Help,
My wife is on oxygen 24/7 and uses a big concentrator during the day. The other night the power went out and she used up both batteries on her portable unit. Inadvertently I was called home from work to move her to power. We live in a rural area and temporary power outages are almost normal.
I came up with this bright idea to build a back up out of a small car battery and a cigarette style power point with a float charger. My original design has 2 sockets for power (also charge the call phone) with a 30Amp inline fuse. I had it setup to physically connect the float charger kind of like my battery maintainers were connected in my boat for the trolling motor batteries. We thought it was a good idea.
So I wired a power socket direct to my lawn mower battery as a prototype to test how long the battery would run the machine to gauge the battery size I would need. Battery is in it's third or fourth season but was fully charged by a automotive battery charger and is kept indoors during the winter.
When connected it lasted 22 minutes and blew the fuse in the power supply, I replaced the fuse and it immediately started to fail (slow blow fuse). After the fuse failed I connected a analog automotive battery analyzer to the battery and it read a good 12v
I am really perplexed on why this did not work, the idea is solid and even the small lawn mower battery should have powered it at least 8-12 hours in my estimate. When connected the charger back to it it read 9.4 volts and charging started at 6%.
My 2 possibilities are the battery has a dead cell shorted across the plates and died way too soon or the output amperage was way too high connected directly to the battery.
Now the details- the power supply has information
Input 11-16vDC,7-5A
Output is 18VDC/3.3A
The internal fuse is 8A250V slow blow.
3 questions from the people that may know the answers;
1- Is this a feasible project that will eventually work well, or a colossal waste of time and money.?
2 - Would you suspect the battery to be bad and be the problem with the results I have.?
3 - Or is the output amperage if the direct battery connection too much for the power supply and can it be reduced at a nominal amount if work.?
Normally the internal battery in the portable lasts about an hour, how long should a regular 12v lawn mower battery last if it would work and if used a small car battery (500CCA) would it be better and how much better.? 8-12 hours is plenty for a back up.
My wife is on oxygen 24/7 and uses a big concentrator during the day. The other night the power went out and she used up both batteries on her portable unit. Inadvertently I was called home from work to move her to power. We live in a rural area and temporary power outages are almost normal.
I came up with this bright idea to build a back up out of a small car battery and a cigarette style power point with a float charger. My original design has 2 sockets for power (also charge the call phone) with a 30Amp inline fuse. I had it setup to physically connect the float charger kind of like my battery maintainers were connected in my boat for the trolling motor batteries. We thought it was a good idea.
So I wired a power socket direct to my lawn mower battery as a prototype to test how long the battery would run the machine to gauge the battery size I would need. Battery is in it's third or fourth season but was fully charged by a automotive battery charger and is kept indoors during the winter.
When connected it lasted 22 minutes and blew the fuse in the power supply, I replaced the fuse and it immediately started to fail (slow blow fuse). After the fuse failed I connected a analog automotive battery analyzer to the battery and it read a good 12v
I am really perplexed on why this did not work, the idea is solid and even the small lawn mower battery should have powered it at least 8-12 hours in my estimate. When connected the charger back to it it read 9.4 volts and charging started at 6%.
My 2 possibilities are the battery has a dead cell shorted across the plates and died way too soon or the output amperage was way too high connected directly to the battery.
Now the details- the power supply has information
Input 11-16vDC,7-5A
Output is 18VDC/3.3A
The internal fuse is 8A250V slow blow.
3 questions from the people that may know the answers;
1- Is this a feasible project that will eventually work well, or a colossal waste of time and money.?
2 - Would you suspect the battery to be bad and be the problem with the results I have.?
3 - Or is the output amperage if the direct battery connection too much for the power supply and can it be reduced at a nominal amount if work.?
Normally the internal battery in the portable lasts about an hour, how long should a regular 12v lawn mower battery last if it would work and if used a small car battery (500CCA) would it be better and how much better.? 8-12 hours is plenty for a back up.