New DEKA "forklift" batteries seem to lack capacity
aj164
Solar Expert Posts: 122 ✭✭✭
We have four new DEKA maintenance saver solar (forklift type) batteries. They are 1304A-H (20/hr).
I've read it takes time before the batteries reach their design capacity. It has been about three months of very light use. We have never done an EQ, but we recently measured SG to be within .02 in all cells.
The problem we're having is a 2.5kW load (50-60A DC) brings the battery bank down to 44VDC in a relatively short period of time. By the voltage readings, I believe we're starting with close to a full charge. In theory, I believe we should be able to get at least 20 hours at 60A DC, but we're getting more like two.
EDIT: I'm actually not sure that the batteries are reaching 44V. I have the XW generator auto-start module with two triggers:
30sec @ 44VDC
load start: 25A (from the manual, I understand this is AC amps) ?
I've read it takes time before the batteries reach their design capacity. It has been about three months of very light use. We have never done an EQ, but we recently measured SG to be within .02 in all cells.
The problem we're having is a 2.5kW load (50-60A DC) brings the battery bank down to 44VDC in a relatively short period of time. By the voltage readings, I believe we're starting with close to a full charge. In theory, I believe we should be able to get at least 20 hours at 60A DC, but we're getting more like two.
EDIT: I'm actually not sure that the batteries are reaching 44V. I have the XW generator auto-start module with two triggers:
30sec @ 44VDC
load start: 25A (from the manual, I understand this is AC amps) ?
Comments
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Re: New DEKA "forklift" batteries seem to lack capacity
What the heck are you charging a 48volt 5000AH+ battery bank with?
OK so I looked at your posts and discovered you have;
(Batteries are 6-M100-23. 6 cell FLA lead-antimony, 1304A-H @ 20hr rate, four batteries in series for 48V nominal)
Or a 1304 AH / 48 volt battery bank...
Are you finishing a bulk charge every day? What's your bulk set at, float? Did you measure the SG when you thought the batteries were fully charged?Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites, Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
- Assorted other systems, pieces and to many panels in the closet to not do more projects. -
Re: New DEKA "forklift" batteries seem to lack capacityAre you finishing a bulk charge every day? What's your bulk set at, float? Did you measure the SG when you thought the batteries were fully charged?
Bulk charge is completed fairly early in the day unless it is heavy overcast. We have a 7.6kW array on two MPPT-60 charge controllers.
SG is 1.250 - 1.260 on a full charge (most cells are 1.255). The voltage on the battery bank is at least 55V before I start the 2.5kW load. -
Re: New DEKA "forklift" batteries seem to lack capacity
So you have the charger and controllers set at 58.8 for absorb for about 4 hours and float set at 56.4 volts? If this is so the next thing that I would check is your cabling, is the wire size adequate? Are the connectors clean and properly torqued. What size cable comes on the battery to the Anderson connector? With a 60 amp load a bad connection could cause your voltage reading to drop much quicker then the battery discharge curve. When you take off the load does the battery voltage pop back up with chargers off?SG is 1.250 - 1.260 on a full charge (most cells are 1.255). The voltage on the battery bank is at least 55V before I start the 2.5kW load. -
Re: New DEKA "forklift" batteries seem to lack capacitySo you have the charger and controllers set at 58.8 for absorb for about 4 hours and float set at 56.4 volts? If this is so the next thing that I would check is your cabling, is the wire size adequate? Are the connectors clean and properly torqued. What size cable comes on the battery to the Anderson connector? With a 60 amp load a bad connection could cause your voltage reading to drop much quicker then the battery discharge curve. When you take off the load does the battery voltage pop back up with chargers off?
Per DEKA tech support last month, we've started with the following:
bulk 57.6 absorb 58.2 float 55.8 eq 60.6 Absorb time is 4 hours. Cable is #4/0 10ft (20 total feet). The long, flat terminal takes two bolts on the battery posts. In the XW box, the other terminal bolts to the bus bar with just the one 3/8" bolt. The + bus bar bolts to the 250A DC breaker.
