narrowboatworld

There are boats around that have modern engines with presumably modern charging setups that have fitted this device and are very happy with it as it has reduced there charging time when moored up.

Probably not getting a 500% increase but definitely getting increased charging rate.

Richard

I do not think that you are imagining the improvement in charge. If it was an ACR (large slotted plastic "pudding bowl" on the back) it would not have been a common one to charge at 55amps, more likely 35 amps. Replacing that with a 70 amp one would double the charge during the first (bulk) phase. or in reality halve the bulk time. raising the charging voltage from around 14 volts or less to 14.5 would increase the charge during the rest of the charging time so you would have got an improvement. The old alternator would have got the batteries just as fully charged but would have taken far, far longer. Almost certainly the maximum state of charge is governed by the time you are willing to run the engine for.

FWIW my Adverc seems to have given up so I intend to see if I can get a 14.4 volt regulator for my Paris-Rhone machine. Preferably battery sensed so I can do something similar to you. However, before readers start messing about with their charging systems to boost the voltage it is important to make sure you do not exceed the maximum charging voltage set by the battery manufacturer, especially if you have sealed batteries.

Tony Brooks

Thanks for the very comprehensive answer, Tony.

The reason I was asking was that earlier this year, I replaced a faulty alternator (a Lucas ACR?? which may have been 55 Amps) with a refurbished 70 Amp A127 which I have converted to battery sensing by fitting a 'tractor regulator' and some variable resistance (220 ohm resistor and 100 ohm trimpot mounted on a small circuit board in a case). It is set at 14.5V.

My gut feel is that the new charging system cuts charging time by over a third. It also seems to bring the batteries to a higher state of charge.

I guess that I will never know how much of the charging efficiency improvement is due to a higher capacity alternator and how much due to ramping up the charging voltage.

What I will say is that I am unconvinced that replacing my £25 conversion (on a £50 alternator) with a  £300 or more Stirling system will give any noticeable improvement.

Regards

Allan

Every battery type will have a designed maximum charging voltage and/or a gassing voltage.  The gassing volatge will tend to alter with temperature etc. If you exceed the gassing voltage - well - the battery breakes the water in the elctrolyte down into hydrogen and oxygen so depleteing it. That is fine for a wet open cell battery PROVIDING you check and top it up regularly. Once it is exceeded by a few 0.1v the  the battery will starts to heat up as well.  If you have sealed batteries the maximum charging voltage is likely to be just below the gassing voltage because if you make those gas they will destroy themselves because you can not top them up.

Older lead antinonmy batteries gassed at about 14.5 or 14.6 volts. modern lead calcium ones at around 14.8 volts or so.

The "resistance" (note the inverted commas) of a battery at any given state of charge is more or less constant so if you increase the charging voltage the charging current will rise. This is how all the  charge controllers get more into the battery than the alternator. 

Once the voltage exceeds about 13.6 volts the battery will charge but very slowly. Given time it would get fully charged but sulphation my harden first.

Early alternators like the 10 & 11 AC and early ACRs used a charging voltage of about 13.8 to 14 volts. More modern ones between 14 & 14.2 volts whilst the later ones charge at about 14.4 volts. There are some modern ones that charge at about 14.8 volts which is in excess of the gassing voltage of some batteries and in excess of the maximum voltage of some sealed batteries so the inevitabe has happened with destroyed battery banks. However in fairness to the supplier the batteries were wet open cell batteries but the owner did not top them up.

The problem is trying to get accurate maximum/gassing volatge figures from the vendor so for wet open cell batteries it would not be wise to exceed about 14.4 to 14.5 volts for long periods.  Modern lead antinonmy and AGM batteries can have a higher charging voltage but you have to be sure.

It takes a while for gassing to start so if the higher voltage is pulsed in about 15 to 20 minute bursts a slightly higher voltage may not damage the batteries.  The higher the charging voltage the faster you charge but it gets closer and closer to the value that will damage the battery. We can only work safely on a few 0.1 of a volt so this is why I view that 500% claim with great scepticism.

Tony Brooks 

To be fair we do not know what Sterling mean by that 500%. They might mean it charges 5 times faster rather that with 5 times the current. However I doubt they woudl get anywhere near that on a modern tollerably well designed system. The device certainly has a place in parallelling twin alternators to give sufficient charge to run (say) a washing machine without discharging the batteries.

Also, just for clarity as long as the charging voltage is at or less than the maximum for that particular battery then the charging current is "controlled" by the battery, not the alternator or any external device. During the first stage of charging the alternator limits the charging current to prevent it burning itself out. Then the battery takes over.

Tony Brooks

Hi Tony.  thanks for getting back to me i too was wondering about your reply in the other place, it was not my intention to cause you any strife, but mearly to glean information, i will as you say contact you directly,

many thanks. Mike.

I note my long answer has not been made public so suspect it will not be. Google my name and you will soon find out where to email the question so I have a reply address for you.

Cheers, Tony Brooks

Hi  Tony.   Many thanks for your reply, the advert does make a good case for its product, especially to those of us who are not technically minded, and it seems to make perfect sence that the product will do what it claims. I am certain" strling power" is a reputable company and would not intentinally make false claims about its products, i look forward to reading your detailed reply on another site,

Mamy Thanks,    Mike.

I have not seen the advert but based on what you claim it says I suggest that you do some serious research into alternator operation and battery charging. I have prepared a much longer and detailed answer to the question you asked elsewhere but it has to be screened by the editor before publication. That 500% (assuming Sterling can substantiate the claim) would in my view be an almost "one off" result and involve a charging system in a very bad state with a very old alternator design and the device only covering up the faults in that system. 

At present I am fighting the ASA to get unsubstantiated (and physically impossible) claims made by another vendor of charging equipment  modified in all publications  so I do not want to take this one on, but I wish someone else would. Alternators self limit for current so you can never get more out of them than they are designed for. You can never  create energy, only change its type so how you increase an alternator's output by 5 times is beyond me. Google for, read and understand the technical details on the Smartguage website.

Tony Brooks

Hello all,   I wonder if anyone has seen the new product from "Sterling Power". It is a alternator to battery charging system, and claims to be able to increase the charge from your alternator to your battery by up to 500%, the clip can be seen on "uk boating" has anyone any thoughts.

Thanks,    Mike