parallax power supply 7345ru parts PWM

[Cstoliker]

My 7345 is not charging the coach batteries but does supply 12power to all accessories. The transformer, fan and relays work fine.
Think i need a PWM circuit for it. Contacted PP tec support and they seamed more interested in selling me an upgraded replacement unit rather then parts to fix this one. Anyone know of a way to get a PWM for this? (Charging controller)
It's a retrofit from an original Magnetek 6345 wich was serviceable. Parts were available and the schematic is even available online. Unfortunately the 7345RU has non of theses things except for a "flow chart" and "installation instructions".

Or even if someone know enough about these to tell me how bypass the PWM and get full output to batteries. I'm not going to leave it plugged in but I'd be nice to be able to charge my batteries in a couple hours running off generator..

[pnichols]

Cstoliker wrote:
... and the voltage does increase with load, ...

Did you mean increase with load, or decrease with load?

I've never seen my Parallax 7345's voltage go up with load. It does just the opposite ... goes down with load. That's why I've never seen it supply anywhere near 45 amps into our AGM batteries - because when charging them, the 7345's output voltage isn't at it's nominal output of 13.8 volts - it's always lower. If it stayed closer to 13.8 volts all the way up to 45 amps it would charge my AGM batteries quite fast - because these kind of batteries charge faster than regular wet RV batteries at all charging voltages. I wish my 7345 would hold 13.8 volts at 45 amps.

By the way, it's probably quite common for many/most chargers to not be able to hold their maximum advertised terminal voltage when supplying their maximum advertised current. I wonder how many multi-stage chargers can supply their full current while simultaneously holding their full boost voltage at the same time when charging a large battery bank that starts out at, say 50% state of charge? It's of course possible to build a power supply that can do this ... but it does cost $$$ to pull it off.

I actually would prefer a Parallax 7345 converter in my RV that they no longer make. It was called their 7345T model. It would hold around 14.4 volts for the first four hours after powering it up, then revert to 13.8 volts from then on. This would have been perfect for my particular batteries - as their recommended float voltage is 13.5 volts to 13.8 volts and their recommended fast-charge voltage is 14.4 volts to 14.8 volts.

[Cstoliker]

Yea that what I figured. It says it can supply 45 to charge batteries if needed and the voltage does increase with load, .but it would need to be close to 15v to get that much current in the batteries. I doubt it would do it.

[tenbear]

The 7345 probably will put out 45 amps, so if you turn on enough lights, run the water pump, the fridge, etc, etc it will probably supply the 45 amps to run things.

However, with a voltage in the 13.4 range, the battery will not accept anywhere near 45 amps, so the charging rate is slow.

[Cstoliker]

smkettner wrote:
No matter how much you save fixing the 7345 you are still stuck with a mediocre converter that just slow charges.

Yes that's true too. It says 45 amp is available but at the voltage it seams to put out I doubt it unless I ran the battery's down to like 10v (wich is on the border of no return) Right now we run off an inverter with 4 small deep cycle batteries. I start the RV's main engine for an hour or two at idle to charge them, wich is quieter then the generator also but that V10 sucks a lot of gas.

Anyway the season is almost done so I've got some options to consider, thanks guys.

[time2roll]

No matter how much you save fixing the 7345 you are still stuck with a mediocre converter that just slow charges.

[pnichols]

My original 7345 had a strange problem ... it would put out full voltage up to about a load of 8 amps. With higher current draw than that, it's voltage sagged way down.

The replacement 7345 has been very reliable for the last 6-7 years. I use it to keep up our 200 amp hour AGM RV battery bank and our AGM batteries are nearly 7 years old.

[jpfx]

do your batteries a favor and forget false economy.
get the upgrade kit from bestconverter mentioned by smkettner.

I did the upgrade on a previous rv and it was easy to do and worked well, especially with the charge programs pigtail.

[Chris_Bryant]

Cstoliker wrote:

Cstoliker wrote:

Chris Bryant wrote:
Did you replace the fuse panel? This unit doesn't have a separate charging circuit, and if it is putting out 13.6 volts, it is fine. There are no relays in it.

Pulling the two 30 amp polarity fuses and the voltage runs around 13.4. When the fuses are out back in the voltage drops to 12.4 (or lowere depending on battery state). Pulling a load and the voltage will increase. Turn on 2 or 3 lights and voltages will I crease to 13.2+\-

As far as I know the two polarity fuses connect the battery to the power supply so they would be the charger fuse?
. There are relays. They switch the internal 12v circuits between battery and converter power. Pointless IMO if the converter was charging the battery's as it should be. Over complicated seams to be the build concept with this unit.

There is no separate charge circuit- the fuses are reverse polarity fuses. This is a "float" type system (not to be confused with float charge voltage), in that the battery is always in the circuit.

[Cstoliker]

Cstoliker wrote:

Chris Bryant wrote:
Did you replace the fuse panel? This unit doesn't have a separate charging circuit, and if it is putting out 13.6 volts, it is fine. There are no relays in it.

Pulling the two 30 amp polarity fuses and the voltage runs around 13.4. When the fuses are out back in the voltage drops to 12.4 (or lowere depending on battery state). Pulling a load and the voltage will increase. Turn on 2 or 3 lights and voltages will I crease to 13.2+\-

As far as I know the two polarity fuses connect the battery to the power supply so they would be the charger fuse?
. There are relays. They switch the internal 12v circuits between battery and converter power. Pointless IMO if the converter was charging the battery's as it should be. Over complicated seams to be the build concept with this unit.

[wa8yxm]

I would recommend an upgraded charger unit myself.. Something NOT made by Parallex, like a Progressive Dynamics 9200 series.

Contact Randy at Best Converters for more

now, I'm going to type this "Blind" as it were but
http://www.bestconverter.com

Will test and edit if needed.

[KJINTF]

While you have it apart you might want to take a look see at the two large caps on the left side of the picture. I have found many times they go bad - On line at Digi-Key you can get quality Panasonic caps for very low price.

PM me if you need more help

[Cstoliker]

KJINTF wrote:
Those units are very easy to repair
A cap hidden behind the large heat sink (missing in the picture) is normally the problem.

Nice units can be run with or without a battery - not the fancy multistage unit but a wonderful 12 DC source for the shop. To date I guess I have repaired 50 or more of that exact unit never more than $5.00 in parts for each repair. Check the resister pack as well they tend to burn the PCB. Repaires to the board usually include adding some wires.

Good luck with the repairs

Thanks I'll take a look. The resisters at easy to test, the capacitor maybe I'll just replace and see what happens.

[Cstoliker]

Chris Bryant wrote:
Did you replace the fuse panel? This unit doesn't have a separate charging circuit, and if it is putting out 13.6 volts, it is fine. There are no relays in it.

Pulling the two 30 amp polarity fuses and the voltage runs around 13.4. When the fuses are out back in the voltage drops to 12.4 (or lowere depending on battery state). Pulling a load and the voltage will increase. Turn on 2 or 3 lights and voltages will I crease to 13.2+\-

[KJINTF]

Those units are very easy to repair
A cap hidden behind the large heat sink (missing in the picture) is normally the problem.

Nice units can be run with or without a battery - not the fancy multistage unit but a wonderful 12 DC source for the shop. To date I guess I have repaired 50 or more of that exact unit never more than $5.00 in parts for each repair. Check the resister pack as well they tend to burn the PCB. Repaires to the board usually include adding some wires.

Good luck with the repairs

[RJsfishin]

Quote:
My 7345 is not charging the coach batteries but does supply 12power to all accessories
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I was going to say it before, but Chris verified it, if the above is true, you have a problem other than the converter/charger !