Do you think I need to raise the voltages although the SG appears to be very good @ 1.255? -
Re: New DEKA "forklift" batteries seem to lack capacityPer DEKA tech support last month, we've started with the following:
bulk 57.6 absorb 58.2 float 55.8 eq 60.6 Absorb time is 4 hours. Cable is #4/0 10ft (20 total feet). The long, flat terminal takes two bolts on the battery posts. In the XW box, the other terminal bolts to the bus bar with just the one 3/8" bolt. The + bus bar bolts to the 250A DC breaker.
Do you think I need to raise the voltages although the SG appears to be very good @ 1.255?
In my opinion the SG is too low. Check with Deka, but the SG should probably be 1.275, not 1.255. Can you increase the ABSORB time? How much time are you spending in FLOAT?
Just so I've got this straight; you've got FOUR 48 Volt 1304 Amp/hr batteries or four batteries that add up to 48 Volts @ 1304 Amp/hrs? -
Re: New DEKA "forklift" batteries seem to lack capacity
You are probably close enough, though raising the bulk and absorb slightly may improve charging, but if using too much water, then back off. I still expect there is a cabling or connector problem somewhere. If you have a digital multimeter then I would measure the voltage drop across each battery terminal to where it connects to the buss bars in your DC box under load. With a 60 amp load, the voltage drop from pos battery terminal to the pos buss bar should only be a few tenths of a milivolt at most. Same for the neg terminal to neg buss bar. I assume the neg bus bar has a current shunt, so check the connections there, though often the current shunt is where the neg cable of the battery is connected. You can expect some voltage drop across the shunt of around 6 milivolts at 60 amps assuming a 500 amp 50 millivolt shunt. Another test is to measure the battery voltage at the battery terminals, and again at the inverter terminals. How much voltage difference between the two? Your SG is correct for that version of the DEKA battery, they have lowered the SG from the regular fork lift versions.Do you think I need to raise the voltages although the SG appears to be very good @ 1.255? -
Re: New DEKA "forklift" batteries seem to lack capacity. It has been about three months of very light use. We have never done an EQ,
I would start with an EQ,
Due to stratification ("heavy acid" sinks to bottom of bat, lighter "Water" floats to surface) I do not think you will be getting accurate SG`s, and it can have a dramatic effect on bat capacity,
Do you have temp sensing on all charge sources ?
Have a good one
Tim -
Re: New DEKA "forklift" batteries seem to lack capacityblackswan555 wrote: »I would start with an EQ,
Due to stratification ("heavy acid" sinks to bottom of bat, lighter "Water" floats to surface) I do not think you will be getting accurate SG`s, and it can have a dramatic effect on bat capacity,
Do you have temp sensing on all charge sources ?
Just did an EQ. The results are interesting:
Before the EQ, we had 1.250 average SG. We topped off the cells with distilled water and ran the EQ. Just after the EQ, we measured SG and found it went down! Most were 1.235, some 1.240-1.245.
Why would the SG go down after EQ? If we had an electrolyte stratification issue, shouldn't we see SG go up if anything?
Also, we ran another load test and recorded voltages (read from the control panel - not DMM). The A/C ran for about an hour. It pulled roughly 2kW this time (50A). Battery voltage went from 50.1 to 49.1 within the first few minutes, then stayed at 49.1 for the rest of the hour. When the A/C kicked off, the battery voltage quickly went back up to 49.9 with a 'light' 400W (10A) load.
Battery temperature sensing is plugged into the XW6048 inverter. However, the manual states that only one device needs a temperature sensor, and the rest will share that reading over the Xanbus communications link. -
Re: New DEKA "forklift" batteries seem to lack capacity
try another eq or even 2. -
Re: New DEKA "forklift" batteries seem to lack capacity
Did you measure the SG BEFORE you added water ? (it was extra concentrated at time, then you diluted it with water)Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister , -
Re: New DEKA "forklift" batteries seem to lack capacity
If you add distilled water, the top of the cell will have the S.G. go down (because the water is "lighter" than the electrolyte). It takes the mixing (and diffusion) of the electrolyte to get the same throughout the cell.
