Re: battery qusetion
Re: battery qusetion
You are not going to hurt the motor. You risk ruining the weaker of the two batteries if you do either of the following :
1) discharge the battery below it's rated capacity
2) Leave the batteries in series and charge them with a 24V source.
Here is a tough issue to get around. Your 12v battery is not really a 12V battery. It is made up of 6 individual 2.1V batteries (cells). These cells are never exactly matched to begin with. Some are weaker, some stronger. The weak ones are more prone to being damaged by overcharging and overdischarging. When you charge your 12V battery, you charge the whole thing by putting current through it. So the weak cells see the same current as the strong cells.
The weak cells hit their fully charged points faster than the strong cells, so they tend to overcharge as the rest of the battery is getting its fill. The weak cells also get more exhausted than the strong cells, which tends to stress their lifetime too. This is made worse if one battery has cells that are significantly stronger than the other battery. Such as using two different batteries in series. The problem is actually worse if you run dissimilar batteries in parallel.
Get a cheap hydrometer to watch your cell life and balance. Once in awhile you need to equalize your battery, which is a fancy way to say "overcharge". This has the effect of leveling things off between cells.
So.... it is not optimal to place two dissimilar batteries (or even two batteries of the same make and model if one is much older than the other for that matter). It won't hurt the trolling motor, but you should expect some slightly increased wearout rate of the batteries in doing this.
