FollowupID: 359535 Submitted:
Wednesday, Mar 09, 2005 at 00:57
Member - Captain (WA) posted:
Well Mainey, no-one here (well, not me anyway) is claiming a solenoid system is technically better than the piranaha. BUT, they are not any worse either and are far more economical to boot.
You seem to conviniently forget the fact that the piranha is merely an electronic version of a solenoid which "opens and closes" depending on voltage, not the position of the ignition key. A "smart" solenoid, like the redarc, does the same thing as the Piranaha, but it uses a mechanical solenoid.
The piranha DOESN'T charge each battery individually, it charges the main first and ONLY when it reaches the target voltage (13.6 I believe) will it join the aux battery (same as smart solenoid).
The Rotronics charge/Isolater battery charger is the ONLY battery isolator/charger that truly charges each battery individually based on voltage and priority to the main battery (that I am aware of). But this feature is not on their base models, so just because one has a Rotronics isolator
does NOT mean one has a true charge/isolator
As for claims of better for disimilar bats etc..., that is partially true! But it is also the same for the smart solenoids to!!! The reason for it is that the main battery is charged to its correct voltage first and only then is the second (potentially dissimilair) battery charged. Theoretically the 2nd battery will now charge faster because the main is already fully charged. Just a twist on facts for slick marketing and partially true (what all good advertising consists of!!!)
But for proper charging of dissimilair batteries in the quickest time, once again the Rotronics charge/isolator
is the best. But bear in mind you are looking at $750 - $1100 depending on options and features, far from affordable for the average 4WDriver.
As for "only recharge it to a maximum of 80% … not my opinion, a fact", well sorry but you are a victim of good advertising and misleading information again. Under CERTAIN conditions, it can true but once again, its the same for piranaha and smart solenoids.
As for "facts are undisputed", you mysteriously forget to state under what conditions or what proof. For example "longer battery life and better reliability" are opinions, not facts, without a documented study.
On the surface, dual battery isolation and charging appears an easy subject, but once you start to dig deeper and understand some electronic theory behind it, one soon realises everything is a compromise and one has to choose what suits their requirements best. About the only isolator
that can fully meet ALL requirements is the Rotronics charge/isolate, but what a price. Also, it has more electronics so more potential areas to go wrong.
At the end of the day, a simple ignition switched isolator
will surfice for many 4WDrivers, then comes a smart solenoid and piranaha for virtually the rest, with a Rotronics charge/isolate only required for the very few who really need the best (gee's, I must sound like an ad for Rotronics by now and I don't even have one!!!).
This thread started out as a decent discussion of various isolation systems before one got confused with marketing hype vs electronic theory. This reply is long enough already and it has really only touched the surface. To fully understand every combination and advantage/disadvantage of every system, one can read some good books on the subject to get a true and proper understanding, not regurgitate some slick marketing advertising.
PS. yes, I am an Engineer