Sun Jun 24, 2018 5:20 pm by cornbinder89
Today was the day for the voltage regulator. I run Delco 25 SI alternators on my trucks. These are also known as the "gray ghost" because they tend to outlast the engine they are used on. They are brushless, internally regulated "one wire" unit. The preform very well for what they were designed to do, recharge starting batteries and carry running loads.
Deep cycle battery packs need a different type of charging. If a deeply cycled battery pack is recharged with a conventional automotive style regulator, it can take days to fully re-charge. In stationary use, multi stage chargers are used to bring batteries up to charge in the shortest time. These fork lift style chargers vary the voltage supplied to the battery to bring it back fast without overheating or damage.
Two marine mfg make voltage regulators to mimic the "forklift charges" using an automotive style alternator. The two main mfg are Balmar (US) and Sterling (UK). I chose the Sterling unit as it better matches my needs and can be configured to control either the + or - side of the field. Balmar only can conrtol the + side. The Delco 25 SI is set-up to control the neg side, and while I could re configure, why?
My project today was to install one of these regulators on my truck. The truck has air start and the battery pack is used for running loads and "hotel" loads when the truck isn't running. So I had to modify the 25SI to work with the remote marine style regulator. I didn't want to damage or make changes that would render to Delco useless if the Sterling turns out to be a bad choice.
So I had to go into the sealed area where the stock voltage regulator is, and bring the field + and - connections outside the case. The 25SI while not "explosion proof" is the next thing to it, and would likely generate even if under water. The 25SI while termed a 1 wire unit, has a 2nd connection for an idiot light or relay connection, it connects to one phase before the diodes. Unfortunately they opted for a "pin" connection on the outside, and it isn't very sturdy or sound. My plan was to replace this with one of the field connection and use a threaded stud. I also didn't was to gut the original regulator in case of failure of the Sterling, I wanted to be able to revert to single voltage set regulator. I then needed to add a 2nd insulated feed thru alt case for the other side of the field. I kept the stock + supply to the field coil via the internal regulator, adding a jumper to the new stud thru the case. I removed the neg side of the field from the original reg and connected it to the other feed thru. If the Sterling failed on the road, I could open the back of the alternator, and re connect to the original reg still in place inside the alternator.
Got it all done and together and test run enough to know it goes to the high charge voltage as it should. from the time it took from when the engine was started to the point the battery reaches .3 volts below the set voltage, the reg computes how long to stay on the "bulk charge" voltage (for FLA cells, 14.8 v) before dropping to absorbsion and later float voltage. Float is 13.6 v, well below the 14.2 v of a std automotive reg.
So it never happened if there are no pictures:
- Attachments
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- Voltage reg I'm useing
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- External mods
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- Internal modifications
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- Delco as built