Battery charger

Submitted: Thursday, Feb 26, 2009 at 07:47
ThreadID: 125424 Views:3346 Replies:2 FollowUps:1
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Hi All,
MyYellow 50amp BT battery charger does not seem to be charging properly, it has been running for 3 hours now off my 2000 Honda generator, load coming off batteries is around 14/15 amps, I have 4 batteries, battery voltage is still only 12.4/12.5 volts, voltage was about 12.2 when charging began. How can you test output of batteHi ry charger? Any ideas of what the problem is, it is charging but not to full capacity.
Thanks for any input
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Reply By: NIK `N` OFF - Thursday, Feb 26, 2009 at 08:02

Thursday, Feb 26, 2009 at 08:02
Eric in my use of the genny charging 4 batteries that were down to around that voltage it took a round 12 hours before they got to float stage
AnswerID: 577107

Reply By: Turist - Thursday, Feb 26, 2009 at 17:46

Thursday, Feb 26, 2009 at 17:46
You can put a clamp type ammeter on the positive lead charger to battery but even this is not a true indication as battery condition can affect charger output.

Charger may be in good working order but if there is one faulty battery in the chain then the charger will not perform correctly.

If after several hours of charging the batteries show no improvement then have the batteries tested
A carbon pile load tester should be used, those little electronic hand held toys will not give a true picture.

If in the field a simulated load test can be done by connecting only one battery at a time to the system.
Turn on all possible appliances including the inverter and put a load on the inverter.
Check for voltage drop.
Repeat for each battery, all should have the same result.

The majority of battery chargers returned to us for service were not faulty, the owner was attempting to charge a faulty battery, sulphated plates, cracked seperator or just old and worn out.


In your case the load coming off the batteries is around 40% of what the charger will be outputting so it will take some time to charge.
Although designated a 50A charger 40A is more realistic.

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AnswerID: 577108

Follow Up By: Eric & Gail - Friday, Feb 27, 2009 at 03:43

Friday, Feb 27, 2009 at 03:43
Hi Bob,
Thanks for your wealth of knowledge, we are camped at Inskip point looking across to Fraser island, have been here for a week now and with cloud and a bit of tree cover have not been getting full input from solar. I have to go to BT factory on the way home to Gold Coast, so will get some testing done there for out put, I dont have one of those clamp ammeters and maybe call into Battery world to get them load tested, they are coming up to 5 years old so could have a dud one. It is working but is not bringing voltage up much, I have tested this afternoon with no load and still only came up from 12.6 to 12.9 volts in 30 minutes, solar was inputing about 7amps, I then turned fridge back on drawing 5.5 amps for another 1.5 hours with little coming in from solar, batteries still only 12.8 volts, does not sound right to me. Last week when we had full sun on 4 solar panels I saw over 30amps coming in, would this suggest that batteries are ok and maybe it is the charger?
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