Quote:
Originally Posted by MrForbes
I wonder how GM got away with it? They ran two batteries in parallel on the diesel engine vehicles in the 1970s-80s....connected together with big fat cables. No diodes.
Huh.
|
It is not just GM many diesel pickups do that to this day as does just about every MD and HD truck, sometimes up to 4 batteries in parallel. In those applications there is one set of cables running to the engine and a bunch of short cables connecting all the batteries together.
This can be done quite reliably, however to do so it is always recommended that the batteries be a matched set, IE same model and age. The other key to making it work is that the batteries are always discharged and charged as a set. The fact that in most cases the vehicles do not sit unused for long periods so the inter-battery discharge is limited in duration. Once the vehicle is started the fact that they are charged together keeps the difference in voltage to a minimum. However if the vehicle is left to sit for an extended period of time the batteries will discharge at a rate higher than the normal self discharge that would occur if they were not interconnected.
Now in a robot application the batteries are likely of different age and/or have been subject to a different amount of discharge/charge cycles. They are also usually charged independently. However if you disconnect them after each use the inter-battery discharge will be minimal.