What is the input voltage range on an Powerex MH-C9000?

Based on yall's recommendation, I bought a Powerex MH-C9000 a couple of years ago. Now, I've gotten an alternative power system up and running and I'd like to be able to use the C9000 to charge AA batteries for my flashlights, powering the C9000 from the giant battery bank for my alternative power system. The C9000 has a nominal input voltage of 12VDC, but it doesn't specify the tolerance on that. The main bank will drop to the low-to-mid 11s during the worst discharges and then rise to the mid-to-high 14s during charging. Will the C9000 tolerate this?

Yes, I've already contacted MAHA, but I've not gotten a response.

I have a Rat Shack IC3 15 min charger and one day, while getting the Maha out to charge some batteries, I mistakenly grabbed the 14+v IC3 power supply and started discharging some cells, which worked well enough.

However, when I went to charge them up, the Maha started out OK, but would then cycle on and off. I couldn't figure out what was wrong and was resigned to the fact that maybe my newish unit was broken.

I ended up looking a bit closer at the wall wart and discovering my mistake. All the wall warts are now clearly marked on their housings.

The Maha still works fine, but that extra two plus volts didn't allow it to operate properly, at least when charging.

Chris

Considering that C9000 has car adapter, and cig. plug voltage can vary from 10V to 16V, I'd say that's the range it should tolerate.

I'm pretty sure several here have used it on "12V" Pb without issue. I personally would probably avoid having it connected while the Pbs are charging.

Shadowww said:

Considering that C9000 has car adapter, and cig. plug voltage can vary from 10V to 16V, I'd say that's the range it should tolerate.

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If the voltage regulator is OK , 14.8V should be the maximum voltage across the battery ... It is usually less than this ... The float value is usually about 13.6V (2.24V to 2.26V per cell) , so the charging volts will be higher than this to allow the car battery to charge.

I guess that the C9000 car adaptor should be built for at least 14.8V to allow for use when the car battery is under a high level of charge.

16V is way too high for a 12V lead-acid battery ... It must be gassing a lot at that voltage.
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"It works where lead works"....meaning it will work just fine from 11V to 15V
But I have problem with mine running at 13.7V (lead standby voltage at my "12 Volt" system) - when charging single cell in bay 1, it produces awful high frequency audio noise....So I connected one diode in series to drop voltage and now it works fine.

march.brown said:

16V is way too high for a 12V lead-acid battery ... It must be gassing a lot at that voltage..

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If I remember correctly, something near 16V is voltage at which Pb batteries get charged in cars at winter, when temperature is very low (below 0°F).

Shadowww said:

If I remember correctly, something near 16V is voltage at which Pb batteries get charged in cars at winter, when temperature is very low (below 0°F).

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I only have experience of lead-acid batteries at about room temperature ... All our battery-rooms were in the main building so never got very cold ... At room temperature , the systems started gassing about 2.4 volts per cell or slightly under ... We had very large capacity systems in 48V , 110V and 240V.

If you ever have a cold , a few minutes breathing the fumes in a large battery room quickly clears it up.
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An answer finally percolated out of Powerex. Their official reply was:

Hi Ty,


Thank you for contacting Maha. The range is 11.4-12.6Vdc. I have
included the specification sheet to the MH-C9000 for your reference.



Regards,



Eric Cheng

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So the gentleman's statement in the 2nd post that it won't work on 14V is spot on.

I tested my C9000 using the Maha MHS-DC0 car 12 V adapter in a 2012 Toyota. Adapter output with engine off 12.6 V; engine idling 13.5 V; engine revving at 3000+ rpm 13.6 V.

The voltages for all three conditions are within 0.05 V using the meter directly on the cigarette lighter outlet, so it appears that there is no voltage regulator inside the Maha adapter (or if there is, its limits are no tighter than the vehicle's regulator).

As far as I could tell, the C9000 charged AAs normally under all conditions. I only tested at 3000 rpm 13.6 V for about 30 seconds while stationary. Driving around with varying engine RPM did not seem to affect the charger but I couldn't keep an eye on it all the time. EDIT: I had set the charge rate at 900 mAh so that if it did cycle off and on, it should have gone to the default 1000 mAh; it stayed at 900 mAh.

I posted this recently into Maha HC-C9000 Support/FAQ..can be useful...

"I was curious if maha measures same capacity when powered from different voltages - I tested freshly opened pack of eneloops lite (because I know when I discharge them all 4 together their capacities are exactly the same +-5mAh) and discharged two at 14V input and two at 11V input - results were exactly same - within 5mAh.

Another test I performed - I again used freshly opened pack of eneloops (in this case AAA lite) and I tested if charging slots are independent - So in slot 1 was measured battery and in other slots were ohers battereis charging/discharging and there were some differences:
first battery (solo) - 397mAh
second battery (other slots charging):407mAh
third battery (other slots discharging):393mAh
fourth battery (other slots charging again) :407mAh

So charging bays are slightly affected by each other but it is not very significant. Charger and batteries were cooled by fan to exclude temperature effect."

williaty said:

An answer finally percolated out of Powerex. Their official reply was:



So the gentleman's statement in the 2nd post that it won't work on 14V is spot on.

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Yeah, I actually tried it by accident with the wrong wart, which is here in front of me: Rat Shack model #23-039 running 14.5v @ 4.5a. It's actually a pretty beefy wall wart.

My C9000 discharged 4 cells perfectly, but it was on the charge cycle, where it would run for a minute, then turn off and reset itself. This was not a normal operation and at least in my experience, 14.5v isn't going to work. 13.0v, probably, 13.5v I guess it works, 14v+, I don't think so.

