal short circuit, probably debris under the plates accumulated and it is bad. I have seen some batteries that you charge to 13.6 volts for a week, and within a hour of shutting off the charger they reach 10 volts or less, indicating a shorted cell, and not good for anything.

It is easy for me to say "Replace all three batteries and you will be fine". However you probably will have to replace the battery soon if you are not doing things correctly. Like charging the engine battery once in a while. Like keeping a eye on the water in the coach battery and filling it with distilled water every couple of months, and then you can get an idea of how often you need to check it, and fill it to stay in range.

Shutting off the disconnect switch when you will not be using the coach for a while is also important. Keeping it plugged into 120 volt power will keep the coach battery full (but use up water too) and will not normally charge the engine battery. Starting the engine once a month and let it run about 10 minutes will top off that battery.

Fred.

[time2roll]

jkc306 wrote:
Any insights would be helpful (New to RVing)

The 12 Volt Side of Life

[pianotuna]

Consider a better way to maintain the batteries.

If these are toast, consider SiO2 chemistry. It costs more initially--but has a lower cost per cycle. They can survive an occasional total discharge (not recommended).

[dougrainer]

1 Hour of running is NOT going to fully charge your dead batteries. Doug

[time2roll]

jkc306 wrote:
Have 2017 Thor ACE, battery dead, jumped started and let run for about an hour. Unplugged from 30amp electrical while in RV barn. Few days later went out to Thor and discovered house batteries are dead...Pretty sure they are "new" still and should be working. Any insights would be helpful (New to RVing)

Maybe the disconnect was left in the in-use position and they discharged?
Plug back in and check battery voltage. You should see 13.6+ volts within an hour. Watch for excessive gassing or heat that would indicate an internal short. I assume you have proper water levels in the battery.