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Author Topic: replace 7345 with Intellipower 9245 or use both  (Read 168 times)

dluck

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replace 7345 with Intellipower 9245 or use both
« on: October 26, 2017, 10:59:44 PM »
Hi,
I'm a new forum member, and this is my first post.
The previous owner of my motorhome replaced the 6345 with a 7345. My research led me to purchase a PD9245C to replace the 7345 to better maintain the batteries and charge them quicker or more safely. However, it seems to me that if I have any other 12V load turned on, various lights, furnace (12V blower), etc. that load will reduce the current going to the batteries. My thought was that instead of completely disconnecting the 7345 from the system, I would wire it in through a toggle switch to the 12V distribution panel. This way when I'm trying to recharge the batteries as quickly as possible (like while running the generator) I can flip the switch and disconnect the 9245 from the 12V distribution panel (fuse board) and power the 12V stuff from the 7345. When I'm no longer charging the batteries, I switch it back. The 7345 would only have a ground in common with the 9245. The 12V output of 7345 and the 9245 would never be connected together since I'd use a toggle switch to switch to one or the other. The batteries would never be connected to the 7345, I'd just be using it to drive the 12V appliances/lights.
Does this make sense? Would it improve the rate of charging the batteries? Or maybe the benefit is to small to be worth the trouble of keeping them both available.

Gary RV_Wizard

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Re: replace 7345 with Intellipower 9245 or use both
« Reply #1 on: October 27, 2017, 09:04:14 AM »
I doubt if there would be much, if any, advantage to that. The main limit on charging is the ability of the battery(s) to accept current and that decreases rapidly after the first several minutes. It is going to take a certain amount of time to charge a battery no matter how many amps you have available.  Learn more about batteries and how they charge at:
 http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery
http://www.chargingchargers.com/tutorials/charging.html

The furnace fan is about the only thing that has much impact on the DC load and that's probably only 5-7 amps. Lighting isn't much unless there is a lot of it, and using leds instead of halogen or incandescent would reduce that substantially.

No harm in trying it, though, if you don't mind the effort it takes to re-wire as you described.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Charlie 5320

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Re: replace 7345 with Intellipower 9245 or use both
« Reply #2 on: October 27, 2017, 03:01:10 PM »
Why did you upgrade in the first place? I wouldn't want anything interfering with the new converter/charger if it were mine. If you want to leave it in place for a backup, but doubt you will need it. All them old converters were good for was boiling the batteries. I just replaced the lousy magnetec converter with a PD9260 in my coach. My magnetec would never charge my batteries fully, it took my 9260 24 hours to go to float mode, and NO noise.   
2003 National Dolphin 5320
496  8.1  Workhorse

98 Damon Daybreak 3130
GM Vortech 454  4L80E
SOLD

dluck

  • Posts: 2
Re: replace 7345 with Intellipower 9245 or use both
« Reply #3 on: October 27, 2017, 04:08:57 PM »
I upgraded to get to the three stage converter, faster charging, and won't boil the battery off. I have two 24 type batteries and was thinking of going to two 27 size batteries. After I took the 7345 out, I thought it still would perform ok as a general purpose battery charger in my shop. The new 9245 is about 1/2 the size of the old magnetek 7345. I have plenty of room for both. I noticed the magnetek fan will go on when temp in the rv gets high, even if there is no significant load. I've already started replacing some of the incandescent lights with LEDs. The suggestion about getting a catalytic propane heater is good and I plan to purchase one.
The only time having the extra 12V power supply around would help is if batteries are sucking up 45 amps during charge (max output) and I think that primarily happens during the bulk charge operation
For now I think I won't hook it up, just keep it around as a spare and concentrate on the other updates I need to do, like replacing the 20 year old LP and CO detectors, fixing the leaks in the windows, etc.
thanks for the suggestions,
dale

Gary RV_Wizard

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Re: replace 7345 with Intellipower 9245 or use both
« Reply #4 on: October 28, 2017, 09:57:49 AM »
 Battery manufacturers recommend only 10-13% of the battery capacity as the max charge rate. That is known as C/10, where C is the the battery capacity in amp-hours.   Two Group 24 batteries have a total of about 170 AH of power, so the peak charge that is desirable would be in the 17-22 amp range. For two group 27's it would be about 210 AH, so 21-27 amps.

In other words, those batteries won't be sucking down 45 amps under any circumstances.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

 

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