Battery Life, Charging Methods

[mitchmitchell]

I would also recommend reading this on RV battery charging, I learned a lot here: http://handybobsolar.wordpress.com/t...ging-puzzle-2/

[Mustang65]

If your TT's battery charge controller, or external generator (with internal charging electronics) is capable of 30 amps, it does not mean that it will automatically be pumping 30 amps into the battery all the time. This is the max output for the charging unit. The only time your battery may draw 30 amps is when it is almost dead or totally dead.

The battery(s) voltage level determines the amount of amps it needs. The battery controller determines the battery charging voltage. So if your battery is at 11.2 volts it will draw a lot more amps from the charger than it will at 12.2 volts. On smart charging units, there is also a programmed amount of time limit that each mode will charge at, ending with the FLOAT at 13.2 to maintain the charge (for a 12 volt system).

One possible problem with inexpensive units is that they do not monitor the actual battery during the charge process and have a fixed voltage output of we will say 14.5 volts constant. If that is the case then you will have an issue of boiling the battery over time, because it does not bring the charging voltage down to 13.2 volts.

When you get into the higher priced and SOLAR MPPT charge controllers they also measure the temperature of the battery (important in charging a battery) and use that in the charge calculation.

As a reference my TT's unit (PD4000 series) provides enough charging power (45Amps) for 2 Trojan T145 (260Ah) batteries (used prior to adding SOLAR). If you do not go below 50% (12VDC) you would have no issues with 4 batteries like mine. The max Amps that I have ever registered was a little over 18 Amps (due to operator error, dumb me).

Just my thoughts,

Don

Here is the unit that is in our 2013 Eagle (not used now because we have SOLAR):
The PD4000 series incorporates a microprocessor to provide a three-stage charge profile to ensure rapid, yet safe recharging of 12 volt
batteries. These three separate stages BOOST, NORMAL, and STORAGE (FLOAT) modes ensure that the battery is automatically recharged
and maintained with minimum maintenance (i.e. reduced need to add water).
BOOST MODE: If the converter senses that the battery voltage has dropped below a preset level the output voltage is increased to
approximately 14.4 volts DC to rapidly recharge the battery.
NORMAL MODE: Output voltage set at approximately 13.6 volts DC.
STORAGE MODE (FLOAT): When the converter senses that there has been no significant battery usage for 30 hours the output voltage is
reduced to 13.2 volts DC for minimal water usage. When in storage mode the microprocessor automatically increases the output voltage
to 14.4 volts DC for 15 minutes every 21 hours to help reduce sulfation of the battery plates.

[Rustic Eagle]

Originally Posted by gypsmjim

snip....... Sooooo, my questions....
1. If I switch to a deep cycle size 27 battery (not a dual purpose), how much better life will I get?

A true deep cycle battery will provide considerably more discharge/charge cycles then the standard OEM marine/RV deep cycle battery, and a standard battery doesn't like being subject to a deep discharge...., compromises battery life.

Also, a shallower average DoD (Depth of Discahrge) will increase battery life. A deep cycle battery with an average 50% DoD will last at least twice as long as an 80% DoD. A typical GC-2 deep cycle battery will average 225 cycles at 80% DoD, but will increase to 750 cycles at 50% DoD

Originally Posted by gypsmjim

snip......
2. I have a good automatic 3-stage battery charger - would this charge it up quicker than the onboard inverter?

The newer OEM 3 & 4 stage converter/chargers supplied by Jayco do a good job of charging the battery compared to the older 2-stage converter/chargers. I installed an updated 4-stage converter/charger in my TT, but found that I can charge my (2) deep cycle batteries faster with my Black & Decker 40amp VEC1093DBD battery charger faster with it connected directly to the batteries. But, in my case the batteries are located at the front of the TT and the converter/charger is located 30ft to the rear of the TT.

Originally Posted by gypsmjim

snip......
3. If so, can I connect the charger directly to the battery without unhooking it from the trailer? Is it a problem if the 2 chargers are connected at the same time?

I do not disconnect my battery connections from the TT when I'm charging with my Black & Decker charger. However, I don't have my TT shore power connected to my genny while using the genny to power the Black & Decker charger.

Bob