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Old 04-16-2016, 05:16 PM
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Power lab 8 burned up again

Guys,

For all the people with power lab 8's, has anyone had issues with it burning up. I am on my 2nd one and its toast. Both times it happened while pulling 60 amps 12v marine battery all within spec. This one is 1-2 months old. I want another but I don't want it to continue to be a problem. I have only owned Revolectrix products And really like the product.

Please let me know what you guys think.

Thanks
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Old 04-16-2016, 07:00 PM
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some chargers have specs that say one thing, but truly have different performance. If the 12v battery was getting low, that stresses it, also if you run them close to their limit parts can get very hot, maybe a hot capacitor got its life shortened by heat and blew
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Old 04-16-2016, 07:23 PM
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According to the specs it is limited to 612 watts at 12 volts. That's 50 amps, so if you were pulling 60 it may have exceeded its design capacity. Never a good idea to run these things up to their limits.

http://www.progressiverc.com/fma-powerlab-8.html
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Old 04-16-2016, 07:33 PM
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So my marine battery had a lot of capacity left as I had it fully charged and didn't charge a lot of batteries. I was pulling 60 amps from the battery which it may be able to go higher but its input was a max of 26 amps as I was charging 6 cell batteries. All within spec.
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Old 04-16-2016, 08:02 PM
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Quote:
Originally Posted by supercub1 View Post
So my marine battery had a lot of capacity left as I had it fully charged and didn't charge a lot of batteries. I was pulling 60 amps from the battery which it may be able to go higher but its input was a max of 26 amps as I was charging 6 cell batteries. All within spec.
If you were pulling 60 amps I would bet a lot of money that the voltage dropped to 12.1vdc or even less. That puts a huge strain on the charger when you run it at low voktage. If I high current charge my batteries run the generator to turn on the power supply. Even charging my receiver batteries my battery drops to the low 12vDC range. And that is a deep cycle marine battery.

Fyi old school battery testing is using a carbon pile load meter. Even under 100 amp draw you can drop well under 12V.
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Old 04-16-2016, 08:16 PM
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If you have to change from batteries you should use two in series (24v). By doing so reduces the current and the amount of heat that the charger has to dissipate.
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Old 04-16-2016, 08:19 PM
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If you have to change from batteries you should use two in series (24v). By doing so reduces the current and the amount of heat that the charger has to dissipate.
That sounds like a good idea. Never tried it but sound like it would work much better. Adding some extra batteries in my trailer and may wire one up like this to see how it works. Would be easy to do.
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Old 04-16-2016, 08:23 PM
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That sounds like a good idea. Never tried it but sound like it would work much better. Adding some extra batteries in my trailer and may wire one up like this to see how it works. Would be easy to do.
The best is a generator and a 32v power supply.
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Old 04-16-2016, 08:35 PM
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60 amps continuous from a battery?
You really want to rethink your charging strategy.
The only time you should ever crank up the charger to a 60 amp charge rate is if its being fed by a beefy 24v power supply.

Time to slow down the C rate on your charging.
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Old 04-16-2016, 08:50 PM
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It might not count, but I had a turnigy 8150 charger rated for up to 8s, 150W, it would hit the thermal cutoff after 5-10minutes if it was charging over 125W unless I added a powerful external fan
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Old 04-16-2016, 08:50 PM
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So according to the tech at Revolectrix my setup was said to be ok. (correction my notes from Howard said 55 amps not 60 which I may have forgot to turn my 12v max current down to 55 amps) I like the marine battery charging as it has worked out great. I don't have room for 24v and it is easier to run off 12v. Yes there is a drop in voltage off the battery of which can handle that and more. However, the tech did say having a good power supply and not straining it too much. Didn't think to much on that, but it is still within spec and may not even be maxed out. So there is no reason for this.
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Old 04-16-2016, 10:57 PM
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Not to argue but it hasnt worked out great since you said you have fried two chargers.
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Old 04-17-2016, 01:54 AM
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Quote:
Originally Posted by supercub1 View Post
So my marine battery had a lot of capacity left as I had it fully charged and didn't charge a lot of batteries. I was pulling 60 amps from the battery which it may be able to go higher but its input was a max of 26 amps as I was charging 6 cell batteries. All within spec.
The amperage on the charge side and the power supply side are not going to be the same. The wattage will be close, with the power supply side needing about 10% to 20% more power than the charge side due to internal losses.

So a 6S pack at 25 volts and 26 amps is 655 watts, that already exceeds the 12V power supply limit of 612 watts. This is why you have cooked 2 of these things.

At the 12 volts of a marine battery (really closer to 13) and 60 amp you are using around 720 watts, which is 10% more than the charging side. So the math works.

While it may be within spec (but not really) it is never a good idea to run it up to its max. And every charger I have seen or used has stated limits for 12V input, and the requirement for 24 volts+ to get full power from them.
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Old 04-17-2016, 07:54 AM
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Ok I see where you guys are coming from and I appreciate the details Judge. With all that being said if I keep the same setup (or possibly have 2 chargers run off 1 battery), what would be the max upper safe limit of current (set within the charger) the charger should be able to pull from the marine battery without it burning up??

With that also being said I have a heavy duty marine deep cycle. What is the max I should draw from it? 1150CCA 205RC 31M
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Old 04-17-2016, 08:24 AM
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Ok I see where you guys are coming from and I appreciate the details Judge. With all that being said if I keep the same setup (or possibly have 2 chargers run off 1 battery), what would be the max upper safe limit of current (set within the charger) the charger should be able to pull from the marine battery without it burning up??

With that also being said I have a heavy duty marine deep cycle. What is the max I should draw from it? 1150CCA 205RC 31M
I think if you are looking at keeping a battery you should look at a golf cart battery. They have a better design for keeping voltage under high amp loading. Marine batteries offer less amp continuous output to sacrifice for longer shelf life and deeper discharge over regular floaded batteries. Golf cart batteries are designed around long amp drain cycles. I think you can find 2 golf cart batteries to make up the same area as the battery you have. Most motorhome people (like myself) use giant 6V golf cart batteries instead of what you are using.
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