Load Tester

[bobking44]

I purchased one of the 100 amp 6/12 volt load testers at Harbor Freight.

Now I read conflicting info. as to when the test should be made.

Should it be done after a full charge and wait period or after discharge.

I know cars are tested when charged but they are not deep cycle batteries.

Bob

 

[dougmcp]

Load test "after a full charge and wait period"
I would also check SG with a hydrometer after a charge and rest. Seems to me you did this but I can't remember.

I just checked my 42v batteries this morning after charging it yesterday 45.0v, not bad for 2004 batteries.

 

[bobking44]

Thanks Doug

Checked the batteriess this morning and found the pack to be at 44.7 and the individual batteries to be at 6.4 with the exception of one which shows 6.3.

I did check the specific gravity after full charge and rest period and found them to be excellent and equal.

A couple of additional questions, if I may.

While recleaning all battery connections I discovered what appears to be a short in the light and horn circuit. When reconnecting the accessory leads to the bat terminal there was arcing/sparking and a very slight hum or buzz that lasted for perhaps 2 seconds and stopped. I concluded there is a short based on the assumption that there should not be any current draw when all accessories are off. Am I correct in my assumption?

Any suggestion as to what the hum/buzz might be?

I have not had opportunity to do a use/charge cycle since finding the suspected short (removed the fuse to isolate that potential). But, since I have done all the other tests I wanted to do the load test as well.

If I am correct about the short, once it is corrected I have a voltage converter to place the accessories on and equal the load across the entire bat pack. Worthwhile expense and effort or not???

Thanks for your insights. They are always helpful. I have learned much from you following other threads as well.

Bob

 

[dougmcp]

Bob.
I'm not entirely sure if there is any draw from the controller while the ignition is off, I haven't checked that. My cart is factory wired and has not been altered.
I do know that Western was never known for their fine wiring skills and all of my accessories are available with the ignition switch off, meaning the lights, signals, brake lights and horn are direct connected to 2x6v batteries in the pack and fused with something like a 10 amp fuse.
I don't see anything from the accessories that would cause a draw if everything is off.
Shooting in the dark here, maybe something has become wet and is leaking to ground or maybe something has become grounded to the frame.
Maybe check your solenoid to see it is not stuck in the on position.
It would be interesting to find out exactly how much draw you have on the batteries. If you have an ammeter, is it possible to check it?

 

[bobking44]

I load tested the batteries after full charge and 12 hour wait.

100 amp load for 10 seconds yielded 5 batteries at 5.8 right on the line between fair and good.

The other two yielded only 5.7 and 5.75 in the very high end of fair.

I am assuming there must be some internal problem with the batteries since the SG and open voltages all tested good.

Am I thinking correctly?

If so, any possibilities short of battery replacement?

I keep reading that the batteries should not be drawn down below 50%.
Does that mean 50% as indicated on the bar meter on the dash?

Bob

 

[dougmcp]

The readings are a little low for batteries that are only 2 years old but it could be the meter as well. I would check the meter against "known good" batteries or against a "known good" meter.
Drawing batteries below 50% only shortens their lifespan.
The bars on the LED SOC meter are 8% of charge for each bar, the 4th bar from the bottom is 50% charge.

 

[bobking44]

Based on all I am reading here and many other places I have developed some suspicions and
formed a couple of conclusions.

I have had the cart for ten months.
When I bought it it would do 36 holes (Course is only 4800 yards and I live 3 miles away) and get me home, but even then the meter was down to the last bar and flashing rapidly.
I am not positive but I believe the run time has been getting shorter with each charge cycle to
the point that it will now do only 18 holes and is in he same condition at the end as before.

I am not wondering if it is possible that the Trojan 105 batteries, stamped A8 could actually be 1998 (13 years from manufacture) rather than 2008 or could they be 2003 that have been over stamped with an 8.

Based on the performance of your cart (36 holes and 4 bars left) my batteries were quite weak when I got the cart. Pulling them down to 25% and less for 10 months (which I did not know was a no no) appears to have done them in.

If my thinking is wrong don't hesitate to tell me so.
It appears to me the only way to get to 36 holes (at this point even 18) and be at 50% when I get home is to replace the batteries.

The pain of new bats is excruciating so if anyone has an alternative I would love to hear it.

Bob

 

[dougmcp]

I hate the thought of parting with my hard earned $ for new batteries too.
A good set of batteries should be able to go 54 holes.
Maybe you can milk another year out of yours, depending on what you demand from them.

 

[bobking44]

Doug

I took it out today for 18 holes and it was flashing on the 2nd bar by the time I got home.
So, next week I am going to get a new set which I will give a lot of TLC.
I also plan to install the voltage reducer and run all 12 volt accessories across the entire pack.
I am considering spending the $40 required to replacing the bar gauge with one that gives a digital numeric readout.

Thanks for all your help. This is all new to me and you have greatly helped me with the learning curve. I don't yet know all I would like to know about it and perhaps never will, but you have been a tremendous help.

Bob

 

[dougmcp]

I think the LED meter you have now will serve you better than a digital voltmeter. You may get too alarmed watch the VM jump all over the place and lose focus on what you are using the cart for.
IMO. I'd relax and enjoy your golf game and let the cart be a tool for you not a concern.

 

[bobking44]

Good point.

Thanks again.

I do love the game.

Bob