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12 Volt 9 Amp Hr. UB1290 AGM SLA
Submitted by MB-1-E on Sun, 06/03/2007 - 16:03
I did quite a lot of research to find as many Amp Hours as I could fit into a limited space.
I'm sure these are not nearly as common as using a couple or even three 12V-12Ah AGMs but I wanted range and I didn't want to have to use more than about half capacity for my trips. As we all know, the less you deplete SLAs, the more cycles they are likely to give you.
I have two battery banks in my array.
Each bank has 4 batteries in parallel. (8 batteries total)
My system is 24V so I placed one bank in series with the other ... A series/ parallel system.
I only have a 12V charger, so I needed a means of switching them all to parallel for charging.
Thanks to some astute, electrical types on this board, I was able to accomplish this with one DPDT (Double Pole, Double Throw) switch.
Time will tell if my Universal UB1290's hold up, but so far, they take a charge well and sure had no problem delivering lots of amps on demand.
3.98" Total Height
The only thing that I really don't like about these is the small terminal size. These only have .1875" wide spade connectors. There may be the same battery available with .25" wide connectors.
I drilled a hole through each in order to place a #4 machine screw through each terminal. I used internal star washers to get a good bite on the screw head and drilled a hole through each of my homemade lugs. I placed a #4 nut directly on to the screw to clamp the lug tightly to the terminal. Some of the screws I left longer so I could connect another lug on top of the first, as needed.
The battery size worked well for me, although I changed my configuration several times before finding the most stable array that would keep the center of gravity low on the bike.
I keep a good charge on them using an Iota 3 stage charger made especially for AGM or Gel type batteries.
From my research, I have found that you want to top these batteries off as soon as possible after use and deplete them as little as possible during use to give them a longer life.
This is the main reason that I wanted the 36Ah at 24V, so I could have a good reserve that I wouldn't need to tap into too deep.
The payoff, of course is the added weight.
I haven't made it easy to do at this point, but I can always use a smaller number of batteries in each bank.
I'm sure after time, I'll find the best balance of weight to Ah in terms of range and battery life.
May all your Amp Hours be happy ones!
Dave (aka MB-1-E)