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Amp Hours

Yahoo Message Number: 5311
I am writing this email to the group in hopes that some electrical guru can help me with understanding (if possible!) the charging and electrical system on my coach.

I have a 2002 Affinity, ALL Electric. So being all electric I have 4 AGM house batteries, 2 Heart 458 inverters, and 2 Link 2000's. This bank of batteries is 880 Amp Hours total. I am sure that the inverter and Links are programed correctly. When I am plugged into 50 amp service (anywhere, so it is not the park) I register negative amp hours to the tune of 20 to 25 a day. So in the last five days I have accumulated -117.8 amp hrs on the readout for the link. I just do not understand why, when I am plugged in and not using excessive amounts of electricity, why I am accumulating these negative amp hours. I have turned off the Bose and VCR and am only using the TV, no A/C running as it is in the 70's and have been barbecuing so not using the cooktop or the microwave.
We also have difficulty in that we cannot dry camp for more that 18 or so hours because our batteries drop to 12.2 to 12.0 and then need to be charged.
When driving down the highway, IF my house batteries have dropped to the 12.0 level, they will not charge to 13.5 even after driving for 8 or 10 hours. In order to charge the house batteries fully, I have to turn on the generator while driving for about 4 to 6 hours.

Sorry to ramble on, but this is so frustrating and hard to explain. I have been to CC and they assure menothing is wrong.
If anyone can give me any input on this I would be appreciative.

Thanks, Dale Hollick Affinity 6129

Re: Amp Hours

Reply #1 –
Yahoo Message Number: 5314
My Magna shows the same negative Amp Hours when charging the house batteries. I have contributed this to the shunt that measures the Amps. This is an imperfect tool, thus it'll be off over time.
When consuming, the Amp Hours will run up, when charging they run down. When you start the engine, my Link 2000 will reset the Amp Hours to zero, probably to make up for the imperfection of the shunt.

You have 4 batteries holding a total of 880 Amp Hours. This is equivalent to about 11 KWh (880Ah * 12.5V). If that lasts you about 18 hours, that means that your average use is about 600W. There will be some loss in the inverters, thus the actual average may be about 550W.
With an all electic unit, that doesn't sound unreasonable.
Half an hour of cooking probably takes 3KWh, or more than a quarter of your capacity.

We like to dry camp sometimes and have propane for cooking and water heating. I suppose that an all electric unit and dry camping are a bit of a contradiction, but then the generator comes in handy :-)

Regarding the rate of charging while driving, mine charges in about
4-5 hours, but I only have 2 house batteries, thus I can see that
yours takes twice as long.

I agree with CC that nothing seems out of the ordinary..

Re: Amp Hours

Reply #2 –
Yahoo Message Number: 5317
Dale,

Our Magna also shows some negative amp hours, so once a year or sometimes shorter we reset the Links as per the manual. In the manual they explain why this happens. I also think that Country Coaches were not made to do a lot of dry camping. The assumption is that if you can afford a CC you can afford a camp site with 50 amps. At most FMCA rallies we have never been able to go more then 12 hours without running the gen. We run it in the morning and then at night, and we have solar panels. But we do not try to conserve power either. Running the gen. is good, the more you run it the longer it will last and be trouble free.

Bill G. 2001 Magna #5998

Re: Amp Hours

Reply #4 –
Yahoo Message Number: 5319
Thank you to everyone for the input regarding the amp hours. The reason I got concerned is that I have been racking up 20 to 25 negative amp hours each day. Steve Stoney at CC is having me reset some things on the link. I will keep the group posted as to what hapqens with the new settings. Thanks again, Dale

Re: Amp Hours

Reply #5 –
Yahoo Message Number: 5327
Dale, I have a simpler Allure 2000 and cannot imagine an all electric coach. A few days ago I included info on the amperages needed by items in my coach. You should do the same for your coach. My Dometic frig uses 3.5 amps but throw in the ice maker and that is another 4A; the battery charges are using 5.5A; the electric hot water is using 9A...there are also many phantom loads and you most likely have more than I with all your sophisticated electronics. In your case you are running items in the electric mode all day. Add up the amps, multiphy by 24 hours in a day, and I think you will be shocked by the total. My experience is limited but I would suggest that you turn off circuit breakers for items not needed as you drive down the road. I turn off all circuit breakers in the rear panel in my bedroom when driving or parked unless I put on the genset. Have you considered adding solar panels? Others with electric coaches such as yours will probably be sending you more accurate advice. Good luck! Mike 2000 Allure 98 CRV

On Tue, 1 Jul 2003 13:06:06 EDT cdhollick@... writes:
 

Re: Amp Hours

Reply #6 –
Yahoo Message Number: 5335
Hi Again! Well, I will give you all an update on the current situation with the "Amp Hours" situation. Country Coach had a tech named Stoney recheck everything on the setting in the coach on both Link 2000,s. It was determined that the link had Not been set correctly even though it had been checked and rechecked by several people at several different times and locations. So with the reset having been done on Thursday, July 3rd, the Link is now reading correctly......no more accumulation of negative amp hours since this morning.
One thing that I believe some people have a misconception regarding AGM Batteries. AGM stands for Absorbed Glass Mat NOT anything to do with GEL batteries. They are (AGM) lead acid sealed batteries. There are several schools of thought regarding equalizing these batteries. S. Stoney told us to equalize them and see if changed anything. So I am going to do this in the next day or two, sometime when I can stay at the coach for the full 8 hour process. I will keep you all posted.

For some unknown reason (at least to me!) my chassis batteries are staying on a negative amp hour situation currently. They are new CAT 8D's so I will have to find out what it going on there.
Sorry to be so wordy. Again thank you to all of you who offered input, it really helped to read everyone's opinion.

Dale Affinity #6129