Mar-28-2020 12:54 PM
Mar-30-2020 02:46 PM
Mar-30-2020 02:35 PM
pianotuna wrote:
Log,
How do you measure fully charged on your battery bank?
Mar-30-2020 12:35 PM
Mar-30-2020 11:24 AM
pianotuna wrote:LOG wrote:
It appears that your motorhome has the voltage drop problem that DrewE was explaining. And has nothing to do with a "smart" charging system.
Maybe you need a better battery isolation manager or combiner.
LOG,
I have dual charging paths with #8 wire (rating 50 amps) with dual solenoids, each rated at 200 amps continuous. I have manual control of the solenoids and charging from the alternator. Each charging path is protected by a 50 amp automatic circuit breaker.
If the house batteries are "hungry", then I see more than 75 amps of charging. (my meter only reads to 75 amps). On occasion I've observed at least one of the circuit breakers flipping off and then on.
On normal use, because my starting battery is given a maintenance charge when ever the sun is shining, I see little charging after the starter battery is full from the ecm's point of view.
I can "force" charging of the house bank by using the inverter and running the 1400 watt water heater. However this does, after about 20 minutes, cause the starter battery to go down to 12.3 volts. At that point, I use my manual control to stop the charging, and I disconnect the water heater. The reason for doing so, is the 1/3:2/3 duty cycle on the alternator which I do not wish to burn out.
After 40 minutes of highway driving, I can repeat the above process. The last hour of driving I use to return some charge to the house bank.
I can "see" one of the breakers flipping in and out if I run the engine and use the microwave (170 amps draw) and the induction cooker (70 to 130 amps) at the same time.
These observations are from 2013 when I had 8 identical marine jars, one of which was used as a starter battery, and the house banks were configured as 3 and 4. Both banks were wired in a balanced manner. The "house" bank was 875 amp-hours @ 12 volts.
Mar-30-2020 11:03 AM
LOG wrote:
It appears that your motorhome has the voltage drop problem that DrewE was explaining. And has nothing to do with a "smart" charging system.
Maybe you need a better battery isolation manager or combiner.
Mar-30-2020 10:43 AM
theoldwizard1 wrote:
A smart charging system WILL NEVER FULLY CHARGE A "HOUSE BATTERY BANK" !
Mar-30-2020 10:12 AM
pianotuna wrote:LOG wrote:
Would you please provide the year, make and model of a motorhome that has a "smart" charging system that would do that.
Thanks.
My own RV exhibits this behavior. 2005 Kustom Koach.
Mar-30-2020 09:52 AM
DrewE wrote:
Yes and no. The ECM sees the voltage at the chassis battery. Provided the two batteries are connected with a low enough resistance connection, the voltage will be practically the same at both batteries, and the ECM will see that same voltage and not deem the battery to be charged and drop the voltage until both are at whatever it thinks is fully charged.
Mar-30-2020 09:49 AM
LOG wrote:
Would you please provide the year, make and model of a motorhome that has a "smart" charging system that would do that.
Thanks.
Mar-30-2020 09:47 AM
DrewE wrote:pianotuna wrote:LOG wrote:
Lets say a new motorhome with a smart charging system also included a battery combiner that connected the chassis battery and the house bank when the engine is running.
Would the ECM still see the chassis battery as fully charged and drop the alternator voltage before both are fully charged?
Yes the ECM "sees" the chassis battery and drops the alternator voltage.
Yes and no. The ECM sees the voltage at the chassis battery. Provided the two batteries are connected with a low enough resistance connection, the voltage will be practically the same at both batteries, and the ECM will see that same voltage and not deem the battery to be charged and drop the voltage until both are at whatever it thinks is fully charged.
Not all motorhomes have a connection between them with a low enough resistance for this to work too well. That could be because the wire is insufficiently heavy, or there's a poor connection somewhere, or in some cases because an auto-resetting circuit breaker is clicking on and off (and, of course, has a very high resistance in the off state). The greater the resistance is in the connection, the greater the voltage drop will be to the house batteries, and the more prematurely the charge voltage will drop.
Mar-30-2020 09:38 AM
pianotuna wrote:LOG wrote:
Lets say a new motorhome with a smart charging system also included a battery combiner that connected the chassis battery and the house bank when the engine is running.
Would the ECM still see the chassis battery as fully charged and drop the alternator voltage before both are fully charged?
Yes the ECM "sees" the chassis battery and drops the alternator voltage.
Mar-30-2020 09:20 AM
pianotuna wrote:LOG wrote:
Lets say a new motorhome with a smart charging system also included a battery combiner that connected the chassis battery and the house bank when the engine is running.
Would the ECM still see the chassis battery as fully charged and drop the alternator voltage before both are fully charged?
Yes the ECM "sees" the chassis battery and drops the alternator voltage.
Mar-30-2020 08:44 AM
LOG wrote:
Lets say a new motorhome with a smart charging system also included a battery combiner that connected the chassis battery and the house bank when the engine is running.
Would the ECM still see the chassis battery as fully charged and drop the alternator voltage before both are fully charged?
Mar-30-2020 08:32 AM
theoldwizard1 wrote:
Check the voltage at the battery. It should be 14.0V-14.5V. Drive for at least 10 minutes. With the engine still idling, check the voltage at the battery. If the voltage is below 13.8V at the engine starting battery, you have a smart charging system.
A smart charging system WILL NEVER FULLY CHARGE A "HOUSE BATTERY BANK" !
Mar-30-2020 06:24 AM