Surrettes, still trying

Blackcherry04

6, 2V, S-1725's @ 12 v, 1300 amp hr. I had them @ 1.265 SG across the board. I removed 560 amp hrs over two days and ran a recharge @ 178 amps @ 14.9v ( took about 10 hrs ) through absorb and they exited to float at 13 ending amps. The SG's were 1.220 across the board. So, Ran a EQ on them @ 15.5v for 20 hrs and I am now back where I started. Anyone even thinking about using these off grid best think of the charging they have available.

I once thought these would get better over time, seems they are getting worse. People can talk about Parallel strings, but be careful because you'll end up with batteries you cannot charge.

Cariboocoot

Re: Surrettes, still trying

A fine example of why I have switched from recommending Surrettes to not recommending Surrettes to warning against using Surrettes.

Tobit

Re: Surrettes, still trying

1300 AH at 12V?

Blackcherry04

Re: Surrettes, still trying

Tobit wrote: »

1300 AH at 12V?

Yes, 12v is fine as long as you have the equipment and a low amp draw, my amp usage is never above 50 amps DC at most and thats with the Satellite Dish and TV on.

jonr

Re: Surrettes, still trying

Blackcherry04 wrote: »

I removed 560 amp hrs over two days and ran a recharge @ 178 amps @ 14.9v ( took about 10 hrs )

You removed 560 amp hours and then had to put more than 1780 amp hours back into them? Sounds closer to an electric heater than a battery.

BB.

Re: Surrettes, still trying

I think 178 Amp charger set at 15.5 volts for 10 hours... Once the batteries hit 14.9 volts, the charging current will slowly taper to a final minimum (13 amps in this case).

So, not 1,780 AH total charge.

BC04, have you ever put a Battery Monitor on this bank to see what the actual charging efficiency is?

-Bill

Blackcherry04

Re: Surrettes, still trying

BB. wrote: »

I think 178 Amp charger set at 15.5 volts for 10 hours... Once the batteries hit 14.9 volts, the charging current will slowly taper to a final minimum (13 amps in this case).

So, not 1,780 AH total charge.

BC04, have you ever put a Battery Monitor on this bank to see what the actual charging efficiency is?

-Bill

The EQ was showing 22-25 amps @ 15.5v. I posted the 178 amps so you'd know I had enough charger capacity to even try to charge them. The batteries show charged if you went by the Voltage and the acceptance rate, the problem is the are not because the SG's are that low ( 1.220 ). if I left them they would sulfate into a death spiral.

Blackcherry04

Re: Surrettes, still trying

There has be something where these batteries only accept a partial plate charge @ 14.9v and the chargers react and cut them selves back based on it. I have the absorb time set to 8 hrs and have moved it to 12 hrs for this week, but I really think it will still be a issue. They are not stratified thats for sure. Every Volt meter has been calibrated, the shunt seems right. It's just perplexing to deal with them.

Vic

Re: Surrettes, still trying

Hi BC04,

OK, so you know that you did not exit Absorb due to time, but rather, it ended based on End Amps (?).

And, regarding the discharge, the rate of discharge has a Peukert factor, as you well know, and have compensated for this?

Have mentioned in the past that I believe that there is a Peukert effect in charging, as well. Very high charge rates result in lower "efficiency" of the charge, I have guessed.

You know batteries, and have more varied experience with them than I. And technically, the Capacity of these batteries is rated as if the electrolyte was 1.280, rather than the shipped SG of 1.265 (for almost all Surrettes). So your bank is probably about 1235 AH -- not that this would explain what you are seeing.

And, in the past you mentioned that you had Floated this bank over the Winter. Do you have a number of cycles on this bank at this point?

