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nswelton
Trad climber
santa barbara and estes park
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Topic Author's Original Post - Sep 1, 2010 - 04:33pm PT
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hi! my hilti drill just took a dump yesterday. for whatever reason, it started taking about 5-6 minutes to drill a hole in granite. i have a bank of SLA batteries powering it and they were charged. i was using a carbide tipped bit that had drilled maybe 5 other holes so it was relatively new. then all of a sudden it just stopped and wouldn't go at all. for whatever reason, today it started working. still goes super slow. i called hilti and they don't service it any more. any ideas? what can i do? it was made in 1994, apparently.
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Disaster Master
Sport climber
Arcata / Santa Rosa, CA
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How hard do you press on the drill while drilling? If you try to much to shove on the drill in high quartz rock, you can overheat the drill and melt the copper wire wrapping. Drill dead.
If that's not it. Its, bad batteries, or conections, wire size.
That's my first two guesses.
Paul Humphrey
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nswelton
Trad climber
santa barbara and estes park
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Topic Author's Reply - Sep 1, 2010 - 06:46pm PT
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today it kind of came back to life... kinda... but it was drilling super slow. i wound up dismantling my battery pack and i get 12v on two of the batteries and 8.8v on the third battery. i am thinking two of the cells might have shorted out in one of the 12v batteries. the whole battery pack when put together reads 33v. i am going to try to charge them individually to see what happens. now i am thinking that losing those couple volts might have just killed the power to the drill, especially since the two "good" batteries are only reading 12v, which is low. if i had melted the copper wrapping, would the drill work at all? i am considering upgrading to one of those lightweight bosch drills, but if i can get this fixed for 20 bucks i'll keep using it...
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tenesmus
Trad climber
slc
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you can buy my TE6A for $500. It works perfectly and will drill 20-30 holes in granite on a single charge.
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Disaster Master
Sport climber
Arcata / Santa Rosa, CA
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the hilti model you have isheavy and large, even compared to an old Bulldog. I ended up using my old bulldog, supercharged of course with gel cells. I put to gell cells in a camel bac pack, instead of the bladder. ran cord from there. If it is the copper in your drill, it is likely bad. otherwise, expriment a little with fresh batteries.
Some new drills are sweet, but think about ease of conversion to climber made battery set ups for more holes, if you need to in the future, before you buy. A good old bulldog online used, converted, is still solid, if the drill is.
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Juan Maderita
Trad climber
San Diego, CA
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It seems that you have a problem with one of your batteries. If a 12v SLA battery drops below 11v, then it is deeply discharged.
I strongly prefer to charge batteries separately. Batteries have differing internal resistance, particularly as they age. Charging separately ensures the best charge possible. Always use a "smart charger" for SLA batteries.
Order on line at Gruber Power Services, $16.
You might also open up the case of your Hilti and inspect the armature and brushes. Replacing the carbon brushes on a Bosch is easy. Can't say about the Hilti. New brushes and cleaning the armature are likely to increase performance.
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WBraun
climber
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nswelton
The Hilti te-10a where notorious for cutting out and running slow.
There's a cut-off circuit built into the switch that almost no one knows about.
This circuit is designed to work with the charger but screws up the battery voltage transfer.
I'm not going to go into the technical aspects of it but that is your culprit with this model and not the batteries themselves.
I debugged and found this problem with our YOSAR Hilti TE-10a which exhibited the same symptoms you experienced.
We got rid of the Hilti and went to Bosch due to the need of robust dependability for rescue work. We can't have equipment that fuks up in the field.
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nswelton
climber
Estes Park, CO
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Topic Author's Reply - Sep 2, 2010 - 03:43am PT
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Were you ever able to make it work after you figured out all this stuff about the switch? Is there a way to disable it?
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Juan Maderita
Trad climber
San Diego, CA
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I did some checking on SLA batteries to confirm the 11V number I threw out there.
"Fully discharged" = 1.6 - 1.8V /cell.
For a 12V battery, that is 9.6V to 10.8V. So you should not run your batteries down below 11V. Over-discharging is death for lead-acid batteries.
I've e-mailed instructions on how to separately charge your batteries, then load test them by drilling some holes and then rechecking the voltage of each battery.
For those who don't mind spending the money to know the condition of your SLA batteries, I like the Triplett "Chek-A-Cell". It tests voltage and also load tests.
http://cableorganizer.com/triplett/specialty-testers/check-a-cell.html
When one battery in a pack is bad, it screws with the other batteries, both charging and discharging. Almost like they are working against each other. Battery condition needs to be balanced when used together in a pack.
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| Messages 1 - 9 of total 9 in this topic |
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