Dodd preamp battery plays 40 minutes

The pre uses 4 batteries an should cost $80 or so. I think the issue with the batteries is if you run them and they don't fully discharge, let's say you operate them 2-3 hours and then you keep'em charging and then play them the next day for 2-3 hours eventually the "memory" of the battery starts working as if a full charge cycle is 2-3 hours so that eventually a full charge is 2-3 hours. I think you need a battery engineer to explain this phenomenon. Managing the batteries properly to ensure 12-15 hours of continuos operation per cycle requires some thought, that can be managed. The preamp sounds incredibly good, so I think it is worth it, but it is not a simple plug and play approach. I wonder if the Red Wine preamp has the same battery cycling issue.

Yes, it's $80 from Gary for a new set (4) of batteries or you can find them from multiple online sources for that price. It cost me $100 to buy a set at my local Batteriesplus store, so it just depends on how desparately you need them. They should last a year or more with normal use. Again, my mistake in killing the batteries was leaving the pre on long AFTER the warning beep went off. My normal listening sessions are less than 5 hours and, in that case, the warning beep never goes off. After a recharge of an hour or so they're ready to go again. I'm confident I could get a least 7-8 hours of continuous use before the batteries need to be recharged under normal conditions. It's really care free, just remember to turn it off when you're done :)

Hi Pabul57,

The "memory effect" is not true for the sealed-lead acid batteries (we use SLA batteries, and so does Dodd). In general, SLA batteries want to always be in the fully-charged state, so it is best to turn OFF and charge as soon as you are finished playing (even if you only play for 30 minutes). They don't have memory effect like NiCads.

What is most important is that you never want to deep-cycle SLA batteries, or you can kill them. This is why we designed our SMART module. It continuously monitors the battery voltage and if it falls below the set threshold, it safely shuts off the unit and automatically begins the charge process. So if you forget to shut off, the unit will shut off and charge for you when the battery voltage gets low enough (but not in the "deep cycle" territory).

Regarding the original post, I have to admit that we have also had a few cases of defective batteries that did not last as long as they should have. We are now using a new make/model of SLA battery that is much more reliable and this has solved the issue.

Sincerely,

Vinnie Rossi
Red Wine Audio

I have spoken with Gary of Dodd Audio, and he adds to what some of you have helpfully posted here. According to Gary, he now realizes the trouble is not with faulty batteries (though he has replaced many for customers) but with the way such batteries work and the way they are often used.

Gary says the batteries lose about 2% of their charge a day without use, and ideally should be played every day. This is partly because of the "memory" of such batteries, about which there seems to be some disagreement. Gary thinks they do have it, and that it is therefore important to use them regularly for near their maximum play time. If you only play them 2-3 hours a day, especially when new (if I understood this correctly), then they will be able to play only something like that time span, so Gary, but actually they can play 10-12 hours at a time if they're used that way to begin with. If you'r away or can't play the preamp for an extended period, it's better to keep it plugged in, so Gary, but it will degrade the life of the battery.

While the manual that came with the preamp says that one should ideally not play the preamp till the beeping starts, Gary says it's better to play it till the batteries are nearly empty, even till the beeping starts, so long as you then turn it off/charge the batteries. The preamp can play another two hours or so after the beeping starts without damaging the batteries, per Gary.

Vinnie, I take it some of this has not been your experience? Also, what brand of battery do you find works better? Gary recommended Powersonic, but said others work fine too.

Finally, Gary said he can sell you (me) new batteries, but it's better for the user (me) to go out and get them locally, because to get a decent price he needs to order several cases of the batteries--and then they sit around and degrade to the tune of 2% a day.

Vinnie is certainly right about SLA batteries. To extend useful life, a 12V SLA needs to be topped off with charge as much as possible, and discharge below 10.5V (even for deep cycle models) will permanently weaken them. It has nothing to do with memory effects. One way to avoid problems is to install a cheap signal-powered digital panel voltmeter across the terminals to keep a close eye on them during operation and charge cycle. Lasker makes a nice $25 model. Enersys probably makes the best SLAs in a wide range of sizes, but no SLA will survive repeated deep discharge.