Generally, you don't add distilled water if the top of the plates are under electrolyte... Add the distilled water after the equalization is done (also helps prevent electrolyte from over-topping the cell during equalization if too much water is added).
-BillNear San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset -
Re: New DEKA "forklift" batteries seem to lack capacity
Please describe your EQ method, But it is not a timed operation, Your batteries must be fully charged before starting, And it is only finished when ALL cells stop rising in relation to each other, not when the clock says so, By what you describe, You have only just started EQ, not finished it,
Temp sensors, Are the charge controller`s linked into to inverter for temp sensing ? , What make/model are they ?
Have a good one
Tim -
Re: New DEKA "forklift" batteries seem to lack capacityblackswan555 wrote: »And it is only finished when ALL cells stop rising in relation to each other, not when the clock says so, By what you describe, You have only just started EQ, not finished it,
Temp sensors, Are the charge controller`s linked into to inverter for temp sensing ? , What make/model are they ?
Yep - just one hour of EQ to date.
The charge controllers are Xantrex MPPT-C60. Both are on the Xanbus with a control panel and a gen start module. -
Re: New DEKA "forklift" batteries seem to lack capacity
I think a proper EQ would make a difference, As you did not carry out the initial commissioning of the batteries as it should be done, You do not have that data, so It is difficult to tell if they have ever been fully charged and where they are now, but they undoubtedly need a proper EQ,
My method for a similar site would be, (Assuming you live on site and are going to do it yourself)
Bulk charge for 8 ish hrs , checking SG`s about every 2 hours, if they ALL stop rising, the bats are charged, if not keep going till they do (rising in relation to each other, you may want to temp compensate, also stop and let bank rest if you get to 45c)
When all SG`s stop rising in relation to each other on bulk voltage, Switch to EQ voltage and do the same, When all SG`s stop rising in relation to each other on EQ voltage, You are done, Keep all the info you now have on each cells SG`s as a future reference point.
Have a good one
Tim
If the bats are not fully charged before, the above can take a very long time, 16 hours + -
Re: New DEKA "forklift" batteries seem to lack capacity
Tim,
When you're checking sg's during the extended eq charge do you stop the eq when you are measuring? The acid mist/smell can be quite uncomfortable if checking when the electrolyte is bubbling at eq charge levels.
Ralph -
Re: New DEKA "forklift" batteries seem to lack capacityTim,
When you're checking sg's during the extended eq charge do you stop the eq when you are measuring? The acid mist/smell can be quite uncomfortable if checking when the electrolyte is bubbling at eq charge levels.
Ralph
Depends on the room, But not usually, the time it takes for it to "calm down" is just too long, I do usually use several fans though, I have tried but find it too difficult to use a respirator,
Have a good one
Tim -
Re: New DEKA "forklift" batteries seem to lack capacity
If you do the basic maintenance you will never have to do this kind of relatively dangerous procedure. I never have had to except once on a island. It did work, it was a major pain and it is scary! I insist on replacement or I walk away nowadays."we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail offgridsolar@sti.net -
Re: New DEKA "forklift" batteries seem to lack capacity
That is basic maintainence, I do it at around 100 cycles (to 50 % DOD) or 6 months depending on site & season (We are a 6 month season holiday destination. about 1/2 of my sites are rentals) and I must say it is the worst part of this job,
One particular site that has a 48v bank of rolls 2430 AH with only enough room to walk in front of them, I have to put a board on top off and lye on to read SG`s is not fun at all, Not to mention the bat room temp around 45 c in summer dressed up in apron/ mask/ gloves etc
,
But as you mention , It does work, The rolls book says you should do it, and would you spend 25 g on a new car and not expect to service it ? (The aforementioned rolls will need replacing some time this year due to lack of servicing & ambient temp`s @ around 1/3 of their expected lifespan) I have another customer that phones me about every 3 months (as a guess 130 cycle`s) to say his gen run time has crept from 7 hours to 9 pd, I go EQ, gen time returns to 7 hrs,
It`s a crap job , but it has to be done and it pays the bill`s :grr
Have a good one
Tim -
Re: New DEKA "forklift" batteries seem to lack capacity
Tim,
Not directing this at you but for others. Basic maintenance to me is a 2 hour EQ every three months. If you are deeply cycling your batteries Tim's method works. I never have to do this as the systems I use rarely cycle deeper than 20% from full. That is the key IMHO to long battery life! The extra capacity is there for the years when the batteries degrade. Rocket science from the 1950's and sailor's who used this technique long before from when batteries first went on boats!