With similar-sized banks here, limit charge current to about 125 Amps max, and have not had this issue. As noted in the past, on a deep discharge to about 50% of 20 hr Capacity, These banks will need to really finish recharging on the second day when using an EA of 11.9 A at 14.5 V (Temp comped) equivalent. (a 48 V bank here). Believe that to be able to recharge these batteries on a single day, without changing the EA value, the Absorb voltage would have to be raised a few tenths of a volt. And, all of these batteries were made in 2005. One would expect the charge efficiency to decrease with age, but, these batteries may have a bit different plate metallurgy than do the current vintage Surrettes -- more Antinomy might cause more vigorous gassing, and so on. Sure do NOT know for sure.

It can be difficult to accurately measure the battery charge current on a 50 mV 500 A shunt. And, small errors in EA readings can have a fairly large effect on Absorb duration, as the slope of the finishing current is quite flat at the end of a full Absorption.

Guessing done for now. Good Luck, Vic

Cariboocoot

Re: Surrettes, still trying

Vic wrote: »

Have mentioned in the past that I believe that there is a Peukert effect in charging, as well. Very high charge rates result in lower "efficiency" of the charge, I have guessed.

I believe this is true also. It would explain the experience many of us have had where charging from solar (with its gradually increasing current to the maximum as sunlight increases) gives a more 'effective' charge than from the inverter which puts out maximum current right from the start and can ramp the batteries up much more quickly.

Curiously longer time at lower Amps at the end of charging (low End Amps setting) does not seem to have the same effect.

I don't know how practical it would be for you to try this but maybe cutting the max current down to 5% (65 Amps) and running a cycle with a ridiculously long Bulk stage will prove more effective at bringing the SG up.

Blackcherry04

Re: Surrettes, still trying

I actually have two charging sources. One Xantrex with 120 amps and a Outback, 70 amps with a time absorb. The Xantrex is set a little lower voltage than the Outback and will drop out sooner than the Outback it would normally at 2 % or so. 1200 or 1300 amp hrs at level makes very little difference.

I may try using the Outback alone and see if it makes a difference next week. The 70 amps would be more than 10% of what I am returning. I already tried the Xantrex ( 120 amps ) that way and it ended with about the same SG level two weeks ago. I would of thought a 8 hour absorb would have been plenty. 1.220 was a shock to see it that low.

I want to add that the Xantrex is 2% or 180 minutes absorb limit, I know that is not enough. I use the Outback's time to offset that. Even with the 8 hours I still have the issue with the low SG's and the EQ time I had to use. Once you get to 14.9 v and after 2-3 hrs of absorb the charge amps drop to 25 amps or so to the end of the time ( 8 hrs ) . The only way to raise the amps is raise the voltage above 15v. I did that with the EQ voltage ( 15.5V ) but it took 20 hrs to get to 1.265 SG level.

At first I thought maybe the Outbacks time was getting short cycled by the Xantrex. No joy. When it drives the set bulk voltage up and goes into absorb the status shows 8 hrs and a normal countdown to the end.
.

vtmaps

Re: Surrettes, still trying

Blackcherry04 wrote: »

There has be something where these batteries only accept a partial plate charge @ 14.9v and the chargers react and cut them selves back based on it. I have the absorb time set to 8 hrs and have moved it to 12 hrs for this week, but I really think it will still be a issue. They are not stratified thats for sure. Every Volt meter has been calibrated, the shunt seems right. It's just perplexing to deal with them.

How do you (or how can you) know they are not stratified?

One aspect of stratification is that you need a higher voltage at the bottom of the plates than the top of the plates to drive the sulfate back into solution. The "partial plate charge" at 14.9 volts may represent the top of the plates being fully charged, but 14.9 may be unable to charge the bottoms of the plates.

--vtMaps

Cariboocoot

Re: Surrettes, still trying

vtmaps wrote: »

How do you (or how can you) know they are not stratified?

One aspect of stratification is that you need a higher voltage at the bottom of the plates than the top of the plates to drive the sulfate back into solution. The "partial plate charge" at 14.9 volts may represent the top of the plates being fully charged, but 14.9 may be unable to charge the bottoms of the plates.

