At 07:42 AM 8/14/00 -0700, mblair1@home.net wrote:
>
>"Les Newman" <lnewman@tridium.com> wrote:
>> http://www.bitwalla.com/cruisers/tech/24v.html
>
>Overall, that's a good article. The most important point is: DON'T tap
>12V from the lower battery. That WILL reduce the life of the upper
>battery... how much depends on the load placed on the lower one.
>
>The comments about headlights in that article don't apply to most (if
>not all) US military vehicles, which use 24V headlamps.
>
>There's one glaring mistake in the article: At the very end, it
>suggests jump starting a 12V vehicle from either of the 12V batteries.
>DON'T do that! That will discharge the battery from which you jump the
>12V vehicle more than the other battery, and will cause the other
>battery to become overcharged. I'm surprised the author recommended
>that after warning against tapping 12V from one battery earlier in the
>article.
For years I ran my M37 with an almost-installed 12V electric fuel pump
wired (by someone else!) to the first battery. I could not understand
at the time why the second battery was gassing so much despite assurances
from the guage that the system voltage was hovering right around where
it should be.
Wiring up 12V equipment that way in a 24V vehicle is a bad idea, and once
cost the cel-phone company I used to work for mucho dollars replacing
the entire charging system in some backhoe or other that the 12V celphone
(3A draw
on the best of days, full transmit power) had blown due to the charging
system imbalance caused by the use of the first battery only.
Andy Hill
MVPA #9211
This archive was generated by hypermail 2b29 : Sat Sep 02 2000 - 09:32:28 PDT