So Tim, your host country is not going to pull a Greece on us are they? :grr"we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail offgridsolar@sti.net -
Re: New DEKA "forklift" batteries seem to lack capacityDave Sparks wrote: »Tim,
Not directing this at you but for others. Basic maintenance to me is a 2 hour EQ every three months. If you are deeply cycling your batteries Tim's method works. I never have to do this as the systems I use rarely cycle deeper than 20% from full. That is the key IMHO to long battery life! The extra capacity is there for the years when the batteries degrade. Rocket science from the 1950's and sailor's who used this technique long before from when batteries first went on boats!
So Tim, your host country is not going to pull a Greece on us are they? :grr
Yes I must agree with all these systems it is a bit " horses for courses" and add that all apart from 1, of "my" systems were put in as a stop gap until grid came, some sites and these are not small houses 3mil€ + are still waiting 6 years later the systems I "look after" are undersized and over stressed to the limit, way too much load for undersized systems, Some of them cycle 3 times a day @ 40 + deg ambient during peak period, other`s are purely gen & bats or only a token amount of panels, So they do get "driven" hard, I have found around 100 x 50 % DOD cycles to be where I can notice a difference in system performance,
Not sure on the Greece bit, Spain, Portugal , UK and then States is the way the list is reading this side of the pond, Lucky I live on a little Island just about far enough away from the lot of it
Have a good weekend
Tim -
Re: New DEKA "forklift" batteries seem to lack capacity
When I try to "force charge" with the MPPT60 or XW6048, it won't let me change the setting. I get something like "warning - failed to change, retry or cancel". Also, the Force Charge option is not shown with brackets, which indicates it is not currently a changeable setting.
Anyone know what needs to be enabled/disabled in order to get Force Charge to be changeable? -
Re: New DEKA "forklift" batteries seem to lack capacity
Set your battery type to custom and pick what ever voltages and times that work best for your battery bank. This can be set in the XW-Mppt for solar based or the XW-6048 for grid/genny based -
Re: New DEKA "forklift" batteries seem to lack capacitySolar Guppy wrote: »Set your battery type to custom and pick what ever voltages and times that work best for your battery bank. This can be set in the XW-Mppt for solar based or the XW-6048 for grid/genny based
The battery type is custom (in order to set according to DEKA recommended voltages). Both the 6048 and the MPPT controllers have the same settings. I thought I could use the 'force charge' option to make it stay in bulk mode.
If I can't make it stay in bulk with Force Charge, would it be the same effect to temporarily re-program the Absorb voltage to the same as Bulk?
Thanks - AJB -
Re: New DEKA "forklift" batteries seem to lack capacityThe battery type is custom (in order to set according to DEKA recommended voltages). Both the 6048 and the MPPT controllers have the same settings. I thought I could use the 'force charge' option to make it stay in bulk mode.
If I can't make it stay in bulk with Force Charge, would it be the same effect to temporarily re-program the Absorb voltage to the same as Bulk?
