Hi all, I have a 2004 HR Alumascape which has given me 18 years of fun. We mostly dry camp. Usually I run the 2000W Yamaha generator every 2 or 3 days for a couple of hours to keep the batteries charged. I have read many comments here about older converters not being very good at charging the two deep cycle batteries. My converter is the Parallax 7355. So far, after 18 years this has worked okay for us but I just had an idea- What if when I fire up the generator and plug in the trailer power cord I also hook-up a 10amp variable rate charger connected directly to the battery posts. Would not this shorten the run time needed to bring battery charge up?

Noooo, you're in California, you have to use solar panels.

Haha, yes we get a lot of sun. Actually we are heading out Labor Day for two weeks and usually try to get a shady spot. Just was reading about the Parallax 7355 and still don't understand how to figure the battery charge rate from the converter. It's variable but Parallax states in the manual that it puts out a rate of about .5amp. I know it starts out at a higher rate of charge but quickly drops to .5amp.Anyone have any idea of how long it charges initially at a higher rate??

I don't know anything about your converter model but it is likely single stage which means it charges at a fixed voltage, usually about 13.5 volts. A multistage converter/charger will start at a much higher voltage, around 1.43 volts and then taper off. This means much less time needed for charging and more likely a better charge with longer battery life.I recommend you check the bestconverter.com webpage and then discuss recommendations with the owner, Randy. He knows his stuff and the prices and services are good and you know you will get the right replacement. I replaced my converter/charger and greatly reduced generator use. Most of my charging is with solar but when that does not work, I still need a generator.

The Parallax 7355 converter is an Old School, single output voltage converter which will do an OK job of powering the RV's 12v system but is lacking for battery charging.It will provide a continuous voltage of 13.6 volts regardless of battery state of charge. This means too slow for charging a discharged battery and too high a voltage for maintenance or float charge. On the latter this means battery will need more frequent "watering" to keep from going dry.I would consider replacing the converter with either a deck mount or replacement section for the Parallax power center (if so equipped) from Progressive Dynamics. It will provide higher (14,4 volt) charging voltage for an "empty" battery, 13.8 volts for the absorption phase (to get a FULL charge) and then switch to 13.25 Volts for a maintenance/float charge that doesn't cause battery to use a lot of water.The higher voltage will charge the battery faster and reduce the needed generator run time. On run time, a lead acid battery really needs more than a couple of hours at a time to fully charge. Generally a 100 Ah battery, discharged to 50%, will need 3-4 hours to reach 90% state of charge and another 3-4 hours of absorption charge to reach 100% SOC. Of course this depends on battery temp too as a cold battery will use the initial charging current just to warm the electrolyte.

Parallax 7355 is a fixed voltage or single stage converter, it will be preset to around 13.6-13.8V. The charge current tapers quickly because of the fixed output voltage of the converter. As the battery recharges the battery voltage rises, eventually it will get up to 13.6 or so volts and when that happens the charge current drops down to .5A or less..If the converter had a higher output voltage then you would see a higher current.. But then you would have the issue of too high of voltage for normal use and the result is boiled to death batteries. As it is with the fixed voltage if you left it plugged in 24/7/365 you would be burning up batteries constantly.Your 10A charger may help some depending on the max output voltage but I doubt it will be enough to make it worth the hassle to hookup and disconnect every time you wanted to recharge.Might be a good time to consider a multistage converter?Something like a PD92xx with Charge Wizard.. With Charge wizard it can deliver 14.4V in bulk mode.. You can get PDs as a lower portion replacement (you pull out the old Parallax and the replacement fits in the same bay) or you can buy a deckmount version you can mount nearby to the breaker and fuse panel and disconnect the old converter.The nice thing about modern multistage converters is they can go into storage mode (13.2V) when not in use, into a higher voltage 13.8V for in use or Bulk mode 14.4V as needed.. Storage mode saves a lot on water use, cuts down on boiled to death batteries.

Charging trailer deep cycle batteries | Good Sam Community

JimK-NY
Explorer II
Aug 28, 2022
I don't know anything about your converter model but it is likely single stage which means it charges at a fixed voltage, usually about 13.5 volts. A multistage converter/charger will start at a much higher voltage, around 1.43 volts and then taper off. This means much less time needed for charging and more likely a better charge with longer battery life.

I recommend you check the bestconverter.com webpage and then discuss recommendations with the owner, Randy. He knows his stuff and the prices and services are good and you know you will get the right replacement. I replaced my converter/charger and greatly reduced generator use. Most of my charging is with solar but when that does not work, I still need a generator.
Dalo
Explorer
Aug 28, 2022
Haha, yes we get a lot of sun. Actually we are heading out Labor Day for two weeks and usually try to get a shady spot. Just was reading about the Parallax 7355 and still don't understand how to figure the battery charge rate from the converter. It's variable but Parallax states in the manual that it puts out a rate of about .5amp. I know it starts out at a higher rate of charge but quickly drops to .5amp.
Anyone have any idea of how long it charges initially at a higher rate??
Fisherman
Explorer
Aug 28, 2022
Noooo, you're in California, you have to use solar panels.

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