Fork-Lift Truck batteries

lazza · December 2015

HI Forum

We've been having a bit of a battery nightmare with cheap AGM batteries (erronously believing costs had come down due to production line improvements- http://freelight.es/es/wp-content/uploads/2015/03/IMG_5025_Large.jpg?w=585). Made by Monbat in Bulgaria, they looked like they were going to mark a quality improvement in our smaller off-grid installations. Turns out they are batteries that fail within a few months.

As an alternative as an intermediate option, without switching to OPzS, we've been looking at 2V cell fork-lift batteries (this type:http://www.motolite.com/products/forklift-traction-batteries). They work out more or less the same price per Ah as the cheap AGM batteries. We just need batteries that dont fail within a few years!!- we're not asking for much. In southern Spain price is everything, jumping from 12V semi-traction type to OPzS not possible for most of our clientbase.

So, does anyone have any experience working with these 2V fork-lift batteries as an intermediate option??. I've been told the tubular plates are identical to the OPzS expect the lead has more antimony and they consume more water. What are the pros and cons of using this type of battery?

Any advice much appreciated

Larry

lazza · December 2015

No comments? have i offended someone?

BB. · December 2015

I just do not have anything to add.... Other than, yes they will (probably) use more water (is getting distilled water expensive/difficult for your customers?) and will your customers maintain water levels properly (no under/over filling)?

And, since forklift batteries tend to be less efficient and have higher self discharge, I would suggest that small arrays (i.e., 5% of 20 Hour battery capacity) be upgraded to ~10% rate of charge minimum to ensure that the batteries are properly charged and that the customers do not deficit charge their bank.

Folks may be focusing on the holidays right now... Hopefully some folks with more European battery mfg. experience can chime in after Christmas.

-Bill

lazza · December 2015

Thanks Bill- I've been reading that they also require higher charging voltages- up to 2.65V per cell- what will happen if you only charge them to say, 29.2V (2.43V per cell) to avoid excessive gassing??

BB. · December 2015

I honestly do not know... Some other brands of batteries (some versions of Rolls/Surrettes appear to be closer to forklift batteries in design) appear to really need the 31-32 volts (for 24 volt 12 cell battery systems) to fully charge and balance.

Here is one such discussion:

http://forum.solar-electric.com/discussion/8753/charging-large-surrette-rolls-batteries

Note, really need 10% to 13% rate of charge to not only quickly and fully recharge, but to "mix" the electrolyte too (tall cased batteries).

What you do not want is to sit at high charging voltage for many hours (equalization)--That creates a fair amount of heat and the oxygen generation on the positive plate cases plate and grid corrosion over time (as well as plate erosion).

Here is another discussion about large capacity battery banks and applies pretty well to any forklift/traction/industrial lead acid batteries:

http://forum.solar-electric.com/discussion/21188/stay-away-from-rolls-surrette

The Rolls/Surrette problem(s) whatever they are--I hope they have been resolved (have not heard too much power their problems lately).

-Bill

Vic · December 2015

First, all three Surrette battery banks here, are in year 11, and doing relatively well -- there have been subtle changes in charge parameters required to maintain SG. But, still we are using about 58.3 - 58.4 V for Absorb, temp compensated.

Many of the folks having trouble with Surrette battery banks appear to have been quite casual in monitoring SGs and maintenance. Often appearing to have been deficit charging for a number of months, and seldom, if ever EQing the banks. Also, some banks giving trouble seem to have had too little PV power available, and fairly in Northern climes, where Winter takes ist toll, IMO.

Most true Forklift batteries have relatively few plates that are very thick, which allows the use of relatively high charge rates.

Also, these batteries often have high SG electrolyte, some approaching 1.300. This will increase the required Absorb voltage.

As BB Bill mentioned, most forklift batteries are very tall. This necessitates a high Vabs for good mixing of electrolyte.

As has been mentioned, there is usually a relatively small Electrolyte Reserve, above the plates of these batteries, which does mean more frequent level checking and maintenance.

Also mentioned by others, is that with relatively few plates per cell, the surge current capability will be lower when compared to traditional Deep Cycle batteries. This will mean that there is greater surge voltage sag, all other things being equal.

One would also expect more splatter of electrolyte around the caps, so more cleaning could be required to keep things sanitary.

But, in the USA, Forklift batteries appear to be a very good value, for those who can maintain them carefully, and use properly-sized PV arrays, chargers and generators.

Just my read on things. Vic

softdown · December 2015

Forklift batteries are outright dangerous to move. Mine weighs 1652 pounds. I could easily have been very seriously injured while moving it into place. A stout automotive engine hoist will move the battery ~one foot at a time. Everything has to be braced for every move. Things can happen very, very quickly.

The sheer danger is a real problem with moving forklift batteries. A one inch pry bar is about as useful as a spoon.

Still...they probably are the best off grid battery with an expected longevity of at least 10-15 years.

Fork-Lift Truck batteries

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