edward t , I get that dead heading the pump draws more amps, during normal operations the cutout would not occur until the battery dropped to a certain level, and, both drive and lift or tilt were used at the same time. The battery indicator didn't give me an accurate reading of the battery voltage, I'd never seen a battery cause this symptom before, which is why I came here. Thanks

no3pike, I think I may have missed getting my "bottom line" point across, which was not about safety (safety being the "first line" point) but about getting an accurate reading of the battery under the maximum load draw, which you don't get driving, and _do_ get dead heading with tilt or lift (which draw MORE amps than driving).

Well then you need to tell him what the issues are & and how much it will cost - give him some choices - new or reconditioned battery or a new model used electric w/reconditioned battery & follow some of the good suggestions that have been offered in this thread.
Tell him it is time to get his short arms into his deep pockets - no real choice.

First, let me say that the battery was put on charge friday, not tested until monday, second, my fluke meter was taped to the back of the mast in plain view from the seat, not puttiong anybody in danger, third, I put the battery on charge for 45 minutes to establish a base line for the failure, ie it changed the timing of the failure by increasing only the state of charge. Thanks again for your input, bottom line... bad battery, I'm a mechanic not an operator, so i'm familiar with charging abuse, this is an old truck with an old battery, and today a tight pocketed customer.

Yep, that has already been stated in a previous post. or is there an echo in hear.

Guys......relax, he has a bad battery. It needs to be replaced with a new one....... Period!!

miloslouis,
Really don't think he found the problem but is creating a problem - using the the key cycling trick to milk more run time only further discharges an already sick battery. By taking a hot battery off the charger, makes the flat line come faster for the battery & truck and is sounded like he does this repeatedly throughout the day. The doctor says only take one charge cycle a day more than will be harmful - like you (truck & battery)will die.

no3pike,
To get an accurate voltage reading on any battery you must let the battery cool down. If a reading is taken immediately after charging, the voltage will be higher than actual as there will be a temporary surface charge that is being read by your volt meter. FYI you will greatly reduce the useful life of a battery by operating you lift immediately after charging - the battery is hot and has yet to reach full voltage capability you maybe be running under voltage. A rule of thumb for industrial batteries is it take 8 hours of charging to fully recharge a battery that has been discharged 80% then 8 hours of cool down time to allow all cells to reach ambient or room temperature, especially the inside cells, the 8 hours of run time.
Another rule of thumb is new batteries have X number of charge cycles in them from day one - some people say 1400 others say 1800. What every the number is a charge cycle is any time you hook up your battery to a charge counts as one charge cycle whether the battery is on charge for 20 minutes or 8 hours. During the start up of the charge cycle, the initial charge amp rate is near max charger capacity let's say 865 amps or greater. The reason for this is to clean off any sulfate build up on the battery plates so full charge can realize. But at the same time a tiny amount of lead is removed from the plates & settles down to the bottom of the battery and stays there. Over time this lead can build up and create a dead short between positive & negative plates - bad news - a battery cell needs to be replaced = $$$ spent. So by frequently doing what you have stated you have or are now doing (charging for 45minutes run it, charge it again, run it you are further shortening the life of this almost dead battery and doing harm to your truck.
Don't feel like you are the only person on the planet that has done this. I have have seen too many case of the same symptoms as you have described that I think a Hotline for reporting ABUSED BATTERIES needs to be established. But the lobbyists for the BATTERY REPAIR guys have been able to stop it.

no3pike.....Cool, glad you found the problem and thanks for the follow up....cheers!!

Miloslouis, you don't need to, and for safety reasons should no try and read voltages while the truck is in motion [other than lift or tilt], also you will not get as accurate a reading, and hydraulics's stalled to deadhead puts more load on the battery than will any sort of driving. I would not want to be responsible for some newbie driving over a pedestrian, because they were watching the voltmeter instead of where they were going.

I'm assuming your battery is 36 volt (18 cell). A new fully charged 36 volt battery will have about 40 V readings. When you drop below 36 Volts you are operating in an under voltage condition which causes higher amperage draw (heat) which will cause you problems. The simplest being burned contactor tips to big check book damage like drive , steering & hydraulic motor damage.

I would venture a guess that the top of the battery & on the sides of the battery case looks a lot like snow. That is an acid sulphate residue cause from the electrolyte (water & acid) which has bubbled out of the battery cells. The more white stuff you see the weaker the battery becomes. Touch it it will burn & make hold in your cotton clothing - jeans, shirts, etc

Solution: Get a new battery that is properly sized (weight & amp/hr rated capacity for that truck & for your charger & if your charger isn't big enough get one that is) or at least one that has been reconditioned by a reputable battery company. They should offer a warranty of some sort - if not walk away.
Either way the battery won't be inexpensive. That truck is 26 years old and is like a boat (a hole in the water you will keep pouring $$$ into). You may want to see want to look at a newer, pre-owned unit would run. There a finance to own programs for used lift to take out some of the sting.
Just my 2.5 cents worth.

Thanks for your input folks, It was a battery issue, fresh off the charger i unloaded a truck, 1.5 hours into it the problem started to occur, battery volts dropped at times to 27.9 volts as drive cut out. While parked immediately after battery volts slowly came up to 34.5 or so, but, within a few minutes of use back to square one. I put on charge for.75 hour and it was good for another hour before the voltage dropped enough to cause the failure.

Yeah.....sounds like a possible battery issue......check the volts with your meter while driving and lifting at the same time....let us know your outcome.......good luck!!!!!

I didn't check for that,and, can't today,but, will monday, the parts book shows mechanical switches only. The battery was getting low on Friday after 1.5 hours of my work so I gave up the ghost and put it on Charge, the operator said that it would do this right after coming off the charger, but only after being used for 10 or 15 minutes straight, then fairly consistantly, let it set for an hour, you'd have to use it for 10 minutes again.

Just a thought....check the battery volts under a load and make sure you don't have a cell or 2 going bad.

Hi no3pikes,
Are the hydraulic operated by micro switches on valve block or are they operated by an opto switch card located onfront of bulk head behind plate but infront of hyd valve block.

Titus