Should I buy these batteries?

[faccnator1]

Hello all,


I have been reading this forum for about a year. I love watching discussions between educated people. Fascinating. Anyway:


I have an opportunity to buy 8ea 12v batteries for $1500.00. I can probably get them for less.

In service since 2/1/17.


Owner says never less than 50% DOD and are just upgrading to lithium batteries.

Model is: Outback EnergyCell 200NC (178AH)


Should I buy these? Is this a good value? If not, what is?


I had planned to upgrade to a 2v based cell bank when I was ready. But these came up. The multiple parallel strings I know are not ideal but for the right price I thought it may be worth it.


My current system is (and growing):



9ea 270watt Renogy panels

Tracer 4215BN MPPT 40A 150V

Xantrex (Trace) SW4024

Outback PSX-240 Autotransformer

4ea 6v Sams Club Batteries


thanks everyone!

[Sunking]

I say go for it. While you are at it want to buy some used condoms?

[faccnator1]

Ha! Well everything has some value.
They are $500+ new and about 18 months old. I thought for 2/3 less they might be worth looking at

[SunEagle]

Used batteries are a crap shoot. If you got the spare $$$ then go for it but don't expect them to last for even half the cycles the could get you if they were new.

[faccnator1]

Ok gotcha.




So I have some bucks and im a gambler. I like to maximize value when making decisions, not necessarily monetarily.




I was more asking about the batteries themselves. Does anyone have experience with this model?




From reading this forum regularly Im trained to reject parallel battery configurations

[SunEagle]

From what I have heard those batteries (while expensive) are high quality.

Although you probably can get 2 volt rated at a higher Ah rating and still pay much less then you would getting the Outback type.

[Sunking]

So what voltage do you want to configure them at? 12, 24, or 48?

There is no good or right answer because they all suck (except 96 volts) because it requires you to parallel them just like the owner had to do. That cuts cycle life considerable to half or less.

[faccnator1]

Ok well thanks all. Im going to pass. I probably would have bought them. Hopefully I can give back to the community

[faccnator1]

Well I ended up buying the used condoms! errr... batteries

The seller actually reads these forums and is a super nice couple. They gave me a great deal and I picked them up last night.

ill keep the forum updated as to their performance.

[littleharbor]

One thing you need to consider is the fact that your existing system was over paneled with 220 Ah. of batteries. Now you are going to make it a 700+ Ah. battery bank provided you use all the batteries. Now you are under powered with a 40 amp controller. Those 700 Ah. of AGM batteries could take 140 amps of charging. 70 amps would work though.
The other issue is You will be going from one string of batteries to 4, (if you use all 8 batteries). You are going to be dealing with uneven charging of those 4 strings. The way I see it is you could go with 4 batteries(2 strings), or, go to a 48 volt system with 2 strings. Obviously you likely don't want re-invent the wheel by changing out a perfectly good SW 4024. so maybe you could find a buyer for 4 of those batteries or just buy 4 to begin with.

[PNjunction]

Those "NC"'s or nano-carbons are actually pretty cool - designed to be used in a PSOC environment, BUT they need occasional "freshening charges" to stay in top shape. Wonder if the original owner was doing this? And with what? Solar only?

I've used / abused an Exide agm nano-carbon sli battery myself doing the bad thing with deep discharges and psoc, and they lasted longer than the usual conventional agm - both getting "freshening charges" routinely however. One sees these in ICE / engine stop-go vehicles, so I had to abuse one for fun. Impressive, even though I was not using it properly.

At this stage, I'd say that unless you have the requisite programmable bench charger, you might want to invest in something like a Samlex SEC-1230UL charger (set to 14.4v absorb), or go for broke with something definitely not on their approved charger list like a Tecmate-Optimate 7 10a charger.

The Tecmate 7 would be a "maintainer" here for those batts, and doesn't use the conventional CC/CV algo. Equalization is performed by reaching 14.4v first, and then pulsing up and down from about 13.2v to 14.4, whereby the shorter pulsing doesn't push the already charged cells way into water regeneration, but allows for the laggard cells to catch up during the leading edges of the charge. I'd bulk-charge via solar awhile first, and then let the Optimate 7 do it's thing for a few days. It's a different way of doing it and I'm not sure if Outback / Enersys would approve, but it works.

That is, on each battery one at a time before you try to put them back in a series / parallel config.

Normally we say don't bother with used batteries - much like borrowing somebody else's toothbrush, but you've already brushed.

Be sure to check out the manual for them, and pay attention to the "NC" part of the charts.

[PNjunction]

Update - further reading from the installation guides about Outback's nano-carbon suggest that if one is doing a solar-only installation, then the batteries should reach FULL CHARGE every day. There goes the psoc advantage.

However, if you can't do that every day, then they suggest that you reach full charge somehow at least once a month. That kind of jives with generic AGM's, although they really prefer a *weekly* refresh. I can agree with that. Thing is, a FULL charge on any agm requires 8 hours or more of float and the sun just isn't out that long. Some other form of TLC may be necessary.

Failing that, I'd think that perhaps if one is doing daily cycling, then do as we always should do for agm - in this case for the Outbacks, just have the controller absorb AND float be the same. That is, for these NC's, 14.4v temperature compensated absorb and float.

Non-daily service is another matter. I'd probably float on the "high side" of their specifications, (because old sol turns out the lights himself) perhaps 13.8v instead of 13.5v, assuming you actually drop well down into absorb during the day.... ah, choices...

[faccnator1]

These batteries have been great by the way

[solar pete]

These batteries have been great by the way

Howdy Faccnator, thanks for popping in with an update on the batteries, how did you configure them I assume 24v, how much do you typically discharge them in a 24 hour period, this is quite helpfull when people report in on how projects or full blown systems are performing, thanks

[faccnator1]

Actually 48v because I have a Conext 6848.

I eventually paralleled them with a set of Chevy bolt lithium batteries. Really weird setup but works great for me!