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PilotAlso 07-10-2008 11:51 PM

Xantrex Truecharge 40+ only charging at 20 amps?
I recently upgraded to this charger.

Our boat is on a mooring ball. We use a Honda 2000 to power the Xantrex.

We have two flooded batteries in one bank (powering radar, chartplotter, and refridge).

The other bank is a two flooded battery house bank.

The last is a simple start battery.

Even when the banks are run down pretty low, we only see a 20 AMP charge on the Xantrex and have never seen 40.

All 5 batteries are brand new (this year) 12 volt flooded deep cycle.

Is this NORMAL or expected? or EXPLAINABLE?


camaraderie 07-11-2008 02:12 AM

From the Manual:
"Truecharge+ has three separate DC positive terminals to allow charging
of three separate batteries (or battery banks). The total current into the
batteries is a maximum of 40 amperes
, which is divided amongst the batteries according to their state of discharge.
Note: The three outputs are not independently voltage regulated so it
is important to avoid systems with mixed types of batteries."

The Remote Display Panel allows you to monitor battery charger activity
away from the charger whenever Truecharge+ is operating. The panel
displays the total charging current and the voltages of the two batteries or battery banks connected to the two positive terminals closest
to the
negative terminal."
Note the wiring issue in bold which depending on your hook up may be distorting charging readings particularly if your start battery is wired in position #1 or #2 immediately to the right of the negative terminal.

If you can switch your batteris OUT of the charging one bank down low till you get a 12.2V reading without any load on it. THEN just charge that battery bank and you should see 40amps or there is a problem. I am not a fan of 2 house banks but if you can isolate each AND the starter battery for charging, you may see better results.

The other thing I would note is that if you are simply using the panel display to read amperage, you are NOT getting the whole could be getting 39amps and never seeing anything but the 20 amp light come on. ONLY when you hit 40 amps will that lamp come on. You need to measure REAL amperage with an ammeter!

PilotAlso 07-11-2008 10:58 AM


I don't care for the multiple battery banks either but due to the physical locations of the banks (opposite sides of the boat) I decided to separate them.

Yes, I can isolate, or combine, each bank.

Looks like its time to buy a real battery monitor system to see actual charge current.

FWIW: The last time I charged the batteries, I tried running one circuit only and hooking it directly to a very low battery (the refer battery after using it all day). I hooked to it with #6 wire positive (6 feet) and #8 neg (8 feet) directly. I had the temp sensor on the battery in 80 deg heat.

I still saw only 20 amps charge indicated on the charger. (wish I had a real ammeter)

I think I'll be calling Xantrex support.

camaraderie 07-11-2008 12:52 PM can disconnect the two other reds t the charger and just try charging ONE well discharged deep cycle bank and see what happens. I am thinking that the voltage from the starting battery is tricking the charger into absorbtion mode rather than bulk if indeed all you are getting is 20amps.

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