EQ Voltage of Trojan SSIG or SIND batteries, Inverter/Charger recommendations?

aksala · April 2018

I'm still putting together specifications for my new home and my battery search keeps landing on Trojan SSIG or more likely SIND line for price per Ah and longevity of the bank. However the specification sheets show 64.8V for EQ. I was looking at using Schneider XW+ 6848 as my inverter/charger and two MPPT 80-600's with 3.6kw arrays on each with a 12kw gen into the 6848. It all looks great except that the 6848 is limited to 64V as maximum EQ voltage. I spoke to tech supp and they said that's as high as it will go, other than actual voltage going higher based on temp compensation.

Do you think the .8V will make a big difference on reaching EQ or should I seek out another charger? Any recommendations?

** I did find the temperature compensation coefficient for the MPPT and I imagine the same is used for the XW. Listed as 108mV per degree C. While not exactly what Trojan calls for (.005V/deg C) x number of cells it works out close to a point. If my bank is between 50-60F most of the time then the resulting EQ charge should be close to 65.2V, yet Trojan's recommended would be more like 66.2V if I'm looking at this correctly.

Estragon · April 2018

IMHO, the EQ voltage is probably close enough.

You might want to run it by Trojan to be sure though, and to have something in case of warranty issues.

Photowhit · April 2018

This is going to be problematic with the 6848 inverter as well, since it has an input voltage limit of 64 volts! So equalizing would have to be manually done or the inverter will shut down to protect it's self.

Other options with similar longevity would be a forklift battery or HUP 1 which is a similar style.

http://www.hupsolar.com/buy-HUP-batteries-prices-pricing

I would check with Trojan, and ask if maintenance/monthly equalizing could be done at 63.6 volts and corrective equalizing, recovery of cells with low specific gravity, be done at the higher 64.8 volt rate.

It appears that these batteries are targeted for the renewable energy market. It can't be the first time they have been asked questions about this. Not many inverters can handle this higher voltage, My Prosine can't! I think 16 volts for 12 volt bank, 32 for 24 volt bank and 64 for 48 volt bank have been an industry standard.

Estragon · April 2018

Realistically, you're not likely to be doing much EQing with the inverter/charger anyway. Typically, if you need to charge with the inverter, you bulk and early absorb with the genny, then let solar finish absorb and EQ. EQ needs higher voltage, but not much current, so you wouldn't normally do it on generator power unless you needed the genny running for something else.

The charge controllers can probably do EQ voltage (check anyway), which is how you'd probably do it 90%+ of the time. My Outback inverters apparently do 67v, but I've never used them to EQ, so kinda moot.

mike95490 · April 2018

I have an older XW, it's charger tops out at 64V, but does not give voltage warning till 67V and faults at 68V

Being a bit short of EQ voltage should not be a big thing, you just won't be able to EQ off your generator. Use the genset to bulk in the AM, and let the solar do Absorb and EQ . Schneider has a firmware update for the solar charge controllers to get them a bit higher voltage than 64V (if you have the XW solar CC)

I run a NiFe bank, and use Morningstar controller to absorb daily at 66V, once in a while in winter, the Temp Comp will kick the voltage up to 67 and I get a warning flag from the XW.

aksala · April 2018

Thanks for the feedback. I tried contacting Trojan but got VM. I sent an email and I'll continue to try on the phone. Good points about using the PV for EQ. I keep falling back to my worst case scenario during winter. This site is in Alaska and Nov - Jan is pretty slim on usable sunlight.

The HUP batteries are still more $$ over time than the SIND line IMO.

Photowhit · April 2018

Forklift batteries, direct from manufacturer could be cheaper, but I suspect it's nice having the weight divided up, they don't look to much more expensive. I paid $2525 delivered for about 660 amphour(20hr) 24 volt. Expecting to get 12-15 years out of it. on 7 years (maybe starting 8)

aksala · April 2018

Photowhit said:

Forklift batteries, direct from manufacturer could be cheaper, but I suspect it's nice having the weight divided up, they don't look to much more expensive. I paid $2525 delivered for about 660 amphour(20hr) 24 volt. Expecting to get 12-15 years out of it. on 7 years (maybe starting 8)

I admit they look somewhat attractive at first. But I see no real specifications for use in RE and repeated cycle life under PSOC. I'm curious what your DoD is per day on your bank? I am looking at 48V, 1600 - 1900aH to keep DoD between 20 - 30%.

aksala · April 2018

Well Trojan wrote back and simply said:

Response:

If 64.8V can’t be achieved by your controller, then 64.0V is OK. The equalizing process may just take longer to complete.

True enough.

