Community Forums

rvjimzhr · 08-21-2009, 06:50 PM

I have a 2000 Model 7371 with (2) 12v chassis batteries. These batteries went dead this past winter and I replaced both in March. I'd like to treat these batteries correctly for maximum life.

A friend who owned a '00 7371 a couple of years ago thinks the chassis batteries charge both when driving AND when plugged into shore power.

I was told by Interstate Battery that the only way these batteries charge, other than using a charger, is by driving the coach. I park it for months at a time so that's not a realistic option. They suggested using a 1.5 amp trickle charger or "maintainer" while it's parked. I am using one of these at the moment and was assuming I was charging both 12v correctly.

TODAY another battery retailer told me that to do the job right I need to fully charge the batteries with a 6 or 10 amp charger, THEN put the trickle charger on and leave it while the unit is parked. If this is necessary I'll go buy a charger and do it this way.

I'm a little confused. Ideally the chassis batteries charge while plugged into shore power but the battery retailers tell me that ONLY the (4) house batteries charge this way and that is standard in the rv industry (I didn't think anything was really "standard" in the rv industry).

So, I'm looking for the right answer: 1) Charge with shore power 2) charge with trickle charger or 3) charge with BOTH a charger and a trickle charger or 4) none of the above.

Any of you National Tradewinds owners up on this subject?

Thanks in advance.

Jim

Richard S. · 08-21-2009, 07:31 PM

I think you will find that National RV used a interconnect and all the battries will charge when connected to shore power. As far as standard in the RV industris, all manufactures connect them the way they want.

rvjimzhr · 08-22-2009, 05:37 PM

Thanks Richard! I hope you are correct. Before I replaced the batteries, I had experienced no problems with them. THe coach had been parked 7 months and then I drove it to south TX and parked for 3 months in a park and had 30a shore power. About 2 months into this period of parking, the chassis batteries suddenly died. We charged them with a good charger for about 8 hours. A month later I drove home, parked until July when I decided to have the batteries checked before a trip. THis is where I was told they needed replacement. SInce they had discharged recently I went ahead and replaced both. All of which brings me to my question......If my coach is wired so that both house and chassis batteries charge on shore power, why did my 2 chassis batts discharge after 2 months of parking this winter? And what kind of test might I run to determine for sure how mine are wired?

Richard S. · 08-22-2009, 06:16 PM

Seeif this helps. item 3 in general

rvjimzhr · 08-22-2009, 06:43 PM

I've downloaded the info you sent Richard. Thanks! It's mostly greek to me and I'm not sure whether this info is the same in your 2007 model as in my 2000. Maybe someone with a 2000 Tradewinds can just tell me how my system works; or refer me to a "Dummies" handbook.

Richard S. · 08-22-2009, 07:05 PM

My error that info was from a 99 dolphin, should be same as yours or very close

Richard S. · 08-23-2009, 10:02 AM

After a little more research it appears that between 1998 and 2001 some National RV’s charged the chassis and house batteries when connected to shore power and some did not charge the chassis. Unless you find an owners manual you will need to test the output of your charger/ converter or charger/ inverter to the chassis batteries.

rvjimzhr · 08-23-2009, 10:11 AM

Richard thanks once again for taking your time to help me here!

Though you didn't specifically address the question of why my batts died like they did in March, maybe it's safe to conclude that they were not being charged by shore power at the time. I have a 2000W inverter. I also have a mutimeter so if I can figure out just how to check like you suggested I will do so. Just out of curiousity, where did you find the info you did during your research. I don't believe I have any owner's manuals which deal with this issue.

Richard S. · 08-23-2009, 10:34 AM

At this group, NationalRV : National_RV in the files and links. Also I had a extra manual from a 01 surfside that I use to have.
For the Yahoo group you will need to register. To test for charging disconect -and + cable at your chassis BAT. plug into shore power and check for DC voltage at the loose BAT. cables

rvjimzhr · 08-26-2009, 08:10 PM

If I understand you correctly, I unplug - and + cables at the battery; plug into shore power; put a multimeter on the cables and if I get a reading I am charging from the shore power. If I don't get a reading I am not charging from the shore power.

So what is the setting for the multimeter and how do I attach the leads to the battery cables? Have you guessed that you have a real slow learner here??

Richard S. · 08-27-2009, 07:31 AM

Put your meter on the 50 volt scale.

12 VDC

Wiring

– It is important to use the correct wire gauge for the specific model selected. As an example the model SRV-32 is a 32 amp Converter/Charger that requires a 10 AWG wire.
• The terminal marked + or POS is for the RV 12 VDC positive connection.
• The terminal marked – or NEG is for the RV 12 VDC negative connection.
• The 12 VDC output wiring does not require over-current protection because the Converter/ Charger limits current output. However, all electrical connections need to comply with the appropriate NEC code.
6. TEST. First, disconnect all loads and battery on the Converter/Charger by removing all 12 VDC connections from + or POS . Second, attach a multimeter instrument between the positive and negative terminals of the Converter/Charger. Then energize the 120 VAC converter circuit. Test for proper output power using the multimeter. Measure the output voltage from the positive and negative terminals. The voltage should read 13.6 +/- 0.2 VDC. Add 12 VDC load connections to about 2/3 of the rated capacity of the converter. Recheck the voltage, which should remain approximately the same as at no load.
7. BATTERY. With the 120 VAC disconnected, reconnect the + or POS positive terminal to a known good battery. With the converter 120 VAC energized, measure the voltage at the converter and at the battery. The voltage should be about the same in both locations. As with any battery it is important that the fluid level be checked on a regular basis. When continuously connected to any charging source all batteries will "Gas" and lose some fluid.

rvjimzhr · 08-29-2009, 10:48 PM

Thank you again for the info Richard! I now know that my 2 12v chassis batteries are charging when I'm plugged into shore power. And I'm just a little wiser having gone thru this exercise.