| Author | Message | ||
| Jerry Coombs (Jerry_c)
Registered Member Username: Jerry_c Post Number: 10 Registered: 11-2005 Posted From: 64.12.117.73 Rating: N/A |
I've always enjoy and do a lot of dry camping, converted my 4106 with that in mind, and, hopefully, again in early Dec will be heading out for a winter trip spending most of our time in Southern Florida -- the longest location will have me dry camping again for 2-3 months. When converting and it was time for deciding on the house battery system I choose golf cart type -- eight of them as they have always worked good for me, were reasonably priced (2003 about $57 each), seem to have a large water capacity above the plates so I don't "have to" top them off as often, and are even locally manufactured. Back when I purchased them they were rated in amp hours and with eight of them in a series / parallel combination I figured up it gave me a total of about 880 amp hours so I figured I'd try and never go much over 400 amp hours of use (and I've a Link system battery monitor system to give me a good idea) before I charged them. Actually I don't think I've ever got that far or even over 300 amp hours of use on the Link system. When shore power is available I always do a complete full charge as well as an occasional equalization charge (I've a good inverter / charger with such capabilities). They are now will be entering their 6th year of use and would sure hate to get far away from home and have to replace them. Wondering if there would be some way to get an idea of their useful life left. Was thinking of maybe doing a draw down test of some type -- put on a fixed relatively low amp load and record the (unloaded) battery voltage verses time and graph it.... or something. If I had done this when the batteries were new I'd have something to compare it to but even then how would this give me an indication of useful life remaining?? Would doing a every so often specific gravity test during the draw down on each and every battery and cell tell me something useful (like maybe at least that battery, compared to the others was weaker)? Thoughts appreciated! -- thanks ahead -- Jerry | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1230 Registered: 5-2001 Posted From: 65.74.65.209 Rating: |
Jerry, if you take your bank capacity and divide it by 20, you will get a figure that will be the best load to run a discharge test on your batteries. Make sure that your batteries are fully charged and your Link is set to read in amp hours. The amp hour reading should show zero or a positive number. Start your discharge and the Link will report how many amp hours of discharge occurs by the time the voltage drops to 10.5. It should automatically shut off at that point. Compare this number to the rated amp hours of the bank, and you will have a pretty good idea of the capacity left in your batteries. This method is described in your Link manual. It will cost you one charge cycle in the life of your batteries, but I think it would be worth it to remove any doubt about the bank. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 600 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
Jerry, Tom gets my vote, as that is the way to do it. I would also do what you are talking about in the last sentence in your last paragraph. Maybe just a digital voltmeter recording of each battery voltage after charging, and before you start? Then read and record them once in the middle of the cycle, and again at the end. If one is lower than the others, by more than about half a volt, it would indicate an imminent failure, and you would only have to replace that one. If they're all about even, keep the recording for next year, and enjoy! The other thing to be noted here, is that by designing your battery bank size as you did, you have gotten excellent output and life out of them already, by not discharging them quickly or heavily! George | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1231 Registered: 5-2001 Posted From: 65.74.65.209 Rating: N/A |
Thanks for the vote, George. Also, your comments about detecting an imminent failure will save him some exposure to acid burns. I've got my share of burn holes! Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| Jerry Coombs (Jerry_c)
Registered Member Username: Jerry_c Post Number: 11 Registered: 11-2005 Posted From: 64.12.117.73 Rating: N/A |
I'll try checking individual battery voltage but one thing I already found by doing a hydrometer (specific gravity test) was that one cell of one battery had maybe 1/3 less than the SG the others did --- I suspect when I check its voltage it too will be lower than the others. So far I've got at least one battery to replace. thanks for the info ye'all. == Jerry | ||
| Jim Shepherd (Rv_safetyman)
Registered Member Username: Rv_safetyman Post Number: 271 Registered: 1-2004 Posted From: 72.171.0.140 Rating: N/A |
Jerry, I am sure others will chime in here, but the strong recommendation is NOT to mix old and new batteries. You have taken good care of your batteries and have gotten better service than many folks do. Might be the time to bite the bullet and buy a new set. The price of lead is down, but I don't know when that will find its way into the cost of batteries. Right now, I think you will have a bit of sticker shock. Jim Shepherd Evergreen CO '85 Eagle with Series 60 and Eaton AutoShift Bus Project pages: http://www.rvsafetysystems.com/busproject.htm |
