ScottG
Bothell Wa.
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Joined: 02/25/2005
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Load testing doesn't tell you much about a deep cycle battery.
It will likely load test perfectly good but have very little reserve capacity (RC) left.
Scott, Grace and Wesly
2003 Dodge 3500 4x4 Cummins (lightly bombed),
2004 Forest River 25RKS many, many mods.
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DAS26miles
San Fernando Valley, California
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Joined: 10/11/2003
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I did check the monitor yesterday while driving home, and the batteries weren't fully charged down 15%. It said down 20 amps. When I got home, they were only down 2 amps from 20 amps. I think the engine battery being low from the start causing a drain on the house batteries. I leave the MH sit for 3-4 weeks between trips and the radio/clock and scangaugeII have a drain on the engine battery. I tried charging the engine battery once or twice before leaving on trips and it seemed to make a difference. I get to the CG with fully charged batteries. If I don't, they are down 10%. The engine alternator must be charging only the engine battery if it is low. If it is charged, then it charges both.
I am going on a beach trip a week from Friday and can better check it out. In the meantime, I will pull the batteries tonight and take them over to Autozone for a load test. I will check the cells first with my hydrometer to see if I have a weak or dead cell.
I did notice that there was a big difference in light brightness when another light was put on or turned off.
2004 Class C Winnebago Minnie 22E
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jauguston
Bellingham, WA
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Joined: 07/03/2005
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DAS,
If you are able to do a little bit of wiring I ran a 120v cord from one of the breakers in my power center along the frame to near my engine batteries. I just used a good outdoor extension cord. I cut the male plug off and threaded it along the frame and up to the power center. I went to Walmart and got a permanent mount Schumacher 1.5a battery maintainer. When ever I have AC power to the power center either shore power or generator the engine batteries are take care of.
Jim
Jim, Sharon and Buddy the Yorkie
1999 Gulfstream Sun Voyager 31' ISB Cummins 210 uprated to 275
Trippe-Lite 1800w inverter 4-6v GC batteries
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BFL13
Victoria, BC
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Joined: 02/15/2006
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I can watch the volts drop from 12.5 down to 11.8 with just a few lights on drawing only about 6-8 amps. Does this mean that although my batteries may be almost fully charged, that when under a load the volts drop too much and mean I need new batteries?
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To help diagnose, since you have 12s you could try it with one battery at a time and see if you have a "bad" one of the pair.
Our two 6v started acting like that after a couple years, but not as much, seeming to be fully charged but "collapsing" under load. After the initial collapse, they would hold not badly under load for a long time without collapsing more, so it was like they were bad at the top of their voltage range but ok below that.
It seemed to be a case of sulfation, but also one of the pair doesn't charge up as fully as the other( possible internal damage of some kind, according to tests) so the pair acts like the "bad" one.
You could have a cell going (internal damage idea) as suggested by others in this thread or perhaps be sulfated (although this unlikely with a charge wizard on the job I suppose)
For replacement or not, IMO it comes down to whether they will still do the job you need done even in their degraded state (like our pair of 6s still can for us.)
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DAS26miles
San Fernando Valley, California
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I tend to use 30 to 40 amps per day in warmer trips and 65 to 75 amps on cold weather trips. Sulfication shouldn't be a problem with charge wizard and 3 stage charger. I have already done two trips with it like this. Next trip is to the beach for 2 days. I can probably get by til then and do further testing.
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BFL13
Victoria, BC
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I tend to use 30 to 40 amps per day in warmer trips and 65 to 75 amps on cold weather trips.
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With 2 24s for 160 you would go down to 80ah for 50% at 80F, but put back 40 and be at 120 or 75% But in cool weather, your bank is at maybe 80% of rated ah? Call it 128 not 160. So now 50% is 64 and you replace that 70ah (cold daily) 64 plus 70 =134, not there!
So you must be going below 50% SOC on cold days and need to recharge to near 100% for endless gen time--not fun.
Perhaps that is what has happened from going below 50% too much. You could replace those 24s with either two 6s at 232ah or two 27s at 115 or 120 each for 230 or 240ah and have a better bank for operating 50-80 with your typical daily useage.
We now have a pair of 27s for 240ah and they act the same as the 2 6s for charging times etc. Perhaps they will have a shorter life than 6s but they are cheaper up front too. Same for camping anyway.
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wa8yxm
Wherever I happen to park
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Joined: 07/04/2006
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First: Check the batteries and add water as needed. (Bring it up to just below the filler tube) After 3 years, even if they don't NEED it. you should do this
Now, clean all connections, DISCONNECT the cable, wire brush it, and re-connect it
Do a full cleaning
The problem with the engine not charging the batteries may be nothing more than a bad connection, likely at the battery but .... Not exclusively It could also be a bad battery control center solenoid (relay) but from other things you said I'm guessing a poor connection.
Nothin adds excitment like something that is none of your business
John is Near Kenwood TS-2000 housed in a 2005 Damon Intruder 377
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PopBeavers
San Jose, CA
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Joined: 03/19/2005
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My Interstate pair of group 24 RV/Marine batteries were not lasting as long as they used to.
I took them out and ran a couple of desulfate cycles and an equalize cycle, one battey at a time.
They work much better now. I have no doubt that I have defered replacing them by a year or two.
Wayne in San Jose
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MELM
GA
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Joined: 12/11/2001
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In past posts, you had a Batteryminder and a Vector charger. Does either of them have the desulfation or equalization (15+ volts) modes? If so, you might help the batteries by desulfating or equalizing them.
The PD does the periodic 15 minute Boost voltage charge, but that doesn't do much for desulfating a battery. Rather, is prevents additional sulfation by ensuring a full charge in cool temperatures and it prevents stratification of the electrolyte with a small amount of gassing.
Since you keep the MH plugged in full time, you might consider adding one of these: Trik-L-Start. Some members have done it, and some have posted that 'Bago is now installing it on some MH's. The converter would keep your chassis battery maintained like it does the house batteries, and the installation is pretty easy.
Mel & Mary Ann; Mo'Be (More Behave...) and Bella
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73 Kountry Aire 31.5 ft (semi-retired) TT
90 Champion LaSalle MH 29 ft P30 (89 Chassis)
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DAS26miles
San Fernando Valley, California
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Joined: 10/11/2003
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Melm-The Vector charger has a desulf mode. I am pulling out batteries tonight and will check SG. I will hook up the Vector. Can I desulf them together or one at a time? Will take them for load test at Autozone this wewkend.
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