Testing Battery Charger???

[eze2bme]

I currently have a Heart Interface (now Xantrex) Truecharge 40+ charger on my
two bank battery system (2-8D's in each bank). The charger has worked without a problem for the past 10-12 years. Two days ago, apparently one of the 8D's shorted out (3.5 years old) and the charger "cooked" it dry. The other battery in the bank was not hot nor was the electrolite/water level changed. The other bank seems normal. I removed the bad battery and turned the charger back on and it "appears" to be OK except that it seems to be cycling more than normal and in the "40 amp" charge quite a bit ... is there any way to check the charger or should I just replace it? Thanks.

[bostonhatteras]

That charger can be used as a stand alone 12v power supply. In other words you don't need batteries hooked to it for operation. Disconnect the batteries and hook up a known load. For instance a series of 50 watt 12 volt light bulbs. Knowing how many amps each bulb consumes will let you test the 3 led power output display as well as seeing that the charger is clearly converting 110 volts to 12 volts as you put more bulbs on it (the brightness will remain the same regardless of how many bulbs). Low tech test but it will tell you something. The test to determine if it can sense a fully charged battery: simply hook up a known fully charged battery and se what the charger does. You can also discharge the known good battery a certain amount with that 12 volt bulb and when you take out, say 20 amp hours, hook up the charger. Watch the led power outputs and record the time and power the charger is putting out. Like I said not high tech.

[eze2bme]

Thanks!

[REBrueckner]

It's possible the second battery in the bank with the bad battery has been partially discharged,,,if so, that might account for the changed cycling you observe.

I haven't used the Truecharge model, buy my STATPOWER chargers (also Xantrex) owner's manual has great detail on the normal cycling of those chargers...It is very helpful in understanding why sometimes they cycle and sometimes they don't.

[Trojan]

Before you do any electrical checking of the charger. Check the charge in each battery cell. Each time you discharge a lead acid battery below the usable point. You will loose 20% of your battery power for ever. It is more than likely that the other battery paralleled was discharged to the extreme when the bad battery shorted. You may now also have a cell going bad in the remaining other battery. I had the same thing happen on my boat last year. Battery chargers are quite reliable and resilient. Lead acid batteries aren't. Check the charge in the other good bank and check the DC voltage in both banks with the charger off. Turn the charger on and recheck the DC voltage.again in both banks. It's very unlikely that you could loose the charging capability in just one half the charger.
There is the tendency in this forum to go to the extreme in over complicating the repair of a simple electrical item.
BILL

[Boatnut]

Before you do any electrical checking of the charger. Check the charge in each battery cell. Each time you discharge a lead acid battery below the usable point. You will loose 20% of your battery power for ever. It is more than likely that the other battery paralleled was discharged to the extreme when the bad battery shorted. You may now also have a cell going bad in the remaining other battery. I had the same thing happen on my boat last year. Battery chargers are quite reliable and resilient. Lead acid batteries aren't. Check the charge in the other good bank and check the DC voltage in both banks with the charger off. Turn the charger on and recheck the DC voltage.again in both banks. It's very unlikely that you could loose the charging capability in just one half the charger.
There is the tendency in this forum to go to the extreme in over complicating the repair of a simple electrical item.
BILL

Very well put Bill. I was helping on a battery problem last week where the owner was losing the same battery every 6 or 8 months. I mentioned to him he was changing what was probably replacing the good battery. Naturally he reacted like I had 3 heads. The bottom loine was he hired someone to fix the problem, and they replaced both batteries, at a much high cost. I also wonder is battery combiners will cause all batteries to over charge if one has a bad cell. I have not taken the time to look into it.

[Trojan]

Very well put Bill. I was helping on a battery problem last week where the owner was losing the same battery every 6 or 8 months. I mentioned to him he was changing what was probably replacing the good battery. Naturally he reacted like I had 3 heads. The bottom loine was he hired someone to fix the problem, and they replaced both batteries, at a much high cost. I also wonder is battery combiners will cause all batteries to over charge if one has a bad cell. I have not taken the time to look into it.


Combiners only let you draw from a battery or a battery bank that they protect. They don't restrict the charging.

BILL