2nd battery charging

[alexvk2 Lurker Find all posts View Profile Close alexvk2]

The guy at TJM said that you can't simply parallel up your second battery due to the smart alternator regulator cutting out charging when the starter batter is charged
..has anyone dealt with this issue?
Thanks Alex

[Symo Advanced Member Find all posts View Profile Close Symo]

All you need is a voltage booster diode off eBay or from ABR sidewinder, this raises the output 0.5v to around 14.1v which is plenty for charging. Any standard isolator will do for cutting the connection when the main drops below 12.7v

Most on here run this setup including me and it works perfectly.

The isolator will still work with out the diode as most 150s seem to output around 13.7v which is 0.5v above most isolator cut in limits.

[alexvk2 Lurker Find all posts View Profile Close alexvk2]

Thanks for reply
Does this deal specifically with the issue of a drop voltage alternator?
Would the voltage boost tend to overcharge your 2nd battery when the starter batt had the full charge coming from the alternator rather than in the energy saving mode?
Cheers Alex

[snapper49 Member Find all posts View Profile Close snapper49]

get a dc dc charger and you wont have any problems

[alexvk2 Lurker Find all posts View Profile Close alexvk2]

Which setup did you use?

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

The booster diode simply restores low output alternator voltage levels to those similar
to pre high compensation alternators.

Cheers
Leigh

[D4D Addicted PP Member Find all posts View Profile Close D4D]

get a dc dc charger and you wont have any problems

Except taking twice as long to charge your battery...

[Symo Advanced Member Find all posts View Profile Close Symo]

get a dc dc charger and you wont have any problems

Don't waste your money unless you have 4-5 hours of driving to complete the charge cycle. The solenoid option is five times cheaper and five times faster for 90% the same effect.

My optima fully charges I an hour, and after two days of running the fridge is fully charged in about 30mins, no dc-doc will come anywhere near that.

[alexvk2 Lurker Find all posts View Profile Close alexvk2]

The booster diode simply restores low output alternator voltage levels to those similar
to pre high compensation alternators.

Cheers
Leigh

Thanks Leigh
I am not quite sure of the implications of inducing a voltage drop with a diode to get ECU to permanently "see" the starter battery as being half a volt lower than it actually is.I note that Sidewinder give plenty of warning regarding voiding warranty and to install at your own risk.
regards Alex

[krypto Avid PP Poster! Find all posts View Profile Close krypto]

If you read any of the countless threads on this you'll find that lots of us have been using the diode without problems for years.

If you feel like spending the money buy a dc-dc, but rest assured that there is no benefit.

[alexvk2 Lurker Find all posts View Profile Close alexvk2]

If you read any of the countless threads on this you'll find that lots of us have been using the diode without problems for years.

If you feel like spending the money buy a dc-dc, but rest assured that there is no benefit.

Thanks
I'll do some more reading ...not keen to spend more than I have to!
PP is a great resource!