--vtMaps

You know what would be cool for this? A separate SG reservoir access hole. Especially on tall case batteries. You could, with a long enough tube, sample SG off the bottom and off the top and compare.

Of course they don't build batteries for solar, they just sell 'em for it.

Blackcherry04

Re: Surrettes, still trying

vtmaps wrote: »

How do you (or how can you) know they are not stratified?

One aspect of stratification is that you need a higher voltage at the bottom of the plates than the top of the plates to drive the sulfate back into solution. The "partial plate charge" at 14.9 volts may represent the top of the plates being fully charged, but 14.9 may be unable to charge the bottoms of the plates.

--vtMaps

Just going by the fact I can hear them bubbling and gurgling during absorb. But it is a point taken that is still could be only part of the plate and they are stratified, but 20 hours is a long time to un-stratify. It is more pronounced during the EQ, but that should be a given. The option is to raise the voltage above 15.xx V for absorb and that would shorten the time. I am charging on-grid so the time is not as big of a issue as the longevity of the batteries at this point.

vtmaps

Re: Surrettes, still trying

Blackcherry04 wrote: »

Just going by the fact I can hear them bubbling and gurgling during absorb. But it is a point taken that is still could be only part of the plate and they are stratified

That is my point... that bubbling may not be from the lower parts of the plate. You may find that no amount of time at 14.9 volts will destratify a battery, but just a few tenths higher works.

I also wonder about temperature stratification in tall batteries... if the bottom of the battery is cooler than the top, the bottom would need a higher voltage than the top.

--vtMaps

Cariboocoot

Re: Surrettes, still trying

So we need a battery design where the positive plates are connected at the bottom and the negative plates are connected at the top in order to even out inter-plate current flow as well as Voltage and thermal differences.

Somehow I don't think any company would go for it.

Blackcherry04

Re: Surrettes, still trying

Well, I removed 200 amp hrs ( 16% DOD ) today and started a recharge @ 175 amps, they went to Absorb @ 1.245 SG level. After 5 hrs of Absorb @ 15.2v ( 8-20 amps ) the SG level is up to 1.265. Based on this voltage ( 15.2v ) I can only raise the SG level .025-.030 per charging hour.

This time I only pulled 200 amp hrs out of them, last time it was 560 amp hrs and they exited absorb with a SG of 1.220 because of ending amps, as you can see if I had to raise the SG .45 I'd be looking at 15-16 > + hours to recharge them back to where I started ( 1.265 SG ) .


I think I have fooled around with these batteries long enough to say that I would not recommend them for off-grid solar. I don't think there are enough charging hours to be able to manage them. You could probably do it, but you have to use EQ voltage to off set their inability to accept a charge. I have no clue what it will diminish their longevity with this kind of charging regime, but for a $2,500 for set 6 of batteries I could of had a set of 10, GC-2's for $900 and get 3-5 years and at least be able to charge them.

There is a danger for me with this setup, If I lose power for a short amount of time it will trigger a full charge cycle, with these high voltage charges ( 15.2 v and 6-9 hr absorbs set into the Inverter, I could do some real damage.

vtmaps

Re: Surrettes, still trying

Blackcherry04 wrote: »

There is a danger for me with this setup, If I lose power for a short amount of time it will trigger a full charge cycle, with these high voltage charges ( 15.2 v and 6-9 hr absorbs set into the Inverter, I could do some real damage.

Full charge cycles may be the best thing for these batteries... Many industrial batteries are meant to be deeply discharged over the course of a day and then have a long overnight high power high voltage recharge. Some industrial batteries also require weekly equalization (not corrective) because the daily charge may leave them a bit stratified.

My point is that I wouldn't worry about the long hours of high voltage in a full charge cycle. What I would worry about (and I do worry about this with my L-16s) is that you/we are usually recharging them from shallow discharge. That means more of their life will be at high voltage... example: if your batteries are rated 1500 cycles at 80% DOD, they will experience high voltage 1500 times. If you have shallower discharge, maybe you could get 3000 cycles, but can the battery withstand 3000 high voltage experiences?