Thanks - AJB
Typically Bulk and Absorb ARE the same voltage, the Bulk , ramps up to the Bulk target ( 57.6 is typical ) and the Absorb holds that voltage until either the time or current hit there targets -
Re: New DEKA "forklift" batteries seem to lack capacitySolar Guppy wrote: »Typically Bulk and Absorb ARE the same voltage, the Bulk , ramps up to the Bulk target ( 57.6 is typical ) and the Absorb holds that voltage until either the time or current hit there targets
That makes sense. I'm trying to understand, then, what holding the charger in 'bulk' mode would actually do. If bulk is voltage-limited, then we're really not doing anything different than 'absorb' once we hit that target V. Maybe what I need to do for the procedure described in this thread is to raise the bulk voltage to a safe maximum (and set absorb to the same, which is currently lower than bulk per DEKA specs). -
Re: New DEKA "forklift" batteries seem to lack capacity
Not sure what the battery manufacture is suggesting, never heard of absorb being higher than bulk, ever.
What works for most flooded batteries is 57.5 for bulk/absorb , 54 float and 64 for EQ, or that what I read and what we used used at Xantrex for LeadAcid battery defaults
I would suggest you just program the XW's to the default LA settings and let them do there thing, the voltages you changed to are wacky IMHO. -
Re: New DEKA "forklift" batteries seem to lack capacityblackswan555 wrote: »Yes I must agree with all these systems it is a bit " horses for courses" Tim
From Mr. Waters? Another Englishmen... Definately a great musician!"we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail offgridsolar@sti.net -
Re: New DEKA "forklift" batteries seem to lack capacitySolar Guppy wrote: »Not sure what the battery manufacture is suggesting, never heard of absorb being higher than bulk, ever.
What works for most flooded batteries is 57.5 for bulk/absorb , 54 float and 64 for EQ, or that what I read and what we used used at Xantrex for LeadAcid battery defaults
I would suggest you just program the XW's to the default LA settings and let them do there thing, the voltages you changed to are wacky IMHO.
Looks like you're correct. Bulk was specified in current, not voltage, so it probably should be the same as absorb. When I spoke to DEKA, the technical support person said that often the charger defaults are not ideal for the industrial batteries. His recommendations were:
bulk: (specified as current; "max. 20% of 6-hr rate")
absorb: 2.40 - 2.45 vpc (57.6V)
float: 2.30 - 2.35 vpc (55.2V)
eq: 2.50 - 2.55 vpc (60V)
I set mine to the middle of the ranges, so I got bulk/abs 58.2, float 55.8, and eq 60.6. (I will go back and fix the bulk setting. )
Thanks,
AJB -
Re: New DEKA "forklift" batteries seem to lack capacity
actually you guys may not be seeing what is happening between bulk and absorb very well. it really isn't quite what you think it is for using no controller is technically in bulk. when you add a voltage regulator it is said that prior to hitting the regulator's voltage set point it is in bulk and when the voltage regulator kicks in it is said to be in absorb. there aren't any special things going on during bulk as far as regulators or controllers are concerned except for the limited current output the regulator or controller can handle. bulk essentially is just the preregulation stage of a voltage regulator activating and means there isn't a voltage regulation set point for bulk as that is the point for absorb to kick in or simply when voltage regulation takes place.
now did i clearly confuse you?
:p -
Re: New DEKA "forklift" batteries seem to lack capacityactually you guys may not be seeing what is happening between bulk and absorb very well. it really isn't quite what you think it is for using no controller is technically in bulk. when you add a voltage regulator it is said that prior to hitting the regulator's voltage set point it is in bulk and when the voltage regulator kicks in it is said to be in absorb. there aren't any special things going on during bulk as far as regulators or controllers are concerned except for the limited current output the regulator or controller can handle. bulk essentially is just the preregulation stage of a voltage regulator activating and means there isn't a voltage regulation set point for bulk as that is the point for absorb to kick in or simply when voltage regulation takes place.
now did i clearly confuse you?:p
That makes sense. However, if we have separate programmable voltage regulation for each stage, we could define bulk to be at voltage X and absorb at voltage Y. (I don't know if there is any particular reason to do this for the battery in terms of chemistry.) Although voltage regulation is simple, as you mentioned, having two setpoints lets us define one as "bulk".
So the recipe might go something like this "Cook until boiling (Voltage X is reached), and then reduce heat and simmer (at Voltage Y) for 4 hours." Of course, this didn't make much sense when I had my simmer set higher than my boil...
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