charging issue

[rtchina]

Started with batteries at 84% full. With the engine running, which has a 40 amp output alternator and using all the electrics, we which is about 10amps load we were charging at about 4amps,. Previously checked the alternator output, 13.5 volts.

Dock, turn of all the electrics, solar is charging at 10.8amps and batteries are at 87.6%. So, batteries can absorb over 10 amps. As previously alternator producing power but only 4amps getting into the batteries. We have a split charging diode and 3 sets of batteries, house, winch and starter.
Why, when running under engine are we not get charged batteries??? 3 hours running should be enough to supply the load and charge the batteries shouldn’t it?

 

[rivonia]

Whilst motoring your alternater is mainly replacing the amps consumed by the engine and any other electrical items that are on such as fridge etc.

 

[silver-fox]

What you may be measuring is the fact that your engine electrics set up was originally designed for automotive use. The typical charge pattern is for the alternator to charge at full alternator capacity for 15 minutes or so and then back off to a level where it can meetservice demand and trickle charge the battery, which is fine for a car.

I suggest you look at adding a digital voltage regulator to your alternator. Here is a link to a Stirling product which I have used with success.

http://www.sterling-power.com/products-altreg.htm

 

[halcyon]

Started with batteries at 84% full. With the engine running, which has a 40 amp output alternator and using all the electrics, we which is about 10amps load we were charging at about 4amps,. Previously checked the alternator output, 13.5 volts.

Dock, turn of all the electrics, solar is charging at 10.8amps and batteries are at 87.6%. So, batteries can absorb over 10 amps. As previously alternator producing power but only 4amps getting into the batteries. We have a split charging diode and 3 sets of batteries, house, winch and starter.
Why, when running under engine are we not get charged batteries??? 3 hours running should be enough to supply the load and charge the batteries shouldn’t it?

Alternator running at 13.5 volt and a blocking diode charge, you are not going to see much charge, you need to te be 14.2/14.4 at the battery.

Check alternator voltage and battery voltage, if alternator is 13.5 volt and batteries lower still get a smart regulator for the alternator.

Brian

 

[Chris_Robb]

Started with batteries at 84% full. With the engine running, which has a 40 amp output alternator and using all the electrics, we which is about 10amps load we were charging at about 4amps,. Previously checked the alternator output, 13.5 volts.

Dock, turn of all the electrics, solar is charging at 10.8amps and batteries are at 87.6%. So, batteries can absorb over 10 amps. As previously alternator producing power but only 4amps getting into the batteries. We have a split charging diode and 3 sets of batteries, house, winch and starter.
Why, when running under engine are we not get charged batteries??? 3 hours running should be enough to supply the load and charge the batteries shouldn’t it?

The alternator charging the batteries at 13.5 is an utter waste of time. You need to see around 14.4 on the batteries. Worth getting a Nasa BM1 to monitor voltage & amps in/ amps out otherwise you will not know what is really going on. As you need to consider how to get your alternator to produce more voltage and thus amps - you should perhaps add a charge booster such as Sterling or Adverc (Adverc are the nicer people to deal with).

If you are in a hot climate, then you may actually need a higher capacity alternator - say 80amps - talk to Adverc as they do a range of adapted automotive jobs suitably wired for their booster.

With your current set up I would be surprised if you saw more than 10 amps even when the batteries were low. If your old alternator is 20 years old or so, it may not like the extra load put on it so you may well benefit from getting a new one and keeping your old one as a spare.

 

[macd]

As said, if the 13.5V is alternator output, it can't possibly charge batteries that are already fairly full, as current can only flow from a high to lower voltage. Your panels are more effective because their (unregulated) output is much higher. Sounds to me as tough your alternator/regulator is too feeble, either in specification or age. Did it charge the batteries more effectively in the past?

 

[Jegs]

The OP has gone quiet on this one. This must mean he's still fixing it or his batteries are so flat he can't power up the laptop?

Would be interesting to know what fixed it.

I give

5/1 Bad alternator
4/1 Bad regulator
2/1 Bad diode in splitter (odds on this will lengthen if the solar panel runs through the splitter.
Evens Voltage drop in wiring or bad alternator earth.

Any takers or is gambling on the YBW forum banned? Make payments to my Paypal account. Place your bets!

A shilling's worth of bitter on Voltage drop or bad earth.

John G

 

[alexsailor]

I suggest you look at adding a digital voltage regulator to your alternator. Here is a link to a Stirling product which I have used with success.

http://www.sterling-power.com/products-altreg.htm

Is this so called "smart regulator" that allows alternator to charge the battery to max (instead of charging it till about 70% or so)?

 

[noelex]

Diode splitters lose about 0.5-0.6v. so I don't think there are any defective components just the standard regulators output of 14.1-14.2v reduced to 13.5v at the battery. I am surprised it is not even a bit less with some voltage drop in the wiring. (If the OP is measuring the voltage at the battery)

As others have said this needs to be much higher to get any worthwhile output from the alternator.

 

[Steve C Cronin]

One of Mr Sterling's Advanced Alternator Controllers is the only way to go. That way your boat's car derrived alternator becomes battery sensed instead of machine sensed. In short, it stops just providing what is being taken out plus 5% but now turns into a REAL battery charger running at around 15 volts until full charge is achieved. It is the ONLY option.