Dodd Buffer Battery

ebag4 · « **on:** 16 Aug 2010, 05:55 pm »

Hey guys,
I am needing to replace the SLA battery I have ben using for my DIY Dodd Buffer. I was going to pick up an Optima Yellow Top battery but I have been reading a lot of good things about these LiFePO4 batteries in both the RWA and the Empirical Audio circles. Has anyone tried these LiFePO4 batts yet? Are there any gotchas I need to be aware of or can I simply order a 6ah 12V A123 battery pack and charger on ebay and be good to go?

Any info or comments regarding this is appreciated.

Best,
Ed

HAL · « **Reply #1 on:** 16 Aug 2010, 06:20 pm »

Ed,
The A123 battery cells come in 2300mAh and 1100mAh sizes. The ones folks have been mostly discussing are the 2300mAh size. The packs will go up to 4600mAh from the A123 site. This will be an 8 cell pack (13.2v @ 4600mAh) so you will need a charger that does an 8S pack.

If you go with a pack, look for a balancing charge connector on the pack and charger. This will give the most life from the pack that I have seen discussed. This may only apply to high rate discharge as they are normally intended.

These are expensive, but are supposed to have a 10 year lifetime and very good storage characteristics.

Mariusz · « **Reply #2 on:** 16 Aug 2010, 06:33 pm »

hi ed

those are a bit pricey but I was (am) thinking about getting those for both, Nelson B-1 and Dodd buffers.

if it helps, here is the link to what looks like a good starting point:

Life battery packs

mariusz

ebag4 · « **Reply #3 on:** 16 Aug 2010, 08:53 pm »

Hal/Mariusz, thanks for the replies. I believe this unit will do the job for my buffer since I was getting a full day of play (about 12-13 hrs) with my 5ah SLA. Please let me know if you see any reason this would not work. The unit comes with the PCBs built in that monitor the battery but I don't believe it does cell balancing, is this important? I would also pick up the smart charger listed on the same page.

http://www.batteryspace.com/custom-lifepo4-26650-battery-12.8v-6.6ah-84wh-14a-rate-w/-pcb.aspx

Best,
Ed

Mariusz · « **Reply #4 on:** 16 Aug 2010, 09:01 pm »

How about this one - same price:

http://www.batteryspace.com/Customize-LiFePO4-26650-Battery-12.8V-6.6Ah-84Wh-25A-rate-in-Aluminum.aspx

Mariusz · « **Reply #5 on:** 16 Aug 2010, 09:05 pm »

Oh yeah
if there is a real interest
we can try group buy

ebag4 · « **Reply #6 on:** 16 Aug 2010, 09:09 pm »

Quote from: Mariusz on 16 Aug 2010, 09:01 pm

How about this one - same price:

http://www.batteryspace.com/Customize-LiFePO4-26650-Battery-12.8V-6.6Ah-84Wh-25A-rate-in-Aluminum.aspx

I looked at that one, I believe the only difference beteen it and the one I am looking at is the "fuel guage" (which is cool) and the input and output connections, are these important? This unit is .4" too long to fit in my Buffer case, the unit I linked to will (just barely) fit in my case.

If their is a technical reason why this one is better (other than the fuel guage) I would pick it up and move the batt outside of the buffer case, otherwise I would prefer to mount it in the case.

Best,
Ed

ebag4 · « **Reply #7 on:** 16 Aug 2010, 09:14 pm »

Quote from: Mariusz on 16 Aug 2010, 09:05 pm

Oh yeah
if there is a real interest
we can try group buy

That would be cool but if I am reading the shipping info correctly the shippers charge an extra $25 per box that contains an LiFePO4 battery(or any lithium battery). This has to be added as a line item to your cart. I have not verified this but that is the way it reads. That would mean that unless they would ship the batts to various locations (doubtful) of those in the group buy we would all be picking up a full $25 charge to our homes and our share of the $25 per box to the group buy organizers home.

