battery chargers and inverters
Hi
In my little world, the plan is to use a 500W modified sine wave inverter to power a couple chargers that I can't seem to find the 12V equivalent for. One would be a regular 110V Ryobi charger and the other a 110V charger for 9 Volt Ni-MH batteries. After getting this stuff together I read that using an transformer with a inverter is bad. What would happen? Would I fry something? Any insight would be appreciated TIA Bob |
battery chargers and inverters
After getting this stuff together I read that using an transformer with a inverter is bad. ** Where ?? Post a link. ..... Phil |
battery chargers and inverters
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battery chargers and inverters
thanks Mike
So the best (safest) way would be to use a full sine wave inverter rather than the modified sine wave one? On Monday, June 25, 2012 6:57:18 PM UTC-4, wrote: Hi In my little world, the plan is to use a 500W modified sine wave inverter to power a couple chargers that I can't seem to find the 12V equivalent for. One would be a regular 110V Ryobi charger and the other a 110V charger for 9 Volt Ni-MH batteries. After getting this stuff together I read that using an transformer with a inverter is bad. What would happen? Would I fry something? Any insight would be appreciated TIA Bob |
battery chargers and inverters
** Why don't you just go drop dead? You stinking damn troll. |
battery chargers and inverters
On Tuesday, June 26, 2012 9:34:30 AM UTC-4, Phil Allison wrote:
** Why don't you just go drop dead? You stinking damn troll. Are you talking to me Phil? |
battery chargers and inverters
|
battery chargers and inverters
On Jun 26, 9:34*am, "Phil Allison" wrote:
** Why don't you just go drop dead? * * *You stinking damn troll. Phil, your act is really tired. Your off-the-meds rants used to be funny, now they're just sad. Get help, and while you are, stay off the internet. John |
battery chargers and inverters
"John-Delusional **** " ** Go **** a dead donk - you psycho troll. |
battery chargers and inverters
dave hillstrom wrote in
: On Mon, 25 Jun 2012 19:32:04 -0700, mike wrote: On 6/25/2012 3:57 PM, wrote: Hi In my little world, the plan is to use a 500W modified sine wave inverter to power a couple chargers that I can't seem to find the 12V equivalent for. One would be a regular 110V Ryobi charger and the other a 110V charger for 9 Volt Ni-MH batteries. After getting this stuff together I read that using an transformer with a inverter is bad. What would happen? Would I fry something? Any insight would be appreciated TIA Bob The problem is the dV/dT. The rectifiers and caps are rated for the current you get when driven with a sine wave. Stresses on those components can be significantly higher. But maybe they can take it. So, my experience is that it's perfectly safe to run most anything from an inverter...EXCEPT when it isn't. Here's an example. Tektronix 211 miniscope. Good company. You'd think they designed good stuff. They -used- to. the TEK of today is not the TEK of the earlier years. the 200 series was a good product,very popular with field service people,especially the 213 with it's DMM. Plugged on into an inverter and it quit. Gazing at the schematic showed why. They use a series cap and rectifier as a charge pump to charge the batteries. The cap has a different value depending on the market, 50 or 60 Hz. The fast rise input waveform from the inverter blew the fuse instantly. Could have been much worse. Compaq laptop. They hooked the battery thru a FET to the input socket. Relied on the current limit in the adapter to set the charge current. If you put voltage into the port, it smokes the FET. But the manual did say, "Use only the recommended charger." Bottom line is that it's a crap shoot. For most consumer devices, vendors are more concerned about saving half a cent than whether it works in an environment not in their spec. Clever implementations that save cost don't necessarily enhance reliability. to follow up on this, if the battery charger is using a cheap cap-based power circuit to produce consant current for fast (15 min to 1 hour) nicd and nimh charging, you may very well get flames and smoke coming out of your charger and/or batteries if used with a poor modified sine wave output from a generator. the TEK 211(and 212,214,and 221) is not a fast charger circuit. in fact,TEK had to add a protection circuit and fuse the individual battery packs to keep the scope from catching fire,literally. One other item to watch out for on the TEK 200 series is that the PCBs are held in place by 4 plastic pins,two on each case half. they shear off under impacts,then the PCBs shift in relation to each other,the female pin connectors spread open and their spring leaves fall out,shorting things out. -- Jim Yanik jyanik at localnet dot com |
battery chargers and inverters
On 6/27/2012 6:32 AM, Jim Yanik wrote:
the TEK 211(and 212,214,and 221) is not a fast charger circuit. in fact,TEK had to add a protection circuit and fuse the individual battery packs to keep the scope from catching fire,literally. One other item to watch out for on the TEK 200 series is that the PCBs are held in place by 4 plastic pins,two on each case half. they shear off under impacts,then the PCBs shift in relation to each other,the female pin connectors spread open and their spring leaves fall out,shorting things out. I have a 213 that's very intermittent. The connections you mention are a mess. Any kluge tricks for making it work better? I thought about just soldering 'em all, but you'd never be able to replace the battery. |
battery chargers and inverters
On Wednesday, June 27, 2012 5:31:25 AM UTC-4, dave hillstrom wrote:
On Mon, 25 Jun 2012 19:32:04 -0700, mike wrote: On 6/25/2012 3:57 PM, wrote: Hi In my little world, the plan is to use a 500W modified sine wave inverter to power a couple chargers that I can't seem to find the 12V equivalent for. One would be a regular 110V Ryobi charger and the other a 110V charger for 9 Volt Ni-MH batteries. After getting this stuff together I read that using an transformer with a inverter is bad. What would happen? Would I fry something? Any insight would be appreciated TIA Bob The problem is the dV/dT. The rectifiers and caps are rated for the current you get when driven with a sine wave. Stresses on those components can be significantly higher. But maybe they can take it. So, my experience is that it's perfectly safe to run most anything from an inverter...EXCEPT when it isn't. Here's an example. Tektronix 211 miniscope. Good company. You'd think they designed good stuff. Plugged on into an inverter and it quit. Gazing at the schematic showed why. They use a series cap and rectifier as a charge pump to charge the batteries. The cap has a different value depending on the market, 50 or 60 Hz. The fast rise input waveform from the inverter blew the fuse instantly. Could have been much worse. Compaq laptop. They hooked the battery thru a FET to the input socket. Relied on the current limit in the adapter to set the charge current. If you put voltage into the port, it smokes the FET. But the manual did say, "Use only the recommended charger." Bottom line is that it's a crap shoot. For most consumer devices, vendors are more concerned about saving half a cent than whether it works in an environment not in their spec. Clever implementations that save cost don't necessarily enhance reliability. to follow up on this, if the battery charger is using a cheap cap-based power circuit to produce consant current for fast (15 min to 1 hour) nicd and nimh charging, you may very well get flames and smoke coming out of your charger and/or batteries if used with a poor modified sine wave output from a generator. when i worked at Black & Decker, we started getting a lot of returns of for commercial and industrial tool 1-hour chargers for just this reason. the more expensive 15 minute charges fared much better, but also would have occassional failures. and we were even using a Honda generator (supposedly quit good) in the lab to do the tests to determine cause of failure. i believe that B&D has made significant strides towards making their chargers not blow up or massively overcharge the batteries under theses conditions, but, as noted above, its something of a crap shoot unless you check with the battery charger manufaturer first. (i would recommend checking with both a power tools manufacturer's hotline as well with their local repair outlet) small trickle chargers, on the other hand, for 8-12 hour AA type charging should be a lot safer IMO and experience, as their low levels of current even if increased 3 times shouldnt hurt the cells much and ive never seen them catch on fire. -- dave hillstrom mhm15x4 meow Thank you too Dave for your input. |
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