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12VDC AGM Battery research for Best Value Cost/Performance

Discussion in 'Mobile Radio Systems' started by WQ6N, Dec 3, 2017.

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  1. WQ6N

    WQ6N Ham Member QRZ Page

    I have been doing some research on various AGM 12VDC batteries for mobile use. Much of this online research was centered on where the battery was made, warranty, weight, recharge cycles, reviews if they were available. cost and working time. I was focusing on 100ah 31 series for the most part. My main performance goal is to provide 80amp power for a ALS-500M amplifier:

    Optima Yellow Top D31A - Mexico with 2 year warranty 300 charge cycles $343
    NorthStar NSB-AGM-31 - USA, 400 charge cycles. 75lbs, with 4 year warrant $360
    ODYSSEY PC 2150T 31 series - USA, 400 charge cycles, 77.8 lbs, 4 years warranty $390
    NPP npd12-100ah - China, 1 year warranty, 65lbs $170 (also a few more China companies in the same ballpark)

    In most reviews the QA of the USA companies far exceeded the others. Optima has a heavy marketing campaign but may be second best in value. The actual lead content for the the Type 31 batteries for NorthStar and Odyssey really stands out at 99.99% and speaks to the quality.

    I tend to not go with the low end China built products and am hedging toward the NorthStar product. I was wondering what others have done with research and experience?

  2. K0BG

    K0BG Ham Member QRZ Page

    If you are using the battery as an SLI (starting, lights, ignition), what you want is a RedTop. If you use a YellowTop, you'll need to size it about 25% percent larger to get the same starting amps. And just for the record, the BlueTop is a true marine. It is meant to sit uncharged for extended an period (over 24 months), and still have enough left to start the engine.

    If you shop around, you can buy the 55 AH, Optima RedTop for about $189, which is about $25 over cost. It will fit about 90% of the medium to large vehicles out there.
  3. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    My search for AGM batteries was predicted on the maximum weight I was willing to carry 50 yards. This worked out to a 38Ah. :)
    N8EKT likes this.
  4. KD4UPL

    KD4UPL Ham Member QRZ Page

    I've installed hundreds of Deka AGM batteries (Made in PA by East Penn) over the last 12 years in the solar business. I've had very good results with their batteries. If I had lots of problems I'd use something else.
    NL7W likes this.
  5. WA4SIX

    WA4SIX Ham Member QRZ Page

    Over decades, I think I've installed over 1K Deka batteries. Great batteries. I only own Deka, except for 1 they do not directly distribute.

    NL7W likes this.
  6. K0BG

    K0BG Ham Member QRZ Page

    We all need to remember that a vehicle battery must be rated for that use. Deka, Optima, and others all sell what are commonly called, SLI batteries (passenger vehicle batteries). But they also sell batteries specifically for solar, motive, and UPS use. If you select the correct one, you're home free. Otherwise? Squat!
  7. WQ6N

    WQ6N Ham Member QRZ Page

    Thank you for sharing your thoughts and experience.

    I should of stated the primary use. I plan to use the 2nd battery bank to power a Ameritron ALS-500m amp which could draw up to 80amps on peaks. I typically do not run anything full power and will most likely center on 250~300watts max output. Isolation between the alternator/car battery and the 2nd battery will be done using a battery isolator (i.e. NOCO IGD140HP). The car has a small 120amp alternator and the is very little room to put in a larger alternator.

    I am seriously backing down from the AGM, mainly due to cost, in favor of set of vented lead acid Costco golf cart cells contained in a dual T-105 type box. The golf cart batteries will give me 225ah vice the 100ah of the AGM. I already have two sets of 4 batteries in series/parallel configuration that I use in the shack and RV which have served me well over the years. I just need to provide proper ventilation and mounting since they will be in the car trunk. I usually get 3~4 years use, with daily charge cycles, before changing out.

    Battery box from BatterySystems is about $60
    Costco Interstate golf cart batteries are $105 ea (66lbs ea. as well)
    NOCO Isolator is about $68

    I have no experience on the TG electronics 80 amp model n8xjk Voltage Boost Regulator other than what I have read. At $195 this will need to come later.
  8. K0BG

    K0BG Ham Member QRZ Page

    John, while battery isolators have their place, it is best not to use one. There are a few made which contain FET switches (they cost a whole lot more than $68!) to bypass the diodes, but they suffer the same scenario—keeping the battery monitoring system happy. The only way to do that is hard wire the batteries together with only a fuse protecting the wiring. And you have to be careful how you wire them together, so you don't bypass the BMS's Hall device.

    As you mentioned, the Costco golf batteries are not AGMs, and if they're inside the vehicle (trunk included), they need to be AGMs; think outgassing. This is one item you don't skimp on!

    The TAG 80 amp unit isn't large enough, even for the ALS-500. Good thing, because you really don't need the booster, as long as you keep the battery voltage around 12 or so, on peaks. You won't be able to do that, unless you follow the advice in the first paragraph.

    You might want to visit my web site with respect to high power mobile.
  9. WQ6N

    WQ6N Ham Member QRZ Page

  10. WQ6N

    WQ6N Ham Member QRZ Page

    Well to make a long story short, venting will be a problem in my Saturn L300. In addition, flooded golf cart batteries would take up a lot of room in the trunk plus make it a challenge to get to the spare tire if needed. So back to the AGM. I have settled on either a FullRiver DC115-12 (China made)(spec's are here: or Deka AGM Grp 31 Part#8A31DTM which are USA made. I have read Alan's excellent online resources and decided to run dedicated cables for charging from the engine compartment to the trunk. I did not have any #2, but what I did have was 4ea 12ft lengths of #2/0 welding lead. I created two 24ft runs for positive and negative. Thinking that 24ft was way too much when laid out on the floor. I spent the day running the two #2/0 lines under the Saturn keeping clear of exhaust lines and moving parts which was no trivial task and was very sore from the effort. There is very little room in the Saturn engine area with the V6. Very tight quarters. I was able to connect the Neg lead to the same location as the car's Alt/Batt. It's done and ready for a battery isolator.
    I will probably go simple with a Sure Power 1314-200 Battery Separator. I have a extra Xantrex C40 charge controller and will set it for 14.7vdc bulk and 13.6vdc float charge rates. I could go higher by clipping R46 (which gives an extra 2vdc range) but do not see a need at this time. I do not drive more than a couple hours a day so charging via the car is short period anyway. I may even think of a small solar panel at some point.

    As I mentioned earlier, I am trying to make the amp portable enough to work when RV'ing. I am installing 175A quick connectors (Battery Quick Connect/Disconnect Wire Harness Plug Connector Recovery Winch Trailer 2-4 GAUGE ) to allow easy disconnect/reconnect. As a side note, I have also modified a Dell PowerEdge KD175 12-14vdc 112.5A power supply (another article on the Amp forum) to use while the RV site has hookup power. Each of the 2ea. Pos/2ea. Neg leads of the amp, will be fused with #10 inline 30A ATC type fuses.
    Right now I an waiting on parts and hopefully Santa will get me a battery for Christmas.

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