Frans,
Can you please share what type of additional alternator you chose?
Reg
Tony Renshaw
On 12/05/2011, at 7:25 AM, Frans Veldman wrote:
>
> On 05/11/2011 10:56 PM, graeme bird wrote:
>
>> sounds good, I have an Odyssey PC310 fitted which is 2.7kg, its 8Ah
>> and has a cranking current of 310 Amps.
>
> Yep, I have two of these babies in my Europa. I have two fully separated
> electrical systems (two alternators, two batteries) but use only one
> system for starting. I have added a cross-over switch to tie both buses
> (and batteries) together but I have never needed it. 8Ah is good enough
> for starting.
>
> However, if you have a 914 (like I have) you need the battery to keep
> the fuel pump running in case of an alternator failure. In that case 8Ah
> is way too small. So either you have to get a larger battery or
> eliminate the single failure point by installing an additional
> alternator. The latter is what I did and needless to say that both fuel
> pumps are fed from a seaparate electrical bus.
>
> When I designed this system I looked into the Lithium thing, but at that
> time I decided that it was not reliable enough. Problem is the difficult
> way of charging a Lithium battery, you can not just connect it to the
> electrical bus like a lead-acid battery but need a very sophisticated
> charge controller. Charge it wrong (a charger failure will do), and the
> battery will explode or catch fire. This also happens if you puncture
> the battery (like during a crash landing) There are plenty of you-tube
> movies showing exploding lithium batteries.
> Common advice is to keep Lithium batteries in a safety shell. But of
> course this compromises the weight savings. With the dedicated charge
> controller plus safety shell there might not be much weight saving left.
>
> So I would recommend to use a PC310. It is safe, reliable, uncomplicated
> and well tested.
>
> Frans
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