View Full Version : Batteries



Major Clanger
27-03-12, 04:08 PM
Looking to make up some of my own packs. Five 1.5v alkaline energizers or two 3.6v lithiums??? Is it as simple as getting the polarity right and soldering a link between them?

Timw
27-03-12, 06:30 PM
Yep. Rob the connector from an old pack. Last time I looked at doing this it wasn't really worth the effort. I'd go for lithiums.

Major Clanger
27-03-12, 07:03 PM
If buying pre-made, where from? Custom divers? Other?

Timw
27-03-12, 07:17 PM
I usually get the lithiums from Divelife or Custom Divers. I tend to change one primary a year and the secondary in on about year 3 so far.

PeterVICEG
27-03-12, 11:45 PM
The lithiums last for a very long time.

I am told that you need to be careful soldering the batteries as it is hard to use a heat sink next on the battery itself. Aparently the commercial jobs are zaped with some sort of welder type unit. All in all a lot of bother for very little savings.

Peter

Major Clanger
28-03-12, 10:08 AM
All in all a lot of bother for very little savings.

Peter

Looking that way. Divegearexpress are pretty cheap but the import duty knocks it out and they're alkaline packs, which don't last well. C Cell lithiums are quite expensive as singles plus the hassle of soldering negates that as well.

windymiller
28-03-12, 10:15 AM
Just get a plastic double AA battery holder and solder the connectors to the top then use 2 3.6v AA lithium batterys. You dont get as long as the c cells but its easier and cheaper when changing them

Dive Africa
05-04-12, 07:22 AM
From the ISC web page:

FREQUENTLY ASKED QUESTIONS
HARDWARE
BATTERIES
Q: What kind of batteries can I use in my MEG if I want to build my own?
A:
(1) Earlier APECS 1 & 2 used a pair of SAFT Lithium C-cells which were wired in series and together produced 7.2vdc at 7300mAH (SAFT P/N: LS26500 for those having access to them).
(2) As of July 2003, we were forced to abandon the C-Cell lithium batteries due to the USA Hazardous Materials (HAZMAT) Regulations having not renewed the exemption on small shipments (by weight) of lithium batteries. The HAZMAT fees on shipping made the availability of these batteries highly expensive. To ship one small box would cost US$50 for the HAZMAT fee. We then switched to the Eveready Industrial Alkaline AA cells and made a 5-pack (7.5vdc). These are rated at 2850mAH per cell. This bundled package fits in slightly less space than the double C-Cell space. We then use a foam pad to take up some of the excess space in the battery box. We use a flat braid “solder wick” type copper wire for jumpers between cells.
Q: What special parts are needed to build my own battery packs?
A: The battery connector that mates with the MEG’s battery box consists of the following components:
1 – Red, vinyl insulated 24 AWG stranded copper wire
1 – Black, vinyl insulated 24 AWG stranded copper wire
1 – heat shrink tubing piece, 1 7/8” long and 3” across, 0.045” wall thickness, color, optional (we use black and white tubings).
1 – MOLEX p/n 03-06-1023 Connector Receptacle 2-pos .062
2 – MOLEX p/n 02-06-5135 Connector Terminal Female 24-30 AWG Gold
These are distributed by GC/WALDOM, DigiKey, and many more Molex distributors, or on a limited basis, ISC can provide you the parts, assembled if desired.
TIPS:
- Black electrical tape can be used if the heat shrink tubing is unavailable, but keep it thin, no more than one wrap otherwise clearance will be tight in the battery box.
Q: Why not use rechargeable batteries in the MEG?
A: Rechargeable batteries, like lithium ion, nickel metal hydride (NIMH), and nickel cadmium, have short times on run time for the APECS 2 electronics. There is also a critical, load voltage you don’t want to be very far under during a dive (5.0 volts) on the primary subsystem. NIMH batteries have a habit of not holding their high charge voltage for very long. Our experience in other equipment with NIMH is the voltage drops considerably a few days after charging to a full charge state thus may be unreliable for a long dive.
Q: I built up fresh Saft Lithium battery packs. They measured only 6.5v and rapidly decayed during their first dive down to below the 5v low battery warning. I soldered the wires between cells as I would for the alkaline batteries. What’s going on?
A: Lithium batteries build up an oxide layer between its internal connections of the cells
and the bulkhead contacts to the outside over time. This makes the batteries appear they
are not fresh, or falsely low. A technique our battery distributor related to us for a partial
cure is as follows:
- Need a 10watt ceramic 7 ohm resistor.
- Need a high impedance multimeter.
- Set voltmeter to 10v DC range.
- Hold the leads of the resistor and the meter leads to the battery contacts (do one
cell at a time).
- Watch the load resistor drop the voltage until it starts to settle out and then it
should start to reverse and go higher. Continue longer for 1 minute. This whole
process per cell should take no longer than 3 minutes.
- Repeat for the second cell.
- Let the batteries set for 15-30 minutes so they have a chance to recover from this
operation.
- Measure the voltage again. If you are getting 7.0-7.2 volts with no load, you
haven’t killed the batteries yet.
- Install the batteries in the Meg and power on the electronics. Check the systems
battery monitor voltage to see if there is an improvement. On the primary, let it
run for about 15 minutes as if in a dive, monitor the load voltage occasionally to
see if performance is better. If it still drops down to 5v, try repeating the above
procedure one more time before giving up on the batteries you assembled.
Things not to do with lithium batteries, especially the SAFT:
- Never short the batteries with a direct short. They have an internal fuse that will
blow. It’s intent is to prevent the battery from overheating and exploding. This is
a non-resettable fuse. If it is blown, the battery is shot, permanently.
- Use caution while soldering wires to contacts. Use low heat and make your solder
connection quickly. The lithium batteries are sensitive to heat. If you solder the
leads then you risk losing performance from the battery. Our battery distributor
uses a spot welder to weld on solder tabs, or the actual jumper tabs between cells,
thus minimizing heat on the internals of the batteries.
Last update: 08 April, 2005

