Czech RF-10 Battery Pack

[Will001]

I just bought a Czech RF-10 military manpack radio. It came with the original battery pack, and it was understandably very weak (I was surprised it worked at all). My question is, how would I go about charging it? There are 5 D-cell looking batteries connected together, and the only corrosion is on one of the connecting wires between two batteries, and it looks like it could be cleaned.

However, I've heard other folks say that these batteries should be replaced. I've seen people put brand new D-cell batteries in there and connect them all, and I've also heard that you can use a 6V sealed lead-acid battery instead. Would you all recommend trying to charge the old batteries, or should I get new batteries for it?

 

[autovon]

Get new batteries. SLAs are pretty cheap.

 

[mmckenna]

I agree. If those batteries have been sitting for a long time, they are probably shot. A couple of charge/discharge cycles might wake them, up, but there will always be a big question mark on them.

A 6 volt lead/acid battery like the type used in backup lighting boxes might be a good option. I know Home Depot sells some, but not sure if it would fit. You might have to do some searching to find one that will fit.

 

[mmckenna]

And I always wondered if anyone had bought one of those radios. I see them frequently for sale.

 

[prcguy]

The original batteries are Ni-Cad and you could replace them with D size Nickel Metal Hydride but 6V gel cells would be easier and simple to charge.

 

[Will001]

Thanks for all the replies. Would this battery work? Universal Power Group UB613 Rechargeable Sealed 1.3 amps Lead Acid Battery - Ace Hardware

 

[mmckenna]

If it'll fit. But 1.3 amp/hours isn't a lot of juice.

 

[Will001]

If it'll fit. But 1.3 amp/hours isn't a lot of juice.

How many amps do you recommend? It transmits at 1 watt

 

[mmckenna]

How many amps it draws will depend on its efficiency. The NiCd D cells probably were a few amp/hours. Looking at Amazon, they sell NiCd D cells that claim 5amp/hours.

Without knowing how much current it draws receiving and transmitting it would be a wild guess as to how long the radio will run on a 1.3a/h battery.
If it was mine, I'd look for something bigger.

 

[RFI-EMI-GUY]

Shelf life of NICAD is about 5 years, probably a bit longer. If they were never cycled you might be lucky. You could try charging those battery cells one at a time until the string is at the correct voltage and all cells are balanced. Then try it out under load and see if the cells maintain a balance.

 

[prcguy]

These radios and batteries are at least 40yrs old.

Shelf life of NICAD is about 5 years, probably a bit longer. If they were never cycled you might be lucky. You could try charging those battery cells one at a time until the string is at the correct voltage and all cells are balanced. Then try it out under load and see if the cells maintain a balance.

 

[RFI-EMI-GUY]

These radios and batteries are at least 40yrs old.

Outwardly from his pictures they look pretty good, no electrolyte spilling out. Its the dendrites that kill them.

 

[prcguy]

They used to power dinosaurs from Ni-Cads, they are old and should be put in a museum, although nobody would go there to look at them. I would consider a string of maybe 28650 LiFePO4 or series parallel 18650s. You can get cheap cell balancing boards off Epay where you can charge the string from a simple power supply.

Outwardly from his pictures they look pretty good, no electrolyte spilling out. Its the dendrites that kill them.

 

[RFI-EMI-GUY]

They used to power dinosaurs from Ni-Cads, they are old and should be put in a museum, although nobody would go there to look at them. I would consider a string of maybe 28650 LiFePO4 or series parallel 18650s. You can get cheap cell balancing boards off Epay where you can charge the string from a simple power supply.

I agree. I have even converted my System Saber radios to Lithium Ion, even repacking my own battery cases. But I would at least try powering that old beast from its OEM pack to see if by luck it was fresh NOS. There are old satellites still using NICD. Last year I bought some MX300 and HT200 (!) batteries from an estate sale (CBP Tech SK) that were NOS and took a charge nicely. Lithium Ion requires a bit more care and feeding not to blow up.

 

[RFI-EMI-GUY]

StackPath

NiCd Battery Still Runs After 28 Years

 

[prcguy]

The LiFePO4 types are bullet proof and don't blow up. You can also get upwards of 7,000 charge/discharge cycles and retain 80% capacity from some US made versions.

When I worked for Hughes Aircraft I was a floor above the satellite battery dept and I can tell you there is nothing in common between consumer and satellite batteries except for some nickel and cadmium. I still have some exotic perforated metal sheets from the 90s they were using inside the satellite batteries, which make grerat metal speaker grills for projects by the way.

I agree. I have even converted my System Saber radios to Lithium Ion, even repacking my own battery cases. But I would at least try powering that old beast from its OEM pack to see if by luck it was fresh NOS. There are old satellites still using NICD. Last year I bought some MX300 and HT200 (!) batteries from an estate sale (CBP Tech SK) that were NOS and took a charge nicely. Lithium Ion requires a bit more care and feeding not to blow up.

 

[RFI-EMI-GUY]

I just bought a Czech RF-10 military manpack radio. It came with the original battery pack, and it was understandably very weak (I was surprised it worked at all). My question is, how would I go about charging it? There are 5 D-cell looking batteries connected together, and the only corrosion is on one of the connecting wires between two batteries, and it looks like it could be cleaned.

However, I've heard other folks say that these batteries should be replaced. I've seen people put brand new D-cell batteries in there and connect them all, and I've also heard that you can use a 6V sealed lead-acid battery instead. Would you all recommend trying to charge the old batteries, or should I get new batteries for it?View attachment 79696
View attachment 79697

New SAFT D cell NICD batteries capacity "C" are 4500 to 5500 mAh. Given the vintage of yours, I would guess about 3000 to 4000 mAh.

Try charging with a power supply limited to 1/10 C or 300-400 mA. I have done this with an incandescent lamp as a ballast in series with a variable PS and adjusting the voltage to get the desired current. You want about 1.55 V per cell when charged. It will take 10 hours or longer depending on the capacity and existing state of charge. I would charge each cell separately the first time to get them balanced. If you simply try forcing 6 or 8 volts into it (terminal voltage 7.75 for the string) initially, one cell might go into voltage reversal.

 

[prcguy]

You would still have memory problems with Ni-Cads. They should be tossed for something more modern.

New SAFT D cell NICD batteries capacity "C" are 4500 to 5500 mAh. Given the vintage of yours, I would guess about 3000 to 4000 mAh.

Try charging with a power supply limited to 1/10 C or 300-400 mA. I have done this with an incandescent lamp as a ballast in series with a variable PS and adjusting the voltage to get the desired current. You want about 1.55 V per cell when charged. It will take 10 hours or longer depending on the capacity and existing state of charge. I would charge each cell separately the first time to get them balanced. If you simply try forcing 6 or 8 volts into it (terminal voltage 7.75 for the string) initially, one cell might go into voltage reversal.

 

[RFI-EMI-GUY]

Will, let us know what you work out and how that radio works .

 

[vagrant]

That radio looks like fun! Too bad I already have small radios that can do that and more. Thank goodness it isn’t $100 shipped, or I would order two.

The 18650 batteries mentioned should fit in that case, after removing what’s in there now. One could put them in plastic holders and wire them 2S2P. There is probably enough room to run them 2S4P, but I might just keep spares in there to swap. Still 2S2P 7.4v @6Ah is better than the 4Ah I read the original batteries were rated for. I would pull the 18650’s out and charge them as needed as that won’t work in the radio.

Czech RF-10 Military Radio