All batteries are a bit different, and I don't really know if my 'industrial battery' analysis applies to your surrettes, but I take to heart, and don't disagree with your conclusion:

Blackcherry04 wrote: »

I have fooled around with these batteries long enough to say that I would not recommend them for off-grid solar.

--vtMaps

Blackcherry04

Re: Surrettes, still trying

In all fairness I am trying to find what it takes to get them back to 100% charge ( 1.265 ) while they are new . On a normal basis 80-90% ( 1.250-1.255 SG ) is a fine charge level and do a EQ once a month or so is Ok. Most of the time they will be in the 50-80% range during use. At 50-80% I still have plenty of working capacity to get through the night.

One thing this does do is bring up the subject of Charge Efficiency and the use of a battery monitor. If a normal batteries are 95% these can't be more than 60-75%, if that. That is a base line I am still developing to come up with a setting. Anyone using SOC as a guide line for recharge should be wary, forget something with LED's on it.

DMJ72

Re: Surrettes, still trying

This may help, From Rolls' RE Tech bulletin :

Blackcherry04

Re: Surrettes, still trying

Thank You for posting the bulletin, I have read it, with these batteries you'd in a world of hurt following the last sentence. 2% = 24 amps. To fully charge these batteries you cannot maintain 2% for 8-10 hours as the acceptance rate drops below that ending amp level after a hour or so into the absorb.

waynefromnscanada

Re: Surrettes, still trying

A view that's a bit different, results a bit different.
Last Spring (2013) my 11 year old "Power Battery" bank of six, 6 volt L-16 batteries in 3 parallel 12 volt strings, finally died.
Replaced them with six 2 volt L-16 Surrettes in one single string. One of the things I really liked about Surrettes, and what sold them to me, was the fact they were the only ones I could find that were constructed as one single 2 volt cell, not 3 individual 2 volt cells wired in parallel in one L-16 package. 6 cells to check for SG and water instead of 18. These new batteries are connected to the same system and loads the old ones were, so they live the same life. Normally they are not subjected to deep discharges as the tiny hydro carries the continuous key loads adding up to roughly 3 kwh per 24 hour day. Big heavy loads are reserved for bright or sunny days. So they don't really have to work hard, but have no problems at all running heavy loads when needed.
Last night was a bit different as early evening the hydro shut down thanks to local beavers plugging off the hydro intake. Yes, I'm in a constant battle with them till Winter freezes over the lake. So, last night the batteries pumped out nearly 1.5 kwh before daylight arrived and began recharging them. The day was cloudy-bright and by noon the controllers has switched to float. Now was my time to check them out closely.
All 6 held at slightly more than 1.265 SG, Happy with that. Until today, the last time I added water was during installation, but had been keeping an eye on the levels. Added a total of 3 litres water. That's roughly 1/2 litre per cell/battery since last July! The old Power Battery units used to suck back a gallon every 2 or 3 months. Same voltages, same loads. That's an extremely low water usage compared to the old batteries. This could be good, or it could be bad, but so far everything is going extremely well.
OH, and today, after adding water, selected manual SG to mix up the fresh water with the rest. That's probably only the second time they've experienced SG since
they were commissioned almost a year ago. Didn't really need it, but felt the need to stir the electrolyte. The old batteries were a pain-in-the ask by comparison to the new ones. So far, after nearly a year in service, the Surrettes appear far better than the Power Battery products.
Will they still be operating OK after this season? Will they still be OK next year? Will they still be OK in 2 years? 5 years? 10 years? Only time will tell.