Photowhit · April 2018

My DOD varies wildly, Perhaps down to 60-70% SOC nightly in the summer, top 10% for much of the spring and early fall, though this spring has been particularly cloudy so far. Late fall and early winter I we can have long periods of overcast skies. had a 13 day period with 1 hour of direct sunlight 3 1/2 years ago. I'm sure I lost some capacity during that time, I was <50% SOC for most of a week, since I don't use alternative sources of power this was rough on my battery. The HUP is touting all sorts of 'new technology' now, but on introduction I believe it was pretty much a forklift battery with a bit more 'room' above and below the plates.

Our sponsor has been selling Crown forklift batteries for RE use for 20+ years. They say;

NAWS said:
These batteries are designed for extremely heavy usage. In a typical solar electric system they will normally last for about 20 years or more. We have been selling these for over 25 years and have the utmost confidence in their reliability.

Link to quoted info;
https://www.solar-electric.com/crinba24vo10.html

aksala · April 2018

Photowhit said:

My DOD varies wildly, Perhaps down to 60-70% SOC nightly in the summer, top 10% for much of the spring and early fall, though this spring has been particularly cloudy so far. Late fall and early winter I we can have long periods of overcast skies. had a 13 day period with 1 hour of direct sunlight 3 1/2 years ago. I'm sure I lost some capacity during that time, I was <50% SOC for most of a week, since I don't use alternative sources of power this was rough on my battery. The HUP is touting all sorts of 'new technology' now, but on introduction I believe it was pretty much a forklift battery with a bit more 'room' above and below the plates.

Our sponsor has been selling Crown forklift batteries for RE use for 20+ years. They say;

I agree, the Crown industrial bats look decent. Although for the numbers I'm after it's either a bit of a wash or a little more. I can get a pretty good price on the SIND bats. I also like putting two 6x8's together so that if I had an issue with a single battery, I could split it off and still be able to get by for a while on half the Ah, just dipping more into 50% DOD and conserving a bit until I figure it out or replace the bat and I can do that for about $17K. Anything else I look at seems to always add up to about $23-25K and often with less life expectancy to boot.

My heavy usage will be winter and Nov - Jan and will rely on the gen. We often have bright clear days in the winter but so little sun it's hardly usable until March. April is actually the best month for my location. The fact that the sun is up so long in the summer at least offsets the cloudy days during that time. So it remains to be seen until it's in operation how my DOD will actually go throughout the year but I plan to use the generator to keep DOD at no more than %35 and Apr - Aug should have the PV's keeping it about 10%.

Photowhit · April 2018

I asked around with warehouse people and a local rebuilder of batteries in St Louis. Non specified any brand that was particularly better than others other than a couple suggesting Hawkins being a good battery. So I ordered directly from GB. The prices look really Great if you just look at the 20 hour rate. But if you compare by the 6 hour rate they, they over rate batteries at the 20 hour rate. Here's a link to their price list, FWIW;

http://gbindustrialbattery.com/

Haha... Their price list no longer has prices!!!

https://gb-battery.com/products?olsPage=products&page=2

The 2nd is a list to prices, the ah rating is for 6 hour rate, You can expect about 25-33% more in a 20 hour rate. If you look at their "price list" without prices...lol. You will see they over rate their batteries, using a 1.576 multiplier.

aksala · April 2018

I happened to find GB before I came back to this thread. The prices look really good but I'm still confused by stated specs. Even on their page they recommend discharge to 80% as each charge, partial or otherwise is considered a "cycle" and they state roughly 1500 cycles. Now 1500 to 80% might be great for forklift use, but I don't see how folks get 15 or more years if they're cycling daily or even every other day. If you're off grid, aren't you cycling almost every day? I know I will be. I'm still trying to compare apples to apples here. How can they say 1500 cycles and then I look at the SIND line and they have a relationship to DOD and number of cycles. If I keep my DOD to roughly 30% my cycles are like 4000 or more. Now we're getting into 10+ years of constant daily discharge/recharge.

Photowhit · April 2018

They are just stating for forklift use. I believe it's to prevent short charging between shifts. They told me, after I had ordered my battery that also make a RE battery. I pretty much got tired of salesman BS. It gets pretty bad and the over estimating the 20 hour rate is borderline criminal.

They even stated that the capacity was the working capacity and they have a 20% reserve above that. I asked if they understood what the numbers connected to the batteries meant. Then explained that 12-85-13 represented 12 cells, with 85 amps per positive plate (6 hour rate), with 13 plates per cell (6 of which were positive), Then asked where this extra reserve was?

They build to order, I asked if I could get cables with 3/8ths inch lugs on 4/0 cable with 5' of extension. She was clueless as to what I wanted. I finally got flag terminals on the battery it's self. They did reduce the price for this change. By the end I was pretty frustrated. They also said all applicable taxes would be paid. Since this is over $1000 (threshold then in Missouri)the state should have been paid sales tax. I asked and they later said that was my responsibility. I kept the receipt stating they paid all applicable taxes.

All in all it was a very frustrating adventure. I would likely try to fax a quote and see if I could get bids next time around. Ask for a quote on the battery by specs and leave it something comfortable for them, like 24-85-13 with 5' lead with 350 amp Anderson connector, with out without lid/cover. Delivered with a lift gate truck.

