Problems Connecting Battery Chargers

A complete circuit diagram would be helpful.

Batteries- What is the history of the batteries? What capacity are they (amp-hrs)? Are they all the same type? What types of connectors (side bolt on, top terminal, top bolt on, etc.) are on the batteries? Are they all the same typed? How old is each battery? Are they deep-cycle or regular car batteries?

Wiring- What gauge wire are you using, for where? Is the wiring identical in size and length for each battery bank? What type of wire terminations are you using? Have you checked the resistance of each set of wires? Voltage drop from the end of the battery wire to the other end under load will be sufficient to tell this. Are there any fuses in the battery wiring, the turbine, the solar panels or the charger? Are there any switches in the wiring? How old is the battery charger? Has the battery been checked for correct operation? Has any battery lug protector compound been used on the junctions?

This additional information would be very helpful.

Good Luck, Old Salt

There is NO USE to have 2 battery banks. For outback it complicates the situation.

Especially when you use a mate 2 or 3 interface. Connect these together and as far as the extra charger: the charger with the highest momentary output will take the lead to charge. With low batteries and a full solar charge you risk to damage your generator charger. A voltage sensing circuit or a isolation diode could be your solution. (remember to adjust the the output of this charger a little higher to compensate for the voltage loss over a diode)

Good luck. D

Hi d, I did burn two battery chargers. I still do not know how. Could you explain your statement to someone like me who does not know the theory.

could you recommend a battery charger. 48 v input 110v , if possible no more than 1300 watt with an output of about 20 amp.

Power is the product of voltage and current; P=E*I, or I=P/E.

Since you specify 110V and 1300W, the maximum input current is I=P/E=1300W/110V=11.8 Amps.

In practice, most "110V" circuits I've measured (all in mainland USA) are in the range of 117-125V, although I have measured at least 128V. If your actual voltage is around 120V, then the maximum input current drops to 10.8 Amps for a power of 1300 W.

I believe the better inverters have an efficiency of around 95%, giving an output power of ≈1230 Watts for 1300 Watts input. The normal charging voltage for 12V Lead-Acid batteries is around 14V, so the charger needs to put out around 4*14=56 volts. 1230 W/56 V ≈22 Amps, so a good inverter should meet your requested 20 A.

On the other hand, in your original post, you specified a 220V inverter output. Which is it? If you connected a '110V' battery charger to a 220V inverter, then it becomes obvious why you blew out a charger or two.

Outback does not foresee a circuit interface to charge @48 Volts from a "third" supplier, in your case your "generator". Every 48 Volt charger will do the job, considered you put a diode in series. When these chargers "end" with a bridge rectifier, each volt higher than what it is designed for will "start shortening" this bridge and possibly destroy it. You can easily find that out when you look at a rectifier bridge's diagram.

I am in costa rica in the mountains , difficult to get things , how about comming here , stay here in our farm for a few days or weeks. Temperature is about 24 degrees centigrade all year around

Juergen, understand your situation. But you are required to have some basic tools to check. A DC Voltmeter and Clamp on DC ammeter.

A circuit diagram will definitely help us to understand the situation, still let us give it an attempt. Understand that you are charging 2 banks of 48V Batteries in parallel for two sources (one at a time or both together).

When there are two sets in parallel, it is not possible that only one of the two banks are charging, unless there is open circuit in one the bank.

it is more likely that batteries are not charging to full capacity. Problem can be verse if both sources are charging simultaneously and both do not have a blocking diode at least in one terminal. It is very likely that without blocking diodes, one source which is at higher voltage will circulate current (feed current) in to other source at lower voltage. Hence the power of Solar Cells or Water Generator will be wasted in circulation than charging batteries.

Hence if you are using two sources simultaneously without blocking (directional) Diodes in both then first do that or till such time use only one source.

The output of PV source will be varying over the day and in morning and evening - water turbine shall be feeding in to PV cells rather than charging batteries and in the noon most likely PV cells shall be feeding in to water turbine.

To further check the problem:

1. Check voltage at terminals of battery and note it.

2. Isolate each source at a time and check voltage at batteries. If this is more than reading in 1 above then the two sources are shunting each other - need diodes or check if diodes already there for any damage.

3. Check voltage at terminal of source as well as at battery. If the difference is more than 1 Volt, use thicker cable. I do not know the type of batteries you are using, a vented cell or valve regulated lead acid cell needs more than 2.7V per cell at its terminal (48V Banks has 14 cells) to fully charge up. At the end of the charge when the voltage reaches that level, the current tapers down and cell start gassing (bubbles are seen after removing caps) it is charged to full capacity. (NO CIGARETTE SMOKING PLEASE WHEN CELLS ARE GASSING).

Normally we leave cells to gas for one hour so that any hard sulphated are on plate regain porosity to ensure active material is charged to maximum capacity.

Yours is a lovely place to stay - I am a small business man and after waiting for 4 to 5 months, now have some hope of getting some projects, otherwise I would have come and stayed there, enjoying weather and also assisting you in the problem.