More Questions re Trojan T105 SG

equis

Hello Again

Please excuse all my questions, I really would like to get this right 

When I equalized my bank it came up to 1.277 no problem.

Now for my daily charge they seem to be only around 1.250 – 1.260 when finished.
It’s a 450ah bank and the end amps was 2.5 at 56.4v after 4 hours absorb, I assumed it was fully charged. (manual says between 1 and 3%)
Is this OK?

If the batteries are only ever charged to 90% does that matter?

Can you tell me the pros and cons of 56.4 vrs 58.8 absorb charge?

At a guess for an off grid solar system, how often would you think I need to equalize charge?
I was thinking of doing it every 3 months
The manual says equalize when SG is low but it doesn’t seem to say how low.

Thanks again for all your help.

Rhys

vtmaps

Re: More Questions re Trojan T105 SG

equis wrote: »

When I equalized my bank it came up to 1.277 no problem.

Now for my daily charge they seem to be only around 1.250 – 1.260 when finished.
It’s a 450ah bank and the end amps was 2.5 at 56.4v after 4 hours absorb, I assumed it was fully charged. (manual says between 1 and 3%)
Is this OK?

You must regularly get them up to 1.277. It takes two things: time and voltage. When the current stops tapering you have reached 'end amps' for that particular voltage. If you then raise the absorb voltage, the current will increase and then start tapering down to a new, higher 'end amps'.

If you have tapered to 'end amps' and not gotten your SG up to 1.277, then you need to be using a higher absorb voltage.

There is a school of thought that daily higher voltages is not good for a battery. Some folks would do a daily lower voltage absorb, and then do a higher voltage absorb (sort of like an equalization) once or twice a week.

--vtMaps

Photowhit

Re: More Questions re Trojan T105 SG

equis wrote: »

...The manual says equalize when SG is low but it doesn’t seem to say how low....

I don't think your manual says that! I think it says, ONLY, when one cells is more than .02 different from the others (or something like that) we have had discussions about Trojans being different from all other battery manufacturers in this regaurd. Almost or all other battery manufacturers ask for a regular "mantanance" equalizing from every month to every 6 months.

You should reach full charge at least once a week and typically, without long over cast days(often found this time of year) you should reach full charge a few times a week.

Battery FAQs

paulskirocks

Re: More Questions re Trojan T105 SG

Trojan says the daily charger setting for a 48 volt bank should be 59.2 volts... This thread is of particular interest, as it is my plan to pick up 4 t-105 batteries this week...

BB.

Re: More Questions re Trojan T105 SG

Dave Sparks, a poster here has related:

Dave Sparks wrote: »

I learned this strategy from Dave Surrette (Rolls) in the late 70's. Pretty much the bible on how I design my systems for off-grid.

Assume that the system will never reach more than a 90% state of charge.
Try not to go below 50% SOC, ever! Complete absorption over 90% of the year

Use the energy stored from 70% to 90% SOC for your daily cycles.
Save the energy from 50% SOC to 70% SOC for aging to get long battery life.

I know Surettes has changed their recommendations over the years but I also know they are in the business of selling batteries! If you do the above you will get 10 to 15 years on their batteries with decent maintenance.

The OP is making it complicated by mixing battery types and not really stating a lot of information that would allow decent specific advice.

Oh yea, I am really happy that Surrette and Trojan are making L16's with 1000 AH capacities @20HR. Been bugging them for many moons to do batteries less than 125LB's!

And, my two cents... If your batteries are using a bit of distilled water per month--you are probably OK. If you are using none, or a lot per month--then you are probably under or over charging.

• Undercharging and operating for long periods (below ~75%) is damaging to lead acid batteries.
• Overcharging is less damaging to flooded cell batteries (at the cost of distilled water and wasted energy).
• Overcharging sealed batteries (AGM, Gel, VRLA, etc.) can be fatal to those types (venting electrolyte).

-Bill

Cariboocoot

Re: More Questions re Trojan T105 SG

Personally I find Trojan's EQ advice works for any sort of flooded cells.

If the SG is low across the board, they're not getting charged enough (either low V set point or most often short Absorb time). It can also help to keep the Float Voltage a bit on the high side in some cases.

If the SG is uneven by more than 0.005 (if you can read that fine) between two or more cells it's time for equalization (hence the term).

Photowhit

Re: More Questions re Trojan T105 SG

Cariboocoot wrote: »

Personally I find Trojan's EQ advice works for any sort of flooded cells.

If the SG is low across the board, they're not getting charged enough (either low V set point or most often short Absorb time). It can also help to keep the Float Voltage a bit on the high side in some cases.

If the SG is uneven by more than 0.005 (if you can read that fine) between two or more cells it's time for equalization (hence the term).

This can be 'Coot's advice, but Trojan's advice is;

Equalizing is an overcharge performed on flooded/wet batteries after they have
been fully charged. Trojan recommends equalizing only when batteries have low
specific gravity, below 1.250 or wide ranging specific gravity, 0.030, after fully
charging a battery.

I will recomend you follow the manufacturers advice. Trojan Link

Most others will want you to do a maintainance equalizing once a month (many) 2x a year (Rolls last I checked) if your buying Batteries with out any recomended Maintenance(Sams Costco...), I'd do at least quarterly equalizing even if there is no difference.

I thought about it the other day, and perhaps Trojan has such a great reputation with golf carts is that they don't ask for this equailizing maintenance charge. I don't think Golf Cart chargers have this function. I've seen people saying that Sams club batts don't last 3 years in a golf cart, where most experienced solar types find they can get 5 years of service....

Cariboocoot

Re: More Questions re Trojan T105 SG

Well yes you don't EQ unless the battery is charged first. You'd be amazed how 'uneven' SG evens out just upon regular charging.

And I seriously don't think anyone can accurately measure SG to 0.005 (hence the "if you can read that fine" remark) but Trojan's 0.030 difference may be a bit extreme for some makes. The point is if you can see an SG difference between cells after fully charging there's a need for an EQ charge.

Usual caveat: not all batteries are the same and these 'generalized' recommendations are for use when no specific recommendations are provided by the manufacturer.

Photowhit

Re: More Questions re Trojan T105 SG

I didn't want you to add a disclaimer, I just want people to understand that there is a very clear difference in the recomended treatment of Trojan batteries and the recomended treatment of pretty much all other flooded lead acid battery manufacturers. Others want you to do a periodic maintenance equalizing, regaurdless of cell inbalance, where Trojan does not...

I guess I should have made "only" in red. "...Trojan recommends equalizing only when..."