Dive Africa
05-04-12, 07:22 AM
duplicate post

NotDeadYet
05-04-12, 07:16 PM
I've never seen the inside of a Meg so this might be a useless idea...

My Mk15 used custom made battery packs which were an absolute bastard to make (18 AA's soldered together). A really easy fix was attaching the connectors to some battery boxes from Maplin like these:

http://i01.i.aliimg.com/photo/v0/212058409/8AA_Battery_Holder_Cell_Box.jpg

You just swap the batteries when they're dead, no more soldering. They do different sizes so you combine them to get the right number.

I don't know if the Meg battery housing has enough clearance though so may be utter bollocks. Saved me a load of hassle.

PeterVICEG
05-04-12, 08:59 PM
I've never seen the inside of a Meg so this might be a useless idea...

My Mk15 used custom made battery packs which were an absolute bastard to make (18 AA's soldered together). A really easy fix was attaching the connectors to some battery boxes from Maplin like these:

http://i01.i.aliimg.com/photo/v0/212058409/8AA_Battery_Holder_Cell_Box.jpg

You just swap the batteries when they're dead, no more soldering. They do different sizes so you combine them to get the right number.

I don't know if the Meg battery housing has enough clearance though so may be utter bollocks. Saved me a load of hassle.

Nice idea, but much too large.

Peter

NotDeadYet
05-04-12, 09:35 PM
Nice idea, but much too large.

Peter

Fair enough. Like I said, never seen the guts of a Meg. Worked really well on my box, making up battery packs was a horrendous job.

Major Clanger
05-04-12, 09:57 PM
I've never seen the inside of a Meg so this might be a useless idea...

My Mk15 used custom made battery packs which were an absolute bastard to make (18 AA's soldered together). A really easy fix was attaching the connectors to some battery boxes from Maplin like these:

http://i01.i.aliimg.com/photo/v0/212058409/8AA_Battery_Holder_Cell_Box.jpg

You just swap the batteries when they're dead, no more soldering. They do different sizes so you combine them to get the right number.

I don't know if the Meg battery housing has enough clearance though so may be utter bollocks. Saved me a load of hassle.

Two C's taped together is all the room you get, almost by design...

bubbleless
06-04-12, 07:48 AM
If your no good with a soldering iron, which means either can't solder or fry the ends of the batteries.

Get someone like cell pack solutions to make them, there charges are minimal over the price of the batteries, which arn't that bad either.
Or buy "tagged" batteries then the frying the battery isnt a problem, if you can solder properly.

Watch a few you tube videos on soldering to get the idea then practice, so you get proper joints, then move onto the batteries.

diveuk
06-04-12, 09:16 AM
Alkaline, Lithium & Rechargeable NiMH & NiCd Tagged Batteries - Cell Pack Solutions (http://cellpacksolutions.com/items.asp?item=TaggedBatteries) may be of interest.