Then do the lugs my self, I just hate the idea of pulling apart a connector hard wired to a large battery.

I've actually been to IBP in St Louis and have a contact there. I understand they recondition batteries there and might see if I could work out a deal there on a New or even rebuilt battery. They mainly deal with other retailers.

aksala · April 2018

Thanks for the the information @Photowhit. I'm still on the fence somewhat regarding the batts. And I still need to work through more quotes in Alaska and where I am now (Idaho) and figure out if I want to go through the hassle of hauling a 14K flatbed up with a genny, batts, panels and associated gear and put into a storage locker up there for installation next year. Shipping is a killer. The initial difference I received for a quote on Trojan's in AK vs's buying them down south was roughly the cost of a 12Kw diesel generator! I'd just need to figure out the logistics of a forklift on either end.

BB. · April 2018

Warning on shipping batteries for installation next year...

Flooded cell lead acid batteries need to be recharged about every 30 days if at room temperature.

AGM batteries need to be recharged about every 3-6 months if stored at room temperature.

In theory (I would be hesitant to tell you that the following will work--But it is a common engineering calculation), for every 10C/18F reduction in temperature, the batteries will go ~2x longer between recharging (self discharge slows down when cold):

75F - 2*18F=39F storage--Roughly 4x longer (4 months for Flooded Cell, upwards of 2 years for AGM).

And, if they are in a storage building that gets hot during the summer, then the batteries will need recharging more often (18F increase, 1/2 the storage time).

Or, at the very least, you need a battery charging source and, at least, a 1% to 2% rate of charge (via solar or AC power). An 800 AH @ 24 volt batter bank, in solar, I would suggest a minimum of:

800 AH * 29 volts charging * 1/0.77 panel+controller deratings * 0.02 rate of charge = 603 Watt solar array minimum suggested for floating a battery bank in storage.

Note that ForkLift and Traction batteries do, generally, have higher self discharge.

The above are just some thoughts--I would not suggest storing batteries for later installation unless you had no other options. Picking different chemistries/configurations like Li Ion LiFePO4 or "dry charged" lead acid, etc. may be some workable options.

One related suggestion... Install your solar power components (chargers, inverters, wiring, etc.) on plywood (or concrete backer-board over plywood for better fire resistance) locally, and test out the pre-wired system before placing in a storage container for shipment to distant lands with no easy access to components.

-Bill

Estragon · April 2018

If no floating available, IMHO dry charged is probably best for ~1yr storage.

Note though that "dry" charged isn't really. AFAIK, the batteries are filled, commissioned and tested, then emptied for shipment. As such, I believe storage is limited to ~12-18 months, some of which will have elapsed during shipment to distributor - getting fresh stock would be important.

One side benefit of dry charged is they're a bit easier to schlep into place. I got 8 wet and 4 dry (only 4 dry were available at the time), and there was a definite difference in moving them around.

aksala · June 2018

FWIW it now looks like I'll just pay the piper and spend the money on batteries that are sold locally in Alaska and through an installer that is quoting me batts, panels and inverter/chargers as a system. He is a master distributor for Rolls, and quoted me a bank of 2 KS 33P's and that's likely the way I'll go. The logistics of moving up is bad enough without trying to deal with a 48V battery bank I decided. The generator on the other hand I may very well haul up and save a few thousand!

MrM1 · June 2018

Sounds like a plan. Are you still planning on using an XW for charging with the Rolls? Do the Rolls require the same higher EQ voltage?

Dave Angelini · June 2018

You can also get a firmware update for taking the XW+ and it's mppt-80-600 to beyond the spec. You will have to contact Schneider for this as they do not install it on production units. This is because of liability at these voltages. Let me know if you have trouble getting it and I will try and help. You will need to be able/know how to install firmware and have the Combox or the configuration tool.

Definitely buy the batteries locally. If you have problems you at least have options.

aksala · June 2018

@MrM1 , I'm not locked into anything yet but at this point I like the Schneider gear for what I'm doing and I can get good support there locally. The EQ voltage from Rolls is now 62.4 - 63.6 for PSOC.

@Dave Angelini, options, exactly! He sells Trojan as well, and Crown too I believe and has been installing solar in Alaska for a couple of decades, so there's both support and experience with what local issues Alaskan's face. I have some questions re: the 80 600 and the panels which you can no doubt answer but I'll post a new thread, likely in the Solar for Beginners section.

MrM1 · June 2018

@Dave Angelini is there also a firmware for the SW that will up the EQ voltage to 2.7+ vpc? Or just for the XW+

Dave Angelini · June 2018

Only XW+ and the -80-600 volt cc to 67 vdc
I try to give general advice but I am in business and add quite a bit of value to my clients in Alaska also

EQ Voltage of Trojan SSIG or SIND batteries, Inverter/Charger recommendations?

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