Chasis battery charging

[Rocky Healey]

A basic question.  Should the chasis batteries be recharged fully during a run of 250 miles 4.5 hours , and if not what should I look for and where will I look.  I know this is a very basic question but am still learning.
Thanks in advance for all info.

Rocky Healey
Patroit Thunder 45 Ft
C-13

[David T. Richelderfer]

If you departed from your parking spot with the chassis batteries well down, then you could have blown the diode/s in the engine's alternator... in which case the alternator would not be offering any charging for both the coach and chassis batteries.  You could also have a bad chassis battery.  You could also have a bad Echo Charger or BIRD System (Bi-directional Isolator Relay Delay), whichever your coach may have, which allows the alternator to charge the chassis batteries after the coach batteries get near charged.  There are other possible causes for the chassis batteries to not receive charging power from the alternator.

So, the first question I would ask is, "Are the coach batteries charged after driving an hour or so?"

[Bill Sprague]

I think David said it, but if everything is working right, the chassis batteries have to be reasonably well charged to start the engine.  Then with the engine running, the alternator should replace the energy used quite quickly.  Maybe 10 or 15 minutes?

[Rocky Healey]

I did forget to say that the dash readout when going down the road is 13.7 to 13.9 VDC.  I hope that this will help me pinpoint the problem.  Thanks for the feed back.

Rocky Healey
2008 Patroit Thunder
45 ft
C-13

[Rocky Healey]

Dave,
in response to your question what should the batteries be reading voltage wise on the volt meter?

Rocky Healey
2008 Patroit Thunder
45 ft
C-13

[David T. Richelderfer]

1. A naked, 12 volt stand-alone battery, that is with no charge being applied, should read 12.6 to 12.7 volts when fully charged; or half that for 6 volt batteries.

2. When parked and plugged into shore power or with the generator running, and applying charging power to the batteries from the inverter/charger, your dash gauges (preferably the Aladdin or Silverleaf) for 12 volt batteries should read 13.3 to 13.5 volts; or half that for 6 volt batteries.

3. When driving down the road, your dash gauges (preferably the Aladdin or Silverleaf) for 12 volt batteries should read 14.4 volts or so; or half that for 6 volt batteries.

The difference is because in events 2 and 3, the dash gauges (preferably the Aladdin or Silverleaf) are showing the charging power being applied to the batteries, not the charge status of the batteries.  Remember, batteries on most coaches are connected together such that all chassis systems are 12 volt, except for solar from the rooftop panel/s down to the solar converter.

[Bill Sprague]

Hoping to add emphasis to David's reply.....

You can't use voltage alone to measure battery health or state of charge in an RV.  The reason is that you can't completely remove the load and (normally) multiple batteries are connected together.   It is not reasonable to disconnect all the batteries from the coach and each other, wait for thirty plus minutes, test them and wire them back up!

You can use voltage to see if the the alternator, inverter, converter or solar is "trying" to charge the batteries. 

In a Beaver with standard equipment the only way to know how the batteries are working is with experience.  Over time you develop a sense of what to expect with your personal use pattern.  When performance drops below that, batteries are getting weak.   If you dry camp ("boondock") once a year (like Quartzsite), you'll not get enough experienced sense of what your rig will do. 

Two useful battery tools are a load tester and hydrometer.  (The hydrometer only works if your batteries have caps. )

https://www.amazon.com/s?k=OTC+4619+Professional+Battery+Hydrometer&i=automotive&ref=nb_sb_noss_2

Schumacher BT-100 100 Amp Battery Load Tester

[Gerald Farris]

Rocky,
Dash gauges are notoriously inaccurate, therefore I say they are for entertainment purposes only. With a handheld volt meter, what is the voltage at your chassis and coach batteries after coach has set with the engine and generator off, and without being plugged into shore power for an hour? After you have those readings, what is the voltage for each battery bank with the engine running for ten minutes? Then what is the voltage for each battery bank with the coach plugged into shore power and the inverter charging for ten minutes? With these voltage readings, I can tell you the functionality of you coach charging systems, and if you need to look at a needed repair or not.

If you do not have a volt meter, you should get one or be prepared to waste a lot of money at RV repair shops. You can get one at Harbor Freight for $5 that is not professional quality, but it will do most everything that the average owner needs.

If I just confused you with this post, and you would like a more detailed description of your coach's systems, just call me at your convenience. 713-254-4156     

Gerald

[Bill Sprague]

Not really related to batteries but Gerald's phone number is a reminder....

One of the benefits of BAC membership is that you can download a copy of the directory with everybody's phone number.   If you are in a jamb, call somebody!   That may lead to two or three more calls, but you'll get help on everything from running the microwave to finding mobile repair. 

[Rocky Healey]

Thank you all. this info has been very helpful.  I now have some homework to do[thought I was past homework].
Gerald I will probably be calling you soon with more ? and suggestions.
Again Thank You all for your assistance.

Rocky Healey
2008 Patroit Thunder 45ft
C-13