Len and Jo
Well-known member
- Joined
- Apr 25, 2005
- Posts
- 1,442
Our 'B' has one group 31 size house battery. (I ASSUME most of you B'ers out there that one battery is the general rule and more would be the exception.) That has a listed Ah rating of 115 amp-hours. On our recent 'Great Northern' trip that battery just seemed to not be really putting out the juice. It surprised me because we has historically always had enough and we had just switched from a group 27 battery (100 amp-hours) to the 31 just two years ago and if anything we should have had even more available power. This is what I have found out:
1) The $16 digital voltmeter that I got from Radio Shack several years ago to monitor battery voltage ain't what it used to be. It now has a 0.15 volt error. This is very significant when the total voltage range one is looking at is about 0.60 volts. That is 12.6v for full battery charge (~115 Ah available) to 12.0v for 50% battery charge (~55 Ah consumed and time to recharge for maximum battery life). So with that voltmeter error we thought we had lost a quarter of useable battery power. Got a new Radio Shack voltmeter - the price is now $19 but I do like the very small size and have it mounted and hard wired on a wall for easy use - If this second sample doesn't last very long I will look for a different brand.
2) A battery capacity test when we got home showed that the battery really is in excellent shape. I load tested the battery: charged battery over night then 100 watts 1 hour, 1000 watts 10 minutes, 100 watts 1 hour. Let battery rest for half a day and then measured the battery voltage ( at 12.35v ) and the reading was in the ball park for draining about 50% of the battery usable power.
So, some of the problem was the voltmeter I was using. I thought we had used up half the battery juice when indeed we still had another 0.15v to go. But my impression was that the battery had even less life then the voltmeter error allowed for.
3) The modern age...... : : We were using the laptop computer much more EVERY night then we have ever done in the past . I really do not know the exact power it was drawing but its power supply says "60 watts". Most every night we would download from our digital camera 50-75 pictures. Review them, delete the bad ones and rename the ones we kept. Joanne would then do our days trip log. So, we now have the computer on for 3-5 hours a night plus interior lights ( 40w-60w at computer table and 20w reading light by my bed).
So, it isn't the battery but our "wild" power use. I have reduced bulb wattage in most light fixtures by 50%. See how that works on next trip. Also, next trip we will run the laptop off its own battery when we do not have shore power and recharge it during the day when we have the vans engine running and are charging the house battery.
How do you control power consumption in your 'B' when not plugged in to shore power for several days?? Any tips?? This of course is not a problem that the large RV's have with large battery banks and build in generators.
1) The $16 digital voltmeter that I got from Radio Shack several years ago to monitor battery voltage ain't what it used to be. It now has a 0.15 volt error. This is very significant when the total voltage range one is looking at is about 0.60 volts. That is 12.6v for full battery charge (~115 Ah available) to 12.0v for 50% battery charge (~55 Ah consumed and time to recharge for maximum battery life). So with that voltmeter error we thought we had lost a quarter of useable battery power. Got a new Radio Shack voltmeter - the price is now $19 but I do like the very small size and have it mounted and hard wired on a wall for easy use - If this second sample doesn't last very long I will look for a different brand.
2) A battery capacity test when we got home showed that the battery really is in excellent shape. I load tested the battery: charged battery over night then 100 watts 1 hour, 1000 watts 10 minutes, 100 watts 1 hour. Let battery rest for half a day and then measured the battery voltage ( at 12.35v ) and the reading was in the ball park for draining about 50% of the battery usable power.
So, some of the problem was the voltmeter I was using. I thought we had used up half the battery juice when indeed we still had another 0.15v to go. But my impression was that the battery had even less life then the voltmeter error allowed for.
3) The modern age...... : : We were using the laptop computer much more EVERY night then we have ever done in the past . I really do not know the exact power it was drawing but its power supply says "60 watts". Most every night we would download from our digital camera 50-75 pictures. Review them, delete the bad ones and rename the ones we kept. Joanne would then do our days trip log. So, we now have the computer on for 3-5 hours a night plus interior lights ( 40w-60w at computer table and 20w reading light by my bed).
So, it isn't the battery but our "wild" power use. I have reduced bulb wattage in most light fixtures by 50%. See how that works on next trip. Also, next trip we will run the laptop off its own battery when we do not have shore power and recharge it during the day when we have the vans engine running and are charging the house battery.
How do you control power consumption in your 'B' when not plugged in to shore power for several days?? Any tips?? This of course is not a problem that the large RV's have with large battery banks and build in generators.