Vic

Re: Surrettes, still trying

DMJ72 wrote: »

This may help, From Rolls' RE Tech bulletin :

[img]https://dl.dropbox ... ][/img]

DM172,

Am certain that this snippet that you posted, is from Surrette Bulletin 614, which disappeared from the Surrette site a number of years ago. Have been told that this was "controversial" within Surrette. Certainly the deep, deep discharge to completely DEAD @ 1.83 Vpc is something that I would never do intentionally, although, suppose this DOD would depend upon what if any current of any discharge happened to be. Also (waiting) to fully recharge at 30 days maximum seems to be pushing it, as well.

Surrette had mentioned, in at least one version of this Bulletin, that it was prepared for off-grid users who had Charge Acceptance concerns, and also were concerned about needing to run a genset every day to fully recharge batteries in inclement weather (etc). The poor charge acceptance appeared to have resulted in seldom/never cycling the battery very deeply. So deep and very deep discharges were suggested as a way of freshening the plates.

Agree with BC04, that ending Absorb at 2% of 20-hour Capacity, would reasonably severely undercharge any of the Surrettes here, at any reasonable Absorb V. Banks here need just under 1% of C, at reasonable Vabs for a full recharge.

And, BC, the rapid fall in charge current, to/below 2% of C seems curious. We are at 2% about 40 - 45% of the way through Absorb, and, that last part of Absorb is a gradual taper to the EA of about 11.9 A at 58.1-ish Volts. This Vabs bould be a bit lower, but have been skipping a Bulk for three days (the CC "Bulks" only to Vfloat each of these skip days, and then just maintains that for the day). Each skip day, the battery does get 60%, or so recharge, just not a full charge.

BC04, I do wonder about the accuracy of the charge current measurement. The charge currents you have noted, must be read from the Charger/s, at least for the EA value being met ... forgot to look around in this Thread and others to see if you have a Trimetric, or something that uses an accurate Deltec (or similar) Shunt. As noted before, making an accurate measurement form a 50 mV shunt can be difficult with many DMMs, although a Trimetric (so similar) device should be accurate enough.

Am using Classics and the WBjr with Deltec shunt, and appears to be very accurate (with a very small amount of jitter).

Surrette gives very good Tech Support, via 800-number telephone, and e-mail. As you probably, Steve Higgins, who spent some years at Outback Power is now Tech Support Manager at Surrette - so there IS someone there with RE background ... realize that you have Grid power available, but Steve has a lot of experience.

Still pondering the behavior of your Surrette bank ... these batts sure behave differently than any of the three Surrette banks here. FWIW.
Good Luck, Vic

Blackcherry04

Re: Surrettes, still trying

Vic, I bought a new Vitron BMS for these batteries, that replaced a Xantrex Link, I have no clue of the Shunt Manufacturers names, but they both read the same. I have to assume they are correct, although they are a little higher than my clamp on meter.

I am on a 4 day outing and they be charged in the 50-80% range several times, by Monday late I will return to shore power and do a 100% full charge. I will try to log every detail I can so I can share it here and let you guys have at it. When I left yesterday I checked all 6 cells and they were all 1.265 + So, in returning 600 amp hrs ( 50% dod ) it should be good indicator of how they react to a charge. If I am at 1.220 after 5 hrs of absorb @ 15 v, I am in trouble. There is definitely something wrong in the way they accept a charge. Keep in mind that it took 20 hrs to raise them back to 1.265 last time out.

vtmaps

Re: Surrettes, still trying

Blackcherry04 wrote: »

Based on this voltage ( 15.2v ) I can only raise the SG level .025-.030 per charging hour.

Blackcherry04 wrote: »

If I am at 1.220 after 5 hrs of absorb @ 15 v, I am in trouble. There is definitely something wrong in the way they accept a charge. Keep in mind that it took 20 hrs to raise them back to 1.265 last time out.

Have you considered raising your absorb voltage a few tenths of a volt? You only have two parameters to play with... absorb time and absorb voltage.... if you can't get there with longer time, then try getting there with higher voltage.