Chris

mine works at 15V right now, charging at 1A. Everything looks fine except this awful hight frequency pulsing noise when charging bay 1. Maybe it depends on revision

That's a very interesting answer from MAHA regarding the 12.6V DC limit. Why then do they supply a car adapter when it is commonly known that vehicle charging systems operate at a nominal 13.6V-13.8V (plus or minus a bit) with the engine running?

I have the C9000 which I bought with the car adapter. I've only used it in the car a few times as I have another unit that's a bit more compact. Unfortunately I have so many car adapters for various gadgets that I couldn't say for sure which one belongs to the MAHA any more.

Yamabushi (post #10), were your voltage measurements open-circuit? ie. Just measured across the adapter with no load?

Can anyone check their adapter to see if there is any electonics in the lighter plug to regulate the input? Even a diode? It should be easy to just unscrew the retaining ring at the tip to have a look inside.

And to the OP, does the spec sheet they sent you advise not to use the charger in a RUNNING vehicle? I don't recall any warning to this effect in my user manual.

This is strange indeed.

Trevtrain said:

Yamabushi (post #10), were your voltage measurements open-circuit? ie. Just measured across the adapter with no load?

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Yes, the first results were open circuit reading the coax plug at the end of the adapter without the C9000 connected.

I tried it again with meter leads directly to the lighter plug and took readings with the C9000 disconnected and connected. Even with the engine idling, the voltage hardly drops under load.

Interestingly, I got higher voltages this time ... 13.88 to 13.91 V with no load, and 13.78 to 13.81 with the C9000 connected and charging.

Try measure voltage as engine is started I predict you'll see a sag down to 9V perhaps as starter is engaged, climbing slightly as starter is runing, and then going all the way up to 14 or more as the engine comes to life.. This 14 is probably going to drop down relatively fast. Another test, turn on headlights at full for a few minutes before doing the above.

march.brown said:

I only have experience of lead-acid batteries at about room temperature ... All our battery-rooms were in the main building so never got very cold ... At room temperature , the systems started gassing about 2.4 volts per cell or slightly under ... We had very large capacity systems in 48V , 110V and 240V.

If you ever have a cold , a few minutes breathing the fumes in a large battery room quickly clears it up.
.

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those fumes are potent, far more so than most people think! Once upon a time, far far away on an airbase, there was a concrete block charging house well away from all other buildings, I think at the far end of a taxiway. A couple airmen went out to the building for their usual charging session of the A/C batteries and had some larger Pb batteries to charge. They started the charge cycle and were idling along killing time when one of them decided to walk around out of the wind and lit up a cigarette. The block house disappeared along with the airmen - as heard all over the base. That was the last cigarette he was ever going to light up. The next day mandatory safety training sessions started for anyone that might have access to the charging stations.

moldyoldy said:

those fumes are potent, far more so than most people think! Once upon a time, far far away on an airbase, there was a concrete block charging house well away from all other buildings, I think at the far end of a taxiway. A couple airmen went out to the building for their usual charging session of the A/C batteries and had some larger Pb batteries to charge. They started the charge cycle and were idling along killing time when one of them decided to walk around out of the wind and lit up a cigarette. The block house disappeared along with the airmen - as heard all over the base. That was the last cigarette he was ever going to light up. The next day mandatory safety training sessions started for anyone that might have access to the charging stations.

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We were installing a very large capacity 48 volt battery system with two sets of cells (each with its own charger) and a common distribution board ... One of the installers somehow managed to put a cell in reversed ... I heard the bang from the mess-room ... Well , you have to go somewhere quiet to do the paperwork , hence the mess-room ... I ran into the battery room to find the fitter covered in acid ... Luckily he was actually wearing protective goggles at the time , but no rubber apron , gloves or rubber boots ... Usually if an Engineer wasn't present , the goggles would apparently be removed as they were prone to misting up.

He got stripped off and showered and he had another shirt in his car , so it was decided to dry off his denim jeans so he could wear them back to his depot ... This decision was made because the local Police don't take kindly to nude drivers ... After the trousers were dried , he put them back on ... Within a few hours , his trousers fell apart where the acid had soaked in ... He drove back to his depot wearing a towel.

There was a big enquiry and it was laid down that full protective clothing must be worn at all times when working in the battery rooms ... Anyone not complying would be banned from the site ... In actual fact , the boys should have been wearing the protective gear anyway ... It was just that they didn't like it ... There was always goggles and aprons and gloves kept in the battery room , but some people just didn't bother.

Strangely enough , when all the details came out along with photographs , we never found anyone in a battery room without protective clothing from then on.

The fitter had no adverse effects other than the disintegrated trousers.
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Yamabushi said:

Yes, the first results were open circuit reading the coax plug at the end of the adapter without the C9000 connected.

I tried it again with meter leads directly to the lighter plug and took readings with the C9000 disconnected and connected. Even with the engine idling, the voltage hardly drops under load.

Interestingly, I got higher voltages this time ... 13.88 to 13.91 V with no load, and 13.78 to 13.81 with the C9000 connected and charging.

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I wouldn't read too much into into a 0.2V-0.3V difference compared with your first readings. I would guess that the battery was not quite up to it's normal level on your first set of readings, especially if you had just started the car that time.

But what interests me is MAHA supplying an adaptor delivering 13.8V when their specs apparently say 12.6V. Perhaps the car adaptor was an afterthought?

You didn't look inside the plug for any electronics I guess? It seems to be delivering pretty much what's going through your vehicle systems plus or minus a tenth of a volt.

I have just sent an email to MAHA tech support asking them to look at this thread and perhaps post here or reply to me.

Apologies to the OP whose question was regarding an alternative power system as his source, but the conversation has drifted into using the C9000 in a running vehicle. Similar but not exactly the same thing.

Anyway, it will be interesting to get an official response. I really can't imagine any problems using it while the engine is running but............