Battery charger

[sassan]

Hi Folks,

 

This is my first winter without shore power, therefore electricity has become a trickier thing.

 

I have an Invertek 60A battery charger installed by the previous owner. As far as I know it's only ever been used on permanent shore-power during winter and never for any other sort of charging.

 

So, I connected up a generator, (1kw, 700kw constant) to the charger and found that the charger briefly flashed its "absorbtion" LED before settling at floating. The voltage was about 12.6. I checked the settings of the charger and it is set up for 14.4V boost and 13.5V float.

 

The first thing I checked (after fuses) was the wires to the battery, these seem to be a suitably large diameter and not excessively long. I tested the voltage at the terminals of the charger and found no significant difference in voltage compared to the battery terminals.

 

Next I noticed that there were wires connected to the BTS (temparature sensor) terminals of the charger which appeared to be connected together! I think these had previously been connected to the positive terminal of the batteries but I had removed them. It is also possible that it actually was a temperature sensor cunningly disguised as a battery connector, but I am more inclined to believe that it was just connected very very wrongly.

 

After removing these connections, the charger now charges at 13.6V and the display indicates "floating". According to the manual, the device should be in boost mode until the maximum boost voltage (14.4V is reached). In reality it starts up with "absorbtion" lit and the jumps to "floating".

 

Several possibilities:

• I believe the charger is a bit too large for my generator, this could be causing the problem. However, I would expect to hear the generator struggle and the fuse/trip switch on it go instead of the charger simply skipping boost mode. The charger manual indicates +10%/-15% voltage tolerance and doesn't specify frequency/waveform tolerance.
• Wiring isn't good enough, leading to the voltage spiking at the controller end to 14.4 on startup causing the switch to floating mode.
• Batteries are no good. They are certainly reaching the end of their life, but I would expect the charger to enter boost mode, the voltage to fairly quickly reach the max voltage (due to reduced capacity) and then float.
• Charger is duff either due to age or mistreatment (shorted BTS terminals for several years).

So firstly, is there likely to be an easy way to rectify this problem and secondly, would I be better off just buying a 30A battery charger, which would also I gather be a better fit for my battery bank (3x110Ah leisure batteries). I will probably be upgrading the batteries soon, but even so, if the charger is oversized for the generator a smaller one may be needed.

 

If I do need a new charger, what do people recommend. I am willing to spend good money to get something that will last and look after my batteries. A few questions:

• Are expensive brands like Sterling worth the extra money compared with cheaper units. Either in terms of reliability, efficiency or function.
• Is built-in desulphation function worth having, or am I better off A: having a seperate unit and a cheaper charger OR B: avoiding such snake oil entirely.
• I can't find much information on the charger (Invertek ADC-60U-123A), would it be worth testing it with full mains power to see if it's working so I can sell it on ebay? Or is it worth sod-all anyway? The previous owner said he spent a fair bit on it but was disappointed with it and that I may well want to replace it.
• Any particularly recommended brands/units? I must admit I'm slightly fond of fancy integrated displays and controls, but not at the expense of reliability.

 

Thanks in advance,

Sass

[Arthur Brown]

If the Battery Temperature Sensor is a thermocouple it will look lie two wires connected together -that's what thermocouples are.

[sassan]

If the Battery Temperature Sensor is a thermocouple it will look lie two wires connected together -that's what thermocouples are.

This looks like two wires connected to one of those rings you stick onto battery terminals (name temporarily escapes me). Can't say for certain it isn't a thermocouple in there as there is some plastic sheathing around it.

[Phil Ambrose]

Sounds like a thermocouple to me and I reckoon a 700watt genny would struggle to drive the size of charger you have, a reasonable solution would be to buy a Electroquest 30amp charger also use a hydrometer to check each individual cell on your bank.

Phil

[sassan]

After examining it more closely and testing with a multimeter, it does look like a thermocouple. Either it or the unit isn't working properly though, since it appeared to be triggering the high-temp cut-out despite the battery box being completely cold.

 

Are the electroquest chargers reliable? Quiet? They look a very good price.

[robo joe]

I have a 45 amp charger.cant hear it even in the engine room.

[robo joe]

Im at seend rusty bridge if you want a look .

[Rob-M]

I have the 45amp charger, it does make some noise before it goes in to float, but once in float I sometimes check to make sure it is still switched on.

[sassan]

Sounds good. To be honest I don't know why I asked about noise level, since it's being powered by a generator sat on my roof...

 

Any reliability problems? Any problems running from generator? I called up Electroquest and the voltage/frequency tolerance sounds good to me (even supports 60+Hz, and apparently my generator can output more power at 60Hz).

 

If I upgraded my batteries to the 6V Trojan batteries, would this charger still be suitable? I don't see much about being able to configure the boost/float voltages mentioned.

[Arthur Brown]

Thermocouples come in different types -J and K are common others exist. They are NOT interchangeable, have you any info on what type your charger should be fitted with?? Also it matters what wire is used to connect them to the charger, just "copper" will not do. Other things that look like thermocouples include PTC and NTC thermistors, all of these can be made into a cable ring tag. Yes the ring is usually isolated from the sensor and the ring can often be screwed down to a battery post to read the battery temperature.

 

Have you really searched the web for the manual for that charger? A multi stage temperature compensated charger would be a good thing to get working for you.

 

http://www.rich-electric.com/wp-content/uploads/2011/12/Battery-Charger-Manual.pdf Would this be the one.

[sassan]

Hi Arthur,

 

That is the manual I have. It does not have any info on the BTS except mentioning it in passing as an optional extra.

[sassan]

By the way, for a lot of chargers it seems you're supposed to connect the several positive battery outputs together if using only one. Manual for this one doesn't mention a need to do so. Any thoughts on that?

 

Edit: note, I have not, so-far, tried this.

Edited November 3, 2014 by sassan

[bottle]

All outputs should be connected.

[Arthur Brown]

From the manual it's a single output charger so the one wire to the battery starts at the one output connector.

Have you read carefully all of the information in the manual? The temp sensor seems to be an optional extra, so it should work without it.

There are controls to limit the peak charge current -check what it's set to. and the bulk absorb and float voltages, you need to understand these settings done with the charger isolated from supply and battery. Tables of switch settings on page 8.

 

Hopefully you batteries are fresh enough to accept the full charge rate as this should/may just be within you generator's peak load capacity.

[sassan]

It's the 3-output model I have. The paper manual I have covers the 3-output version but does not mention connecting outputs together. I will try that at the weekend (not usually home early enough during the week to run generator).

 

I also didn't see any control for limiting charge current, only voltage. My charger is not quite the same one as the pdf manual is for.

[George94]

BTW, Sterling is not an "expensive brand". Mastervolt and Victron are the top end of the market, with Sterling very much in the middle. I personally would never buy anything made by Sterling.