Best,
Ed

Danny Richie · « **Reply #8 on:** 16 Aug 2010, 10:07 pm »

I bought a couple of the Lithium batteries and charger last year. Gary Dodd has them. Ask him about them. I'd even be willing to sell them as I am not using them.

HAL · « **Reply #9 on:** 17 Aug 2010, 12:27 am »

Ed,
From the spec sheet on the website, the LiFePo4 3.3VDC/3300mAh cell has higher the internal impedance than the A123 3.3V/2300mAh cell (0.03 ohms vice 0.008 ohms). The max current draw seems in line with that impedance difference. This is probably why folks have been very happy with the A123 cells.

Danny,
You have email.

ebag4 · « **Reply #10 on:** 17 Aug 2010, 01:42 am »

Quote from: HAL on 17 Aug 2010, 12:27 am

Ed,
From the spec sheet on the website, the LiFePo4 3.3VDC/3300mAh cell has higher the internal impedance than the A123 3.3V/2300mAh cell (0.03 ohms vice 0.008 ohms). The max current draw seems in line with that impedance difference. This is probably why folks have been very happy with the A123 cells.

Danny,
You have email.

Hey Hal, thanks for the info, much appreciated. After speaking with a few people I think I am just going to go with a Optima Yellow Top ( I can get one at a good price once a year) and build a box for it.

Best,
Ed

HAL · « **Reply #11 on:** 17 Aug 2010, 01:49 am »

Ed,
At this point I am using an Optima Blue Top with the Buffer and loving life!

Jeff G · « **Reply #12 on:** 19 Aug 2010, 01:54 am »

Are any of you guys using a Genesis or Enersys Battery (NP Series General Purpose Float and Cyclic Sealed Lead Acid battery)?? I have found a 12v 7.0 Ah battery for $21. I was going to order one in hopes of building Gary's Tube Buffer down the road. If so, any issues?
JG

HAL · « **Reply #13 on:** 19 Aug 2010, 02:10 am »

Another alternative are two UB1250-F1 AGM batteries in parallel that are about $12 each + shipping. This gives 12VDC at 10Ah. Gary uses them in the Battery PA.

Just a thought.

praedet · « **Reply #14 on:** 19 Aug 2010, 10:39 pm »

I will be using one of these very soon to power my Buffer along w/ some other stuff. I had it out in the garage doing nothing

ebag4 · « **Reply #15 on:** 29 Sep 2010, 09:08 pm »

Quote from: HAL on 17 Aug 2010, 01:49 am

Ed,
At this point I am using an Optima Blue Top with the Buffer and loving life!

Hi Hal,
What are you using to charge your Optima?

Best,
Ed

HAL · « **Reply #16 on:** 29 Sep 2010, 09:16 pm »

Ed,
Since I have a lot of large AGM batteries, I needed something fast to charge them.

This is what I bought:

http://www.amazon.com/BatteryMINDer-Battery-Charger-Maintainer-Desulphator/dp/B000JFLSL6/ref=sr_1_2?s=gateway&ie=UTF8&qid=1285794887&sr=8-2

ebag4 · « **Reply #17 on:** 30 Sep 2010, 01:57 pm »

Thanks Hal,
This is my first AGM and I wanted to make certain I picked up a compatible charger. I spoke with Optima, although they don't recommend a specific charger they did name a couple brands that many used with success (one was Ctek, I don't recall the other). The unit I picked up is made by Schumacher, he said that many Optima users were using these with success and the price was right so I picked it up.

Best,
Ed

praedet · « **Reply #18 on:** 8 Nov 2010, 03:24 pm »

A few pictures of the "Power Source" I have built for my DODD Buffer and other battery powered devices. Gary is helping me with the front so it will be done soon!

praedet · « **Reply #19 on:** 19 Nov 2010, 06:11 pm »

Last of the pic whoring I think

Here is the face plate Gary was nice enough to make for my Battery power source, along with the voltage gauge