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replacing 8d gels with 6v lead acid golf cart batteries

PostPosted: Tue Jul 21, 2009 1:10 pm
by stansroga
Because we liveaboard a boat at anchor our house batteries are heavily used. We are only getting about 3 years out of our East Penn 8d gel cells and I am looking at a less expensive solution. My friend is using 6 volt lead acid golf cart batteries with good results. They are much cheaper and rated at 1000 recharge cycles instead of 300 for the gels.

However my friend charges his gofl cart batteries much differently than I charge my gel batteries. My friend uses a wind generator and a solar panel over many hours each day. My charging is done using a 13O amp alternator and a Next Step-2 regulator. My engine must be run daily for one hour at 8:00 am and 8:00 pm to accomodate the engine drive refridgeration. My daily power needs are about 150 ah and the engine/alternator has comfortably supplied that.

Today I have two 12v 200 ah Deka gel batteries connected in parallel. Considering my daily recharge cycle described above, does it look practical to replace my Deka's with four 6v 235 ah lead acid gofl cart batteries? I know the battery cases will allow the golf cart batteries to fit and the battery compartments are well ventilated.

Re: replacing 8d gels with 6v lead acid golf cart batteries

PostPosted: Wed Jul 22, 2009 1:45 pm
by Coulomb
People throw out gel batteries because they ignore our advice to do a couple 100% discharges at least once a year and then recharge them FULL. Full and in full, not when your regulator switches to float.

We have a pallet out back where people can deposit old batteries. Presently in our Genie test area we have four 8Ds gel batteries that were thrown out a couple years ago. After doing the break-in procedure described in the Primer the batteries acted like new again.

With engine drive refrigeration, you energy consumption sounds very high. What are you using to measure it?

Golf cart batteries are good value. We've had good luck with Trojan liquid electrolyte type, (T125).

Re: replacing 8d gels with 6v lead acid golf cart batteries

PostPosted: Thu Jul 23, 2009 9:57 am
by stansroga
I've read your Primer for re-juvinating a gel battery. Thanks very much for the tip. We'll try it in the fall when we return to he boat.

We use a LINK display to keep track of amp hour usage. The reason that we use so much power daily is that we run an inefficient 110v refrigeration system via an inverter at mid-day to supplement the engine drive system. This uses about 90 ah daily. We're gone from the boat at mid-day.

I've located an inexpensive, new, analog 500/1000 amp carbon pile battery tester made by Chicago Electric Power Tools for about $62. This tester seems to good to be true since the local battery store had something similar for about $550. What do you think?

To test the 8d gels I have been told to charge them up to 13.5, then set the load tester to 675 amps and test the voltage drop over a 15 second period. 11v is good, 10v is ok and below 9.6 is bad. I planned on running a test using the carbon pile tester before and after your Primer's break-in procedure was done. What do you think of this test procedure?

Re: replacing 8d gels with 6v lead acid golf cart batteries

PostPosted: Thu Jul 23, 2009 10:35 am
by Coulomb
Your gel batteries will fail the carbon pile test! Those things are made for testing starter batteries and even then most people don't know how/when to use one. But they do help counter sales at your local auto parts store sell a new battery when often the problem is in the charging circuits.

If you're leaving your boat for an extended period it's certain that you need to do the break-in procedure on the batteries when you get back.

It would be interesting to know the dollar value of batteries discarded by people who haven't read the book, "Living on 12V with Ample Power". It has to be many millions of dollars. Get a copy yourself and start managing batteries instead of letting them manage you.

Re: replacing 8d gels with 6v lead acid golf cart batteries

PostPosted: Mon Aug 17, 2009 11:18 am
by cfvabch
4 questions.
1. Can I consider my 2 Interstate DCS-100l AGM House Batteries and my Optima Red SC34A Starting Battery as Gel cells??
We get the boat (Catalina 30 sail boat)out about three times a year, maybe 2 or 3 days each time.
This was a very informative topic. I have your book(s) and somehow missed the "total discharge and total recharge at least once a year" subject.
I have a Next Step Regulator, an ISO Eliminator, ENMON II-H1, and Trace 1.5kw 3 stage temp compensated charger/inverter (inverter never hooked up). I recently thought both the house and starter batteries required replacement because the were "flat" and would not recharge. I disconnected them from my system and recharged them using my SEARS 12v charger. I watch the recharging very closely and kept touching the batteries and posts to prevent overheating. After bringing them up to sufficient voltage I finished them with the Trace Charger. The batteries seem to be fundtioning properly now.
However, by the answers to previous posts on this subject, my finish charge with the Trace, was not the way way to complete the "full" recharge.
2. Should I have kept using my SEARS charger and closely monitoring the temp and measuring the voltage and amps with my FLUKE 83 digital tester???
3. Based upon our present underway usage, should I run the batteries fully flat once a year and use my SEARS charger to bring them back up???
4. I understand that the (original) Alternator on my 23hp Universal-Westerbeake is rated about a 55 AMPs. It seems to be sufficient for our needs, but after reading your books I often wonder if it's output is really adequate for properly charging my system??
Hope this has not exceeded my question quota on a topic.
Thanks, Charlie

Re: replacing 8d gels with 6v lead acid golf cart batteries

PostPosted: Mon Aug 17, 2009 4:42 pm
by Coulomb
Both of those batteries are AGM types.

Total discharge is down to 10.5V at about 5% current relative to capacity. The Trace probably won't start charging on a battery with less voltage, while the Sears charger will. Done right, you shouldn't need the Sears charger, but as long as you monitor the battery voltage and temperature it's OK.

FLAT is 10.5V!

The alternator is more than likely chronically undercharging the batteries. If you don't tie up to shore power frequently to fully charger the batteries, expect poor battery performance.