Is it possible and practical to modify the standard Yanmar 80 amp alternator with internal regulator so that I can have an external smart regulator. I find that my house bank does not charge sufficiently fast with the OEM (Hitachi?) alt/reg. I don't want to replace the alternator.
Smart regulator
- Thread starter GWG
- Start date
GWG,
http://forums.catalina.sailboatowners.com/showthread.php?t=125392
We've found that external regulation really helps when you upsize your alternator. Since you don't want to, the link explains why you don't need to do so.
http://forums.catalina.sailboatowners.com/showthread.php?t=125392
We've found that external regulation really helps when you upsize your alternator. Since you don't want to, the link explains why you don't need to do so.
Unless you are deeply discharging the bank >50% or you bank is huge > 500AH a bigger alternator is not going to help much. neither will a smart regulator. The battery internal resistance, in wet cell lead-acid batteries, goes up as the SOC gets higher. So for low SOG the battery can accept lots of amps as the SOC approches 75% the internal resistance increases rapidly and the charge you can push into it goes down. Above 90% SOC the internal resistance is so high the size of the alternator or smartness of the regulator does not really matter as the battery is the limiting factor.
Since there is nothing much you can do to increase the speed of recharge your only solution is either a wind, hydro or solar to constantly charge the batteries. Improves the average SOC and battery life too.
Since there is nothing much you can do to increase the speed of recharge your only solution is either a wind, hydro or solar to constantly charge the batteries. Improves the average SOC and battery life too.
We really could use some more specifics.....
*How big is the bank, in amp hours, at the 20 hour rate?
*What type of bank AGM, GEL, Flooded?
*Where are you measuring the current?
*What are you using to determine lack of or slow charging?
*What is your daily consumption in Ah's?
*What is the voltage at the battery bank when charging?
*What is the voltage at the back of the alternator when charging?
*When the bank is known to be full what is the alt voltage (tested at the back of the alt)?
You might want to check this out with an "expert" but it seems as though from what I have heard, as a battery starts getting more fully charged, it's "acceptance rate" goes down making it take increasingly proportionaly more time to reach full charge. One suggested "work around" for this condition that I have heard is to put a series diode in the + DC lead to the regulator. this makes the regulator think the battery voltage is lower than it really is and calls for a higher alternator output thus speeding up the charging rate. This action however must be moniitered so as to not too grossly over charge the battery. It is also a good idea to put a SPST switch across the diode to allow the circuit to be returned to normal when not needed or not being monitored. A small silicon diode, of sufficient current rating, will provide about a 0.5 volt drop to the regulator.
Gene Fuller / ESCAPADE II C27 TM #4816
Gene Fuller / ESCAPADE II C27 TM #4816
The simple answers to the original questions are yes and maybe - you will need to open up the alternator and rewire to bring the field wire out to attach to your regulator. If you're not comfortable and don't want to take the chance on frying something - you'd need to take it to an alternator shop. Likely by the time you pay for shop labor you could have bought something else that would bolt in.
Google it. Instructions are out there.
Google it. Instructions are out there.