Converting Delco 22Si to external regulation

[Singularity]

This will not be a technical post per se.

EVM1024 created an excellent thread that inspired me to look for a 28si alternator to convert to external regulation while looking for an alternator solution in a 12v to 24v conversion:

http://www.cruisersforum.com/forums/...on-204361.html

My goal was similarly to have a medium-duty truck type alternator to run at de-rated capacity. I came across a good deal on a 22si ($75, so I bought two). At 24v the 22si produces 70a (140a 12v equivalent). The 22si is also a J180 frame with internal regulator and diodes.

I could not find much information on the 22si other than they can run hot. Insofar as solar is my primary electric source with a diesel genny backup I see the alternator as deep backup. When coupled with a newer external voltage regulator (e.g. Balmar 624) the alternator can be set to operate at reduced production/temperature mode, which is where I plan to set it for everyday operations (after full check---out). I can always ramp production in anger if need be.

A benefit of the 22si in conversion to external regulation is that the posts on the back of the frame can be preserved after removal of the internal regulator. A local alternator shop charged $30 per alternator to remove the internal regulator and wire the field to the "I" post on the back of the frame, with the R post on the frame preserved for the stator lead. With more time/interest someone could rewire it themselves (without having to create an external board/posts as with the 28si conversion).

[aquabelle]

Very helpful information....thanks for posting. It's been a while: any feedback on how the 22Si performed under external regulation? Did alt heat result in serious output throttling?

[Craig C]

Appreciate you guys posting this. I just converted my 12V 145amp 22si to an external regulator and found your posting above helpful - thank you!! Posting some pics and how I did it here for the benefit of the next guy.

I ended up doing this myself as I just couldn't find a shop in the San Francisco area that was capable/knowledgeable.

This can be done by any DIY'er. There were no special tools required. The only thing I needed to purchase was a small piece of 10mm thick fiberglass board. 10mm is the same thickness as the internal regulator that will be removed.

1) Disassemble the alternator (remove case bolts, pull off back cover and remove stator).
2) Remove the brush assembly, regulator and the diode trio (provides power to the regulator). Discard the diode trio and regulator.
3) Use the regulator as a template and drill holes to match in the 10mm fiberglass board. Trim fiberglass board to roughly shape of the regulator. You will need to grind a small relief for the brush wire. Note - all of this is required because the brushes were attached to the regulator so this fiberglass piece is just a dummy spacer (non-conductive).
4) Re-use the metal connector shown to route one brush to the outside of the case. This will be the field + from your external regulator. Note that you need to re-use all of the insulators that were with the bolt.
5) Install the brush assembly and 10mm spacer. The other brush will be the ground and the ground will be achieved with the bolt passing through the spacer to the case. I ran an extra ground to the external ground connection. Likely not needed.
6) Push in the brushes and insert a paperclip to hold them in.
7) Re-assemble, pull the paperclip to release the brushes..... should be good to go.

I suppose I could have just bought a Balmar alternator, but the 22si I had was nearly brand new and I had a spare. This is also on my long range trawler - so when I run the engine, it often runs for several hours at a time. I didn't need 200 amps. 100ish will do.

What motivated me to do this was that my current house bank is AGM and the charging voltage was a bit high taking some life out of the AGM's. I'm also planning to replace the house bank next year with LiFePO4's. Will be doing DIY battery build and aiming for ~1,800 amp hours. When I complete that I will post, but on the trawler forum. I posted the alternator mods on this site, because this is where I found the inspiration to attempt it from the post above.

Note - as of the date of this posting I have not ran it. If someone sees a flaw in how this was done, please comment. Cheers.