Battery Life Problems (Primetest 350)

[HWUGTB]

Hi,

We have several Primetest 350 units and are having the same problem with them.

The units are reporting flat batteries and powering down when in fact there is still approx 70% charge left in the batteries.

I know this because I have done several tests to confirm the batteries capacity when Primetester indicates flat batteries (with each unit)

Steps Ive taking -

1. Charge batteries in PAT tester fully.
2. Perform some PAT testing until unit flashes "low battery symbol" and unit powers down / switches off (never anywhere near amount of tests you should be able to perform on a full charge).
3. Take batteries out of PAT tester then check them using a battery checker to determine the capacity that was in batteries. This is usually still around 1400-1500maH

I thought it may be a firmware problem so I upgraded but problem is still there.

Any help appreciated

[scottpeters90]

Hi
I have the same problem except the unit is saying batteries are 75% full but still shutting down during tests?
Did you solve the problem?
Regards
Scott

[stoneworld]

My thought would be to check what life you get from a non rechargable battery then consider that a rechargeable is 1.2v rather than 1.5v. It does surprise me that these units are not built with a rechargeable battery pack designed to do many hours of testing.....

[HWUGTB]

My thought would be to check what life you get from a non rechargable battery then consider that a rechargeable is 1.2v rather than 1.5v. It does surprise me that these units are not built with a rechargeable battery pack designed to do many hours of testing.....

Yeh could be worth a try using non rechargeable batteries although it shipped with Ni-Mh so should be fine with these.

Maybe the firmware has been set to look for 1.5V battery levels by mistake instead of 1.2V. Only seaward could check this though. Be nice to hear their thoughts on this.

But yes a stand alone charger with 2 battery packs would be the ideal "upgrade" to this kit. Like a cordless drill set, you get charger and 2 battery's to alternate.

[stoneworld]

But yes a stand alone charger with 2 battery packs would be the ideal "upgrade" to this kit. Like a cordless drill set, you get charger and 2 battery's to alternate.

yes I like that idea!

[HWUGTB]

I have recently had this problem though I suspected it was the new batteries that I used...Perhaps not.
Because of a problem with in situ battery charging which seaward were unable to resolve. I use an external charger, I too would be interested to hear a comment from Seawrd about this problem.

Yes me too...do they not read their forum

[Duff1]

As I reported elsewhere we have no less than 8 PT350's, personally I never use the on board charger and always charge my batteries (Mainly Uniross or Encore 2700mAh NiMh) externally. I've received many reports from members of the team that with onboard charging the batteries are only good for 5-6 tests before they switch off whilst externally charged batteries will go on for 2-3 days of testing. I don't have time to mess about so don't take any chances. I don't know if it is just on 1, 2 or all 8 of the units this problem occurs.

It's clearly not just a one off problem so would like to here others experiences and comments from Seaward.

[Jim Wallace]

All

Several people have comments that when the PT350 indicates that the batteries are low there is still charge in the batteries. This is because the terminal voltage drops to a point where there is insufficient voltage to drive some of the internal components before the batteries are fully discharge. As mentioned above, NiMH batteries have a lower terminal voltage that alkaline cells. Although the microprocessor and most of the electronics can operate down to around 3V, there are other components, in particular relays, that need at least 6V to operate reliably. The battery indicator on the PT350 works on terminal voltage rather than remaining charge - it indicates when the terminal voltage has dropped to a point where operation cannot be guaranteed.

After reports from several users that they were not getting the expected life from the NiMH batteries we carried out a series of investigations. We suspect that the charge sensing on the intelligent charger was not functioning correctly - explaining why users were getting better performance when using a seperate charger. The charger unit used for in-situ charging was modified to increase the charge rate and the feedback from customer trials was that this resolved the issue with the in-situ charging.

I have noted the comments about dedicated battery packs - definately a good idea and food for thought.

[HWUGTB]

All

Several people have comments that when the PT350 indicates that the batteries are low there is still charge in the batteries. This is because the terminal voltage drops to a point where there is insufficient voltage to drive some of the internal components before the batteries are fully discharge. As mentioned above, NiMH batteries have a lower terminal voltage that alkaline cells. Although the microprocessor and most of the electronics can operate down to around 3V, there are other components, in particular relays, that need at least 6V to operate reliably. The battery indicator on the PT350 works on terminal voltage rather than remaining charge - it indicates when the terminal voltage has dropped to a point where operation cannot be guaranteed.

After reports from several users that they were not getting the expected life from the NiMH batteries we carried out a series of investigations. We suspect that the charge sensing on the intelligent charger was not functioning correctly - explaining why users were getting better performance when using a seperate charger. The charger unit used for in-situ charging was modified to increase the charge rate and the feedback from customer trials was that this resolved the issue with the in-situ charging.

I have noted the comments about dedicated battery packs - definately a good idea and food for thought.

We have did several battery checks with them and it seems like the PT350 indicates flat batteries at around 7V.

On a fully charged (using supplied charger) we got 21 pat tests over 1 month before PAT tester shut off.

At this point i took the batteries out and tested them in our battery checker using a 1A discharge current. On first switch on the batteries were around 7V (@1 Amp discharge).

Discharging them at 1 amp down to 6V took over an hour and the capacity left in them was reported at 1364maH.

[Jim Wallace]

Thanks for the additional information on the tests you have performed. I will pass this on to our development engineers and ask for their comments.