| Author | Message | ||
| Craig Smith (Craigs)
Rating: N/A |
Hi All, In the 91 BB we got a few months back, are 7 Interstate deep cycle batteries. These are not stock factory issue. Someday I may change to T-105s or something. In trying to get a grip on the AHs avaliable, I have looked around and found that you're supposed to take the RC(reserve capacity) and multiply by .4167 to arrive at the AH capacity. In my case that's 160 * .4167 yielding 66.6AH per battery. Now, my question is, is this the amount used to pull the battery down to the half charged state or is this total AH with only 33AH available? Craig S | ||
| Henry R. Bergman, Jr. (Henryofcj)
Rating: N/A |
Best quess half-charged state, but we need more info. They may be a amp hour rating printed on the cases, then as a rule of thumb take half of that for a 50% discharge rate. Good luck. | ||
| James Maxwell (Jmaxwell)
Rating: N/A |
Craig: Manufacturers seem to get vague about these figures and what they really mean. I have seen Trojan literature that translated the AH rating as being anywhere from 50-75% available, down to 10.5v I have seen other specs that say 50%. My MK AGM's specify 50% of AH total as usable,rated down to 10.5 volts. This site may have an answer: www.uuhome.de/william.darden/ | ||
| Craig Smith (Craigs)
Rating: N/A |
Thanks guys, On the case, it states the CCA and the MCA. I had to look on the Interstate site to find the RC. They have no other AH specs. I'll look some more. It's not that important. I was just doing some math to predict the state of the batteries after a night of boondocking. Maybe I should experiment in the dooryard to get a better feel for things. Thanks again, Craig S 91 BB & 75 MC8 | ||
| joe padberg (Joemc7ab)
Rating: N/A |
James thank you for that link. Anything and everything you ever wanted to know that is battery related but were afraid to ask. Joe. | ||
| James Maxwell (Jmaxwell)
Rating: N/A |
Joe: Your welcome; that's what all of us are here for. I got it from somebody on one of these boards a yr. or so ago when I was researching AGM's. | ||
| FAST FRED Rating: N/A |
Usually if only reserve capacity is given , and NOT the "twenty hour rate" for Amp hours , the battery is a start and not suitable for any deep cycle applications. FAST FRED | ||
| niles steckbauer (Niles500)
Rating: N/A |
As all AGM/deep cycle batts are rated both AH rating and # of charge/discharge cycles - It is best to discharge at no more than 40%(AGM) and 50%(Std Deep Cycle) of Rating and to bring batts back to their 'memory' charge level (as close to 100% as possible) - regularly discharging AGM/Deep Cycle batts to 10.5 volts can reduce the # of charging cycles (battery life) in half - Batteries have/and/develop memory patterns - its best to follow a regular pattern in cycling the charge/discharge rates to maintain a long term 'useful life' of your batts - Niles | ||
| Tom Caffrey (Pvcces)
Rating: N/A |
Craig, I'm with Fast Fred on this. A manufacturer brags up what his battery will do best. If the battery has CCA given, it is not a deep cycle even if it says so right on the case. CCA and amp hours ratings are entirely inconsistent; this is why you only see one or the other. If you're interested in good service, you don't want a hybrid, either. The most successful hybrid is the big marine battery. They would do a fair job going either way. This would not apply to any battery weighing under 100 lbs., because the plates and separators are too thin. The marine batteries will be 8 volts, or 4D or 8D. All of the smaller ones are bad compromises, AFAIK. 63 lb. 6 volt deep cycles ought to be around 220 amp hours(golf cart size) and 125 lb. L16s are around 350 amp hours. If you are looking at deep cycle batteries, you can pretty well figure out the amp hours by the weight and voltage. Golf cart batteries store 1 1/3 kwh and are good for 1/2 kwh per recharge, using 50% DOD and recharging to 85%. L16s are a little over 2 kwh. If you figure about 1 kwh of total capacity per 60 lbs. of battery, you should be fairly safe. The reserve capacity formula you mention is invalid because the fixed discharge rate is applied to different sized batteries, with small batteries doing much poorer. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher | ||
| ChuckMC9 (Chucks)
Rating: N/A |
Tom, thanks for the easy-to-remember rules of thumb! This cheat-sheet in the wallet will help save a lot of head scratching.  | ||
| Tom Caffrey (Pvcces)
Rating: N/A |
I will start a new thread with pictures for the run-up blocks when I get the drawing like I want it and I figure out how to use another browser to upload the images. It should be worth waiting a bit for. Tom Caffrey PD4106-2576 Suncatcher |