My L-16 bank cannot get up to 1.27 SG in a day's time at 29.2 volts absorb, but at 29.6 volts I can usually get there in 2 - 2.5 hours. It's too soon to say (4 years) whether the higher voltage is shortening their life, but I'm sure that the lower voltage will lead to sulfation.

--vtMaps

Blackcherry04

Re: Surrettes, still trying

vtmaps wrote: »

Have you considered raising your absorb voltage a few tenths of a volt? You only have two parameters to play with... absorb time and absorb voltage.... if you can't get there with longer time, then try getting there with higher voltage.

My L-16 bank cannot get up to 1.27 SG in a day's time at 29.2 volts absorb, but at 29.6 volts I can usually get there in 2 - 2.5 hours. It's too soon to say (4 years) whether the higher voltage is shortening their life, but I'm sure that the lower voltage will lead to sulfation.

--vtMaps

Yes and No, I have it now set @ 15.2V absorb and 9 hrs. Before I had it at 14.9V and 4 hrs. When I did the 20 hr EQ to get them up from 1.220 I was at 15.5V. Thats where I came up with the ( .025-.030 per charging hour ).

Blackcherry04

Re: Surrettes, still trying

I started at 1.265, removed 626 amp hrs I started charging back at 8:00pm yesterday evening and ended at 10:00am this morning. It was a lot of amp hrs, but it's the long absorb time that seems way to long. I watched a set of GC2's with close to the same number of amp hrs to be returned and in 8 hours they were done and sleeping. The Surrettes ended up with a 3 hr Bulk and a 11 hour absorb. A little different from last recharge, but somewhat disappointing ( 14 hrs ). Here is a condensed version, I was sampling every hour, but to much data. I stopped with 1.260 sg level it was close enough and another hour wouldn't mean that much. Most of the SG increase was at .010 per hour. The ending amps was 13 amps.

Set Absorb 15.2V & 200 amps (15.2 temperature compensated @ 14.9v and 91° cell temp. )

8:00 pm, 1.165 SG 626 amp hrs to be returned

Absorb Started
11:00pm, 1.170 SG 252 amp hrs to be returned

10:00am, 1.260 SG BMS reset

Vic

Re: Surrettes, still trying

Hi BC04,

Thanks for the update. Good that you have battery monitors. Think that the Victron and the Xantrex Link are both quality gear, so your readings should be accurate.

Think that, perhaps your batteries needed some more cycles. But, the EA OF !2 A and 1.260 SG agrees very closely with the Surrettes here.

The batteries here, started out with shallow discharges, and an occasional discharge to 70-ish percent SOC. They have many cycles on them ... hope that all yours need is some more cycles.

And Wayne, great that your Surrettes are doing well. Your break-in process is probably similar to the one used here. Hope yours work out well, too.

Good Luck to you both. Sure am hoping for the best! Vic

waynefromnscanada

Re: Surrettes, still trying

Vic wrote: »

Wayne, great that your Surrettes are doing well. Your break-in process is probably similar to the one used here. Hope yours work out well, too.

Good Luck to you both. Sure am hoping for the best! Vic

Thanks for your comments Vic, and it's good to know my break-in process has been similar to yours, that yours are working out well for you.
Not kidding, the ones I have now, compared to the attention demanding Power Battery units, are acting more like (or almost) install and forget batteries. Perhaps because of the light duty they are tasked with, but the old ones had the same life. And after 11 years of dealing with 3 parallel strings, I LOVE the single string! Hope we'll still be saying that in 5 or 10 years.

Blackcherry04

Re: Surrettes, still trying

Another week, 582 amp hrs to be returned, 15.2 volt absorb, ( 14.9v corrected ) entered absorb @ 1.190 SG level. 13.5 hrs later 1.260 @ 12.8 amps exit to float.

Cariboocoot

Re: Surrettes, still trying

Let's see ... hours spent trying to get Surrette batteries to work time minimum wage .... you could have bought a new set of batteries by now. (JOKE)